+++ #824 Subject: 023 Progress and Lessons Learned From: William & Delinda Johnson Compressing the landing gear shock strut took some thought. I used a bar clamp - very long - and it worked fine. Later Bob told me he used his drill press with the table moved off center - I wish I thought of that! Oh well, some days I make things harder than necessary. +++ #1041 Subject: Re: washer welding From: William & Delinda Johnson > A question for those that have built the the landing gear shock strut, > what is the source for the 1018 steel cap material? I can't find any > pipe in 2 5/16 O.D., or greater, with enough wall thickness to get the > inside dimension. Is it going to be necessary to bore out the cap > from a solid steel bar? I bored out the cap material from a solid bar. However, it was material I already had on hand (4140 instead of 1018) . . . . I used a boring bar which uses TPG221 carbide inserts. Really did not take very long at all. +++ #1673 From: Tim Anderson Subject: [Bearhawk] Re: Rough field-Shock absorbers Boy does that ski flying story bring back memories (My first remote lake landing was on ski's ALMOST had a simular outcome). Just a thought - maybe a limiting cable, say at 75% of the extension point) would save the day and at least enable one to fly the plane out. Kind of a last resort- if all else fails type of thing. Maybe weld some tabs above and below the shocks and install a cable with some slack. If the shocks fail, the cable will keep the gear at a point where one can at least function. +++ #1674 From: Tim Anderson Subject: [Bearhawk] Re: Other - BIG Tires I saw a cut-away of the Alaska Bushwheel tire, as I recall they had a tremedous sidewall - double layered about 1 or 2 inches apart. Nice- but very pricey +++ #1675 From: budd davisson Subject: [Bearhawk] Re: Rough field-Shock absorbers Tim, Good thought on the limiting cables. All Pitts have them and they've saved lots of airplanes. The shock would be so great, however, rather than tabs it might make sense to weld heavywall bushings through the stock struts and thread the cable through. Again, I caution, this is only for those folks planning on beating the hell out of their airplanes and those kinds of pilots accept breakage as the price of playing the bush game. We just try to avoid it as much as possible. Look at it this way: by the time guys like Rod and Tim have 200 hours on their airplanes they'll have destruct-tested every part of it and the rest of us will know what not to do or what piece to beef up. +++ #1715 From: William Johnson Subject: [Bearhawk] Re: Tail Flying Wires - Order Process The [shock] springs are from dayton progress. The part number is in one of the newsletters or on Russ CD. I can't remember and all my paper work is at the airport! +++ #1891 From: Rod Smith Subject: [Bearhawk] Axle Nuts As shown on drawing 23 the 11/16" of thread on the axle seems narrower to me than I recall the width of the round type axle nut. Looking in Spruce and Wicks catalogues they also show a hex style nut that is narrower. Is this what Bob intended us to use or should I just make my own out of 4130 to match the length shown on the axles? Just wanted to get this figured out before cutting the axles to length and cutting threads. Been having great fun with the lathe at work making the shock strut parts. +++ #2066 From: Rod Smith Subject: Source for Landing Gear Shock Springs Dayton Progress Corporation which Bob indicated in the newsletter was the preferred source for shock springs, has a different phone number than listed in the newsletter. Actually only the area code has changed, but if you call directory assistance for them you get their fax number instead of voice. Call 937-859-5111 when you are ready for the springs. They were $37.80 each. I received mine promptly. +++ #2114 rsmith Subject: Alaska Bushwheels A few days ago, after pounding on ribs for a few days, I felt the need for some motivation. I hopped in the truck and drove 40 miles down the highway to the Alaska Bushwheel "factory" in Eagle River. The "factory" is a three man operation in the owners garage. I watched some tires being made and got to learn quite a bit about them. For the uninitiated the bushwheels are a donut shaped, tubeless tire. They are similar to the old Airstreaks. They are designed to be run at a wide range of pressures depending on what kind of surface you will be landing on. They are made in three sizes: 26x12x6 26# each $2295/pr 29x13x6 33# each $2995/pr 31x13x6 38# each $3395/pr When lined up together, the 26" tires seem to be a lot smaller than the other two. The above prices are for certified aircraft, for experimental use they will custom make them for your intended use and they are a little cheaper. The advantages of the bushwheels over other tires are they are large enough to have great floatation, they are very flexible to minimize shock loads to the gear and fuselage, and they require no adaptors. One thing I learned is that if you are going to be using them on pavement frequently, you can have them made with a harder rubber compound that is only slightly less flexible. Other tires used for tundra tires are designed for much heavier airplanes and are not flexible. If run at lower pressures they will sometimes spin on the wheel and shear the valve stem. The tire molds are interesting. They are machined from a solid block of aluminum. For the 26" tires it cost $32000 in 1986 to have the mold machined by a boeing subcontractor. While I was there a Maule driver from Eastern Oregon was agonizing over which size to get. We had fun swapping Maule lies. I think when the time comes, I will go with the 29". If you are going to get serious about bush flying with the Bearhawk these are the hot item. The price seems prohibitive, but just consider the cost of a new prop and engine rebuild etc. etc. They also have a 8" and 10" tail wheel in the works. Turned out to be a very motivational field trip. +++ #2115 From: budd davisson Subject: Re: [Bearhawk] Alaska Bushwheels About bushwheels...I personally think the guy is way off on his prices, but he's just about the only game in town. There's another, much smaller tire that I wish I had the info on, which I think is 24 x 6 and go for about $400 each. I saw them at Oshkosh last year but I've lost the info on them. If memory serves, and it seldom does, they were Goodyears. I've flown all sizes up to the gigungous ones on the Sherpa (which are actually 4 x 4 tires with the tread ground off), most recently the 31" on a Husky. Don't forget how heavy those puppies are: 44 pounds a piece. The spin up inertia on touch down on pavement actually tries to raise the tail and they try to "fly" a little bit sideways, when slipping. No biggies, just worth remembering. We ought to charge everyone with tasks at Oshkosh when prowling the fly-market and one of them should be to be on the look out for the 24" tires. Another should be bearings. If someone happens on to a big cache, at a low price, they should buy them all and sell them to the group. +++ #2124 From: Rod Smith Subject: More Bushwheels > About bushwheels...I personally think the guy is way off on his > prices, but he's just about the only game in town. There's another, > much smaller I totally agree with you there > tire that I wish I had the info on, which I think is 24 x 6 and go for > about $400 each. I saw them at Oshkosh last year but I've lost the > info on them. If memory serves, and it seldom does, they were > Goodyears. If they were smooth tires I believe they are the Goodyear Blimp tires. The problem with them is that they are very stiff. Kelvin asked about a price on the tailwheels. I didn't think to ask +++ #2248 From: Rod Smith Subject: Shock strut fill plug The plans shows a 1/8th npt plug used as a fill point for the shocks. It looks like a short piece of tubing is welded into the cap and tapped for the plug. I guess an alternative would be to just tap a hole through the cap and body, I am not sure the material is thick enough to support the plug. I cant tell from Bill's pictures what he did. Also any suggestions for finding the hard bronze for top piece. We have lots of brass stock around the plant, but I cant find the bronze that is specified. This amateur machinist is having lots of fun machining pieces for the shocks. It's definitely a learning experience. +++ #2252 From: bearhwk272 Subject: Re: [Bearhawk] Shock strut fill plug& Brass source I do not have my plans with me at the moment but if my memory is still working.... The little boss welded on is indeed for the pipe threaded plug. The boss is utilized so that no stress risers from the threads are present in the strut body. Brass : The brass that is used is commonly called Naval Brass and you want half hard. Either leaded or unleaded. Full hard will have have brittleness problems. Brass is hardened by working via rolling or drawing and annealed by heating. Brass will machine beautifully and the temptation is to hog it off because it comes of so well....too much working stress when turning will harden smaller sections. Remove the material in a pleasant manner, leave no sharp corners, radius at least .020 to prevent cracking on fillets and edges. Sources 1st Choise McMaster Carr sells by the foot.( There must be a catalog in AK or online) Copper and Brass sales in Los Angeles, CA Benjamin Metals +++ #2269 From: William & Delinda Johnson Subject: RE: [Bearhawk] Shock strut fill plug Rod, I tapped a hole through the top sleeve and body as you have plenty of material. You will need a GOOD US made tap as the craftsman (made in Taiwan) did not work for me. Also, pay attention to how the spring is positioned in the body during assembly. If not just right, as the spring compresses, it will cover a large percentage of the hole. You may also have to grind a small amount off the bottom of the plug so an allen wrench type plug is not the best (I have an allen type in my pictures but will be changing upon final flight ready assembly). Get one that works with a wrench so you have room to grind some off the bottom if you hit the spring when tightening. Order 2.25 solid 932 bronze round material from MSC (800.645.7270) or other specialty metal shop. Also know as SAE660 bronze. +++ #2270 From: William & Delinda Johnson Subject: RE: [Bearhawk] Shock strut fill plug& Brass source Opps, I made my previous posting before reading all my e-mail. I agree that Naval Brass would also work. If you have some brass, use it. If you must purchase, Bronze will be MUCH cheaper for the same amount. MSC sells 13 inch lengths of SAE660 for around $60. Will be much more than you need but you will have plenty if a mistake is made. Also, comes in handy for other bushing needs. +++ #2776 From: Barry Schutt Date: Thu Jun 22, 2000 3:40pm Subject: landing gear shocks I posted this before but I don't think it went so here goes again and if it's the 2nd time then I apologize----OK, I received my springs yesterday, the EH 200 800 and WOW are they stiff or what. It looks like they need to be compressed to fit in the assembly. Can anyone confirm that? and if so how did/do you accomplish that, it seems impossible. Also, did anyone do anything for corrosion prevension on the piston rod, like hard chrome---or---?? Thank +++ #2784 From: Rod Smith Date: Fri Jun 23, 2000 0:57am Subject: Re: landing gear shocks --- In bearhawk@egroups.com, "Barry Schutt" barry.c.schutt@b... wrote: > I posted this before but I don't think it went so here goes again and > if it's the 2nd time then I apologize----OK, I received my springs > yesterday, the EH 200 800 and WOW are they stiff or what. It looks > like they need to be compressed to fit in the assembly. Can anyone > confirm that? and if so how did/do you accomplish that, it seems > impossible. Also, did anyone do anything for corrosion prevension on > the piston rod, like hard chrome---or---?? > Thank > Barry(036) I have access to a large arbor press at work that I believe will do the trick. You could probably rig something up to work with a hydraulic jack that would compress it. I hadn't really thought about what to do with the piston rod. Most of it will be in an oil bath but the end will be exposed. I probably will just have it powdercoated with the rest of my steel. +++ #2785 From: William & Delinda Johnson Date: Fri Jun 23, 2000 1:04am Subject: RE: [Bearhawk] Re: landing gear shocks Rod, Bob Barrows used a drill press with table moved off center to compress. I used a long bar clamp. I did not do anything about the corrosion on the piston rod except a good coat of oil. +++ #2787 From: Date: Fri Jun 23, 2000 5:58am Subject: Re: [Bearhawk] landing gear shocks Bob Barrows wrote in, I believe, the last Beartracks, that he used his drill press to compress them. I asked Bob if he chromed his piston rods. He did on one airplane, but not the other, don't remember which was which. I believe he said he used a single step chrome process, rather than the two or three stage process you would use for a bumber. He said it isn't necessary, but I would like to chrome mine. I intend to call a chrome shop, if I can find one here in the environmental wasteland of Southern California, to see how thick the film is when finished. Don't really want to turn down the rod to compensate for the film thickness. +++ #2793 From: Date: Sat Jun 24, 2000 5:32am Subject: Re: [Bearhawk] landing gear shocks Chrome The one step chrome plate process that would be utilized on the struts is called Thin Dense Chrome. It is an electroplate process that will deposit about .0004 to .0007 thick per surface. Total buildup will be about .001 on the diameter. The rod to be plated should be polished smooth with 600 grit wet dry in a cross hatch pattern. The plated rod must be post plate baked to eliminate hydrogen embrittlement. A good plating house will do this. Just specify it when going in for plating. After plating the rod should again be polished to remove "tooth" from the outer surface. This type of plating will have a satin, matte finish and have excellent abrasion resistance. Cost will be about $50.00 if you go the commercial no certs route. +++ #2796 From: Rod Smith Date: Sun Jun 25, 2000 11:01pm Subject: Re: landing gear shocks Chrome > The one step chrome plate process that would be utilized on the struts > is called Thin Dense Chrome. I assume this process would need to be done after welding the piston to the rod. Will this present a problem assumming some minor contact between the piston and cylinder? I've wondered why Bob calls for the piston to be made of 1018 steel (availability?) +++ #2799 From: Schutt, Barry C Date: Mon Jun 26, 2000 11:54pm Subject: RE: [Bearhawk] Re: landing gear shocks Chrome I think that only the top maybe half of the rod needs to be plated, the part that could extend thru the upper seal, the piston and lower half would always be in an oil bath and would never extend beyond the seal and therefore not need to be plated. Barry(036) +++ #2800 From: Date: Tue Jun 27, 2000 4:14pm Subject: Re: [Bearhawk] Re: landing gear shocks 1018 piston heads In a message dated 06/25/2000 4:02:35 PM US Mountain Standard Time, rsmith@a... writes: << I assume this process would need to be done after welding the piston to the rod. Will this present a problem assumming some minor contact between the piston and cylinder? I've wondered why Bob calls for the piston to be made of 1018 steel (availability?) Rod Smith #246 Wasilla, AK >> Plating the piston head will be just fine and chrome is run on pistons in hydraulic systems in 4130 bores all day long. Just remember to remove the "Tooth". Bob most likely used the 1018 because of ....... 