Glider cradle causes tow plane instability
We are working on a cradle to use to carry a glider up for release. We started by flying the Alpha trainer with just the cradle installed and found it very unstable. We suspect the cradle is causing turbulence around the vertical stabilizer, the plane lacks lateral stability that gets worse as the speed increases.
To test our theory, we used our G3 simulator, modified the Alpha trainer by reducing the size of the vertical stab and the rudder. We were delighted that the simulator modified alpha flew jusr like the real alpha when the cradle was installed. I was impressed. I have just finished adding two vertical stabs on the ends of the horizontal stab, they are about half the surface area of the existing stabilizer. Has anyone had a stability problem similar to this and if so what did you do to resolve it?
1. The cradle is mounted solid and square to the fuselage.
2. The cradle looks very similar in size and weight to the great planes cradle.
3. The center of gravity of the plane is the same with or wiothout the cradle installed.
4. This is a 40 size Alpha trainer with a 60 Super Tiger installed.
5. The plane flies perfectly before and after the flight with the cradle.
Thanks, Denny