Don shares some secrets to adding a some lightweight strength to the roadkill models.

From : Don Stackhouse

One other hint: things like wing tips tend to accumulate a lot of dings. Cut out a border about 3/16" wide for the wing tip from bond paper, then glue it to the underside of the tip with white glue. This adds an amazing amount of strength for very little additional weight.

Also, I've found that a strip of 1 ounce fiberglass about 1 1/2" wide running from the forward part of the wing (basically the area between the leading edge and the high point) to the motor mount area of the nose, on both sides of the nose, applied with either thin C/A or with water-based urethane varnish (Varathane or equivalent) adds a huge amount of strength to the nose. If you're flying in a constricted space, where you stand a good chance of running into walls, etc., it could save a lot of repairs to the nose. Without this mod, the long-nosed RK models in particular (like the P-40 and the Mustang) tend to break between the aft edge of the motor mount doubler and the leading edge of the wing if they're subjected to a serious head-on collision. It's best to apply this before applying the ply motor mount doubler and the wing root doublers.

Don Stackhouse
DJ Aerotech