Paul Hanson wrote:
VNE in free air is determined by the amount of lift
a wing can generate vs. it's load strength; ie the
wings can only generate as much lift as the spar/structure
can safely handle.

With respect, this is entirely wrong. In straight free flight the wings
generate exactly enough life to counter the weight of the airframe and
its contents. If the wings generate more lift than that the aircraft
will loop: if they generate less its called a "stall".

I suspect that Vne is more often determined by the torsional resistance
of the wing. That's certainly the case for an ASW-20.

--During a winch launch there is
significantly more stress for a given airspeed.

Correct. The minimum amount of lift needed must counter the weight of
the airframe and contents plus the weight of the cable plus the vertical
component of the tension in the cable.

The upper maximum amount of lift is the point at which the wings fail in
bending unless other factors such as elevator power or the wing's
accelerated stalling performance intervene to set a lower limit.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |