Airfield Models - Designing a Wood-Composite Landing Gear for a Model Aircraft

December 18, 2021

Trimming, Sanding and Axles

From the beginning I intended to trim the gear with my scroll saw because I knew I would be able to. I could also have used a jeweler's saw or if the gear is not too much oversize, a disk or belt sander.

I wouldn't even think about a wood plane or a knife due to how difficult it would be to cut through the laminations and the awkward shape of the gear.

Trimming and Sanding the Landing Gear

Before laying up the gear I drew the outline on the underside. As with everything else, aligning the drawing to the drilled blanks was done by aligning the pin holes (which later became holes for the mounting screws).

I could only cut to the middle from the end at the front and back because the area where the gear was being cut was suspended above the table which is not only dangerous but causes a lot of tear-out.

The gear was suspended because the leg under the saw hit the underside of the upper arm and the gear couldn't be rotated any farther.

It came out well and now it just needs to be cleaned up.

I taped a piece of 120 grit sandpaper to my workbench and worked the gear over it for until I was happy. Probably about 10-15 minutes all together.

Adding the Axles

The second gear I made had one axle hole above the other because I used marks I made on the underside of the blank before the lay-up instead of measuring afterward.

It wasn't a big difference but the plane had a noticeable list and it really bothered me. There wasn't enough material left in the foot of the gear to correct it.

With the third gear I didn't take any chances.

Drill the axle holes undersize and check that they are level to the ground.

I drilled the hole 5/64" and then put a 1/16" music wire through it to ensure I could fix the location if I mis-drilled again.

I need to learn to take more care when measuring and I'd have fewer do-overs.

Drill the axle holes to the correct size for the axles.

The axles have a 1/4" threaded hub.

Which is a little tight in a 1/4" hole so I reamed the hole to get a slip fit.

All that's left to do is apply a finish to the gear.

All that's left to do is clean up the feet and drill out the mounting holes.

I've considered some additional work on the gear such as a balsa lamination on the top and bottom with added leading and trailing edges. The whole thing gets sanded to an airfoil shape.

I've also considered just a hardwood lamination to the leading edge to hide the laminations and provide something easier to round over.

Right now it's just a sharp edge from being sanded on my bench. It will work fine like that but it looks unfinished.

Whether you fly glow, gas or electric, this is an unfinished wood piece so fuel, water, dirt, etc. will all get into the grain. I glassed mine with lightweight cloth and resin but any finish you'd use on a flying model can be used.