On Mon, 14 Dec 2015 06:05:33 -0800, Bruce Hoult wrote:

On Monday, December 14, 2015 at 4:18:52 PM UTC+3, Martin Gregorie wrote:
That's 80-90m, but implies that you'd need to be rather higher if
flying slowly or hovering. Bruce's figures for the R22 autorotation
recovery (400ft/125m hovering, 200ft/62m at 55 kts) indicate that a BRS
system would need 150% more height than an R22 for a safe BRS recovery.

Just to amplify: 200 ft is always the corner for the R22. 55 knots is
the critical speed at max AUW, worst CG and about 3000 ft density
altitude. At sea level 53 knots is ok at any altitude, and at 7000 ft
you need about 58 knots.

Understood. I was comparing that 200 ft with the BRS site's quoted 'might
get away with popping it at 260-280ft', this presumably including both
height for the chute to inflate (minimal at speed since the aircraft
pitches up on deployment) followed by the height used up waiting for the
plane to be swinging gently enough for the crew to survive meeting the
ground.


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