Lift coefficient and drag coefficient
Flying Dutchman
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Lift coefficient and drag coefficient
Hello,
Is there anyone that can help me with the following questions?
What is the lift coefficient and what is the drag coefficient in relation to the lift to drag ratio?
Why is the relation lift coefficient/drag coefficient minimum and the lift/drag ratio maximum at Vmd?
Thanks!
C-T
Is there anyone that can help me with the following questions?
What is the lift coefficient and what is the drag coefficient in relation to the lift to drag ratio?
Why is the relation lift coefficient/drag coefficient minimum and the lift/drag ratio maximum at Vmd?
Thanks!
C-T
Flying Dutchman
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I guess that a coefficent is proportional to the actual value (coefficient of lift is proportional to total lift in Newtons)
but I still don't understand why L/D is minimum at a high l/d ratio...
Thanks Dude!
C-T
but I still don't understand why L/D is minimum at a high l/d ratio...
Thanks Dude!
C-T
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Absolutely right - the total lift L = [(1/2)*(density)*(relative velocity squared)*(wing surfrace area projected on the chord line)] * lift coefficient.
Sorry I couldn't help with the other Q, but I'll have a look at my notes and get back to you if I can find something on it.
Sorry I couldn't help with the other Q, but I'll have a look at my notes and get back to you if I can find something on it.
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That second question sounds like a typo/SNAFU.
Lift = qS CL
Drag = qS CD
where q = kinetic pressure = 1/2*density*speed squared (as mentioned) and S = nominal wing area
So Lift/Drag = CL/CD
both are a minima at the same time, both are a maxima at the same time (unless you take the nonsense case of qS=0, which is physically pretty meaningless)
Lift = qS CL
Drag = qS CD
where q = kinetic pressure = 1/2*density*speed squared (as mentioned) and S = nominal wing area
So Lift/Drag = CL/CD
both are a minima at the same time, both are a maxima at the same time (unless you take the nonsense case of qS=0, which is physically pretty meaningless)
Flying Dutchman
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That makes more sence, Scientist. The thing that threw me off was a question in an exam paper that suggested the opposite was true.
Thanks for your input guys!
C-T
Thanks for your input guys!
C-T