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  • Thank you friends, I'll test it with a real model because it is easier than compute the 2+order transitions of the movement. Project flight mechanics hypothesis has been: weak disturbances, none inertial forces were neglected and flying parameters achieved instantaneously.

  • For stability, you need to keep the centre of mass ahead of your neutral point.  If you start moving it around, chances are your stability will go to zero.  Your further research on aerodynamic stability will show you this.

    Also, in this application, the trim of the tailplane will mean the amount you have to move the CoG will be enormous for any appreciable change in pitch.  To increase the angle of attack of the main plane, you have to change the effective decalage (angle between the main and stabilizer planes)

  • Could you elaborate a bit on your objection to pitch stability? I think if the geometry is designed properly, mass transfer should work for pitch.

  • You need to do a little more research on aerodynamic pitch stability.

    You might be able to get roll control with a moving mass, but not (much) pitch. 

  • Great Chris. I have nice computation in flight mechanics for the Albatros UAV. Look for annex IV:

  • Nice idea! I'm working on something similar for pitch trim. I have an empty carbon tube between the fuselage and the empennage of an aircraft design I'm working on. The tube diameter is large enough to house 18650 cells and a small linear actuator with 10cm of travel (aircraft is ~1.5m-2m in span, and between 1-2 kg). I'm just waiting on some high discharge 18650 cells to  build up a demo. I'm also working on a JSBsim model predict the actual impact of moving the CofG. Have you done any calculations to predict if mass transfer is significant/fast enough to fly a plane? 

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