1 Cost, 2 Avalibility, 3 There is enough difference in hardness and properties that the piston will not gall to the cylinder wall. 4130 on 4130 is not always pretty. +++ #2776 From: Barry Schutt Subject: landing gear shocks I posted this before but I don't think it went so here goes again and if it's the 2nd time then I apologize----OK, I received my springs yesterday, the EH 200 800 and WOW are they stiff or what. It looks like they need to be compressed to fit in the assembly. Can anyone confirm that? and if so how did/do you accomplish that, it seems impossible. Also, did anyone do anything for corrosion prevension on the piston rod, like hard chrome---or---?? Thank Barry(036) +++ #2784 From: Rod Smith Subject: Re: landing gear shocks > OK, I received my springs yesterday, the EH 200 800 and WOW are they > stiff or what. I have access to a large arbor press at work that I believe will do the trick. You could probably rig something up to work with a hydraulic jack that would compress it. I hadn't really thought about what to do with the piston rod. Most of it will be in an oil bath but the end will be exposed. I probably will just have it powdercoated with the rest of my steel. +++ #2785 From: William & Delinda Johnson Subject: RE: [Bearhawk] Re: landing gear shocks Rod, Bob Barrows used a drill press with table moved off center to compress. I used a long bar clamp. I did not do anything about the corrosion on the piston rod except a good coat of oil. +++ #2787 From: Subject: Re: [Bearhawk] landing gear shocks Bob Barrows wrote in, I believe, the last Beartracks, that he used his drill press to compress them. I asked Bob if he chromed his piston rods. He did on one airplane, but not the other, don't remember which was which. I believe he said he used a single step chrome process, rather than the two or three stage process you would use for a bumber. He said it isn't necessary, but I would like to chrome mine. I intend to call a chrome shop, if I can find one here in the environmental wasteland of Southern California, to see how thick the film is when finished. Don't really want to turn down the rod to compensate for the film thickness. +++ #2793 From: Subject: Re: [Bearhawk] landing gear shocks Chrome The one step chrome plate process that would be utilized on the struts is called Thin Dense Chrome. It is an electroplate process that will deposit about .0004 to .0007 thick per surface. Total buildup will be about .001 on the diameter. The rod to be plated should be polished smooth with 600 grit wet dry in a cross hatch pattern. The plated rod must be post plate baked to eliminate hydrogen embrittlement. A good plating house will do this. Just specify it when going in for plating. After plating the rod should again be polished to remove "tooth" from the outer surface. This type of plating will have a satin, matte finish and have excellent abrasion resistance. Cost will be about $50.00 if you go the commercial no certs route. +++ #2796 From: Rod Smith Subject: Re: landing gear shocks Chrome > The one step chrome plate process that would be utilized on the struts > is called Thin Dense Chrome. I assume this process would need to be done after welding the piston to the rod. Will this present a problem assumming some minor contact between the piston and cylinder? I've wondered why Bob calls for the piston to be made of 1018 steel (availability?) +++ #2799 From: Schutt, Barry C Subject: RE: [Bearhawk] Re: landing gear shocks Chrome I think that only the top maybe half of the rod needs to be plated, the part that could extend thru the upper seal, the piston and lower half would always be in an oil bath and would never extend beyond the seal and therefore not need to be plated. Barry(036) +++ #2800 From: Subject: Re: [Bearhawk] Re: landing gear shocks 1018 piston heads > I assume this process would need to be done after welding the piston > to the rod. Will this present a problem assumming some minor contact > between the piston and cylinder? I've wondered why Bob calls for the > piston to be made of 1018 steel (availability?) Plating the piston head will be just fine and chrome is run on pistons in hydraulic systems in 4130 bores all day long. Just remember to remove the "Tooth". Bob most likely used the 1018 because of ....... 1 Cost, 2 Avalibility, 3 There is enough difference in hardness and properties that the piston will not gall to the cylinder wall. 4130 on 4130 is not always pretty. +++ #2943 rom: Bruce A. Frank Subject: Parts at Merril Field Was in Anchorage for a few days last week. Stopped in to one of the "parts" stores on the north side of the field (Merril). There were a pair of 8.50 X 6 tires with the wheels for $500. That is about what I paid for wheels only. There was also a pair of Goodyear smooth "tundra" tires. I did not understand the size designation, but they were for 6" wheels and appeared to be 10.00 size (at least) for $700/pr. The last time I saw tires that size they were almost $1000 each. +++ #2945 From: Float-By Shooter Subject: Beartracks Index The updated Beartracks index has been added to the FAQ. Got my copy of the newsletter in the mail tonight, and share Planter Bob's surprise at seeing one of my egroup messages printed. I guess turnabout is fair play, since I reserve the right to put anybody else's posts in the FAQ if I think they might be useful to somebody later on. I did take particular note of the brake cylinders available at a great price, I think I will be buying a set. The cylinders that my brother just replaced on his Citabria (the shafts were bent so the originals couldn't be rebuilt) looked exactly like the ones in the newsletter picture. He called several places all over the country before he found a set of replacement cylinders in Anchorage, and lets just say he paid considerably more than what the supplier in the newsletter is asking. Made the mistake of showing him the newsletter; "why didn't you tell me about this before?!?!!" "I'm sorry, it just came in the mail tonight" as I desperately pried his fingers from my throat..... Now that I think about it, maybe I'll get a spare or two while I am at it. +++ #3675 From: Tim Anderson Subject: tires Question regarding aircraft tires..... Looking through the various catalogs, some give the max wt for each tire size/ply. I would suspect this corresponds to each tire???? ie, if the max wt was say 1500 pounds, then a pair (3000 lbs) would support the max gross of the airplane such as the Bhawk. Probably have to use a safety factor such as 1.5 times the gross wt. to find an apporpriate tire. The catalogs said nothing about this factoid. Am I correct or all wet??? +++ #4324 From: Brian Cox Subject: RE: [Bearhawk] Wheels and Brakes? Here are a couple that I found on www.wingsonline.com. 600 X 6 Cleveland wheels, brakes and disks, $475. Call 888-353-6257 or doug@dougronan.com 600 X 6 Goodyear wheels and disk brakes, make offer. leewhite@flash.net. +++ #4789 From: "Rod Smith" Subject: Streamline Tubing According to some folks on the Biplane e-mail group, Summerhill, the only manufacturer of streamline 4130 tubing is no longer making it. One of the members found this out when he tried to order from Spruce. Apparently Dillsburg bought up the entire remaining stock and says they have a several month supply. That may dwindle rapidly as word gets out. As much as I hate to contribute to a run on Dillsburg, I wanted to let you guys know so you dont get caught short. My next project is going to be a Pitts M12, ordered the plans late last week, so guess I will have to bite the bullet and get all the SL ordered for it $$ :^( What a pain. +++ #4792 From: Ken Beanlands Subject: Re: [Bearhawk] Streamline Tubing You could always use round stock and then streamline it. It's a little heavier but it is avaialble. Also, check with Univair. THey were the cheapest around when I bought the MK 1 struts (thier 4130 was even cheaper than Wag Aero's 1020 stuff. +++ #4795 From: Rob "I really should be working" Gaddy zippydogg@a... Subject: Re: [Bearhawk] Streamline Tubing Streamline tubeing is used for the landing gear strut that containes the spring/shock unit. Although not called for on the BH, I've seen small streamline tubeing used to brace the horizontal tail, especially on the bottom. Don't know anywhere else streamlined is used on the BH, with the exception of maybe an entry step. +++ #4801 From: Del Rawlins Subject: Re: [Bearhawk] Streamline Tubing > Although not called for on the BH, I've seen small streamline > tubeing used to brace the horizontal tail, especially on the > bottom. Actually my BH drawing number 19 shows exactly this setup, using 1.012x.428x.035 streamline. The landing gear shock struts call for 2.02x.857x.049. Both applications are sized to fit so I'm going to order an 8' length of each so I will have plenty of excess, but it should still ship UPS at that length. Too bad this couldn't have happened in a few more months, when I would have been ready to place my big order for the rest of the steel. +++ #4804 From: "Rod Smith" Subject: Re: Streamline Tubing You need 7' of the 1.012x.428x.035 streamline and 6' of the 2.02x.857x.049 is definitely enough. When I ordered mine I took a measurement off the front view on the 3 view plans and only ordered 5' of the 2.02 material. I got the material and cut it in half and then realized that the struts also angle back 13 inches out of plane. I panicked at the thought of having wasted $80 of tubing. As it turns out, if I have done the trig correctly my struts should be long enough, barely. Wont know for sure until I fit the landing gear. Maybe Bill Johnson can tell us how long a piece of SL he used on his shock struts. So probably best to order 6' until someone can verify that 5' is enough. +++ #4810 From: "Rod Smith" Subject: Recalc on SL Tubing Length I carefully went back through the landing gear plans. It looks like 30" of SL tubing per strut will give you 2" of extra material to work with for fit. Makes me feel better as the landing gear struts represent some of my best work to date and I dont even want to think about the time and money to redo them. So 5' of the 2" SL should do it. Price from a 2yr old Dillsburg price sheet is $11.52/ft for the 2" material and $7.07/ft for the 1". Their phone/fax # is 717-432- 4589. +++ #4815 From: "Rod Smith" Subject: Re: Recalc on SL Tubing Length > I was thinking about getting 8 feet of each, but at those > prices, WOW. Do you have an estimate of the material needed > for the 1 inch material? 7' of the 1" SL is plenty. +++ #4817 From: "Kent White" Subject: Re: [Bearhawk] Streamline Tubing For another source of streamline tubing you might try: www.chassisshop.com +++ #4836 From: "Tim Anderson" Subject: Re: [Bearhawk] Streamline Tubing at Wicks Just a thought...My kitfox uses round tubing on struts and landing gear but then adds streamlined PVC plastic fairings to cover the round tube. The have a seam in the back that snaps togther. I haven't looked as to what sizes it comes in but it's a thought. Probably cheaper then buying steamlined tubing. +++ #4838 From: Budd Davisson Subject: Re:Streamline tubing Streamline tubing thoughts: Fortunately for BH builders, we don't need much streamline tubing and, as someone has mentioned, streamlining round tubing works well and has been done often. The PVC shell fairings may or may not hold up at our speeds, but aluminum ones would, or we can go back to WWI type measures and shape balsa or foam front and back and cover w/fabric or 'glass. At the same time we ought to think about fairing the shocks themselves as they are a fairly high drag item. As I've said from the beginning, I'm convinced there is a minimum of 10-15 mph more in free cruise speed available from nothing more than fairings, none of which will compromise its utility, except possibly the wheel pants. When we get our demonstrator flying, free speed is going to be one of the first things we investigate. +++ #4845 From: "Bruce A. Frank" Subject: Re: [Bearhawk] Streamline Tubing at Wicks These streamline snap-on covers used to be available through race supply outlets. Also many of the ultralite manufacturers had it available. Does anyone know a source these days? Using round instead of streamline really increases drag. It might change your 150 mph cruise to 140 mph cruise with just those few feet used in the gear struts. +++ #4850 From: "Tim Anderson" Subject: Re: [Bearhawk] Streamline Tubing at Skystar When I installed mine, it had a tid bit loose fit around the tube. One could glue it (probably best) with a flexable silicon-type cement. I installed a few pop rivets to keep it in line, not sure if that was the best solution in hind site, but it has worked so far. +++ #4851 From: "Bruce A. Frank" Subject: Re: [Bearhawk] Streamline Tubing at Skystar The only hesitation I have about covering the tube is the inability to inspect something because it is covered. I would certainly feel a bit uncomfortable with rivet holes considering the ADs issued on TriPacer (and other Piper high wing series) lift struts. +++ #5164 From: Del Rawlins Subject: streamline prices In case anybody was wondering about the current price for the streamline steel tubing used in the Bearhawk, I just received my order today. For cut lengths 1.012x.428x.035 is $7.07/ft and 2.023x.857x.049 is $11.52/ft, as of 1/26/01 (when I placed my order). Although it appears that the "crisis" is probably over, its good to know that I have mine. +++ #5240 From: Pat Fagan pfflyerz@c... Subject: AN fittings I am starting to lay out my brake plumbing and got to wondering about installing AN bulkhead fittings. Specifically the AN833 elbow connection between the landing gear and fuselage. In trying to install the fitting to the .032 landing gear top cap I discovered you must use at least a 1/8 inch shim to get enough bulk under the nut. I cut some 3/16 inch thick washers from aluminum bar stock but then wondered about vibration. Is there a locking device to be used on these fittings, or will the washer be sufficient? +++ #5243 From: Kevin Deutscher bearhwk272@a... Subject: Re: [Bearhawk] AN fittings This fitting thing is one of life's little mysteries. Somewhere out there is a nut that is extra thick, made for thin bulkhead work, do not know the AN number. I believe that the extra thick nut has a lockwire hole in it. There is also a fitting that is extra long on the bulkhead leg that allows the use of 2 nuts to clamp a panel down to zero thickness. Most often the bulkhead nut is just torqued down. In high vibration, or areas where movement could cause a problem, little fold up locking tabs are used. Only the psychotic will delve deeper into this topic, because, then you have to ask....... What do you do to retain the tubing nuts? Then you find out that the recommended tubing nut torque is far less than the same torque for a fastener with the same thread. So then you are stuck in thought gridlock pondering how is the tubing nut going to stay in place when it is wet from seeping fluid? You would think that it will spin right off. You might call ALLEN AIRCRAFT in Burbank, CA they make a jillion of the fittings. +++ #5254 From: Pat Fagan pfflyerz@c... Subject: Re: [Bearhawk] AN fittings > Only the psychotic will delve deeper into this topic, because, > then you have to ask....... What do you do to retain the > tubing nuts? Funny you shoud mention that. While writing up the question I did indeed wonder about the tubing nuts. Thanks for the insight +++ #5568 From: "Bruce A. Frank" Subject: Re: [Bearhawk] Re: folding wings...Towing???? > > Also towed fuselage, sans tail (a Taylorcraft in this case) > > with lights installed on prop. No problem.