drgondog
Major
Or from Iwo Jima and fight over Tokyo..
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If they both took off from England and fought over Berlin I'll take the Mustang.
So, like I said - this is true for each wing at a specific AoA and Velocity.
Sources Soren. Truth always has a foundation in physics and math. References Soren. Applied math to a physical model, measured against test data and refined to a 'truth'
I don't claim you are a liar - just uninformed.
Then tell me with numbers where I got the term lift-loading from - that makes about as much sense as what you just said
I would not presume to tell you where you got either your notion of lift loading as an 'efficiency' or WL/CLmax as an efficiency or anything else you have said.
Only you can reach for the sources or references
Bill, I've had heated discussions about wing loading and its importance many times before and it always ends up with all parties using the term lift-loading when relating to turn performance of an a/c, wether it be the right term for the subject or not.
Lift loading in the context of manuevering is a perfect way of contrasting Wing Loading to actual aerodynamic loads. Wing loading and Lift Loading are only the 'same' at one G.
I took it to me as I found it an easy and logical way to explain the importance of knowing the Clmax while at the same time showing the true difference between both a/c percentage wise.
QUOTE]
You are free to take anything anyway you want - doesn't mean we (or I agree). You are still avoiding sources and references to show why your brand of 'stuff' regarding dividing WL (or Aerodynamic lift Loading) by CLmax means anything at all.
The one and primary 'efficiency' indicator for a wing is L/D - and you note it is non-dimensional.
Again where did I say that lift-loading was an efficiency factor ?
Cl is an efficiency factor, that is what I said.
If that airplane is in a 3g turn in horizontal plane the Lift Loading is far higher than the airframe weight on the ground - and more than 3x as the total lift and normal forces on the wing are greater than the lift force vector equal and opposite the accelerated mass vector."
Bill,
I was talking about the lift coefficient, that is an efficiency indicator/factor. I never said lift-loading was an efficiency factor, you're twisting my words.
Bill how does my analysis not prove it ???
To do an accurate comparison you HAVE to know the Clmax and you HAVE to divide the wing-loading with it. Why ? Because it's a coefficient, it's meant to tell you how efficient the wing is at providing lift pr. surface area.
So if the wing of aircraft A has a lift coefficient which is 30% higher than that of aircraft B, then aircraft B's wing provides 30% more lift for every square cm, m, foot etc etc than the wing of aircraft A. The very purpose of Cl as an efficiency indicator.
So - you say
"You have to know ClMax (TRUE) and you HAVE to divide the wing loading with it (FALSE)". BTW -I'll assume you meant wing loading in the context of the aerodynamic loads..
"The very purpose of Cl as an efficiency indicator" (FALSE- L/D and Cl/CD are 'efficiency indicators'. Cl is merely a plot point for a 2-d airfoil section as a function of AoA. Cl may also be derived in test or wind tunnel conditions for level flight without knowing the AoA - at 1g level flight - when the gross weight, wing area and true airspeed is known.
CL absent context of CD is NOT an efficiency factor
Here's what I said in post #146 from the very beginning of our discussion:
"Wing loading is simply weight divided by wing area, while lift-loading is weight divided by wing area and then divided by the lift coefficient in order to get the true difference. (That is the point of establishing the coefficients, they are efficiency indicators)"
You said this and you are wrong. You are wrong that Lift Loading is Wing loading divided by Cl, and wrong about the usefulness or relevance of dividing lift loading by lift coeeficient. When you do that you get "q" or dynamic pressure - which gets you 'q', not a true difference, not an efficiency
I don't see how one can translate that into me claiming lift loading is an efficiency factor from this at all. What I am saying however is, like I explained afterwards, that establishing the lift loading is a great of accurately comparing a/c percentage wise.
Back to nonsense.
That is true, and as you can see from my posts I said that as-well;
Saying it is true time after time doesn't make your case Soren.
