Builder's Corner
By Bob McDougall
(from Oct. '99 Leading Edge)

Many of today’s .40 size or smaller sport planes really don’t have a large enough firewall to support both the engine mount and a separate nosegear bracket. Although several companies manufacture combination engine/nosegear mounts, sometimes you just can’t find one for your particular plane and engine setup. Mounting the nosegear on the backside of the firewall is not always possible or practical, and many engine mounts don’t have enough material to safely drill 5/32" holes in them. If your next building project (or tri-gear conversion) requires a nosegear setup that you just can’t handle with off-the-shelf parts, and your nosegear steering linkage can be routed below the fuel tank instead of beside it, try this approach (All the following dimensions assume you’re using a 5/32" nosegear strut):

First, trace the pattern of the back of the engine mount onto 1/32" plywood, making sure you mark the engine mount mounting holes. Make two of these. Mark a center line on one of them, in the position and direction where the nosegear strut should be. Check to be sure that the upper (straight) portion of your nosegear strut is at least 1/2" longer than this line.

Next, dig up a piece of 3/16" scrap balsa (the harder the better) or plywood, and a piece of 3/16" brass tubing. If you have no 3/16" balsa or ply, try laminating 3 pieces of 1/16".

Cut the tubing to the same length as the center line you marked on one of the 1/32" plywood plates. Rough up the outside of the tubing and spot-glue it in place lightly with just a drop or two of CA.

Cut two pieces of the 3/16" ply or balsa to fit on either side of the brass tubing. These should be slightly larger than the 1/32" ply plate. Epoxy both of them in place, and at the same time flow the epoxy around the brass tubing. Before the epoxy cures, smooth off any excess so that the second plywood plate will fit on top of the 3/16" balsa and brass tubing. Next, epoxy the remaining plywood plate on top, so that you have a "sandwich" consisting of two slices of "plywood bread" with the balsa/ply/brass "lunchmeat" in between.

Sand the edges smooth, and drill the mounting holes to match the motor mount. While you’re at it, de-burr the ends of the brass tubing. Temporarily close off the ends of the tubing with wax, clay, or whatever and fuelproof the whole assembly with epoxy or whatever. Unplug the brass tubing.

Bolt the motor mount and the "sandwich" onto the firewall. Slide a wheel collar or steering arm onto the nosegear strut. Slide the strut through the brass tubing and retain it with a wheel collar (or steering arm) at the top end. Tighten the steering arm. Hook up your steering linkage.

If this was a tri-gear conversion, rebalance the plane ‘cuz the engine’s 1/4" further forward now. Move the main gear to a point just behind the CG. ("But how do I move the main gear??" Well, kids, that’s in a later chapter..)

This page last updated 10/16/99 16:58