The Islander

Extract

The Islander is extremely simple and has had few aerodynamic problems; the exception was a persistent elevator “buzz” in some aircraft which was annoying more than it was serious and the cause of which was never satisfactorily established, despite an investigation that took six to seven months and which included wind tunnel testing and elaborate flight instrumentation. It was eventually reduced to an acceptable level by improved detail engineering.

The NACA 23012 section that we use is not a popular section nowadays despite having a good C_{L max}, low C_MO and low C_DO. Its main drawback is the abrupt stall it can give to a wing. The usual cure for this is to provide generous washout. We chose to confine our washout to the wing tip and, as no dihedral was necessary apart from the tips, we achieved a very simple rectangular box structure with no joints—both a stressman's and a production engineer's dream. It is not often that you can please them both.