> > >Just curious...Don't most airplanes have a bit of toe-in >designed into the mains? I know this would mainly be a problem >at high speed, but has anyone had problems with the bird >starting to wiggle back there while towing it backwards? Most mains are dead-on straight. If there is any toe it must be slightly out. Think about it, with toe-in, in a swerve as the weight came off the inside main the outside main would have a tendency to steer more to the inside further exaggerating the turn and tipping up till the outside wing touches the ground. With slight toe-out, as the outside wheel becomes more loaded it tends to steer away from the turn bringing the inside main wheel back down to the ground. With a nose-wheel it is less important, but with a tailwheel toe-in could make a plane almost un-manageable. +++ #6082 From: "Float-By Shooter" Subject: desert hawk I was just wondering if I could get some comments from Budd (or anyone) on the following thought: The Desert Hawk drawing shows 15" prop clearance with 31" tundra tires and the 6" extended gear. With the 31" tires alone, there should still be enough clearance to use the normal length gear (I'm assuming it would still need to be reinforced). I know it would lock a builder into using the big tires (or make new gear later on) but my thought is that with all that power, the extra drag might be helpful in keeping the plane within the speed limits, even though it would cost some extra fuel burn for the same cruise speed. And keeping the normal length gear would help keep ground visibility reasonable. Del Rawlins-- +++ #6083 From: Budd Davisson Subject: Re: [Bearhawk] desert hawk Anything is possible but don't forget the effect of the spreading gear. I don't know how much clearance you lose when the gear spreads on touch down or with loads. You have to get a ride in a 260 Bearhawk before you get too jazzed over the Desert Hawk verson. Remember, that in the 260BH, you have an airplane with the wngs and wieght of a 172 with significantly more power and cubic inches than a Cessna180. You have to experience it to understand what I'm talking about. With the 260 you have great visibility and amazing performance without the hassle of a "unique" engine. Doesn't look as cool, but makes much more sense. We'll have to get Bob Marek's input from his flying 180 BH, but I think that airplane comes close to matching what a C-180 does and it has a much larger engine. bd +++ #6368 From: Ken Beanlands Subject: Tires/wheels I've want to replace the 600-6 tires and tubes that came with the salvaged PA-28-160 wheels (Cleavlands). I'm a little confused about tire sizes though. what does the 6.00 and the 6 mean? I know that 8.50-6 and 8.50-10 are bigger, but by how much? I was thinking that the 6.00 was the inches from the rim to the outer edge of the tire, but that doesn't seem to work for tailwheels or tundra tires. The -6 I assume is the max width of the tire. The reason I ask is that I'd like to outfit the plane with tires that can better manage the homes of our local gopher population. These guys love to dig 6.00-6 holes in the fields that could certainly do in a taildragger. I figure that with larger tires, I could eliminate this threat. Thanks, Ken Beanlands B.Eng (Aerospace) +++ #6369 From: Budd Davisson Subject: Re: [Bearhawk] Tires/wheels Here are the rolling diameters of the more common six inch tires. 600 x 6 =13.8 800 x 6= 15 8.50 x 6 = 16.8 9 x 6 = 18.2 bd +++ #6372 From: rsmith@a... Subject: Re: Tires/wheels Budd gave you some dimensions, I know that a 8.50-6 tire will fit on a 6.00-6 wheel but a 8.50-10 will not without a conversion kit. Gra- Aero in Homer, Alaska sells tundra tire kits that uses rim extensions bonded to your 6.00-6 wheels. Besides the 8.50-10 setup he has a larger 29" wheel. There have been some incidents of the bond failing with very undesirable results. There is a 26x10x6 Goodyear tire that will fit the 6.00-6 rim. They have no tread and were originally made for the Goodyear blimp. Then there are the Alaska Bush Wheels, 26,29, and 31" tires, and seriously expensive,undoubtedly the best tundra tires available www.gtesupersite.com/alaskatire/ For the type of use you are talking about I think the 8.50-6 tire would make a good compromise. I've landed in some pretty rough stuff with them and never had a problem. Rod Smith #246 +++ #6373 From: "Bruce A. Frank" Subject: Re: [Bearhawk] Re: Tires/wheels I looked at a pair of the Alaskan Bush Wheels at Sun 'N Fun. With the 6" rims, to replace the 4" on your Cub, the price was $4500.00. I have a pair of 6 ply 8.50 X 6 tires I bought 8 years ago for my project. At the rate I am going they'll probably dry-rot by the time I need them. Since we are not limited to certified equipment an option that I have seen on several homebuilts in Alaska is automotive racing slicks mounted on aluminum automotive wheels adapted to the plane's axle. This option is not the least expensive way to go but is a far cry from $4500. +++ #6374 From: Budd Davisson Subject: Re: [Bearhawk] Re: Tires/wheels I was just passing on dimensions of commonly available 6" tires. Not two out of one hundred reading this really need any thing bigger than a 8.50 and 85% of those reading this would probably be fine with 6.00 x 6". We tend to characterize the BH as a bush airplane, which it is, but we forget that it is also a terrific airplane for anyone who just wants to haul 4 people because the choices within the homebuilt industry in that area are limited. I think I've flown all of them but the Bushmaster and the BH is the hands down winner in terms of general useability and handling. I'd love to see one of these with 600 x 6 and wheel pants. I'll bet its cuter'n-a-bug natural look would be increased a huge amount. Actually, now that I think about it, I'll bet there is a surprisingly large number of the audience here that has never landed on a grass strip and/or never landed on anything shorter than 1800 feet and probably never will. Most folks' flying doesn't include those kinds of runways. Let's hear from the lurkers out there. What kind of flying do you usually do and how would you use the BH, if you had one? bd +++ #6396 From: Ken Beanlands Subject: Re: [Bearhawk] Re: Tires/wheels In my searches I found the following: http://cubcrafters.com/cc/products/TundraTires.asp They sell a set of 26x10.5x6 tires for only $1190 and they will fit a standard 6" wheel. I've also heard that there is a 23" tire out there that would also fit but I haven't had any luck finding it. Most likely, the 8.5-6 will most likely find their way onto my plane at only $300 for tubes and tires. Ken Beanlands B.Eng (Aerospace) +++ #6406 From: "Bill Cox" Subject: Re: [Bearhawk] Re: Tire Size I have 700X6 on now with about 20 lbs air. In the past I have used 800 or 850X6. I didn't see much advantage for our conditions which is hard wet sand. Unless you can find some tire tracks, the dry sand further up the beach is really treacherous. The Pacer is 150 hp so lightly loaded it will easily fly out of any place you can successfully land. Several years ago I was coming home from Saint Joseph Island with a friend in his PA16 when he saw a school of fish and landed in a less than ideal place. The left wheel hit a soft spot and yawed us into the dunes. Bent the gear and prop. Fortunily we were near a ranch outpost at a time when a hand was there. He loaned us tools and with some angle iron scrap and his stick welder we managed a repair that was adequate to get off the island to a nearby duster strip on the mainland. While the prop was being overhauled we built a new gear leg and the next weekend brought it home. +++ #6410 From: zipppydoggg@y... Subject: Tire and Wheel alternatives I hesitate to bring it up, I got Poo-Pooed so bad last time. But wouldn't you suppose there is a suitable lower cost alternative out there. I suggest an automotive type hub, with lug nuts to mount an aluminum wheel, disk motorcycle or race car caliper, and light weight tire. I was thinking of a "sand-rail" tire, Large ATV, or lawn equipment tire. Even a standard old car tire could be used. I wouldn't risk a (my) shinny new plane on truely experimental wheels and tires, but there is an alternative. I was thinking of makeing a rig to fit on my pick-up, that would hold a candidate wheel/tire combination. I would use a car coil spring and/or dead weight to simulate the weight of the aircraft. I would go down the road about 60 to 70mph, then "drop" the wheel/tire and haul down on the aircraft brakes. One would work up to higher and higher speeds in increments for safety, of course. A lifetime of abuse could be accumulated in a few days. I work as an test engineer, I think I could pull it off. One would think that there is a "free minded" individual that is running a "home brewed" wheel/tire combination somewhere in Alaska, Montana, or Idaho (have I left our any likely states?). Rob "looking for motivation to keep drilling holes" Gaddy BH401 +++ #6413 From: Budd Davisson Subject: Re: [Bearhawk] Tire and Wheel alternatives Personally, I think there are lots of ways to go utilizing automotive stuff. Also, there are dozens of wheel companies that can make up any combination you'd need. As for testing the combo, I like your approch, but I think it's overkill. Any car tire rated for the weight will do the job. the only thing of concern would be the possibility of the tire rotating on the wheel on touchdown and I do n't know how real that is. That could be fixed with screws through the rims like we used to do with low buck race cars. There's a cheap way to skin the fat tire problem hiding out there in automotive land. 'You coming over next Monday? bd +++ #6415 From: "Tim Anderson" Subject: Re: [Bearhawk] Re: Tires/wheels Do most 8.00 or 8.50's require an 8.00 wheel, or are 600X6 wheels useable with most wider tires? +++ #6416 From: "Bill Cox" Subject: Re: [Bearhawk] Re: Tires/wheels Your comment about the tailwheel is the main problem with the Pacer. The 8" tailwheel digs in to the axle if the sand is soft at all. My usual technique is to taxi back to the takeoff point and get pointed for takeoff before I shutdown. There is some comfort when several airplanes are about, since you can help each other if its soft. Our tides only change 1 to 2 feet normally, so if you pay any attention you can get back out. Bill +++ #6419 From: Budd Davisson Subject: Re: [Bearhawk] Re: Tires/wheels yes. All x6 tires can fit on a standard six inch rim. bd +++ #6422 From: "Bruce A. Frank" Subject: Re: [Bearhawk] Tire and Wheel alternatives I have looked at many aluminum/mag wheels to see which had a center section that could be bored and machined to take mounting of the aircraft wheel bearings directly in them. Many appear suitable to me. After those alterations it would be straight forward to adapt an aviation brake disk that bolted to the wheel's existing lug holes. As a welder with access to lathe and mill it seems feasible to machine an aluminum hub, to fit the axle, which includes a brake disk mounting flange and a lug bolt circle to mount the wheel. The steel lugs and nuts are going to add two or three pounds at least. There are no automotive brake disk/hub combination that I have seen that are light enough (we're talking tens of pounds here) With this setup the big balloon 4 X 4 tires would be easy to mount. The lugs of the tread can be sanded off to make a smooth tire, but most all such off-road tires these days are very heavily constructed so they may not provide the soft flexing desired even when inflated to very low pressures. Bruce A. Frank +++ #6423 From: "Bruce A. Frank" Subject: Tires/wheels Ramblings >Do most 8.00 or 8.50's require an 8.00 wheel, or are 600X6 >wheels useable with most wider tires? The 8.00 or 8.50 is a sectional designation for the "fatness" of the tire. The X 6 means a 6 inch rim. 8.50 X 6 is stated eight fifty by six. Or just eight fifty six. All automotive tires used to be designated this way until the advent of low profile and radial types. We then adopted designations such as F70-14 or GR60-13. The lawn tractor uses 6.00 X 6 tires on the front axle. Over the years I have mounted good (for lawn mowing) discarded aviation tires on the tractor when the hardware store tires wore out. My old Fiat 600 used 5.50 X 12 (that's 12 inch rims). I built a trailer from salvaged Fiat axle parts. Years and years later, when one of the tires finally wore out, I stopped in a gas station in Delta Utah trying to get a replacement so we could get back to Salt Lake after a long weekend desert trip. The kid in the station didn't have any "trailer tires" so he called his boss to have him bring one from their other station in the next town. The kid told his boss that the tire was a 5.50 X 12. Then after much animated discussion the kid handed the phone to me. The guy asked me to tell him directly what was the size of the tire. When I told him he proceeded to announce that there is no such designation and hung up on me. Luckily about then a local farmer stopped in and heard the tail end of the conversation. He apparently knew the boy in the station, told him to go get a "boot" patch from the farm equipment tire repair supplies. The farmer took my tire, threw it on the machine, trimmed the patch and repaired the tire and tube and wouldn't take a cent for his time and effort. He went back with us to where we'd left the trailer, just to make sure we young whipper snappers knew what we were doing (after all we were only in out late 20's). When I thanked the farmer for saving us he chuckled and suggested next time I should ask for C80-12's. Anyway, after