Tip: Countersinking vs. dimpling for gear attach screws

[mcencula]

Well, I'm still working on deburring fuse components in preparation for dimpling / priming, and riveting and thought some may find this interesting:

After deburring the forward bottom skin, I countersunk the forward bottom skin and the lower longerons for the 509-10R12 screws that attach the fuel tank support bracket and the forward arm of the landing gear weldment. The plans actually call to countersink through the side skin, the bottom skin, and the lower longeron. But if you do that, the countersunk hole in the .032 side skin will have almost no bearing surface for the screw to pull against. I thought it would be a better idea to dimple the side skin (sample dimple in scrap shown here) and countersink through the bottom skin and the lower longeron. Now the screw head will have a nice large surface to seat against...and it will actually trap the bottom skin countersink between the dimple and the lower longeron.

If you desire to do this yourself, you'll need to plan quite a bit ahead because the instructions and plans have these assemblies riveted together long before these holes are even drilled.

Quickbuilders...well I think you're pretty much SOL here.

[rvbuilder2002]

Nothing wrong with doing it your way, but their are literally thousands of tri-gear RV's flying, built per plans with no indication of an issue. I agree it does not meet standard practice guidelines, but in this application it is plenty strong.

I know of instances were bad piloting resulted in punching holes in the bottoms of the wings with the wheel pants. The only repairs required on the main gear structure were replacing the gear legs