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General control line discussion => Open Forum => Topic started by: Motorman on March 31, 2014, 11:32:42 AM
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What's a good alloy to use for Aluminum landing gear struts on a profile? I've seen gear made from 6061-T6 that holds up about as good as a wet noodle. I have a set from Brodak that's 3/32" thick and seem to be fairly hard and looks like 2024-T6. I like them, they hold up well. If I land too hard they bend a little but I just bend them back. My thinking is to use 7075-T6 but, I'm wondering if the stronger alloys would crack if bent back and forth like that.
Thanks,
MM
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I was talking to Eric Rule about CF gear and he asked me if I was going to make CF profile gear. I said maybe if there was a market. 20.00 a pair.
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hello motorman
I use 7075 T6 for the landing gears I make for my planes. I made a small aluminum form and I use it to bend the aluminum. The gear comes out light and springy ,you have to give it a radius.here are pics.
Juan
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Thanks Juan, How thick is that stuff, where did you get it?
MM
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What's a good alloy to use for Aluminum landing gear struts on a profile? I've seen gear made from 6061-T6 that holds up about as good as a wet noodle. I have a set from Brodak that's 3/32" thick and seem to be fairly hard and looks like 2024-T6. I like them, they hold up well. If I land too hard they bend a little but I just bend them back. My thinking is to use 7075-T6 but, I'm wondering if the stronger alloys would crack if bent back and forth like that.
Thanks,
MM
7075 or 2024 are a fairly poor choice for any application that requires an inside bending radius tighter than about 5 thicknesses of the material. Essentially both of these alloys have a tinsile limit and a yield limit that are very close together...hence very little stretch before it breaks. Bending obviously compresses the material on the inside radius and stretches the material on the outside radius. An inside bend radius smaller than 5 times the material thickness will stretch the material beyond it's yield point and cause at least permanent damage to the material in the bend and weaken it (maybe even break it). Certainly in this state it will take very little additional stress to cause a failure. Certainly bending back in the opposite direction will cause a failure. Fatigue from vibration or stress loading will cause a failure, ie...Your landing gear may fall off in the air...
6061 is a much more malleable material and will tolerate inside bend radii as small as 1 1/2 times the material thickness without serious damage. If the landing gear is too weak to withstand the landing loads imposed on it, the best solution is to increase the material thickness which lowers the bending stress from landing loads.
Randy Cuberly
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My profile landing gear is made from 5083-H166 3mm plate.
It's not bad:)
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That new nose on the ARF Nobler looks GREAT!!! y1
Maybe a new post in the Building Section with some more details? (hint-hint) :)
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The minimum would be 2024T3. Not likely to break when bending, yet fairly strong. Next would be 7075T6. difficult to bend, yet would bend 45* with no problem. Best would be titanium. Light, strong, not likely to crack when bent. Hard to find and expensive.
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I have no problem making a 1/2" radius bend. My struts don't usually have sharp corners they look like a big S bend to make a good shock absorber. I can only find 7075 in sheets but I think one of my buddies might have a shear.
Thanks,
MM
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I used the Brodak 38 Special profile aluminum gear on my Flite Streak and Ringmaster... very reasonably priced.
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Hello Motorman
I used 3/32 7075 T6 and gave it a 1/4 inch radius and have had no problems with the bends. The bends don`t look real sharp but they hold well.
Warbird I will post some pics for you in the building section of the nose for the nobler arf.Here is a shot of the finished plane.
Juan
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Or you could call Randy at Aero Products and get some nicely finished, high polished gear!
w.
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Or you could call Randy at Aero Products and get some nicely finished, high polished gear!
w.
Hi Ward-O!, I called Randy about some .40 size alum. profile gear and he told me he didn't have any, only CF gear. ??? (looking for the ones on Macaluso's F-14 TomCat II)
BIG Bear
RNMM/AMM
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Forget the aluminum gear and go with Sparky's carbon fiber gear. S?P S?P S?P
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The Fazer gear is fine, and I was kinda surprised to see that the Ultimate Bipe gear is different. I didn't check to see if it would be better or worse for our purposes. Brodak sells the Fazer gear, if that helps. You can bend it to make it a little wider track, and you can trim the legs a bit narrower if you want, to get some springiness and save weight.
Here's SIG's catalog URL. It's interesting that it says "kavanrc" at the front. I was told (by Hobby-Lobby, who used to stock Kavan and Graupner, plus some other Euro stuff) that SIG bought Kavan, but this makes it look like Kavan bought SIG. Which they didn't, and I don't see any Kavan products in the catalog, which I would expect. n~ Steve
http://www.kavanrc.de/instructions/sigcatalog.pdf (http://www.kavanrc.de/instructions/sigcatalog.pdf)