Re: A brief commentary

From:         Daan Vlaskamp <vlaskamp@cuci.nl>
Date:         07 Jul 96 14:15:59 
References:   1 2
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At 12:42 27-06-96, you wrote:

>But upon checking the power to weight ratios of the respective
>aircraft it seems as if the 777 does have far more power than the A340 (both
>were fully loaded by the way).
>

Part of the answer to this may lie in the fact that the A340 is four-engined
airplane and the 777 has only two engines. You would expect that the four
engine aircraft had more power, but the opposite is true. This is because of
the climb requirement in an "n-1" (one engine out) situation. With one
engine out the two-engined airplane would lose over 50% of its power. The
four-engined airplane would lose a little more than 25%. So the climb
requirement would have to be met with respectively one and three engines.
That's why two-engined airplanes are usually "overpowered" when all engines
are operative.

Daan Vlaskamp
The Netherlands
vlaskamp@cuci.nl