to ftp and Christiaan -
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I have seen many Vspeeds and Mspeed definitions and limits.
Some are "official" accepted names... some are not.
I got trained in the USA... and I came across books from UK with other names or definitions.
As pilot, after all, we only need to study/remember a few, that are our aircraft limits.
The others you forget. Heaven's sake, for me was 40+ years ago...!
Alzheimer is taking place...
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A fact of interest, about V speeds and M number limits...
Some airplanes have V speeds
and Mach limits, some do not.
Examples -
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Boeing 747 landing gear placard indicates -
VLO/MLO Extension = 270 KIAS or Mach .82
VLO/MLO Retraction = 230 KIAS or Mach .82
VLE/MLE Extended = 320 KIAS or Mach .82.
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But for 747,
flaps there are only Vspeed limitations,
no Mach number.
The VFE Flaps 1 in the 747 is 275 KIAS - nowhere a MFE limitation.
This because Boeing 747 max altitude for flaps use is 20,000 feet.
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Compare to the DC8-63/73...
The DC8 has a VFE Flaps 12 of 230 KIAS and MFE Mach .46...
Because Douglas does not have 20,000 feet max altitude flaps extension limit.
You could extend flaps at high altitude, with a Douglas DC8...
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Happy contrails
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