0 votes
asked by (12 points)

Problem in  X-Plane 10 and 11

At the October launch for X-Plane 11 in the UK Austin showed how passionate he was about getting the physics of flight correct, well here is a problem for the team to solve.

When launching the default ASK21 glider by winch the launch cable is attached to the front hook on point where it should be the rear hook on point. When the winch cable is attached to the rear hook on point, the forces exerted by the cable passes through or nearly through the CofG for the aircraft, allowing the aircraft to rotate into a 45° climb that is normal for this type of launch. At the top of the launch the cable is still acting near the CofG so there is no violent reaction on release.

With the X-plane model the cable is attached to the front hook on that is some 45 inches forward of the CofG that has a turning moment which is pulling the nose down this prevents the glider from achieving the desired climb angel of 45°, and worse at the top of the launch, on release the nose of the aircraft pitches up violently almost putting it into a steep stall.

Modeling of the aerotowed launch is correct at the front hook on point as tow rope alignment virtually passes down the center axis of the fuselage and through or near the CofG so the forces are nearly in balance

The following images show the problem

Winch Launch Diagram

Aerotow Diagram

Log file

 

1 Answer

0 votes
answered by (19.3k points)
I'm not sure if X-Plane models different the different hooks to attach the winch/tow aircraft to. I have filed a bug for consideration.

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