Old 16th Apr 2014, 12:32
  #93 (permalink)  
Join Date: Jun 2001
Location: Australia
Posts: 890

Hazelnuts' graph is only generic, as you said. But the point remains true that Vs changes more than Vmc with different configurations or weights.

Here are real numbers from my turboprop. I've included only changes in configuration, keeping weights the same.

Vs @ MLW: F0 104kts, F35 79kts
Vmca @ MLW: F0 94kts, F35 78kts

Why have a wastefully large fin & rudder, you asked. The fin & rudder is designed for the most limiting case. At other weights or configurations, Vs and Vmc won't match up.

My turboprop lacks the high lift devices of a jet, so there is "only" a maximum 10kt split between the two. I would expect the difference between F0 Vs and F0 Vmc to be even bigger in a jet.
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