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Are you really increasing CLmax with power on? Or are you accelerating the air over the wing, so while the CLmax would be constant but the lift is greater due to the faster moving air (possibly at lower AoA)??But on top of all these numbers comes another caveat: These are the power off (with power on the Clmax is much higher) stall and turn Clmax numbers at low altitudes, and if you throw the effects of Mach into the mix as well (which comes into play at higher altitudes because you're going faster in turns), or look at instantaneous turns starting at higher speeds, then the Clmax numbers will be even lower due to buffeting effects.
Are you really increasing CLmax with power on? Or are you accelerating the air over the wing, so while the CLmax would be constant but the lift is greater due to the faster moving air (possibly at lower AoA)??
Another cavaet would be, you need control of the aircraft as it approached CLmax to determine the "in service" value. Planes with nasty stall characteristics make testing...challenging.
I would also note that flying anywhere near the max coefficient of lift means the plane is flying at an angle 15-20 degrees from the direction of travel. Basically the wing is acting like a giant airbrake (fuselage lesser) and you are not going to be flying at that speed for very long or you are going to be flying very, very slowly.
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Each airfoil is going to have it's own set of curves but a lot of them are going to be close.
It this example the best lift to drag is about 6 degrees angle of attack and the CL is 0.5 and the CD is about .0400.
At the CL of 1.5 with the airfoil tilted 20 degrees higher than the line of flight the the plane has stalled and the CD is off the chart.
Backing off to 18 degree angle of attack the CL is around 1.43 (?) the plane is flying (barely) and the CD is about 10 times higher than high speed level flight.
Figure out for your favored airfoil but extreme CLs are going to only apply at a tiny fraction of the flight envelope and if the pilot is using them he has either successful shot down his opponent and/or he is about to be shot down by another aircraft in a better energy state (flying faster).
WI means "water injection" (MW 50 to the Germans). Not all planes had WI even if they used the same basic engine, you do have to fit the water tank and the associated plumbing fittings.
What is fair is to use the max boost used in service (or soon to be) for the different airplanes.
Air cooled radial engines never operated at the same max boost as allied liquid cooled engines using the same fuel.
War Time R-2800 Bs never operated at over 54in with any supercharger unless they had water injection.
Then there is the shifting of the rations. Its not like your car where you can let off the gas to ease the shift, the shifts are happening at full power (what I would call powershifting, you push in the clutch, while pulling the shifter into next gear, never lifting off on the throttle). And that was a problem for the F4U-5 side winder - the load was so high, it broke things. So, rather than use clutches, P&W used more/less torque convertors. And "hydraulic connection" of torque convertor smoothed the acceleration of the auxiliary stage from neutral to low and from low to high (and back down again). Once the supercharger impeller had been accelerated, the connection speed was more/less constant. So, the R-2800-32W has a geared drive supercharger, it just has a fluid coupler for shifting, so it have the same jagged profile as the Merlin would.
Good post. I would add that while Induced drag is high in a constant altitude high G turn, that Pressure Drag as a function of CL (different from Induced Drag) is very high also.Absolutely, the wing profile drag rises a lot when you approach stall. However, I think the figure you posted is more schematic when it comes to drag close to stall and attempts to show that it increases a lot (which it certainly does) only perhaps not as dramatically as that figure suggests.
Below is the profile lift/drag for the NACA 230 (Figure from airfoiltools.com) which is used on a lot of WW2 aircraft, and as can be seen, the drag does rise quite a lot close to stall, but as long as you stay close to the Clmax but don't actually stall it, it's not "inifinite". (Note that this is at Re=1M and that at higher full-scale Re the Clmax is closer to 1.7)
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Added to this is the fact that the major part of the drag in tight turns close to stall is not from the rise of the profile drag, but rather from the so-called induced drag which is much larger and is the major determinant for the drag in tight turns.
