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Old 13th December 2006 | 09:43
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Jonty
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Joined: Mar 1999
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From: big green wheely bin
Blip,
Nothing quantifiable for performance, as its more to do with controllability near Vmcg, than take off distance performance.

For the 757 the manual states that at normal UK temperatures and sea level Vmcg is 111kts

Now at light weights and short, wet runways the V1 can be below that:
80,000kgs, flap 15, 6000ft wet runway V1 is 109kts and at 70,000kgs its 101kts

Now without getting into a full blown disscution about take-off performance, which I know very little about, you can see that V1 and Vmcg can be that same and that can create controllability issues with spoilers up for the B757. Other aircraft my not have this issue.
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