Eagler's Nest
General Category => Off Topics and General Interest => Topic started by: Vince Carucci on December 09, 2015, 06:24:28 AM
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I have a question for those of you who've used the 20" Tuff Wheels (or equivalent):
- Did you purchase a set of wheels; 2 front wheels or 2 rear wheels? Or are front and rear they the same after removing the bearings and workings?
- Did you use Teflon inserts between the wheel and the axle? If so, do the Teflon inserts need to be a snug fit and/or glued in to the wheel?
- If you used this type of wheel, are you sorry you did? Or if you didn't, do you wish you used this type of wheel?
- How do the disk brakes attach to the wheel?
They seem to be fairly light weight and a very economical choice. Because the axle height governs the final geometry of the landing gear, I'm just trying to have my mind made up in advance.
Vince
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I am using what Joe Spencer used. 20" Tuff wheels with special hub, Leading Edge Airfoils SKU J1115. The special hub is made to take ball bearings, SKU J4129. Joe's videos on YouTube show these wheels in action.
Having found these wheels, I wouldn't go with plastic bearings. However, if I did, I would use Nylon or UHMW, not Teflon. I would also press aluminum inserts into the hubs so the bearing could have a thin wall section. There would be less unwanted flexing if you did it this way.
I haven't done my disk brakes yet, but there are a lot of pictures on the web. You can still go to the old site, and Joe Spencers "Putt-Putt up close and personal" video shows it I think.
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I haven't done my disk brakes yet, but there are a lot of pictures on the web. You can still go to the old site, and Joe Spencers "Putt-Putt up close and personal" video shows it I think.
Steve Kiblinger was going with the drum brakes at first, but decided to do a sanitary installation of the Mt. bike discs...
http://angoraaffaire.com/leu/id48.htm (http://angoraaffaire.com/leu/id48.htm)
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Does anyone recall the size of the tires that they put on these rims? I found lots of tires that are 20 x 2.125. I found a tire that measures 20 x 3.0 (http://www.niagaracycle.com/categories/sunlite-flame-tire-20-x-3-0-black-bsk) and one at 20 x 4.125 (http://www.niagaracycle.com/categories/stingray-tire-20-x-4-1-4-black-black). I'm wondering at what point they become to large and just add weight.
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There are few factors to think about here...
One is how wide are your rims? Going too wide on the tire while too narrow on the rim will lead to a reduction in lateral stability as the beads start walking side to side. For a standard bike rim the 2.125 may be a practical limit to push.
The wider tires you are finding go along with a wider rim. There are a few of those out there for spoke wheels as they are popular with the chopper and unicycle crowds. At least some of these use a spread spoke pattern which might be good for an Eagle wheel if paired with a wider hub too (wider hub is a good idea for Eagle in any case).
Another factor is the weight we are putting on these. Figure about 500 lbs for the pair with a 103 legal airframe weight plus pilot plus fuel, so 250 lbs per. This is a bit higher than the bicycle design target. If you are running a 40 PSI tire pressure... 6 square inches of contact patch. This works out to 2x3 for a 2.125 or 3x2 for a 3", the longer contact requires more deformation of the tire and thus makes the tire work harder to carry the weight. Beneficial here to go wider.
Not sure in the end if it is weight that is the problem as much as aero profile drag.
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Um, just a comment on this fine post by S. jahr: Using 500 lbs/ 250 per side will possibly cause a wheel failure on the first imperfect landing.
A general rule of thumb on wheel strength is that they need to handle a 1.5 g bump. I do my " spokers" based on 2 G's ( a comment on my flying skills, possibly) .
Side load is another issue entirely.....ignored on most LE so far as I can tell. Again on "spokers" I try to calculate at 1 g side load ( gross). This is so the tire will slide rather than collapse the wheel.
This is perhaps not what builders would prefer to read, but.........
If you elect to upgrade your wheels to a real wheel, one avenue is BMX rear 2.25" dual extruded aluminum rims; HD. Spokes on a double cross pattern with a homemade hub using 4130 sheet and tube; sintered bronze bushings on a polished axle . Oh, and BMX smooth pattern tires and tubes with 90 psi inflation ( the tires are good to 100+ psi).
Sounds pretty involved, darn it! If this was 1930 we could acquire these kind of wheels ....now......no so much.
If anyone is interested, I will try to post a pic or two of what I am trying to describe.
Regards,
Nick LELX E-20
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Vince, re: your question "If you used this type of wheel, are you sorry you did? Or if you didn't, do you wish you used this type of wheel?"
We used the 20" plastic spoked bicycle wheel (not sure if it was Tuff brand) on LEU Treehugger. We damaged one while test taxiing, crow hopping type of activity when "we", meaning "me" hit some rough stuff on the edge of the strip. The side forces distorted and cracked one of the spokes and we had to replace the wheel. After we learned how to handle the plane, had no further trouble.
The black max or other small diameter wheels would be much more resistant to this type of damage.
But, it's clear to me that the 20" looks the best on the Eagles.
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As suggested by Will, I ended up buying the 20 inch Tuff Wheels and bearings from Leading Edge Air Foils [LEAF]. Others have done so, the price is right, and I think they are lighter than Black Max. If I end up breaking one on landing, taxiing, or drag racing, its straight to the Black Max. Sam Buchanan had a really nice setup. I bought a set of Shimano Disk Brakes (http://www.amazon.com/SHIMANO-BR-BL-M395-Hydraulic-Brake-Rotors/dp/B017146QDW) and designed a set of hubs to mount them on the rims. I was able to 3D print the mounting hubs to test for size and they worked great. Next, one of the fellas at work is gonna machine them out of 6061 T6. I've decided after some constructive feedback to get the Odyssey Tires 20 x 2.2 (http://www.niagaracycle.com/categories/odyssey-chase-hawk-black-hawk-tire-20-x-2-2-black-with-black-reflective-stripe). Then, in order to use a single brake handle with two calipers, I bought a Hydraulic Spitter (http://www.tartybikes.co.uk/hoses_and_fittings/trialtech_sport_hose_splitter/c598p11623.html) from a shop in the UK. Next I have to buy 5mm Hose Connectors (http://www.chainreactioncycles.com/us/en/hope-hose-connector/rp-prod3257) to connect all hoses to the splitter. When this is all done, it may not be much cheaper than the Black Max but I'm not going to worry about that now.
I'll post pictures as soon as I have something worth posting. No one needs to see another stack of ribs. By the way, the average weight of the ribs is approximately 100 grams. I think that makes puts it at about 3.6 oz each. That makes the whole lot about 5 lbs, 4 oz.
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Attached are the dimension of the mounting hardware. The outer holes in the wheel hub with be threaded for 1/4-28 bolts from ACS. Since the wheel hub will be effectively be the nuts, the bold heads on the outside will need to be safety wired. The rotors that came with the brake set have 6 metric spaced holes, so the size and location of those holes are unique to that brake set. The outer holes fit the geometry of the Tuff Wheel hub.
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Vince, those look remarkably similar to mine! I tucked my wheels in so close to the cluster to reduce axle bending moments that I had trouble getting the bolt heads holding the disk on to clear the tubing. I had to go to button heads to reduce the head height. I used 12-24 screws because they fit better in the holes in the brake disk than the metric screws do.
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That's a great looking setup! I'll keep the spacing between the wheel and the cluster in mind during assembly, thanks. And congratulations on the progress of your build.
Keep the pictures coming. They're inspiring and informative.
Vince
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Will,
Do you have any other pictures of your axle, down tube and cluster? I am just now building my welding fixture for the landing gear and I thought some visuals might be helpful.
Vince