On rough landing today, the landing gear block broke loose from the fuse and the gear went through the wing. No bad damage to the wing as it hit mostly covering area only.

Any suggestions on strengthing the block?

Gary

Sure, I do it to any ARF I assemble for people. You just epoxy in some angle stock around the LG block and anchor it to the fuse. I use both hard wood and balsa depending on the airframe. Most ARFs use a hot glue when they assemblem them instead of epoxy so there are often weak spots in them.

I don't fly 3Dplanes like the U-Can-Do, but there's a guy at our field that just about exclusively flies them. He repairs his gear only to the point that it will handle a regular toreasonably rough landing. Hisrationale is that he doesn't want to take out more of the belly of the fuse than he has to on rough landings.Essentially, he repairs them so that they can intentionally fold up again but not enough to cause even further damage.

Since 3D birds are built to be so light there's bound to be a weak point, and the gear is usually the prime spot for this.

Not a bad idea, and I have often wondered the same thing about wing bolts. A force strong enough to shear the bolt is likely to do some real damage to the wing. Best advice is to land softly...

To your point, I had a similar experience. I dead-sticked into the high grass and this broke my landing gear block. My fix was to peal back the monokote around the area and fiberglass in the block from the area where the cooling channel is for the engine (on the bottom) up to the bulkhead in front of the wing. I only went about 1/2 inch up the side of the fuse as I figure most of the force on the landing gear block is front to aft. It has held up very nicely ever since.

YES!!!

That is exactly what I do.

If anything planning for the next mishap saves you a lot of effort later.

Some people suggest nylon bolts for the gear, which is not a bad idea, but to do this you normally need much bigger threads than is used for metal bolts.

I use several of the same size bolts normally used to attach wings for the gear.

Hobby Lobby sells bags of them with pre-threaded wooden mounting blocks for about 6.00 or so a bag of 10 or more.

The bigger nylon bolts will hold through most landings, but will prevent the wood in the fuselage from ripping out.


Also another thing that helps....

I see many people complaining about "overly weak" aluminum gear. They go out and purchase CF or other fairly strong gear, only to do far more damage on their next hard landing.

The weaker aluminum gear tends to splay out on a hard landing, protecting everything.

Better to use that gear instead.

Good input from all. I thiink I will try the nylon bolts and a softer aluminum gear.

Gary

If you have wheel pants on the UCD, remove them.

This will also prevent the pants from cutting through the wings on a subsequent gear collapse.

When re-inforcing the gear mounting area ( assuming you are putting on the larger nylon bolts ) remember that your intent is to spread the torque forces out over a larger area.

Slopping on a bunch of epoxy is not good enough.

The gear act as a relatively long lever acting on a small area, much like a nail puller on a hammer.

You want to spread that torsional force out as much as possible.

Adding longer runner strips of bassword or heavy ply along the bottom of the fuse, prevents the block area from ripping out.

But you want to identify your purposely created "sheer point"... in this case those larger nylon bolts....

On a hard landing the bolts will fracture or bend saving the fuse and hopefully the wings from damage.

Of course the best thing to improve, is the pilot, so this does not happen.