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Design => Stunt design => Topic started by: Tim Wescott on May 01, 2012, 11:01:45 PM
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Any trick ways to do it? Or is it really as complicated as it's shaping up to be? I'd like to be able to put a trike gear on a profile, but I can't come up with any simple, good looking ways to do it. I may have to go back to Plan A and just use conventional gear.
All of these are intended to bring the landing gear out of the fuselage quite far forward -- about 1/2" or 3/4" behind the nose. I want the wire to be slanted slightly backwards both for looks, and so that in a "plane meets ground" incident it is almost certain to bend the wire before it bends the plane.
Of course, I'm not the Master of Simple -- so if anyone has suggestions (or, better, pictures!) do share.
"Under the motor mount":
Put a vertical hole in the lower motor mount between the engine mounting holes, make a 'Z' bend in the front of the gear. Plug the gear into the hole and clamp the front of the 'Z' to the front of the motor mount.
Advantages: puts the gear right in the center of the fuse, puts the highest stress on the motor mount right where it's being held together by screws.
Disadvantages: complicates fuselage finishing, puts a honkin' big slot in the fuse right where you want it to be strong -- and how in heck do you clamp that @#$% gear on?
On the inside:
Put a horizontal hole in the upper motor mount ahead of the engine. Make a simple bend in the gear. Plug the gear into the hole, and use a regular landing gear strap to hold it onto the side of the nose.
Advantages: it's as simple as I can think of.
Disadvantages: puts the gear into the weakest part of the motor mount. Detracts significantly from aircraft looks.
Under the mount, II:
Drill a vertical hole in the bottom motor mount and fuse. Braze or clamp a bar onto the landing gear such that when the gear is plugged into the hole, the bar acts as a stop and clocks the gear so the wheel points forward.
Advantages: Relatively simple, relatively light, doesn't look too bad.
Disadvantages: Brazing may cause a weak spot, clamps can fail (and a clamped lever would either be cheezy, or require custom work).
Stop messing with those mounts, son:
Use a short section of maple underneath the lower motor mount block, drilled for the LG wire and captured on either side by the doublers. Plug the wire into that and let it's upward travel be limited by the lower motor mount, but don't let it otherwise rely on the motor mount for strength. Use an RC nosegear steering arm bolted to the fuselage to clock the nose gear.
Advantages: Should be stronger, and in a crash it should be less likely to split the motor mount.
Disadvantages: would be a bit heavier, the steering arm wouldn't be super-pretty (but would still be better than the side mount!!). Could still break out of the fuselage in a severe crash.
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How about this..
I put an short 3/8x1/2 engine beam between the plywood doublers, but make it long enough to be strong. Its anchored with two 1/8 dowels about 1/2" from the screws front and back. The blind mounting nuts for the screws are attached before inserting into the fuselage.
This detail is for a one wheel glider.
Roger
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Hmm...
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Tim, think the same thing as a wing gear mounting block,, as in maple block, about 1 inch long but oriented fore and aft. You still need the spur block, but not as long since you are hopefully not resisting torsion ( that would be left to right movement,, and if you are seeing that on a nose gear,, well brother you got bigger problems) Then you simply use the same little metal or nylon straps you use to hold the wing gear in the slots,, I recomend metal... I can snap a picture of hte Electrajet tonight, its mounted this way. The block is captured between the doublers by the way,,
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Tim, think the same thing as a wing gear mounting block,, as in maple block, about 1 inch long but oriented fore and aft.
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I was stuck on thinking in terms of trying to mount it to a motor bearer -- now that I'm getting unstuck from that, things are looking much more possible.
Finding a strap that fits on a 1/2" wide block will be challenging (I may end up making something), but that's a minor detail.
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Mine are place diagonally across the block ,
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Mine are place diagonally across the block ,
Of course, I'm not the Master of Simple
D'oh.
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LOL,, well what can I say, you is an engineer after all,,
further notes of value for you ,, you overthinker you,,
I oriented my gear wire so that the spur block, and spur were on the aft portion,, then my nose gear angles aft slightly, thus when you land it pushes the spur into the block,, of course this puts a higher load on the front tie down strap,, so more substantial screws are used there,,
I also do not use a maple landing gear block even in my wings,, I use what Pat showed me,, 1/8" ply ( five ply) and cut a base plate,, then cut two plates , each is half the width of the fuse ( between the doublers) minus 1/16" . These glue to the base plate flush on the outside edges,, ( epoxy please!! no aliphatic resin or white glue allowed) This leaves a slot 1/8" wide,, and since the ply is 1/8" thick, its a 1/8" deep slot as well,, imagine that, its just the right size for **wait for it,, waiiittt for it** a 1/8" landing gear wire,, H^^ H^^
drill your screw holes to fit the DIAGONALLY oriented landing gear tie down straps,, screw the screws in,, then take them out,, saturate the hole with thin CA , which will soak into the surrounding ply and harden the threads,, then rerun the screw into the hole to clean the threads,, ( normally I fill the hole with CA, then using compressed air to keep your face away from the blow-back, blow the excess CA out of the hole,,) give it a few minutes,, then re-screw the screw into the hole,, don't let it stop rotating because there may be some liquid CA in there that wants to glue it in place again,, if it does,, generally some heat on the screw will break the bond enough to get it out,, It would not hurt to lube the screw a bit first with some vaseline,,
thats how I do it,,
now, hows that for overthinking and overdetailing a description,,
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The nose gear mount on my FJ-4 Carrier design is a little complicated but it's really strong and completely hidden. Next time I'm on the other computer I'll try to remember to pull an image from the plans and post it.
Found it, This requires a Dremel router table or a real steady hand to cut the grove in the bottom motor mount for the wire but it has been proven on 4 carrier airplanes to take a pounding without any ill effects other than a bent wire. The screws are 2-56, that info somehow didn't make it when I selected the parts to convert to an image.
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If you like the look of alloy plate legs then you could simply incorporate the lower engine mounting pad into it.
It would look like a one piece 'T' shaped alloy plate that uses the lower engine mount bolts as a retaining system and would have to be by far the simplest way to do it and if a one sided plate is not deemed strong enough then just use both sides.
Are you stuck on having to use wire though?
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author=Bob Reeves
Found it, This requires a Dremel router table or a real steady hand to cut the grove in the bottom motor mount for the wire but it has been proven on 4 carrier airplanes to take a pounding without any ill effects other than a bent wire. The screws are 2-56, that info somehow didn't make it when I selected the parts to convert to an image.
Bob,
That is absolutely a great drawing and an easy way to get it done. Kudos!
I see the same diagram but instead of the nose wheel, it would work just as easily for a tail wheel!
So, I'm downloading your diragam as forgetful as I am, hope you don't mind, and I will use that method on The Interantional's tail wheel. Absolutely. Presto! Something I now don't have to think about.
Keep an eye out on The International Build Thread, you will see your idea there, AND you'll get credit for the method.
Thanks again for the idea and the drawing.
Charles
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Tim is clearly an engineer. He overcomplicates things.