all that, aircraft, lawn and farm equipment still use the older designations. The 8.50 X 6 is just about the largest 6" made today. Not to many years ago one could still buy 11.00 and 12.00 X 6's, but the primary manufacturers stopped making them. Now such sizes are very high priced "speciality" items. -- Bruce A. Frank +++ #6425 From: Budd Davisson Subject: Re: [Bearhawk] Tire and Wheel alternatives "Bruce A. Frank" wrote: > > I have looked at many aluminum/mag wheels to see which had a > center section that could be bored and machined to take > mounting of the aircraft wheel bearings directly in them. Many > appear suitable to me. After those alterations it would be > straight forward to adapt an aviation brake disk that bolted > to the wheel's existing lug holes. A while back i was looking for alternative wheels for the Howard Pete replica I was building and needed a set of 17" (I think) wheels. I started calling folks who specialized in aluminum racing wheels and found they could make nearly anything and the price wasn't all that bad. For the BH application, they had something even better. They had aluminum wheel blanks with no center holes drilled so they could drill them to order. For a fourth the price of a set of the Alaska tundra tires, you could have anything you want. I looked at the Sherpa on Airbum.com and they used steel truck rims to mount the shaved 4 x 4 tires. It would be interesting to know the actual weight penalty of a steel wheel over an aluminum wheel versus the price. bd +++ #6428 From: "Bruce A. Frank" Subject: Re: [Bearhawk] Tire and Wheel alternatives I haven't compared the weights of the aluminum rims versus the steel. As in many cases where aluminum has been substituted for steel the thicker sections of aluminum required to approach the needed strength may make the weight difference insignificant. Several of the planes I have seen in AK did use steel rims with those racing slicks. Bruce A. Frank, Editor +++ #6430 From: "Float-By Shooter" Subject: Re: [Bearhawk] Tires/wheels Ramblings > The 8.00 or 8.50 is a sectional designation for the "fatness" > of the tire. The X 6 means a 6 inch rim. 8.50 X 6 is stated > eight fifty by six. Or just eight fifty six. All automotive > tires used to be designated this way until the advent of low > profile and radial types. We then adopted designations such as > F70-14 or GR60-13. To elaborate a bit, the height dimension for most tires is not typically measured in normal units, but instead is a percentage of the width, otherwise known as the profile of the tire. On the 2 examples given above, the "F" and "G" are sort of a code for standard tread widths, with the number immediately after being the tire profile. So the F70- 14 would be some standard width, with the height being 70% of the width, on a 14 inch rim. If the first letter is followed by an "R" it signifies that it is a radial tire. On a tire like an 8.00x6, the 8.00 is the width of the tire in inches with the height being some standard profile which we apparently don't need to know. Since they were mentioned as a possible alternative, most US manufacture off-road tires use a somewhat easier system, using the overall diameter and the tread width to determine the size. So the 30x9.50R15LT on my Jeep have an overall diameter of 30", are 9.5" wide and fit a 15" rim. This should make it easy to find a tire equivalent to whatever size bushwheel you had in mind. I just had an idea for a tire source which might be worth pursuing; dune buggy paddle tires are often custom made for a particular rig/customer by sticking whatever number and pattern of sand paddles on the bare tire are needed to soak up the horsepower produced by that particular machine. Maybe they'd sell just the bare tires without any paddles. Del Rawlins +++ #6431 From: Joel Mayhall Subject: Re: [Bearhawk] Re: Tires/wheels A few thoughts on automotive wheel, tire, and brake applications. A good place to start would be with a spindle from a 4X4 front, solid axle housing. These spindles with their caliper support bracket would bolt directly to the landing gear with four or six bolts. There are shims available to use for adjlusting caster and camber. I believe newer independent suspension axles would be more difficult to adapt. Most axles are load rated so you could get one that is close to the bearhawk gross weight. Also some of the newer vehicles are lighter in weight. There might also be some motorcycle applications but that's not my expertise. Be sure to get wheels that have the right offset for the axle (You've seen cars with the wheels sticking way out - very bad!) otherwise you can really overload the bearings. There's a ton of information on off road flotation tires out there for the asking (Lots of sand here in Arizona has been used to test them). Joel +++ #6438 From: Brian Cox Subject: RE: [Bearhawk] Tire and Wheel alternatives Here's my idea for more economical wheels, call them poor man's tundra tires. The 310 was designed in the 1950's, and one consideration was flying in and out of grass strips. The tire/wheel combination on the mains is 6.50 X 10. They came from the factory with the 10 inch Goodyear wheels and brakes. Most of them have since been converted to Clevelands (including my 1966 K model). The Goodyears were prone to going through brake pads. There's just gotta be a whole lot of 10 inch Goodyears available from somewhere at a reasonable price. How about setting some up with 8.50 X 10 retreads from Desser, as 6 plys cost $115.95 each? The downside would be extra weight and the possibility of nosing over if brakes are applied with too much enthusiasm. The 310 grosses out at 5200 lbs. and comes over the fence at 105 mph. Therefore, the pad wear issue won't apply to the Bearhawk. The brakes will be overkill. Tire sizes available are 6.50 X 10, 7.50 X 10 and 8.50 X 10. If the s! ize of these wheels is objectionable, the Beech B55 Baron uses 8 inch wheels, and 6.50 X 8 tires, with retreads priced at $59.95. Anyway, the use of salvage wheels from a twin might be an easier alternative than converting auto wheels. Brian Cox, #478 +++ #6441 From: "Bill Cox" Subject: Re: [Bearhawk] Tire and Wheel alternatives I saw a pair of 6.50 X 10 Clevelands at sun n fun for $300. I went back to them several times, but decided I don't need that much wheel. Since there is limited application for these wheels as salvage that might be a good low cost source for the serious bush pilots. Bill Cox #303 +++ #6511 From: bearhwk272@a... Subject: Wheel size. OK Got most of the discussion of tire size. Question, I have two rims that have an axle of 1.500 dia. and three bolts thru the rim. The measurements across the rim where the tire bead will seat is ( Width ) 5.00 in. Diameter is 6.00 in. Are tire sizes Measured where the bead seats? What size is it? What is the "normal" size of tire for this rim? Is this size adequate for Bearhawk? Is the load rating OK? Kevin Bearhawk #272 +++ #6737 Date: Tue, 03 Jul 2001 14:44:09 -0000 From: bcox@ Subject: Wheels Good Morning, Just a follow up on wheels. I bought a set of wheels on ebay. Following my own advice, I bought 6.50 X 8 wheels. The 6 inch diameter wheels tend to be pretty expensive, as they are much more in demand. I got three wheels and disks, along with two calipers and a couple of sets of pads, for under $40. Even if they don't work out in the long run, I'm not out too much. Typically the used 6 inch wheels go for ~$100-$200 a set, and that's usually just wheels and disks - no calipers. I can use 6.50 X 8 tires, which are a common size. They will weigh more and have a bit more drag, but should work out pretty good on unpaved strips. Note that these wheels are the Goodyears, not Clevelands. Brian Cox, #478 +++ #7207 Date: Tue, 14 Aug 2001 15:23:05 -0000 From: bcox@ Subject: Deal on Tires/Tubes Good Day, I bought a part from Preferred Airparts. When I received it, they included a couple of pages listing tires and tubes on clearance (all brand new). They have a number of 7.00X6 and 8.00X6 tires of various brands, mostly Goodyear/McCreary. Prices range from $30 to $75. Tubes are $15-$20. Contact is (800) 433-0814. [www.preferredairparts.com BJH] Happy hunting, Brian Cox, #478 +++ #7358 Date: Thu, 23 Aug 2001 09:31:07 -0600 (MDT) From: Ken Beanlands kbeanlan@ Subject: Re: Flamming, subgroups, and idiots When I was in Arlington, there was a company selling replacement gear for the 180 made of sheet Titanium. They are much lighter (less than half the weight, if I remember correctly), thinner and not nearly as prone to cracking as the spring steel. However, they are not cheap. I'll try and find the info if anyone is interested. Ken Beanlands B.Eng (Aerospace) +++ #7383 Date: Fri, 24 Aug 2001 10:01:32 -0600 (MDT) From: Ken Beanlands kbeanlan@ Subject: Re: Flamming, subgroups, and idiots > When I was in Arlington, there was a company selling > replacement gear for the 180 made of sheet Titanium. Try http://www.xpmods.com/ They claim a 50 lb weight savings! They don't give a price but they advertise that they are "slightly" more than steel gear. Hope this helps Ken Beanlands B.Eng (Aerospace) +++ #7488 Date: Wed, 29 Aug 2001 21:39:41 -0700 From: Benton Holzwarth bcgh@ Subject: landing gear > has anyone considered spring steel gear for the bearhawk? Now that we're all friends again... anyone want to dig into this question a bit? I've got ideas, but limited practical experience. Conventional wisdom would have it (i.e. what I've been told is) spring gear is more likely to spoing you back into the air than the Bearhawk-standard oleo-shock setup which actively disapates energy rather than just storing it and giving it back at the least opportune moment. Having been re-introduced to wheel landings in a Citabria a couple weeks back, after not working on 'em in a year or so (I've been flying the Champ) -- and making a royal *mess* of it -- I'm all for any gear that will be as forgiving as possible. How about drag? I'd have assumed with the fabric between the two legs, and the other of streamlined stock drag would be minimal, and neither is going to make a whit of difference when mounted to an unfaired tire. Maintanence? Sure, and construction time. The oleo-shock will demand more effort to make and keep. But to me the other item -- energy disapation in the landing -- far outweighs the construction/maintanence issues. I won't go into folding wings, but are wheel-skis really easier with spring gear? What does anyone else with experience with both types think? Benton +++ #7489 Date: Wed, 29 Aug 2001 22:34:32 -0700 From: Budd Davisson buddairbum@ Subject: Re: landing gear Spring gear has it's pros and cons. It's cleaner and faster with less maintenance. On the "con" side, it's really difficult with a tubing fuselage to get enough metal in the right place to keep it from cracking longerons and local fittings. The problem is the spin-up and braking loads, not the impact loads and the problem gets really bad with big tires. On touch down, for an instant it is as if the tire is frozen in place so you've got something like a four foot moment arm and you're trying to control that with a pad at the top as wide as the gear leg. Maybe five inches. It takes a lot of beef in that area to take care of that. Look at an Extra 300 fuselage, if you want to see metal. There's a cute way to react that load out which involves an arm bolted to the bottom of the spring clamp that goes back to the next cluster on the bottom of the fuselage. All that having been said, a correctly designed spring gear is generally more forgiving on roll-out, less forgiving on touchdown on a rough field and tends to mask exactly what the airplane is doing because it gives so much. Personally, I like the positive nature of any kind of a "V" gear. And I've got nearly 1000 hours in Citabrias, owned a C-140A and other spring gear, but never did like them. It's a personal taste thing, I suppose. Besides, The Bob's podiatric design for the Hawk works so well, why screw with it? bd >>> 2mar02 #7686-9153 +++ #8457 From: Russ and Penny Erb Subject: Brake Disks Okay, time for those of you with opinions to sound off again... Cleveland offers both "standard" and "chrome" brake disks. The Spruce catalog recommends that if you fly less than 200 hours a year you should use the chrome disks to control corrosion. What do y'all think? What's your experience? Russ Erb +++ #8458 From: "t18cox" Subject: Re: Brake Disks Here on the Texas coast corrosion is a problem. On my T18 I went through 2 sets of steel disks in 10 years. I am now 11 years into a set of chrome disk. A side benefit is the pads last a lot longer, which helps to offset the cost difference over the years. I don't know if the heat generated in stopping a fast landing plane is a factor in the rust. On our restored Pacer we have 8 years on the steel disk with only minor corrosion. The brakes on the Pacer are primarily used for taxi, whereas the brakes on the T18 are used on most landings. I bought used wheels with steel disk for the Bearhawk and if necessary later I can always go to chrome. I have a question about horizontal stab rigging. In 1998 Bob issued the engineering change to raise the front stab mount 3/8" to accomodate a wider variety of engines. Does this imply less than 4 degrees is needed for the larger engines? I am somewhat reluctant to fab the strut for 4 degrees only to have to change it during the test flying. Does anyone know what angle of stabilizer incidence Bob uses on the Proto II? Bill Cox #303 +++ #8461 From: "rodsmith52" Subject: Re: Brake Disks Bill made some good points on Chrome versus standard. It really depends on climate and usage. If you fly regularly, standard disks will stay pretty clean and bright. Another somewhat cheaper option if buying new wheels is grove aircraft at www.groveaircraft.com/ I dont believe they have a chrome disk option however. I'm still looking for a set of used cleavelands with double puck brakes, but will go with the grove wheels with two calipers per side (for tundra tires) if I have to buy new. Rod Smith #246 +++ #8484 From: Ken Beanlands Subject: Re: [Bearhawk] Brake Disks > Cleveland offers both "standard" and "chrome" brake disks. Another cost-saving tip is to go for seconds (no, not a second helping of turkey ;-). Seconds are brake parts with minor imperfections that do not make the FAA cut, but are perfectly acceptable for a homebuilt. Ken Beanlands B.Eng (Aerospace) +++ #8501 From: Ken Beanlands Subject: Re: Brake Disks > What is your source of these "seconds"? I'll have to dig it out. I first bought them a few years ago. Ken Beanlands B.Eng (Aerospace) +++ #8572 From: "Chris Vuxton" Subject: Car Strut Alignment tool I just ordered a strut alignment tool from Harbor Freight. At $10 it seems you can go wrong. Its a magnetic disk with a spirit level sticking out. Seems like just the ticket to align those landing gear legs before welding. The number is 42496-0VGA $9.99 STRUT ALIGNMENT LEVEL See attachment for a picture. Chris +++ #8710 From: Russ and Penny Erb Subject: 6.00x6 or 8.00x6 tires? To start a new discussion thread, let's air (pun not intended, but accepted) our opinions on tire size. Some info to start us out: 1. The plans (Drawing 1) specifies a tire size of "6.00x6 or larger" 2. Proto 1 at Sun N' Fun '99 was sporting 8.00x6 tires We've talked in the past about huge tires for the bush, but what about those of us living in the more developed areas of the world? I expect that most of my flying would be from hard surface runways, with one airport that has a runway paved for about the first 1000 feet and the remainder is gravel, with parking in dirt and grass. 