Fatal crash Arizona

On Thursday, May 8, 2014 7:43:42 PM UTC-6, son_of_flubber wrote:
On Thursday, May 8, 2014 8:55:27 PM UTC-4, Bill D wrote:



Why would anyone lower the nose? The glider is presumably at aero tow speed - 65 - 70 knots which is way above the pattern speed.



Perhaps I have a fundamental misunderstanding...

but I thought that the AofA at 65 knots on aerotow is steeper than the AofA at 65 knots in free flight.
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I think you are confusing pitch attitude with angle of attack. In unaccelerated flight, for a given weight and airspeed, the AOA will always be the same whether you are being towed or not.
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So if you don't reduce the AofA (aka drop the nose) after the rope breaks, the glider will slow down.
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Yes it will slow down if the pitch attitude isn't reduced. However, lowering the nose to establish a normal glide at pattern speed will actually see an increase in AOA due to the lower speed - you're just changing the flight path from a climb to a glide at a slower speed.
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If you start the turn before reducing the AofA, you may find yourself going too slow for the turn.
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What you are saying is if the pilot attempts a turn while continuing the nose-up climb after a rope break, the glider will slow down. Of course it will but in most cases this is desirable since the tow speed was well above pattern speed. Just don't continue the slowdown below pattern speed. The AOA is more closely related to airspeed than pitch attitude.



It is true that you can use the speed coming off aerotow or PTOT to gain a bit of altitude, but that just means lowering the nose gradually as you bleed off the speed. In both cases the AofA needs to be adjusted to match the desired free flight speed. I thought that we practiced this 'gain altitude and slowly drop the nose' every time we release from aerotow?

Yes, this technique is correct but the glider is just transitioning from being towed to a normal glide. The AOA will actually increase as the glider slows down.

Discussions like this highlights why gliders should have an AOA indicator in addition to and ASI.