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Building Tips and technical articles. => Building techniques => Topic started by: Andrew Hathaway on February 23, 2009, 04:08:11 PM
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I've been flying my Nobler for awhile now, and having trouble with the landing gear. The gear is bolted to the plywood former at the rear of the tank compartment, and exits through balsa at the bottom of the fuselage. I fly off of grass 99% of the time, and the gear wire flexes and tears up the balsa at the exit point. I've patched it back together once already, and added a layer of fiberglass cloth and epoxy to tie it all together. The fix lasted less then a dozen flights. I'm sure I'm not the first person to have this problem, so how does everyone else approach the problem?
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I installed wing gear with a Gieseke style wheel pants.
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I gave that some thought, but I've got one complete Nobler, and another in the works, both with no provisions in the wing for a gear. Also I'd worry that a wing mounted gear wouldn't be as strong as the fuselage mounted gear. I thought about going from 1/8" wire to 5/32", but I'm not sure that would really make enough difference. I've got the old gear and ply former out of the finished Nobler, and a new ply former ready to go back in but I don't want to start mixing epoxy till I've got a solution.
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I make the L/G opening oversize a bit, and fill the void with a (paintable) Silicone Sealant. Still have to do touchup occasionally, but no actual repair is required.
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my solution
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Extend the plywood former through the balsa fuselage bottom, so that any flexing occurs outside. It wouldn't take much, you could make it barely beyond flush with the outside surface.
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Thanks for the feedback so far. I still haven't decided how I'm going to approach the problem, but I'm getting closer.
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Sounds like your gear may be too springy---and the field too rough.
Assuming you stick with the wire gear, perhaps you can come up with some extra cross-wire support ---sort of like what you see on a Piper Cub--between the wheel and the opposite gear leg.
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My profile Nobler with wing landing gear & Gieseke wheel pants.
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Sounds like your gear may be too springy---and the field too rough.
Assuming you stick with the wire gear, perhaps you can come up with some extra cross-wire support ---sort of like what you see on a Piper Cub--between the wheel and the opposite gear leg.
I did that with one of my Ringmasters...but not across, I extended one wire each side forward to the motor mounts...but you cant do that[with a Nobler].....what you might try is a size larger wheels, and if weight is a problem...use the super light foam tires. The problem I have with grass and small wheels is that the grass grabs them...bigger wheels have a better chance at rolling the grass down. I know how sweet Noblers land, but on grass....I try to have a nose high attitude when I touch down. It may be hard to do with a nobler, because they land so sweet and level....but barring a complete gear replacement/re-design.....you are gonna hafta try to land a wee bit nose high. TJMHO ;)
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Andrew,
I think one of the main problems with the ARF's is that the wire used to make the gear is too soft.We have started buying cold-rolled 1/8th wire frfom McMaster-Carr.It is the "good stuff" and makes strong gear.You can buy it in 36" length's online and have it shipped.We use two vise grip type pliers with the corners ground off to bend the wire.Works great.
Charlie Reeves did a write-up on the vise grip method recently in a magazine,I think it was Flying Models.
Good luck and have fun.......
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You also may give these a look. Ply gear designed by Bill Gruby. These are very cooooool. H^^ Here's a link to the article he did. http://www.brotherhoodofthering.info/flightline/forums/thread-view.asp?tid=1924&posts=20&start=1
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Glen --- sorry but I cannot take credit for designing the molded plywood landing gear. It was done by someone at Airfield models. I just reworked it a little for our needs at the "Brotherhood".
Andrew I do not think there is a way to use the molded gear on a Nobler short of fabricating it in the same shape as the dural gear. No sense in going to all the trouble of molding a gear if one is available already. Have you tried Randy Smith, maybe one of his CF gears will do.
With wire I would go with what Ray said, extend the bulkhead it is mounted to.
"Billy G" H^^