frequent flyer

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Has anybody made aluminun Landing gear? I need to make a fixed langing gear for a scratch built Ugly Stick I made. I have some 1/4" x 2" 6061T6 aluminun I've cut it to size but before I bend it I wanted to check with all of your experiences. Some tell me it will crack or break. If that is the case them how are all the aluminun landing gear made? I have a sheetmetal brake at my shop. But I'm not sure the Aluminun won't crack.

stang

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I've made a few with T6. Never had any cracks.

frequent flyer

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How did you bend them? How thick were they?

Edwin

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Depends on your radius. At 1/4" it would have to be pretty big to not crack. I tried a 1/8" radius on 3/16", got lots of cracks. If you heat it you will have to retemper it to gain some strength back. Dont know how to do that. Someone else here might.
Edwin

Laird SS

My guess is that 1/4" is too thick. Most of the commercial gear that I've seen on Stiks looks more like 5/32". The best bet would be to check in a hobby shop. Since all of your bends will be less than 90 degrees, I don't think you should have any problems with cracking. That seems to be what Stang is hinting at too.

Let us know how it turns out.

scottm50

following this thread with interest as i am building a tail dragger stik - i intend to buy a fibreglass u/c - what is the best way to fix? - self tapping screws? - thanks for any responses

da Rock

As long as there is sufficient support anything will hold the gear to the airplane BUT........

Most times you'd like to have an easy to create, light weight design that holds the gear but lets it break away on bad landings or crashes without ripping the support out.

Nylon bolts work great. Drill and tap the wood support to fit, CA to strengthen the holes, and you've got about the best design for model airplanes ever. Choose the bolt size to suit and pick up a tap to match. The taps aren't too expensive. They're actually the best money you'll spend on a dedicated tool because they let you modify every plane from then on.

I recently assembled a cheap Asian ARF that used 4 huge metal bolts and T-nuts for a 60-90 size plane (that was also overweight for it's size). Bad combination. The bloody bolts/nuts were about 2 ounces of dead weight. And since the support plywood wasn't exactly well supported, the future of that fuselage around the gear was rather bleak. Using two 1/4-20 bolts and tapping the support plate improved that sucker in more ways than one.

Edwin

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I'm a firm believer of nylon bolts on the landing gear. I use 8-32 on my rascal 110 and 1/4-20 on most of my 80" to 90" gassers.
Edwin

scottm50

thanks for the advice - could i use the nylon bolts with nylon nuts epoxyed on the landing gear support? or is tapping a thread the definately the best way to go?

Edwin

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I use T-nuts. Just my opinion, but I think it helps provide a clean break.
Edwin

frequent flyer

My Feedback: (6)

On my 1/3 scale Cap I have 6mm aluminun gear which is .024" and it is just a little larger than the Gas Ugly Stick that I need to bend gear for. I used 1/4" x 2" aluminun for this reason. The bends are 45 degrees. I only want to make it once and all the advice I can get before I do it the better. The Cap gear does have a small radius, maybe 1/4" in the bends. I was thinking to possibly make a steel plate with that radius to clamp next to the aluminun to prevent a shape kink...and cracks hopefully. I could do it in a vise or I do have a 12 ga. sheetmetal brake at my shop that might do it. Heating I have been told is bad and will age it and weaken it . Trying to retemper it is not possible in a home oven I have read. Bending cold is my only option I guess. What do you guys think?

da Rock

T-nuts work great.
Nylon nuts can be epoxied inside, but probably would need some kind of backup for the epoxy. Epoxy doesn't really get a grip on plastics worth spit. Some plastics are too "greasy" and some get greasy over time. Others flex and defeat the already marginal bond.

If you can get to the nuts to tighten, then they'll work ok without the epoxy if the hole through the wood plate is a tight fit to the bolt. The plate's fit is what snaps/cuts the bolt to release the gear on bad landings.

If you don't have a drill and the tap, the nylon bolts give the best combination. But the t-nut will give the easiest retrofit job, that is, if the existing holes accept the nylon bolts. If you're going to have to drill out those holes for the t-nuts, it's not much more effort to drill for the tap and tap the smaller hole.

I didn't think the $8 tap would be worth it way on back when I bought mine (and it was only $4.50). I've used it on every ARF done since I got back into the hobby. You'd be surprised how good an investment tools can be.

Edwin

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frequent flyer,
I think you have a good grasp of the task at hand. The last gear I made was 1/8" T6061 at 1/8" radius. You could see there were signs of stress but no cracks. A larger radius would have helped. This was used on a 14lb sport plane with 31cc rycobi for many years with no problems. I had to add some suspension work to it by using some 1/16" aluminum to go axle to axle and bend up to within 1 1/2" of the center. I used rubber bands to create a suspension that worked pretty well. I just didnt like the looks of it.
Edwin

da Rock

I've been lucky enough to find/have T6 once. I was told by the guy who gave it to me to bend it cold and then give it a couple of days to restore it's temper. It worked. No mention was made of the radius of the bend and I bent it in a vice between jaw fillers that had a radius, but not much of a radius.

Anybody know a realistic source of aluminum that'll do gears? I found some untempered stuff at hardware stores, but nothing like T6.

Edwin

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I get my metal from a local source and Enco. www.use-enco.com
The price difference isnt that much. A couple of web sites with finished gears. I've ordered from the first two with no problems.
https://sdp-si.com/eStore/
http://www.pololu.com/catalog/category/22
http://www.smallparts.com/
http://www.wmberg.com/
Edwin

Champ-RCU

My Feedback: (132)

Frequent Flyer,

Here are pics of the gear that was on my GUS that was way over weight at 21 lbs. Gear was cut and bent by me and a friend. The aluminum I believe is T6, cut the blank on a band saw with a metal cutting blade and bent it on a 20 ton press (Hand press that used a bottle jack.) Placed the blank on a V block and used a piece of metal to push the blank into the V Block. It's 3/16 thick, 1 3/4 wide at the top were it's bolted to the fuse. Bent to a 40 degree angle.

This gear was up to the task. Had a few rougher than normal landings without any major deviations. Even survived the last rough landing (straight in from about 300 feet, full power!)

At the bends it does show what I would describe as stretch marks on the outside radius. But like I said this gear held up to a 21 lb. plane on a turf field.

Hope this helps.

Mark

kdc

The right material for u/c is Duraluminium (dural ) an alloy of aluminium with copper, maganese and magnesium. This can be identified because it has a distinct ring sound if tapped sharply. Dural can be softened by heating and then bent cold. Leaving it a few days rehardens it itself, no treatment is necessary. The temperature for softening is found by applying some soap, then heating and when the soap turns black the temperature is sufficient. Leave to cool and bend cold.
Maybe T6 is one type of dural ( does it ring when tapped?).

bps

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Your might want to search the Tower Hobbies ARF gear to see if you could find something compatable. I found a gear that worked for my 30% BD8 for $17.

frequent flyer

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Jeb that's the first place looked. Thanks for the thought anyhow.

frequent flyer

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Well I went ahead and just bent some in a vise and it turnned out perfect, no problems, no cracks.

bps

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A safe bet on bending is to use twice the thickness of the material for the bend radius.

scottm50

hi - what's the motor?

frequent flyer

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it is a FTL 45 from Hobby City