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View Full Version : Gliding- Range or Endurance?


Wander
11th Nov 2003, 03:05
We are all pretty familiar with the standard u-shaped drag curve for cruise flight...on this curve max endurance occurs at min drag ie the bottom and best range is at the tangent a little faster.

Question= What happens when you shut your engines? Are there still two different speeds- one for staying airborne the longest and one for travelling the furthest?

Cheers,
Wander:hmm:

Miserlou
11th Nov 2003, 03:14
Yes, there are still two speeds and are as close as makes no difference to the former speeds. The speeds refer to angle of attack of course, and the lack of prop wash may have a minor influence.

Crossunder
11th Nov 2003, 19:17
All engines out:

Minimum ROD: fly at speed for min. power req'd (lower than Vmd)
Maximum range: fly at speed for min. drag

But when engines are shut down, the drag curve will look different than for all-engine case, so the speeds will not be the same...

Tinstaafl
12th Nov 2003, 03:39
And interestingly (and usefully) in piston lighties best glide range is near-as-dammit the same as best rate of climb speed, while minimum sink speed is matched by best angle of climb speed (more time in the air to think what to do)

Near enough to be useful.