If I wanted to find the actual lift vs the weight of the a/c then I'd use an entirely different approach as I then need the actual speed of the a/c and the air density of the inviroment it flies in:
In level flight for one g - the Lift IS the weight... the lift loading IS the wing loading. This is a little simpler than
Aircraft weight: 4,000 kg
Aircraft wing area: 20 m^2
Speed: 120 m/s
Alt: Sea level
Clmax: 1.50
Lift = Cl * A * .5 * r * V^2
at 1 g you go no further ----> Lift = weight = 4000kg
Lift loading = wing loading at 1g = 4000/20 = 20Kg/m^2 but this a/c must flying at a very high AoA for CLmax=1.5 - did you want this illustration?
1.5 * 20 * .5 * 1.225 * 120^2 = 264,600 Newtons
264,600 N = 26,981.690 Kgf
26,981.690 Kgf / 4,000 Kg
________________________
= 6.74 G
????
After all the math Lift should be equal to Weight (4000kg) at 1g. For a higher value of lift than weight the little beastie will climb, for a lower value of lift than weight - it will sink!
I never claimed that lift loading was an efficiency indicator or factor, just a way of easily and accurately comparing a/c percentage wise. It is the lift coefficient I say is an efficiency indicator/factor, and it is.
I give up, you only wish to twist and misunderstand what I say, even when I cut it out in cardboard for you.
Mis understand and disagree are two different concepts Soren. I understand what you want and I disagree your physics.
While I was poking fun at you - there were no boundary conditions to prove that that particular ship had the Thrust available to maintain that velocity to sustain 6.74 G's
Don't you even understand that my calculation was for an a/c in a turn ?? Hence the use of Clmax!
Yes Soren
What I established in the above calculation was the G-forces a 4,000 kg aircraft with a 20m^2 wing with a Clmax of 1.5 will pull at 120 m/s when doing a max performance turn, which is 6.74 G.
See above. What you say is true if the one takes into evidence that the ship illustration you used in fact can do that turn at that bank angle and maintain level flight.
A similar a/c with a lower Clmax will only be able to pull less G's,
THE SAME a/c with the same wing but a lower CLmax (say - no slats) will be able to pull less G's. To get to the different a/c with different a/c the available Thrust in excess of drag, the total drag in the profile are also important variables. CLmax is Important but not determinant.
hence why dividing wimg-loading with Clmax is good for comparative reasons as you can then directly compare the turn performance of a/c percentage wise.
nonsense from a rigorous mathmatically sound repeatable basis as a unit of direct comparison -
see if works when you compare a B-36 to say a Mustang. IIRC the 63-420 airfoils have a ClMax at 1.6+ and WL of 34 empty and 55 loaded and fly it with your values against a maxed out Mustang at 11,800 pounds and WL of 60.
That's it for me, I don't wish to continue this anymore as you really don't wish to understand, just preach.
No, the problem with the original comparison- in the post that launched this thread, five years ago- was that it was always bunk.
The Spitfire XIV had a Griffon engine- a more advanced powerplant. The P-51D was still using the Merlin. That's why there was 8,000 + P-51Ds made and less then 1,000 Spit XIV's were made- the Griffon was more expensive, and American/British factories were already tooled to produce the Rolls-Royce Merlin in quantity. Many P-51s were needed to escort American daylight bombing, and the D model with the Merlin could already whup any German fighter in the air, so it was pointless to try and re-tool factories to produce Griffons.
The net consequence was that the Spitfire's capabilities jumped ahead of the Mustang's for a time because of production priorities, not any advantage inherent to the airframe. The P-51K would be the proper comparison- at combat weights, too, none of that "let's compare the Spitfire's loaded weight, with 1 hour endurance, to the Mustang with 8 hours of fuel" bunk.
A troll thread still alive five years after it was initiated? Must be a record.
Demetrious - I believe you meant P-51H not P-51K as a proper comparison. The only true distingushing difference between D and K was the Hamilston Std vs Aeroproducts prop/pitch controls, whereas the H was lighter, more powerful and essentially a new design.