a70eliminator

Hi, I've been flying a weeks special that weighs 18lbs and yesterday i dropped short of my pavement landing strip and the high grass caused the gear to break away leaving the plane belly skidding across the pavement causing damage. I can't help to think that if the gear was bolted on the gear would have easily survived because the grass wasn't that thick.
This is the second time the gear has blown off, anything more than a light hop and the gear comes off. It uses 4 nylon 1/4-20 fasteners and I don't think I've been streching them too tight, but maybe I am. Either way I'm wondering if it's even a good feature to have, I mean what good is it ?? thinking about using some steel or aluminum bolts to eliminate the breakaway.

grosbeak

I've heard of using nylon bolts before so that that gear breaks away instead of the gear mount. However, the gear can drag and tumble under the plane cause damage to the wings, fuselage and horizontal stabilizer. I'll stick with metal bolts myself.

a70eliminator

And even worse than that, the first gear shear caused not only a broken prop but also took the muffler down pipe and broke it right off the muffler, had to tig it back together, the wheel pants punched the bottom wing. The landing gear plate on my weeks is the strongest part of the fuse next to the main bulkhead and I think the gear would bend before that pulled out.

MTK

Pretty much all gear I've seen offered commercially tend to be too stiff. Stiff gear transfer landing loads to the mount and don't do much absorbing of the landing load. Whether the gear is secured with steel or ally bolts or not, the fundamental problem is still relative lack of load absorption by the gear itself. The folks that offer LG commercially don't have much of a clue of what it takes to design for real effectiveness without breaking the weight bank.

I decided long ago to design my own gear as much for proper absorption of landing loads as lightness. Nowadays, my gear weigh less that 2 ounces per side for planes that weigh as much as 15 lbs, flex properly without delaminating, absorbing the load and transfer the least load possible to the mount. I don't have gear failures or pant failures. My landing strip is grass.

Speaking of fuse mounting of gear legs, no heavy plates and such in my set-ups. Just a simple carbon reinforced 1/32" a/c ply box molded around each strut and epoxied to each fuse side. It is the simplest and lightest way to mount the gear. It is also much stronger than pretty much everything I've seen to date in commercial stuff. Just a little imagination and you should be able to figure it out too.

a70eliminator

My gear is not more than a piece of 1-3/4" x 1/8" Aluminum bent into an A with a 6" long flat on the top with 4 mounting bolts, it sits in a plywood box that ties the fuse sides to the main forward bulkhead and firewall.

CafeenMan

I am absolutely convinced that landing gear should never come off an airplane. if it's properly designed it will absorb landing loads. If the bolts shear then the gear can punch holes through the plane in other places and who knows what.

I do make sure the mounting system is tied in well and have never had one pull out no matter how rough the landing. And I have flattened a few aluminum and music wire gears.

So my advice is never use nylon bolts to attach landing gears.

a70eliminator

Funny you should mention flattened gear and I completely agree with you the gear is now mounted with aluminum bolts. My 1st flight the control throws way too much like 3d rates, I thought it may help me in the case of a tip stol, Anyhow the plane went up nice and level before I knew it the plane was 200' up and 200yrd away, with the 3d rates I got disoriented and lost control, she came down nose first spinning, then at the very last moment She flattened out level just before hitting the ground, I thought the plane was toasted but to my surprise the damage was minimum, it had landed perfectly flat and pancaked the gear flat in to lower wing, that was it! I had patch a couple tears and two ribs per side of lower wing and straightened out gear, Tthis fuse is built super tough to take that force. I learned a good couple lessons that day.
Where I'm flying now landings have to be rather steep and hot because of this tree line on the downwind leg, hard landings are common until you get the hang of it.

sensei

Yes, the landing gear should stay on/with the airplane.

Bob

CafeenMan

Yep. That's what muti-rates and expo are for. But yeah, I've done it a few times. If your gear and mounting system are right and you don't go in at weird angles you'll find that your gear will take the brunt of it and the plane will survive.

I've seen too many guys think they're clever with detachable gears and the result is always pretty nasty. I've never done it because of what i've seen and then using my brain simulator (flying it in my imagination) and what I see happening isn't very nice).

a70eliminator

Expo..whats that? Just kidding I'm still using my Futaba FG Gold Box from 1989, but yea my dual rate was on 3D throws thought it would help in case of something going bad and ironically it was my demise and last time i ever try that on maiden.
By the way all repairs finished my new prop came via E-bay 19.99 free ship, Top Flight Power Point, cheapo prop but WOW the motor likes it, without touching any screws the RPM's are up to 78K from 68K 1000 R's going from a 22X8-14 to a 22x6-10 I don't want to fly around at full throttle but I can't wait to see how She climbs.
I can't justify an expensive prop just yet because I'm still in the crashing stages of mastering an aerobatic 1/3 scale bipe, breaking props gets expensive real fast this is my 3rd one in 4 flights.

CafeenMan

I still have two Futaba gold boxes. They were my favorite radios until I bought my first futaba pcm radio in 2000 (an 8UHP). One was a 4 channel and the other a 7 channel. As you know you could get them as a dual rate OR as expo. I got both of mine as dual rate.

I was so poor when I had them that when I had more than one plane I had to remove the entire flight pack and switch them back and forth between planes.