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Old 19th Sep 2004, 15:48
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hawk37
 
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Alex. I too get the Vmp/Vmd ratio to be about .76
Actually, my math gives (3)^.25 as the "exact" answer.

I'm thinking there can’t be any generic relationship of Vmd to V stall, except that a wing designed for higher speeds will have a greater Vmd/Vs ratio

Examples:

1. Slow speed, C172 Vcal mph = 57 flaps up, power off, max weight
Emergency procedures give 75 mph for engine fail after takeoff, 73.5 cas, likely max L/D speed.

Vmd/Vs = 73.5/57 = 1.29

2. Westwind, Mmo .765

Vmd/Vs = 1.43 at low altitudes

3. Falcon 50, Mmo .86

Vmd/Vs somewhere between 1.5 and 1.7

4. concorde Mmo 2.2 (?)
Vmd/Vs unknown, but I’d expect greater than any subsonic aircraft.

thoughts?
Hawk
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