Thursday, 7 January 2016

There is NO SUCH THING as stall speed!

de Havilland Chipmunk
There’s no such thing as stall speed! A wing does NOT understand stall speed, all it knows about is angle of attack (AoA). Have a look at the video at the end of this piece.
I've been banging on about this on aviation forums for decades! - there is NO SUCH THING as stall speed, only stall angle. Yet every time the tired old responses come back supporting monitoring of indicated air speed in stall avoidance.
The General Aviation world does NOT think AoA, they think stall speed. The airliner world is obsessed by 'speeds', and the only airliner I know with an AoA indicator is Concorde!
Vortex lift visible on a Concorde wing at high AoA
As the video says, the military know better. They always think AoA, just as the aeroplane does.
I've said it before, and here it is again.... I'd trade just about any instrument on the Chipmunk's or Yak's panel for an AoA indicator! Especially for aerobatics.
There's been a problem to date with fitting them to prop singles - the propwash mucks up AoA measurement using conventional vane sensors. One wonders if it's significant that the aeroplane in the video is a pusher?
I really hope these guys have produced an affordable dependable AoA indicator for GA use. If they have, it will be a game changer.

Click the link below for the video:
Angle of Attack video


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