Carbon Fiber Landing Gear

[Brad Clayton]

Some information on making Carbon Fiber gear.

[Greg Doe]

Thanks Brad for posting the picture. We are showing our process for vacuum forming carbon fiber landing gears. We started with a wooden mold made from 1/2" plywood that gets glassed, and painted. Make the mold over size, especially on the feet where the axle attaches. The layup is 9 layers, alternating between carbon (at 5.5 oz. per sq. yd.) and glass (at 8 oz. per sq. yd.). Cut the cloth a least 3/4" over size A typical layup yields a "rack" (think of a rack of ribs) that will produce 5 to 8 landing gears. I use PVA on the mold as a release agent, and peel ply (nylon dress liner material) on the other side. The rack in the upper right was made on an inside mold (think of a gutter on your house), and the 4 blanks on the lower right came off an outside mold. The inside mold will make gears where the shiny side is up, and the outside mold will make gears where the shiny side is down. The inside mold is a little more challenging to get the resin squeegee out. I use West Systems 105 resin, and 209 (slow) hardner. There are better epoxies out there, but I find the West more then adequate. Place the wetted out cloth on the mold a layer or two at at at time. I use bleeder felt around the edges to wick off the extra resin. Put it in your vacuum bag and draw at least 20 to 25 in. of vacuum. I use nylon vacuum bagging material, and I have a lifetime supply for me and all my friends. If I like you, I'll ship you some at no charge, except you pay the freight. After It's cured, I "post cure" only the rack at an elevated temperature (170 dg.) in our oven for 30 or so minutes. I lop off the blanks one at a time on my table saw, and use a master template, which is C clamped to the blank, to drill the axle holes, and the mounting holes. I then bolt the blank to the master form using bolts through the mounting, and axle holes for shaping. I can rough shape the rear tapered side of the gear with a saw, and then sand the blank down to the form. On the left bottom is the best template which is a steel master. Next up is a fiberglass template which is the least desirable, because if you are not careful you will repeatedly, and slowly sand down the template. The template on the top left is plywood with 3/32" music wire glued around the edges. I put brass eyelets in the holes on the template for both the plywood, and fiberglass templates to protect the them from gradual erosion. This is a bare bones description of the process. If you have questions, I will try to answer them.