Originally Posted by
Rodney
A good rule of thumb is to place it at an odd multiple of the span; i.e. 1/3, 1/5, 2/5 2/3 etc. This minimizes the chance of flutter as it tends to cancel out some of the possible flutter frequencies. For best use of the forces required of the servo, the farther out on the wing the better.
1:3 can still set up a strong resonance. 1:4 is better but still possible. 1:5 is better again but still possible. The problem is that you're still using evenly divisible ratios. The higher the ratio the less strong any resonance will be but it can still achieve a size based resonance.
What's needed is a real oddball like 1:3.2. The surface may still flutter but with a non integer based ratio such as this it'll be due to other factors than resonance due to the horn location.