6.00x6 would seem to make more sense for installing wheel pants. Standing by to receive your recommendations of what tire size I should use for these conditions. Of course, if I expected to go somewhere like a grass strip or even worse I could change to bigger tires. Russ Erb +++ #8711 From: Mike Subject: Re: 6.00x6 or 8.00x6 tires? Both Bearhawk Prototypes use 8.00 X 6 tires - Condor brand on the original and Goodyear on the 260. The Goodyears seem to be wider although all the specs are the same. The Condors seem to check-up (good term for surface cracks) when exposed to a lot of ozone caused by a powerful electric motor running in the same area - like a compressor. The 260 has been in the hangar now going on 2 years and no sign of checking. 6.00 X 6 will work fine if the worse you will do is land on grass every so often - Pacers do it all the time around here. You will defiantly want the 6.00 if you plan on wheel pants otherwise your britches will be HUGE - just think of the butt crack when you bolt those puppies up - yech! Don't think that you will be swapping treads on a whim - it is a lot of work and you will tire (pun?) of it very quickly. Anyway it is a good question and I will be interested to see the replies. Later - Mike +++ #8713 From: "Del Rawlins" Subject: Re: 6.00x6 or 8.00x6 tires? My brother has a pair of 8.50x6 tires on his Citabria. They are large enough that he has landed on the beach on Hinchinbrook island with no problems, but are not so large that he loses a lot of cruise. With the field approved modifications on his airplane, an O- 290 rated for 135hp continuous, and a cruise prop, he is getting somewhere in the neighborhood of 120mph indicated cruise down around sea level. He doesn't do any extreme bush flying like our buddy "Boog" does, but it isn't because his tires are too small. He's also got a set of wheelpants and will probably eventually get a set of 6.00x6 tires so he can mount them for cross country flight, but since he already gets good cruise (for a Citabria 7ECA) it isn't really a priority. Del Rawlins +++ #8714 From: "rodsmith52" Subject: Re: 6.00x6 or 8.00x6 tires? I doubt that my Bearhawk will ever see smaller than 8.50 x 6 tires, but thats just my bias considering what I will be using it for. For an airport to airport Bearhawk, small tires and wheel pants actually makes a lot of sense for wringing some more knots out of the airframe. Personally I would find that too limiting and will live with a slower plane or higher fuel consumption. Wheelpants and snow dont get along at all either. Its going to be interesting to see 8 or 10 Bearhawks at a flyin someday with all the different mods and ideas expressed in metal and fabric. Rod Smith #246 +++ #8716 From: Benton Holzwarth Subject: 6.00x6 or 8.00x6 tires? > We've talked in the past about huge tires for the bush, but > what about those of us living in the more developed areas of > the world? I'm told by my TW instructor that smaller tires are more forgiving of slow feet on paved runways. Being low time, I'm expecting to start with a set of relatively small tires. When I've burned through those, will consider whether to stay with that size, or graduate up. I'm also anticipating that most of my flying would be from/to formal strips, and probably a good many of them paved. Benton 21jan02 +++ #8718 From: "t18cox" Subject: Re: 6.00x6 or 8.00x6 tires? > We've talked in the past about huge tires for the bush, but > what about those of us living in the more developed areas of > the world? I have 700X6 on the Pacer and fly off a fairly rough grass strip. Most of the trips are to pavement with the occasional trip to the beach. If there is a problem on the beach it is with the tailwheel sinking in the sand. I had a set of 850s for a while and they were somewhat destabilizing on that short plane. It would as soon fly half a ball out as straight. Also noticeably slower. I am thinking 700X6 on the Bearhawk with a pant similar to what was on the Stinson. It seems to fit the style better than 600X6 with modern type pants. Probably worth several mph though. Benton, if there is a trick to learning to fly taildraggers I think I would learn on grass if possible. If you're a little miss aligned on grass you tend to slide a little. On pavement the tires grab and corrective action is necessary. A few hours on grass to get the feel and then move to pavement would be my choice. Bill Cox #303 +++ #8719 From: Brian Cox Subject: RE: 6.00x6 or 8.00x6 tires? I have scrounged a set of 6.50 X 8 wheels from a Beech T-34. Here's my logic: 1. Just like 6 cylinder engines are in less demand than 4 cylinder engines, thus making them relatively less expensive to acquire, most homebuilt planes can only handle 6" or smaller wheels. Not much demand for 8". I got a set of wheels, brake calipers, disks and spare parts for less than $40. 2. It may be heavier, but 6.50 X 8 tires and wheels are probably not too much heavier than 8.50 X 6 tires and wheels. 3. Larger diameter for off pavement. 4. Not practical for wheel pants, but I would consider fabricating a pair of spats to clean them up. 5. This Bearhawk is going to be used for local operation in Colorado and surrounding states. 6. Who knows, I may fabricate a 5.00 X 5 bobwheel that was mentioned on an earlier thread and nickname the plane Sasquatch. Kind of a baby Sherpa. Brian Cox, #478 +++ #8720 From: Budd Davisson Subject: Re: 6.00x6 or 8.00x6 tires? Go with the 600s. I've got thousands of hours founding around on grass with both 500 and 600 tires and never had a problem and some of the strips were quite rough. The 800's really smooth things out, but unless you expect to land on some seriously rough grass/dirt, the 600's are plenty. Also, just the tires size reduction in itself is worth at least 3 mph and with wheel pants, versus the unfaired 800's should net out a solid 5 mph or more. at the same time, I'd incorporate a stream lined bubble on the back of the pant that goes out aroun the brake AND the intersection of the axle/gearleg/shock strut attach. It would have to be a fairly deep bubble, but that's one of the dirtiest parts of the airplane. It's hard to calculate, but I'd almost guarantee 7 mph or more with pants incorporating that mod. bd +++ #8724 From: sonny cilley Subject: Re: Digest Number 669 Hi guys, if it is faster to run 500 or 600 tires with wheelpants, who says one couldn't fabricate wheelpants for 800 series tires, Sonny #234 +++ #8725 From: Brian Cox Subject: RE: Digest Number 669 I still think spats would look pretty neat. In fact, on larger wheels, maybe you could scrounge wheelpants from a smaller wheel, say a couple of nosewheel pants, that are damaged. Cut off the front, maybe cut a section out of the middle, and use this to build a set of spats? Just glass over the profile and build in some mounting hard points. While you're at it, have the inside continue on in and cover the brake assembly. Might be an interesting project. Spats would be easier to keep clean, smaller and lighter, and still manage to look pretty jaunty. I've seen them on an Ercoupe, and I think a T-Craft and Luscombe. Brian Cox, #478 +++ #8726 From: Budd Davisson Subject: Re: Digest Number 669 You can and they have. See some of the shots of the yellow Husky I did for Aviat a few years ago. Panted 800's. the only problem with any bigger pants is that to make them actually flow the same as the smaller ones they get really big (it's a cubic thing), so Aviat made sort of schmushed versions of them which actually don't look bad at all. "Bigger", in aerodynamic terms means more frontal area, more wetted area, more weight, more AOA to carry the weight, less payload,yada, yada, yada, the usual pitch. Since the majoriity of the drag comes from the back of the tires, those little half-pants, that look like you've glued snow cones on the back of the tires probably reap most of the speed rewards with none of the mud-gagging, weight stealing, problems, but I'll bet you have to be ingenious in mounting them. them's my thoughts. bd +++ #8938 From: "Bruce A. Frank" Subject: Landing Gear Track Width This has been touched on a bit, but I have some questions in which many here have experience, both practical and theoretical. When I originally put my fuselage together I had visions of landing in sage brush and muskeg with a McCauley 9055 prop. So to get the suggested tip clearance I extended my gear legs. The result was a somewhat wider track. Recently I read that a wider track can cause problems in cross wind landings....which contradicts information I read early on about the PA-22 fuselage benefiting from the later wider track design that Piper adopted. Any suggestions about wider track or what is considered too wide a track combined with height off the ground on a these similar rag and tube type aircraft? Bruce A. Frank +++ #8939 From: Budd Davisson Subject: Re: Landing Gear Track Width I don't know who gave you info that wider track is a problem on crosswinds. Unless it's really rediculously wide, you won't notice the difference. There's an optimum track to length ratio (which I don't remember) but the acceptable range is really wide. A long tall fuselage on narrow gear has problems for obvious reasons, a short fuselage on really wide gear does too, but they have to be really out on the edge for it to matter. There are a lot of other things that can cause more problems in x-winds than gear track. bd >>> 4sep02 #9154-11297 +++ #10418 From: "zipppydoggg" "Rob Gaddy" Subject: Moose slippers Just slinking around the photo section and noticed the new tundra tires/ wheel combination on the Murphy Moose. This is about what I plan on doing, just will use a bigger brake disk, lots of room inside a 15 inch wheel. Probably woundn't need twin calipers with a bigger disk. Check out the Murphy site for details. Boy does that look like a chevy 6 bolt wheel? +++ #10421 From: "Dan Shilling" Subject: Re: Moose slippers I saw a Honda 4-wheeler this past weekend up in Fairbanks with similar looking rims. I didn't think about them for aircraft use until today, but the size looks about right. I will see if I can find out the size used. +++ #10422 From: "zipppydoggg" "Rob Gaddy" Subject: Re: Moose slippers > I saw a Honda 4-wheeler this past weekend up in Fairbanks with similar > looking rims. WARNING - WARNING - DAN SHILLING, as the robot might say. I brought up the concept of using non-aircraft tires on a BH and got PooPooed fairly good. I chalked it up to the down side of a vivid imagination. +++ #10423 From: "Dan Shilling" Subject: Re: Re: Moose slippers I have also heard of and seen the use of drag racing wrinkle slicks as bush tires up here in the north. A lot of the tread thickness was shaved down, but what about getting some used up tires from your drag racing buddies? I'm always looking for a cheaper, but usable and safe alternative. Let the poo-poo begin. +++ #10565 From: "zipppydoggg" "Rob Gaddy" Subject: Moose Slippers continued Did anyone else notice in the latest edition of Custom Aircraft they mention that the Murphy Moose uses Corvette wheels and tires from a manure spreader? Not being a "country boy" I'm not familiar with this type of tire. Anyone out there know of this type of tire, especially the weight? +++ #10570 From: Jeff Griffin Subject: Re: Moose Slippers continued These tires look just like av tires but fewer plies, usually 4-6. Nice rounded shoulders and all. +++ #10908 From: Budd Davisson Subject: Re: Don't hold your toes in and Keep your pants on! > First, a question for those who have completed their main landing > gear: The plans do not specify a toe-in or toe-out amount, so I am > assuming that the axles are intended to be aligned (zero toe-in/out). > Since they're not real close to each other, how did you get them to > line up? Slide a bare wheel on the axle and clamp a 4 foot piece of aluminum angle to each. Then drop a centerline and measure the different distances from the centerline to the extended ends of the bars. > Second, I've been thinking a little about wheel pants lately, > primarily for those long cross country trips on hard surface runways > to cut drag a little bit. > > The question is how are wheel pants attached? I understand there is a > flange on the inside and it attaches to the axle nut on the outside. > Is that flange attached to the brake mounting flange somehow or is it > separate? They are attached various ways, depending on the pant. The most common is to weld a couple of 1" x .065 tabs, front and back at the base of the landing gear V and the pants bolt to them. The outside attach varies, but again a common way is to simply machine a piece of aluminum bar stock 3-4" long so it barely slides into the end of the axle. It is tapped for a 1/4" bolt that goes through the wheel pant and into the end of the bar. The bar just floats inside the axle but provides up and down, fore and aft stability to the wheel pant. I know it sounds flimsy, but hat's the way my Pitts is done and the redline is 204 mph. This airplane would really benefit from a big teardrop fairing that covers the brakes and goes around that awful axle/shock strut interface. Incidentally, The Bob is moving that bottom hinge point an inch towards the wheel. Not sure why, but it'll make it easier to stream line. > Third, I saw double puck brakes on some airplane (180? 