My local flight school just bent their Cessna 172RG, which was a really nice airplane to fly. Someone was doing touch&gos when they lifted the gear too soon, settled back down and the nosewheel collapsed. The mains stayed locked. Almost new engine and prop totalled, cowling bent, but the gear doors took the brunt of it. The plane was an insurance write-off, they bought it back and are hoping to fix it.
Here's the joke - Cessna wants $4300 for the gear doors. EACH!!
None can be found at salvage places, anywhere.
Knowing I mess with homebuilts, they gave them to me to see what could be done. They are a mess and only the hinges can be salvaged.
Now, I think there is nothing that can't be done in metal, but this looks pretty tough. Compound curve outer skin. Matching inner skin with a stiffening bulge running down the center. Spot welded edges. 0.025" 2024.
One could use an English wheel and a wooden buck to do the outer skin, but it won't work for the inner. One way to produce these from scratch would be to:
Produce pattern/plug from wood to match the contour of the skin and the hole the doors cover. Modify the pattern to allow for springback.
Make a concrete, female mold from the pattern, line with felt and beat the outer skins into it. Remove and planish. Make the stiffener bulges out of hardwood and lay into the mold in the correct position and beat the inner skin into it. Remove and planish that.
Joining them by spot welding is a little tough for the home workshop. I guess you could dimple them and use flush rivets, since they don't interfere with anything.
I am thinking I'd be nuts to attempt it, but considering their only alternative is $8,600, maybe I ought to give it a try, since anything less than that would be a bargain for them??
Here's the joke - Cessna wants $4300 for the gear doors. EACH!!
None can be found at salvage places, anywhere.
Knowing I mess with homebuilts, they gave them to me to see what could be done. They are a mess and only the hinges can be salvaged.
Now, I think there is nothing that can't be done in metal, but this looks pretty tough. Compound curve outer skin. Matching inner skin with a stiffening bulge running down the center. Spot welded edges. 0.025" 2024.
One could use an English wheel and a wooden buck to do the outer skin, but it won't work for the inner. One way to produce these from scratch would be to:
Produce pattern/plug from wood to match the contour of the skin and the hole the doors cover. Modify the pattern to allow for springback.
Make a concrete, female mold from the pattern, line with felt and beat the outer skins into it. Remove and planish. Make the stiffener bulges out of hardwood and lay into the mold in the correct position and beat the inner skin into it. Remove and planish that.
Joining them by spot welding is a little tough for the home workshop. I guess you could dimple them and use flush rivets, since they don't interfere with anything.
I am thinking I'd be nuts to attempt it, but considering their only alternative is $8,600, maybe I ought to give it a try, since anything less than that would be a bargain for them??
