The Spirit of St Louis flew a treat, but it took more than a few attempts to get it unstuck from terra firma. The Royal kit showed a mid-cabin cg and therein lay the problem. We tried shimming the stabilizer (scale size – small), the wing leading edge, lowering both ailerons with no success. Finally we moved the cg to the front of the wing’s leading edge and off the Spirit soared.
The engine was an OS .80 with a rear rotor intake. I see no muffler. The plane in flight was a show stopper; flight was slow and very steady. If I remember correctly I used that engine in the 1/4 scale Camel.
The film shows the Robin Regent’s entire flight history. The plane was too heavy for the engine.