Wanted: Expereienced Flight Aerodynamicists for Winch Launch Investigation

I looked a little more into x-plane

The X-plugin data interface data items are listed at.
http://www.xsquawkbox.net/xpsdk/docs/DataRefs.html

search for fside_plug_acf
Appears to be 6 data items for extra plugin provided 3d force and 3d moment.

The simulator also include a builtin winch launch system.
Not sure what the model for the winch power curve is, but the parameters controlling it appear to be at /sim/world/winch in the same file.

On Sunday, October 6, 2019 at 7:30:51 AM UTC-7, wrote:
I looked a little more into x-plane

The X-plugin data interface data items are listed at.
http://www.xsquawkbox.net/xpsdk/docs/DataRefs.html

search for fside_plug_acf
Appears to be 6 data items for extra plugin provided 3d force and 3d moment.

If you need a plan B. Instrument the cable with a tension logger. Instrument the winch with throttle position indicator, cable angle & Drum RPM. Take it to a winch clinic. Compare the graphs of the instructor's demo's with the students flights. In my opinion you could do it with speed control, cable angle, ramp rates, and tension limiter overrides. All the winch driver has is the throttle, his process seems pretty repeatable from launch to launch once he gets dialed in on speed. The students actions will be all over the place. Reliable control based on glider pitch angle, and Launch phase combined with the lag in the system with possible signal loss might be a tough go when the pilot does something stupid or the coms break down. These days you can't neglect the inherent liability of designing a fool proof system that encounters a master level fool with a competent lawyer. Good luck, this is interesting stuff, sorry I can't help with the math.

SF

On Monday, October 7, 2019 at 5:26:40 PM UTC-7, SF wrote:
If you need a plan B. Instrument the cable with a tension logger. Instrument the winch with throttle position indicator, cable angle & Drum RPM. Take it to a winch clinic. Compare the graphs of the instructor's demo's with the students flights. In my opinion you could do it with speed control, cable angle, ramp rates, and tension limiter overrides. All the winch driver has is the throttle, his process seems pretty repeatable from launch to launch once he gets dialed in on speed. The students actions will be all over the place. Reliable control based on glider pitch angle, and Launch phase combined with the lag in the system with possible signal loss might be a tough go when the pilot does something stupid or the coms break down. These days you can't neglect the inherent liability of designing a fool proof system that encounters a master level fool with a competent lawyer. Good luck, this is interesting stuff, sorry I can't help with the math.

SF

SF,

We have inline instrumentation pods with tension sensing, GPS tracking, and accelerometers. We also have instrumentation packages for monitoring the winch during the launch. We have logged a number of launches on several classic winches. Those logs have validated many of our theoretical models for winch launching. In particular, they show the oscillatory behavior predicted by the mass-spring-mass model during the ground roll and early rotation. But during the climb, the observed behaviors are not so clear. That is why we are looking for a flight dynamicist to help us improve that model to include aerodynamic effects. Knowing how/if the aerodynamics affect this mass-spring-mass oscillatory system will greatly simplify the design of the control law for the tension servo system on our prototype.

-George