185?), but I > don't see anything except what appear to be single puck brakes. > Apparently the prototypes have double puck brakes. Pictures of Pat's > (#232) appear to have single puck brakes. Those of you with opinions > on brake puck numbers, please express them now. If you're planning on running big (8.50 and higher) I might go for the double puck. Other wise, I don't think it makes any difference. On a taildragger it's better to be under-braked than over-braked. Ask anyone who owns a Cub with a Cleveland conversion. +++ #10912 From: "Bruce A. Frank" Subject: Re: Don't hold your toes in and Keep your pants on! Oh, no! This may be one of those Ford vs. Chevy discussions, but yes, zero toe in/toe out. If you error, error on the side of toe out (a cat's whisker from zero). Mount rims on the axles and clamp a 4-6 ft long piece of angle to each wheel...extending forward 3 to 5 feet. Measure the distance between at the wheel and at the tips of the angle. When those measurements are equal you're at zero. It can also be done with the tires on, but it takes several people to help. With angle and clamps on bare rims one person can do it alone. If you do it with the tires on, they should be sitting on two pieces of sheet metal with grease between. You'll be surprised at how much the friction of the tire on the hangar floor can effect the measurements. If you're doing it with just the rims in place still use a piece of sheet steel or aluminum under each to allow easy movement and protect the rims from the floor material. Dave Blanton, on our V-6 STOLs, used to say that we could set the toe by slipping a long pipe (12-15 ft) over the axle, have a couple of friends hold the fuselage and cold bent the legs. I haven't found anyone yet who hasn't had to heat the axle just outboard of the leg junction (between the leg junction and the brake flange) to get alignment. Maybe the design of the Bearhawk gear will lend itself to the cold bending method. With the help of a friend who used to help his A&P/AI father do this stuff it took me a couple of hours to get it dead on. Bruce A. Frank +++ #10913 From: Budd Davisson Subject: Re: setting toe in/out Pitts gears are always bent cold. It just takes a helluva long cheater and a bunch of friends to hold the airplane. +++ #10914 From: "Bruce A. Frank" Subject: Re: Re: setting toe in/out Maybe we just haven't had enough people to hold the fuselage. I tried it at one time. The three people helping weren't able to resist the 20 foot lever on the axle well enough to make repeatable changes. +++ #10915 From: "Dan Montee" Subject: Re: Don't hold your toes in and Keep your pants on! You didn't mention a centerline reference but I assume you drop a centerline to assure the parallel lines are tracking the airframe and to verify the gear is square to the centerline? I would think there would be a lot of plumb bob work here before any welding takes place. +++ #10916 From: "teyeomans" "Tom Yeomans" Subject: wheel alignment If I remember correctly Bob indicated in one of the news letters to set the strut shock to about 1 inch spring compression. I did that by putting blocks in the shock instead of springs. Then I clamped the axles to a long heavy angle Iron and squared that to the center line of the airframe. After the landing gear was welded then added the brake mounting flanges etc. +++ #10917 From: "t18cox" "Bill Cox" Subject: Re: wheel alignment I used a method similar to Toms and the gear is nice and straight. I moved the shock strut at axle attach out 1". Bob suggested this as a way of cleaning up that intersection. If I remember right he did this on the 2 place. I found a fairing strip similar to what Bob uses. It is a 1"X1/4" screen frame. It comes in 16' lengths. I bought it locally for .45/ft. +++ #10918 From: "Bruce A. Frank" Subject: Re: Don't hold your toes in and Keep your pants on! Certainly before any welding took place there was care to center the fuselage correctly between the wheels. One of the advantages of starting with a TriPacer fuselage was that all the mounting points were "pre-located" so locating the gear was simplified. Thinking back on how Blanton's manual said to do things there was still a lot of head scratching. What I did was to build a frame out of 2 X 4s on the floor of the hangar which I glued to the floor with plaster of Paris. I elevated the fuselage above the frame work, checking relative datum lines, and built the gear to fit. That all assured that the wheels were correctly placed relatively to the CG and center of lift, but aligning the axles so that the track was straight was another effort altogether. +++ #10919 From: Budd Davisson Subject: Re: alternate alignment method. A method I've used is to run a long piece of tubing that fits tight inside the axles, then hang that from the ceiling and put the fuselage under it upside down and do everything with levels, plumb bobs and compass strings/boards (wires actually). Don't measure much of anything. Dead nuts on every time. +++ #10920 From: "Matt-" mprather@s...> Subject: Re: Don't hold your toes in and Keep your pants on! A quick and (maybe overly) dirty method if checking toe is stretch a string tightly between the front of one wheel/tire/break-mounting- plate (somthing that you know will be parallel to the tires intended direction of travel) and the corresponding part of the gear on the other side. Then take your carpenter's square and lay its short side against whatever flat reference plane you are using, with the long side pointed (hopefully) along the string to the other side. Errors in toe will show up with the string not sitting exactly parallel to the carpenter's square. If you had a really long square (maybe clamp an extension to one side) you don't need the string. This will work if your gear geometry is otherwise correct, and you just want to check the toe. The other method mentioned is better if you aren't sure that the gear is other wise square. +++ #10921 From: Pierce Terry M Civ 416 FLTS/ENI Subject: RE: Double Pucks I don't know about the BH (or other tail draggers) but I have had serious brake fade with the single pucks on my big tailed Stinson. For those of you who know the Mojave Desert, I actually left the plane at Fox Field one day because I couldn't taxi crosswind to the parallel taxi way. Since I've installed the double pucks, I spit at crosswinds. Now if I could just remember to turn my head downwind first. The disadvantages: weight, partly the calipers but mostly that much thicker rotor; and of course, bent metal if you get a little injudicious in braking application. +++ #10922 From: Budd Davisson Subject: Re: RE: Double Pucks -3 Stinsons are famous for crosswind taxi problems. You hang a sail out in the wind and you have to expect that. The BH doesn't have that much tail working against it. +++ #10925 From: Russ and Penny Erb Subject: RE: alternate alignment method. I thought about using a long piece of tubing, but that would mean that you would have to weld the shock strut attachments after welding the axles to the struts. Of course, that's at least worthy of considering. +++ #10926 From: Budd Davisson Subject: Re: Re: wheel alignment > Huh? Call me a doofus today (or any other day...), but could you > further explain what was moved 1"? Okay, you're a doofus. Feel better? I don't know if he's changing the plans or not but he has us moving the pivot point, where the bottom of the shock strut bolts to the axles, towards the wheels one inch. +++ #10927 From: Russ and Penny Erb Subject: RE: Re: wheel alignment budd, I always feel better when you call me a doofus...(I'm not even sure what that means, but it seemed appropriate...) So you're shortening the axle on the side without the tire? Thought that looked rather long and cantilevered out there... +++ #10929 From: "Pat Fagan" pfflyerz@c... Subject: Re: Re: wheel alignment It may stick out there, but it looks as though it will make a nice pad for a scissor jack if you need to remove the wheel. There aren't any other obvious jack points on the structure. +++ #10933 From: Joel Mayhall Subject: Re: Don't hold your toes in and Keep your pants on! An old automotive way to check toe-in is to spin each tire and mark a centerline around each tire. Then measure the front and rear distances between the centerlines. They should be the same for 0 degree toe-in. +++ #10935 From: "zipppydoggg" "Rob Gaddy" Subject: OT - Pilot math and toe in I was just thinking that if I were to use 60 inch (5 ft) boards attached to each wheel (sans tires) and set 1 inch of toe out on each wheel, (two inches difference in distance between front and rear of 60 inch boards), then I would have (approximately) 1 degree of toe out on each wheel. The 60-to-1 rule (pilot math) says that 1 degree is one inch of cord on a 60 inch circle. (do the math, use 3 for pi, its fun) Then with 1 degree of toe out, the tire would have to move sideward 100 feet for each mile of travel. The 60-to-1 rule says that 1 degree is 100 feet of cord on a 1 mile circle. (use 6000 ft per mile) Then with 1 degree of toe out, the tire would have to move sideward 1 mile for each 60 miles of travel. The 60-to-1 rule says that 1 degree is 1 mile of cord on a 60 mile circle. (use 1 mile for the radius of the circle) No wonder that the toe out should be less than 1 degree (I've heard), to minimize to tire scrub and early wear. The 60 to 1 rule have several applications in navigation and planning descent rates, especially on approaches (former military IP) +++ #10936 From: "Greco, Bob" Subject: RE: OT - Pilot math and toe in Just as a point of reference, Piper shows 1 to 1.5 degrees toe out for the Pacer and Cessna does the same for the 180 and the 185. I have flown a tail dragger with 1 degree toe in and don't want to repeat the experience. +++ #10937 From: "Bruce A. Frank" Subject: Slight Ramble on Gear Alignment All these methods of making measurements on the tire, tread groove to groove, line to line, sidewall to sidewall, work and I have used them dozens of times on my automobiles over the years, but an automobile has the power and the squat balance to overpower any slight inaccuracies. A landing tailwheel airplane is a dynamic balance like a ballerina on point. Using extensions of the geometric plane of the wheels allows for a more accurate parallelogram of the track of the tires improving the chance that the landing will end like a grand jet? rather than in a ground loop. +++ #10939 From: Budd Davisson Subject: Re: Slight Ramble on Gear Alignment > I have to ask regarding this thread.....is this 1" reposition > something that someone should be askingThe Bob about? We never talked about the reason for the change, or if we did, it lot lost in the daily neuron die-off I seem to suffer. +++ #10942 From: "Collin Campbell" Subject: More gear alignment ramblings Since this gear alignment thing has come up, might as well share what I did. I pretty much followed the suggestions in the newsletter. Jigged the fuselage up in a level position over the table, clamped the axles in place to a steel angle, measured everything several times to be sure everything was just right. I do recommend that you have your wheels and brakes on hand to check their proper fit on the axles. I did find that the measurements on the plans were off just a bit, it will work as per plans, but I found the axle nut would not screw on as far as I liked. I think someone else mentioned this before. I cut, fit, and welded everything up. Everything came out real nice. Perfect alignment. Hard to believe. Then I welded the shock strut attachments to the axles, fitted the shock struts with the recommended 1" compression of the spring. Now comes the part that I am wondering about. When I assembled the strut assembly with the spring and put the plane on it's gear, of course the spring isn't compressed that 1" yet, even with the wings on and the engine case and crank. Sure, there is lot's more weight to be added, but in checking the alignment of the gear at this stage, I have a slight toe-in. The toe-in is worse in the 3-point attitude than when it's level. This is all sort of complicated to explain, but apparently the alignment will only be right on at the exact weight that makes the shock strut springs compress 1". Study the hinge axis of the gear, and maybe you can understand why. It makes sense to me now why this is so, but I lack the words to properly explain it here. The best I can do is to state that the hinge axis of the gear does not align with the longitudal axis of the aircraft. In other words the front gear attach points are closer together that the rear ones. I am sure this is not a design problem or anything and I feel sure that everything will work OK once the gear is splayed out to the same position that they were jigged up in. Of course there is the adjustment on the strut rod ends and that may be what it takes to make things work. Sorry for the rambling... +++ #10943 From: Russ and Penny Erb Subject: RE: More gear alignment ramblings Well, now I feel a little silly. I started this whole thread, and never bothered to think to check if this had been covered in Bear-Tracks. So many things are not (i.e. are left up to the builder) that I forget to check that option. I certainly don't remember (very well) what I read 5 years ago, especially when it didn't apply to the task at hand at the time. Of course, if I had bothered to look up Bear-Tracks, we might not have learned something that we did in this exchange. Then again, as I go through the archives, I find ideas that I said I was going to use that I had since forgotten about... +++ #10947 From: "Pat Fagan" pfflyerz@c... Subject: Re: More gear alignment ramblings When I assembled the strut assembly with the spring and put the plane on it's gear, of course the spring isn't compressed that 1" yet, even with the wings on and the engine case and crank. Sure, there is lot's more weight to be added, but in checking the alignment of the gear at this stage, I have a slight toe-in. The toe-in is worse in the 3-point attitude than when it's level. I noticed the same thing when I first installed my shock struts with the springs installed. The tires were obviously not aligned. I removed the springs and reinstalled the shocks with 1" extension and everything lined up perfectly. > Of course there is the adjustment on the strut rod ends and that may > be what it takes to make things work. This brings up a good question, what are we supposed to do with the adjustment provided by the upper bearing? There is nothing stated in plans or Beartracks about how deep to set the bearing in the strut. Exciting progress yesterday, I finished wiring my first system and my wife and I spoke to each other over the intercom. +++ #10989 From: Russ and Penny Erb Subject: Putting My Pants On Once again, it's a chance for you to express you opinions again, and this time its about the Bearhawk. Since I will occasionally be flying long cross country trips, it would be nice to regain a little efficiency by panting up the wheels, brakes, and axles. It seems to me that it would be best to design the mounting for the wheel pants as the gear legs are being built rather than trying to modify them later. But before I acquire a set of wheel pants, I have to decide what style I want to use. Go to http://www.eaa1000.av.org/pix/erbpix/erbpix.htm and go about halfway down the page. Search for the words "I'm considering setting up my landing gear" and click on the thumbnail of four Bearhawks next to it. This is a drawing of my best rendering of four types of wheel pants available in the Aircraft Spruce Catalog that fit a 6.00x6 tire. Your mission is to respond back to the list with which design of wheel pant looks best in your opinion. To keep from influencing your choice, I'm going to wait a few days to tell you what I think and why. +++ #11010 From: "Murray Huffines" murrayhuff@a... Subject: Wheel Pants Russ if you are going to fight the