Re: Aircraft speed and weight at cruise.

Date:         21 Nov 97 01:59:54 
From:         tyler@plk.af.mil (David Tyler)
Organization: Air Force Phillips Lab.
References:   1 2 3 4
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Simon Ellwood <Simon@cv990.demon.co.uk> writes:

>>The statement "A wing generates a lift value which is proportional to the
>>air speed" is completely right.  since:
>>
>>    L=1/2*pho*V^2*S*CL_alpha * alpha
>>
>>        L is lift, pho is density, V is speed, S is area, CL_alpha is
>>        lift curve slope, and alpha is angle of attack
>>
>>Therefore,
>>    L is proportional to air speed is a completely right statement
>>    L is also proportional to density, wing area, and lift curve slope

>Since when has a "squared" relationship been proportional ?

it's not.

>I'm suprised an aerospace engineer fell into that hole.
>Perhaps it's language here.

no; it's wrong.  for two quantities to be proportional, there
must be a _constant_ of proportionality (emphasis on ``constant"
not a coincidence).

dave
______________________________________________________________________
-David W. Tyler               "It seems you feel our work is not
-USAF Phillips Laboratory         of benefit to the public."
-Albuquerque, New Mexico
-tyler@plk.af.mil                         --Rachel