Explaining 4 Graphs About Wing Sections

[Veer]

hello

Im new to the forum i hope u guys can help :)

I was wondering if u can explain these 4 graphs to me:

In the attachment thanks.

Its about has wing sections.

sorry about the rubbish quality of the pic the attachment size is too small.

 

[Veer]

damn its impossible to read sorry

 

[enigma]

What are the units on the axes?

 

[russ_watters]

If you could double the size of the pic, I might be able to read it.

 

[Veer]

It won't allow me to make the picture bigger.

 

[enigma]

I'm not going to be too much help...

C_L is the coefficient of lift. I don't know what the WFP or L on them mean.

c is usually the chord length, the distance from leading edge to trailing edge. I don't know what c bar means. Average chord length of the wing, maybe?

Do you know anything else about the graphs? Where did you get them from?

 

[Veer]

its a graph for lift distribution over a wing.

The W=Wing, F=Fuel, P=Pod.

What i wanted is a precise explanation of the graph like where the figures on the axis came from. But i can't seem to find it.

Thnx for ur help.

 

[enigma]

I'm shooting from the hip here, so take it with a grain of salt.

I'm referring to: Fundamentals of Aerodynamics by John D. Anderson on p 20/21 and 367. I have used the book, but my classes focused on nozzle flow, not wing flow.

2y/b is your distance along the wing. 'b' is the wingspan, and 'y' is the distance from the center of the plane. When you're at the tip, y = b/2, so nu will be 1.

My guess is that the Y axis is a measurement of lift per unit span, although it's in a form I've never seen before. I'm guessing, but I think the c/c_bar term is the ratio of chord length to average chord length (just from standard terminology). This would give you 0 at the tips, and a number greater than 1 at the root. c_bar may be root chord length. That would seem to make more sense to me, anyway.

The C_LL/C_LWFP I'm not sure. Maybe C_LL is the lift coefficient of the entire plane, and C_LWFP is the lift coefficient of just the wing?

It sort of makes sense. For a constant lift coefficient per unit span and dynamic pressure, lift per unit span is a function of chord length alone.

I don't know the reason for making it so bass-ackwards if that's what it is showing, though.

Any chance you could contact the person who gave you the graph to find out for sure?

 

[Veer]

Thanks itwas very helpfull

Would u know why the area under that whole graph will =1 by any chance. Is there a reason for this.

Thankyou very much for taking the time to answer this.

 

[enigma]

If you take the lift per unit length as a function of distance along the wing, and integrate over the entire wing, then of course your total lift will be the same as the lift of the entire wing.

If you then divide by the total lift, you'll normalize your numbers to make 'total lift' = 1.

My guess is that they've just done that with coefficient of lift instead of lift, and thrown the chord length in there as well to give you fraction of total lift as a function of distance.