trouble of wheel pants go all the way with MF 11, but don't use wheel chocks. A flat tire makes a mess of pants. +++ #11067 From: Benton Holzwarth Subject: re: Putting My Pants On > wheelpants on a Bearhawk? blasphemy How about sno-cones? (What are they really called?) Here's a picture of some I saw at OSH a couple years ago. These were on a Luscome, tho' I can't remember whether it was the Don Luscome Foundation's one or the one parked next to it.... They look a little funny but seem like a compromise between some streamlining, and a minimum chance to foul and maximum opportunity for clearing once on the ground. Re: the thoughts about fairing in the caliper, I'll toss out again the numbers I remember hearing about Van's wheel pants for RVs. On a faster plane but with smaller tires than ours, the older style pants were good for 4 kts; and the new style, with greater frontal and wetted area, but that fairs over the brake rather than showing a blister on the side is good for an additional 4 kts. Re: most Bearhawks would land on grass only 25% of the time or less -- how about attaching the pants with some sort of quick-release mechanism, so that they could be removed and tossed in the back seat when the next stop is expected to be grass? Or be removed for tire inspection. If the whole thing came off easily, you could skip the little inflater door. Seems like there are optimum shapes and 'fineness ratios'. I'd be tempted to start with one of those (and maybe tweek from there to something that looks acceptable), rather than just do a TLAR drawing. Had another thought along these lines -- I've been pondering a sort of 'clam shell' type wheel pant that would open, completely retracting away from the wheel (hinge-line along the top) when open, and when closed completely enclosing the wheel. (I know, the first thought is 'what will I do when it freezes shut?', but work with me here.) Would offer good streamlining while in flight, with no tire opening on the bottom, and good access when open on the ground, for checking pressure, inspecting the tire, etc.) Question: would the FAA consider it a 'retractable gear'? It has moving parts and clear flying and landing states, even if the leg and wheel themselves don't move. +++ #11068 From: Budd Davisson Subject: Re:Pants/drag, etc. > How about sno-cones? (What are they really called?) Here's a > picture of some I saw at OSH a couple years ago. These kinds of pants work exceptionally well and probably work on bigger tires (where they look expecially ugly) better than on smaller ones because of the amount of drag being generated by the blunt back end of the tire. > Re: the thoughts about fairing in the caliper, I'll toss out again > the numbers I remember hearing about Van's wheel pants for RVs. Our brake/axle intersection on the inside is MUCH dirtier than any RV, although we aren't as fast so the increase may not be as dramatic. but, it's free speed. > Re: most Bearhawks would land on grass only 25% of the time or less > -- how about attaching the pants with some sort of quick-release > mechanism, so that they could be removed and tossed in the back seat > when the next stop is expected to be grass? The pants on my Pitts (204 redline, sees 5-6 G's regularly) are held on by two #10 screws on the inside and a 1/4" bolt on the outside. 60 seconds to remove. > Had another thought along these lines -- I've been pondering a sort > of 'clam shell' type wheel pant that would open, completely retracting > away from the wheel Jim Bede beat you to it years ago. He had closable clamshell doors that covered the wheels he was going to put on a BD-4. +++ #11074 From: Russ and Penny Erb Subject: RE: Re:Pants/drag, etc. > Jim Bede beat you to it years ago. He had closable clamshell doors > that covered the wheels he was going to put on a BD-4. And if you forgot to open the doors, it only mattered for the first few feet. After that the doors were gone and you were rolling on the tires. >>> 20may03 #11298-18250 +++ #11882 From: Russ and Penny Erb Subject: Rear Landing Gear Leg Question For those of you who have done this (or at least figured it out): On Drawing 23 the top of the rear gear leg has me confused. On the side view, it looks like two pieces of T21 mitered together to make the bend. On the front/rear view, the short little top tube is angled in to the tube that accepts the bolt. How did you approach this? Did you weld on a tube and then squish it down or did you approach it some other way? Russ Erb +++ #11891 From: pfflyerz@c... Subject: Re: Rear Landing Gear Leg Question > On Drawing 23 the top of the rear gear leg has me confused. On the > side view, it looks like two pieces of T21 mitered together to make > the bend. On the front/rear view, the short little top tube is > angled in to the tube that accepts the bolt. I made mine as you describe it from the side view, mitered together. I don't recall also having to angle it toward the bolt tube. Pat Fagan #232 +++ #11899 From: Russ and Penny Erb Subject: RE: Rear Landing Gear Leg Question > I made mine as you describe it from the side view, mitered together. > I don't recall also having to angle it toward the bolt tube. Pat--I don't think you understood my question. How did you get the 1-3/8" tube from a circular cross section at the miter joint down next to the 9/16" tube that the bolt goes through? On other ends, such as the aileron bellcranks, we heated the tube and squished with pliers. What did you do to "squish" this large of a tube. Russ Erb +++ #11904 From: pfflyerz@c... Subject: Re: Rear Landing Gear Leg Question > How did you get the 1-3/8" tube from a circular cross section at the > miter joint down next to the 9/16" tube that the bolt goes through? > On other ends, such as the aileron bellcranks, we heated the tube > and squished with pliers. What did you do to "squish" this large of > a tube. Same process. You will already have the top of the 1-3/8" tube split for insertion of the tab that is welded to the 9/16" tube. I tacked the ends of the ears to the bottom of the slit, then heated the large tube and squeezed them down to the 9/16 tube. After trimming the upper edges of the large tube where they splayed out, I welded the whole thing. Firewall is now finished, the engine goes back on, to stay, today. Pat Fagan #232 +++ #11910 From: "t18cox" Subject: CD version 3 Russ, The CD came today and I spent a while looking at some of the new material. You're still doing a great job of documenting the building of this airplane. That CD really helps on some of the head scratching. Unfortunatly for me I caught you at about the end of version 2. So I'm doing my own head scratching. I did something similar to Pat on the rear gear fitting, except I cut a pie shaped wedge from the front and rear at the top to give the material somewhere to go when it was formed down. I did practice a little on a piece of scrap before I got something acceptable. Bill Cox #303 +++ #12076 From: Russ and Penny Erb Subject: Paying Penance Again... Grumble...grumble... I write this to you as I'm re-making yet another part. The bad news is that I found my mistake after I had welded the first one to the fuselage. The good news is that I found my mistake before all of the other parts were welded to it. You might want to pull out drawing 24 and make some notes... Take a look at the wing strut attachment. It is made in two pieces--one that is bent more than 90 deg and goes up the side of the fuselage, and one that goes under the fuselage, taking the wing strut loads in shear like a good welded joint should be. Take note of this latter piece and the corresponding piece at the front landing gear attachment point. Here's the important point: The rear one is 1-5/8 inches wide, the forward one is 1-3/4" wide, just like it says on the plans. "Yea, so?" you're saying... The problem arose as I was drawing patterns for these two pieces in CADD (because I'm too stupid or anal to just trace them off the plans like Planter Bob would). I had done such a good job drawing the rear one, and the forward one looked very similar, so I copied the rear one and changed the end to make the forward one. Or so I thought... Of course I ended up with the forward piece 1/8" too skinny. I figured this out as I was checking the other pieces to be welded on for proper dimensions. Of course, the first thing I thought (after "Oh, @#$%") was "Does it matter?" How much extra strength can be in 1/8"x.100 steel? Of course, that wasn't the problem. The problem is that the forward landing gear tube is 1/8" bigger than the rear one. Therefore, the forward part needs to be 1/8" wider. Considering that we have heard that the landing gear is the limiting factor on the gross weight, I'm not about to reduce the diameter of one of the landing gear tubes. So I cut it off the fuselage, and now I get to go make new ones. Joy, joy... joy, joy, joy..... KRAP! Russ Erb +++ #12702 From: "rodsmith52" Subject: Cleaning Cleveland Wheels A few months ago I bought a set Cleveland wheels and double puck brakes on Ebay. I finally got around to taking a closer look at them. The bearings appear to be good although they were very dry. The wheels appear to be in real good shape but are very dirty. I scrubbed some on one with MEK and a rag and the crud came off with some work. We have a large hydroblast cleaner at work that uses a soap solution to clean turbine parts. I wonder if that would safely clean them? I dont think I should bead blast them since they are magnesium? Interested in your thoughts. The brake disks are slightly pitted and when I got them off the wheels, realized they are different thickness and heights, so will buy new ones. Rod Smith #246 +++ #12703 From: "rodsmith52" Subject: Axle too short? I believe it was Russ awhile back who put out a warning about the axle diameter. I checked mine and they were about 5-6 thousands over 1.500 and my wheels wouldn't fit on them. This is not something you want to find out after your axles are welded to the gear. The quickest thing to do would have been to turn them down but I was worried about getting a good smooth finish. Instead I took a piece of 80 grit emory paper and looped it around the axle as it was turning 500 rpm in the lathe. Took about 10 minutes to get it back to 1.500. I then installed the wheel to check the dimensions. As far as I can tell with my wheels, the 3 13/16 dimension from the end to the 1 5/8 diameter stop is about 1/8 too short. Holding that dimension when I screw the axle nut down so there is quite a bit of drag on the bearings, the cotter pin holes in the nut are half hanging off the end of the axle. Has anyone else had this problem? I'm not real distressed as I had already decided to redo the axles with .188 thick tubing for ski flying. Thats what my Super Cub buddies use. Rod Smith #246 +++ #12705 From: Russ and Penny Erb Subject: RE: Axle too short? I haven't done it yet, but Pat Fagan said he made his axles to plan and they are just barely long enough to get the nut on and cotter pin in. He recommended to me making them slightly longer. Russ Erb +++ #12706 From: "Bruce A. Frank" Subject: Re: Cleaning Cleveland Wheels I used to work is a place that used a soapy water blast to clean parts. The soap was a very caustic one which worked VERY well and caused no problems on aluminum or magnesium parts as long as the parts were rinsed with clean hot water immediately after the soap wash then high pressure air blown dry. The process did etch the surface slightly and would dull a polished surface, but parts that had been washed that way for years showed no dimensional change. Bruce A. Frank +++ #12711 From: pfflyerz@c... Subject: Re: Axle too short? > Holding that dimension when I screw the axle nut down so there is > quite a bit of drag on the bearings, the cotter pin holes in the nut > are half hanging off the end of the axle. I noticed the same thing and made a comment to the group about it a while back. I was able to put on a cotter pin, but would have liked another 1/8 inch of thread if possible. Easy enough to do if you plan for it ahead of time. Pat Fagan +++ #12712 From: Budd Davisson Subject: Re: Axle too short? Don't forget that there are at least three different types of nuts with different dimensions for the notches. bd +++ #12713 From: "rodsmith52" Subject: Re: Axle too short? I noticed what looked like some nuts with shorter spacing when looking through the Aircraft Spruce cat last night. Will order some to give them a try. Rod Smith #246 +++ #12721 From: "Lee H. Erb" Subject: Re: [Bearhawk] Axle too short? Correct. A castle shear nut AN320 is good if you can get one bing enough (although some people don't like to use it with axles) or the MS21025 Axle nut (4140 steel). Aircarft Spruce has both. Lee +++ #12736 From: "Brandon France" Subject: Re: [Bearhawk] Re: AviPro Wing Test & newsletter You need them to hold the skis! Brandon +++ #15596 From: Budd Davisson Subject: Re: Landing Gear > Looking at the bear hawk i see many places to reduce parasitic and > interferance drag. I wonder why the bearhawk does not employ spring > aluminum or seel gear legs (cessna type) with fairings? Spring gear has it's place. In fact, we've beaten that to death various times. Springgear benefits: -aerodynamically cleaner -let you be sloppier on landing roll-out and get away with it Spring gear disadvantages -heavier -hard to attach to tubing fuselage and avoid eventual cracking -undamped rebound (this is a biggie) -masks what airplane is actually doing on landing and takeoff roll -harder to control exact moment of takeoff on rough surfaces. That's my list. bd +++ #15597 From: Del Rawlins Subject: Re: Landing Gear > Looking at the bear hawk i see many places to reduce parasitic and > interferance drag. I wonder why the bearhawk does not employ spring > aluminum or seel gear legs (cessna type) with fairings? FYI: i have > a hard time leaving anything well enough alone, i'm always trying to > modify somthing You might do well to check out the following file: http://www.rawlinsbrothers.org/bhfaq/sywtbaad.html If after reading it you still want to make the mods, please post your results here once you are flying. Keep in mind that the landing gear as designed is already the limiting factor in determining gross weight, and in changing the loading points from 3 to 2, you'd have to do some serious beefing not to make matters worse. -- Del Rawlins +++ #15599 From: calbru@a... Subject: Landing gear jack? Speaking of landing gears, I've been following a thread on the Harmon Rocket list regarding jacking up the aircraft fot wheel changes and brake maint. Is there enought axle to get a jack under, or what are people doing? I noticed on Russ's site that he's considering wheel pants--made me think of the option of having a second (smaller) set of wheels and tires that could be exchanged for longer XC's. What size of tires and wheels (Main and Tail) are the group using or considering? Any thoughts on installing "lifting