That little nylon thrust button

17 January 2025

All the Veron's rubber powered model plane's plans I have seen uses a tiny nylon thrust bottom. This little nylon thrust button has a hole which allows the propeller wire shaft to spin within and the nose end of this button is dome shaped, presumably to space the plastic propeller away from the bulkhead and provide flange support to prevent the button from being pulled in. A small cup washer is always indicated and it appears to it is inserted dome-shaped washer to dome-shaped button, presumably to reduce friction.

I only have various plastic tubes (from pen's tubes) but they are simply tubes without the flange. I am thinking it might be possible to use 2 sizes of plastic tube. The larger tube will be the outside tube and the smaller tube will be the inside tube, within which, the wire shaft spins inside the inside tube. The gap between the inner and outer tubes can be occupied by rolled paper (or stuffed with cotton wool). Some superglue wicked to the paper will make the 2 tubes as one, the outer tube being the flange support on balsa bulkhead. The inner tube unhindered for the wire shaft to spin.

The simplest solution is to glue a single tube in a piece of hardwood or ply. Drill on a piece of plywood or any lamination that is about 3mm thick, a hole the external diameter of the plastic tube. Trim this flange support to shape, insert the inner tube, lock in position with superglue. An alternative is to superglue a ring of rolled paper.

The tube/tube or the ring/tube would look neat, but it doesn't mean that the flange must be circular, the ply flange can be circular, or triangle, or rectangle or any shape!