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Explaining 4 Graphs About Wing Sections
- Thread starter Veer
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Discussion Overview
The discussion revolves around the interpretation of four graphs related to wing sections, specifically focusing on lift distribution over a wing. Participants seek clarification on the axes, terminology, and the significance of the graphs in the context of aerodynamics.
Discussion Character
- Exploratory
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- One participant expresses difficulty in reading the graphs due to poor quality and requests assistance in understanding them.
- Another participant identifies the coefficient of lift (CL) but is uncertain about the meanings of WFP and L, suggesting that 'c' refers to chord length and speculating that 'c bar' might represent average chord length.
- A participant proposes that the graphs depict lift distribution over a wing and attempts to clarify the meanings of the variables used, including W=Wing, F=Fuel, and P=Pod.
- One participant references a textbook, suggesting that the Y-axis may represent lift per unit span and speculates on the meaning of the c/c_bar term.
- Another participant explains that the area under the graph equals 1 due to normalization, indicating that total lift is represented as a fraction of the total lift of the wing.
- There is uncertainty regarding the specific definitions and implications of the terms used in the graphs, with participants offering hypotheses without reaching a consensus.
Areas of Agreement / Disagreement
Participants express varying levels of understanding and uncertainty regarding the graphs, with no clear consensus on the meanings of all terms or the implications of the data presented.
Contextual Notes
Limitations include unclear definitions of terms such as WFP and L, as well as the potential for misinterpretation of the graphs due to their quality. The discussion also reflects a reliance on assumptions about standard terminology in aerodynamics.
- #2
Veer
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damn its impossible to read sorry 
- #3
enigma
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What are the units on the axes?
- #4
russ_watters
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If you could double the size of the pic, I might be able to read it.
- #5
Veer
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It won't allow me to make the picture bigger.
- #6
enigma
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I'm not going to be too much help...
CL 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?
CL 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?
- #7
Veer
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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.
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.
- #8
enigma
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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 CLL/CLWFP I'm not sure. Maybe CLL is the lift coefficient of the entire plane, and CLWFP 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?
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 CLL/CLWFP I'm not sure. Maybe CLL is the lift coefficient of the entire plane, and CLWFP 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?
Last edited:
- #9
Veer
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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.
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.
- #10
enigma
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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.
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.
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