rings" such as on Huskys? Bothering everyone who has a project underway (and further knowledge) while I wait for my QB, Cal B +++ #15600 From: Budd Davisson Subject: Re: Mods, was Landing Gear Actually, as we've discussed in the past, the BH is an ideal airplane for doing speed mods but not a good one for doing anything structurally or to improve handling. Any fairing put on any part of the airplane will do wonders, with the shock struts and axle intersections heading the list. We've estimated 6-9 mph extra from fairings. However, something you should know about this group: speed doesn't count for much. Handling, load carrying, etc, does. bd +++ #15603 From: Holger Stephan Subject: Re: Landing Gear > I asked the same question when I got interested in the Bearhawk. The > simple explanation that I was given was that the oil-shock-strut > type of gear is much more solid on landing---it doesn't bounce the > way you always do in a Cessna. If speed isn't such a factor I'd be happy with the stock BH gear. Spring gears are bound to be heavier. We have a long history of problems with our spring gear in the BD-4. Holger +++ #15604 From: pfflyerz@c... Subject: Re: Landing gear jack? > Is there enought axle to get a jack under, or what are people doing? I wondered about this as I was building and decided there would be enough room to put a scissor jack under the shock strut attach point. Now there is talk about making the inboard end of the axle about an inch shorter to lessen the drag in that area. If you do that, you probably won't have enough room for a jack anymore. But wait, there's a better idea. The glider school where I sometimes tow uses Pawnees as tugs. In all the preflights I've done, I never noticed the small stud welded to the bottom of the shock strut an inch or two above the axle/strut attach bolt. Never noticed it, that is, until I saw the mechanic put a regular floor jack under the stud to jack up the plane. What a great idea. A very easy thing to add to the doubler. Pat "In the news" Fagan #232 Pearblossom, CA +++ #15609 From: Del Rawlins Subject: Re: Landing gear jack? > Speaking of landing gears, I've been following a thread on the > Harmon Rocket list regarding jacking up the aircraft fot wheel > changes and brake maint. > > Is there enought axle to get a jack under, or what are people doing? > I noticed on Russ's site that he's considering wheel pants--made me > think of the option of having a second (smaller) set of wheels and > tires that could be exchanged for longer XC's. I can't imagine it would be a big deal to make a Bearhawk specific adapter for whatever jack you happen to be using. The main thing is to make it as secure as possible. I don't think that even a means for bolting the jack to the gear would be overkill, considering the consequences of the plane slipping off the jack. > What size of tires and wheels (Main and Tail) are the group using or > considering? I'll probably buy a set of 8.50x6 tires just to give me a place to set the Bearhawk while I am building the floats. > Any thoughts on installing "lifting rings" such as on Huskys? The lifting rings are going to be needed for changing over to floats anyway, so yeah. -- Del Rawlins +++ #15989 From: "rodsmith52" Subject: Wheel Ski Installation I plan on building hydraulic wheel skiis for my Bearhawk eventually. That requires some axle modifications. A couple years ago I wandered around the ramps at Merrill Field in Anchorage looking for installations to photograph (today I would be in jail just like that poor guy in El Paso nearly was for lurking on an airport). I have uploaded a couple photos of a ski installation on a Maule. The Maule uses the same landing gear lay out as the Bearhawk. The outside attach is a tube that slips inside the axle. I was confused at first,thinking there must be a more secure attachment than just the cotter pin through the axle nut. Looking at the installation you realize that as long as the ski stays attached at the inside attach point, there is no way for the tube to slip out at the outside attach. I have studied the FluiDyne "Fli-lite" ski attach diagram and it looks like it is just a slip fit. If anyone has any additional details please let me know. I went with .190 thick steel for the axles. My Super Cub pilot buddies were horrified that I would think of using anything lighter. I guess I get to blame them when my Bearhawk empty weight makes Pat Fagan's look like a light weight. They have a good point though. Short of a crash there is nothing harder on landing gear than ski flying. I made it a point when flying my Maule on skiis to change out all landing gear bolts when I removed the skiis. I found a few bent and one nearly sheared through. The shock strut to fuselage connection took the worst beating. Rod Smith +++ #15990 From: Budd Davisson Subject: Re: skis, etc a note on landing gear and skis: We looked seriously at going up to .190 axles but decided against it for a couple of reasons. Because of a near-crash Bob had (caught in a serious shear that slammed him in from 10 feet) we have a real-life data point of what the weakest part of the gear is in that situation and that's the front gear leg. It bowed slightly but bent easily back into shape. The axle wasn't effected. After a lot of discussion we decided we'd rather have some weak points in the gear outside of the fuselage. If the gear is made to be totally bullet-proof it would move the failure points up into the fuselage and that's not good. In a bush type situation, you could use a couple pieces of gas pipe as cheaters and bend any kind of gear deformity back into flyable shape. Jam a super-stiff gear into the fuselage attach structure and fail the longerons and and everything around that area and you have a structure that is unsafe to fly home. Skis impose terrible loads and, conventional wisdom is, if you ever going to bust your airplane (of any kind) it'll be on skis. Just thought I'd pass that long. bd +++ #16498 From: "ken wardstrom" Subject: camber and toe in On #357 we have set the toe in and camber at 0 with the wheels at the 72" spacing, but we get toe in and camber change as the wheels come closer together ( as in first touch down).We don't know if this is going to be an issue or not. any input would be appreciated. thanks - ken +++ #16501 From: Russ and Penny Erb Subject: RE: camber and toe in If you look at the geometry, that's inherent in the design. That's why it is very important to set the camber and toe-in at the proper shock strut length. Russ Erb +++ #16504 From: Budd Davisson Subject: Re: camber and toe in > We don't know if this is going to be an issue or not. It's not an issue. bd +++ #16507 From: pfflyerz@c...> Subject: Re: camber and toe in I had been somewhat vexed by this very thing when I first mated the skeletal plane with the wings and tail, but finally decided it must be the gear geometry. That must be it as mine tracks as straight and true as you could wish for. Pat Fagan +++ #16801 From: Ken Beanlands Subject: Re: Re: N285ES Info (Floats?) UPDATE That seems to be a BIG difference in cruise speed from the proto II and from Pat's machine. I can't help but wonder if there is an ASI miscalibration here. Did he mention what 8.50 he was running? As I recently foung out, 8.50 x 10 are a lot bigger than 8.50 x 4. BTW, here is an interesting databook from Goodyear Tires that answers a lot of tire questions: http://www.goodyearaviation.com/img/pdf/db_airdatabook.pdf They also have a cool wallpaper site: http://www.goodyearaviation.com/wallpaper.html Ken Beanlands B.Eng (Aerospace) +++ #16829 From: Sam Butler Subject: Tires Looking at the sherpa which has 42" tundra tires on it, and Talking to Byron Root, he told me that what they are are using is used Super Swamper pickup tires, with the tread ground off, mounted on aluminum wheels, they have served him well, and he says they're easy to come by. Sam Butler +++ #16832 From: "zipppydoggg" Subject: Re: Tires >> Looking at the sherpa which has 42"... used Super Swamper pickup Sam, I also checked the tires on the Murphy Moose last year at Oshkosk, farm emplement tires (manure spreader tires to be exact). Brings a whole new meaning of landing in the back pasture. Rob "more than one way to skin a cat" Gaddy +++ #16839 From: Sam Butler Subject: Re: Re: Bush Tires > I hate to show my ignorance, but I was wondeing how these bush > /tundra tires are mounted. On the sherpa Byron runs tubes, and very low pressure, 2 - 10 psi if I remember correctly. At those pressures a tubeless would have some real problems of leaking around the bead. He carries a hand pump, and adjusts the pressure depending on the surface. Sam Butler +++ #16847 From: "RJS" Subject: Re: 8.50x10 tires Some time ago we traded E-mails regarding testing of tires/wheels. At that time I indicated I was working on an M14P powered project. (4000#, 6 place etc.) Attached is a photo taken Dec 2002 showing our prototype landing gear arrangement. Tires are 30-9.5 x 15 radials with the tread shaved. (Used) Rims are std, Ford 5 bolt alloy. (Used) Spindles, axle, aluminum caliper dual pot brakes and Stainless rotor from Tie-Down Engineering, (Salt water capable boat trailer equipment. Yes they are on the net.) Total cost $150.00 US per side as you see it in the photo. Shaving the tire is not ideal for aircraft use since the resultant surface is very flat hence high drag. We will be investigating a Carlisle farm impliment tire with a rounded cross section. This is for farm wagons not honey wagons, one must watch the weight when looking at farm tires. (The one we are looking at is 25 #). Other manufacturers tires have a flatter cross section. We have approx 85 # per side for landing gear, including the struts shown but no oleo in that estimate. I would strongly suggest the book "Landing Gear Design for Light Aircraft" by Ladislao Pazmany, published by the author's company as an excellent resource. Regards, R J Skinner +++ #17022 From: Dan Shilling Subject: Re: 8.50x10 tires This arrangement looks intriguing to me. I checked out their web site and found the hub, brake and rotor with bearing comes to 23 lbs. a side. This sounds higher than clevelands or comparable aircraft brakes, but also many $100s of dollars cheaper. Plus we are now using auto tires. I don't see much of a down side except the weight. What think the minds out there? Dan Shilling +++ #17023 From: Budd Davisson Subject: Re: 8.50x10 tires It's a shame we have to waste so much effort on something that will only be used twice each flight. Incidentally, when thinking about 46 pounds of brakes versus probably 10 pounds, try to picture weight in terms of bags of cement: that extra 35 pounds is 70% of a bag of cement. Do we really want to carry that around on every flight flight for the rest of the airplane's life simply because we wanted to save money in the beginning? Tough call -- dollars for pounds. bd +++ #17900 From: Russ and Penny Erb Subject: Bearhawk Feet If the landing gear has legs, then I figure the wheels/tires (and pants for us infidels) must be the feet... I did manage to figure out that I want to start with 6.00x6 tires (mostly hard surface runways, smaller tires for less drag). I *thought* I had figured out what to get, but on closer inspection, I figured out I wasn't even close. I thought I wanted the Spruce package 3A, with two Cleveland 6.00-6 magnesium wheels and brakes plus two 4 ply tires and tubes (P/N 06-00700). Then I looked at the load ratings on 6.00-6 4 ply tires - 1150 lbs. Even if we add two together, we get 2300 lbs, which is still 200 lbs short of a 2500 lb gross weight. That simply won't do. 6 ply tires have a load rating of 1750 lbs (*2 = 3500 lbs). 8 ply tires weigh 0.3 lbs more than 6 ply tires and have a load rating of 2350 lbs (*2 = 4700 lbs). So now what I'm thinking of ordering is: 1 Pair 199-104C Cleveland Wheels and Brakes (Chrome Disc) 2 06-08600 6.00-6 8 ply McCreary Tires 2 06-08700 McCreary Tubes I know most of you come readily equipped with opinions, so please express them now. It'd be even better if they were opinions on this subject. Russ Erb +++ #17901 From: Ken Beanlands Subject: Re: Bearhawk Feet Probably the easiest way to do it is to check what comes on a Cessna 180, and duplicate it. They weigh in at 2800 lbs gross, and have a faster landing speed (so the brakes should be up to snuff). I'm pretty sure they use a 600x6 6ply (cause I used the Christavia wheel as a spare once). Hope this helps... Ken Beanlands B.Eng (Aerospace) +++ #17902 From: "doug" Subject: Re: Bearhawk Feet Russ, What we all want are 30-52 brakes and 40-75B wheels & chrome(C) if you want them. Thees are in kit form P/N 199-133x and they come with master cylinders P/N 10-35. If you don't like the masters in this kit, the same wheels and brakes are in a certified package of P/N 199-60 or 199-60C (chrome). Tread? buy the cheapest for your first set. Doug +++ #17905 From: rsmith@f... Subject: Re: Bearhawk Feet I finally figured out that is what I have. The used parts came with no ID. I'm not sure if the double puck brakes are necessary. Bob has them on proto 2 with the bigger engine, but not proto 1. I have them because I plan on big tires. They certainly add weight, the disks are thicker. You might want to check with Bob on that Russ. How about you Pat. Double puck, or single puck brakes? Also for wheel and brake service and maintencance and parts info, check out www.clevelandwheelsandbrakes.com. Really good info available. Rod Smith #246 +++ #17911 From: "Bruce A. Frank" Subject: Re: Bearhawk Feet Early in my project a friend gave me a brand new pair of 6" wheels with 8.50X6 8ply tires and slightly used double puck brake calipers with new pads. Only trouble was they were intended for 1.25" axles rather than the 1.5" on the TriPacer salvage from which I started. In the long run it was easier to fabricate new axles than to find any other solution. I wasn't about to complain that they didn't fit, after all he just saved me almost $1000. Later I had the chance to buy the feet from a 180 on the airport. My fate (to stick with the 1.25 axles) was sealed when the seller wanted $850 for a well used setup. Man, did I get a deal on that 1.25" package ! Bruce A. Frank +++ #17990 From: Budd Davisson Subject: Re: wheel pants > We've heard Pat's opinion on wheel pants...just curious if anyone > expecting to finish before me (next 2 years?) is planning to install > wheel pants? The two demonstrators will have wheel pants, although one of them may have pants over 800 x 6's. The one that's going to fly to Paris ( Jim Clevenger's airplane) will definitely have 600 x6's and lots of fairings (LG struts, brakes, etc). With any luck we'll have at least one, or both flying, by around December or before. bd +++ #18040 From: AI Nut Subject: Re: Re: wheel pants Is there a good source for the "pressure recovery" wheel pants to fit a 15-600x6 wheel? Thanks, AI Nut +++ $Id: 2.3.2-Fuse-LandingGear,v 1.13 2003/05/22 03:21:51 bentonh Exp $