I see that the 'some people' I referred to have turned up.
Yes the aircraft flies with respect to its airmass, but its momentum is related to groundspeed.
My heavy helo strong wind example:
Airspeed 60kts,
Headwind 30 kts,
Groundspeed 30 kts
Turn downwind:
Airspeed 60kts
Tailwind 30 kts
Groundspeed 90 kts
A GS acceleration of 60kts is required to maintain the steady state, equilibrium airspeed. There will inevitably be a lag (more noticeable, the more aggressive the turn) resulting in a temporarily reduced airspeed.
This effect can be very noticeable in the circumstances I described, as can the opposite, turning into wind. As I acknowledged in gentle winds and gentle turns this effect will not be noticeable.
If my statement is wrong, explain to everyone how rapid changes of windspeed can affect airspeed in windshear.
Beags, Wizowaz? I'm waiting. HAVE A THINK ABOUT THE KINETIC ENERGY OF THE AIRCRAFT INTO WIND AND DOWNWIND.
LP, the speed (not velocity) is constant. No tangential acceleration.
Last edited by Mike Oxmels; 11th May 2007 at 22:28.