Finally, as long as we are talking about sea-level up to medium altitudes, the best turn rate is actually attained at the intersection of the stall boundary with the power limited turn rate (enigmatically called angle of straight climb in figure below) as shown in the figure below for the Spitfire MkI and Bf 109E at an altitude of 12,000 ft (Figure is from the British RAE report RM 2361).
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Good post. I would add that while Induced drag is high in a constant altitude high G turn, that Pressure Drag as a function of CL (different from Induced Drag) is very high also.
Also notable is that wind tunnel testing on the P-51B showed much higher CLmax for dive pullout (circa 1.8) which leads us to all question 'aircraft vs Wing' in CLmax discussions for accelerated flight.
The F4U and P-47 didn't have the range to prevent catastrophic losses to 8th and 15th AF over key strategic targets (Schweinfurt and deeper) pre D-Day. Summer/fall 1943 was nearly catastrophic for post war USAF ambitions.If the US had to make do without one of the aircraft, I would say dispense with the P-51 and keep the F4U. We could have won the war with the P-47 in Europe, but the same could be said about the F6F in the Pacific. But what about 1951 in Korea? I know that I would rather be flying an F4U than a P-51. This is not meant to be a slight to the P-51 in any manner.
I would say dispense with the F4U, asIf the US had to make do without one of the aircraft, I would say dispense with the P-51 and keep the F4U. We could have won the war with the P-47 in Europe, but the same could be said about the F6F in the Pacific. But what about 1951 in Korea? I know that I would rather be flying an F4U than a P-51. This is not meant to be a slight to the P-51 in any manner.
Out of curiosity, of both types listed, what were the numbers for losses against enemy aircraft versus enemy ground fire for each type?As for Korea, from a quick memory check (flying very similar mission profiles in the same environment):
F-51 Losses = 341 combat related and 474 overall
F4U losses = 325 combat related (Navy & Marines combined) and 495 overall
Without the Hurricane Spitfire P40 and Wildcat you don't have an island base or aircraft carriers so you've lost the war before the F4U P47 F6F and P51 have even entered production. All those aircraft entered production and were used in all theatres, because all of them were needed.If the US had to make do without one of the aircraft, I would say dispense with the P-51 and keep the F4U. We could have won the war with the P-47 in Europe, but the same could be said about the F6F in the Pacific. But what about 1951 in Korea? I know that I would rather be flying an F4U than a P-51. This is not meant to be a slight to the P-51 in any manner.
that interesting, I always thought that Corsair is more durable given that it is armored against 0.5 caliber machine gun while P-47 is notAmong the R-2800 fighters, the Corsair was not as resilient against enemy fire as the Jug and Hellcat due in part to the oil coolers in the wings. It probably didn't help that it was a handful to land on a carrier under ideal circumstances, let alone battle-damaged (more likely to be ditched when the others could have been saved)
it has been discussed in great detail over the years on this site, there are some good tidbits here P-47N Thunderbolt vs. F4U-4 Corsair - Which was superior?that interesting, I always thought that Corsair is more durable given that it is armored against 0.5 caliber machine gun while P-47 is not
The P-47's turbo system was more vulnerable, being in the belly of the fuselage and unlike the F4U and F6F, never had to ditch due to battle damage...Among the R-2800 fighters, the Corsair was not as resilient against enemy fire as the Jug and Hellcat due in part to the oil coolers in the wings. It probably didn't help that it was a handful to land on a carrier under ideal circumstances, let alone battle-damaged (more likely to be ditched when the others could have been saved)
I'll dig out the book this weekend, the numbers I posted I copied out real quick for another post quite some time back and they were still sitting in that pile of papers on my desk. Going from memory however (DO NOT quote me on this but...) I believe for the mustang it was only 10 lost in air to air vs MiG-15s and about a like number for the F4U, all other combat losses were to GF.Out of curiosity, of both types listed, what were the numbers for losses against enemy aircraft versus enemy ground fire for each type?