As I said before my numbers are based on graphs coming from the Mfr and the the Air Force.
I gave a reference to an AF flight test report that identified a specific AF aircraft by number and you seem to disregard that data. Also, here is a manufacturer's data sheet with the manufactures logo that also disputes your input (
http://www.wwiiaircraftperformance.org/mustang/na-46-130-chart.jpg). These seem to be
high quality data. These are two different data sources reflecting the same information. Also, comparison to P-51B flight test data is consistent.
Everything I have ever read about the P51D says that it's Vmax at it's critical alt( slightly less than 25000 ft) was 435 mph. At that point the superchargers ability to maintain power begins to drop off significantly and if you could see the graph you would could readily see that at 30000 ft it could not do 430 mph.
The chart I referenced shows hp vs. altitude and reflects your comment about dropping off. However, airspeed does not drop off at the same rate as hp. It would if drag was a constant, but, as altitude goes up, drag drops off. Less hp is required to maintain airspeed. This is chart is consistent with other aircraft performance charts.
There is an interesting test report from a comparison test performed by Flight Test, U.S. Naval Air Station, Patuxent River, Maryland, titled "Evaluation and Comparison Trails of the P-51B and F4U Airplanes" (see
http://www.wwiiaircraftperformance.org/f4u/p-51b-f4u-1-navycomp.pdf). Test included the F4U-1 and F4U-1A. These
Naval test show that the P-51B was capable of 445 mph at 30000 ft. This is not inconsistent with the P-51D doing 430 mph at that altitude.
This data is from "America"s One Hundred Thousand" an exhaustively researched and footnoted book by an aeronautical engineer which goes into the design, development and manufacture and deployment of all US fighters in WW2. I recommend it to you
Hmmm, I not sure of what "exhaustive" means, since your data does not relate very well with what I have researched. I'll have to see about getting that book.
All I am saying as far as the F4U is concerned is that because of it's superior range in the 1 version that had fuel tanks in the wings, it could have stayed with the bombers longer than the P47s could and saved some lives in 1943. Also think about a redesigned version meant strictly for the AAF. Surely there could have been weight saving measures other than fixed wings and no tail hook that would have allowed the performance of the F4U to be even better.
The load carrying ability (gross minus empty weights) of the P-47C, F4U-1, and FG1 (F4U-1 with fixed wings) is a follows:
P-47C 3600lbs
F4U-1 3057lbs
FG1 3344lbs
As you can see, the F4U or FG1 could never carry as much fuel as the P-47 so it could never have a greater range.
As it was the F4U1 in 1943 was already a better climbing and turning a/c than the P47 and it was a hands down better fighter until the fight got above 20000 feet or more.
An escort fighter for B-17/24 should have optimum fighting ability between 20k to 30k+. This is where the F4U-1 begins to fade. I fail to see the F4U-1 advantage here.
Just it's ability to use a much shorter field would have been an asset in England.
I am not sure this was important in '43 England.
Of course, I know why that idea was never tried as the AAF would never admit that an a/c designed to be a ship board fighter could never outperform a fighter designed for the AAF. The reason that the RN had no decent carrier fighters was that the RAF controlled design of the RNs a/c and they flat rejected the idea that a carrier fighter could compete with a conventional fighter.
I am sure this is true.
That inline engine idea was in vogue in the US also in the 30s and the only thing that kept the radial engine of high enough power to give the fighter the performance needed to keep up with inline engined fighters was the US Navy, that was responsible for it's own procurement of a/c. Thus the PW R2800.
I do not agree with this statement. It is true that the in-line engine was in vogue but the Navy was not the only service using and proposing to use radial engined aircraft in the 30s. The AAF designed or built radial fighters in the 30s included, P-26, P-35, P-36, and P-43. In addition, and probably more influential to radial engine development, was the bombers, B-17, B-18, B-24, B-25, and B-26. There were probably more bomber funds provided to radial development than any other source.
Back to the P51, I have no doubt that a specially prepared a/c with perhaps special fuel could exceed the figures I have quoted.
The configurations of the tested aircraft are defined. Only minor modifications are mentioned in some instances and in other instances the aircraft were standard production aircraft. The only fuels used in these test were those available operationally, except where the fuel were being tested for proposed for use (like higher octane). These fuels were later operationally implemented.
I do think the figures I have quoted are more representative of the average production a/c.
Average performance of in-use aircraft is usually below those that are flight tested. However, this applies across the board to all aircraft. You cannot claim data is not good for one aircraft because it is not "average" and then compare that to the tested values of another aircraft. Since "average" performance is very difficult to get a handle on, comparing performance to "tested" levels is much more consistent and is a better way to compare aircraft.
Just checked on combat radius for P47c-d and F4u1. P47 with internal fuel had a CR of roughly 225 miles. This with 370 gallons fuel and includes warmup, climb out, cruise, 5min at combat power, 15 min at military power, cruise back, fuel reserve of 30 min at min cruise power. F4U1 had CR of roughly 450 miles with 361 gal internal fuel with same profile. A significant difference. Which one would you rather have escorting you in your B17 or B24?
Neither one of these planes could make it to Berlin. Both would have had to have been modified to carry extra fuel. As mentioned above, the P-47 had equal or better fuel carrying potential with drop tanks. I like the larger internal fuel capacity and it would probably have reduced some bomber exposure (although the P-47 could be modified for more internal fuel, in fact, the P-47D had 370 gal internal fuel). I do not think the F4U-1 would have made much of a difference. These planes were very similar but tuned to perform at different envelops, the P-47 at high altitude and the F4U-1 at lower altitudes. Both could probably be tuned to do the others job (except carrier ops. No carrier would be long enough for a Republic aircraft to take off on).
I do think that the higher altitude operating range of the P-47 gives it a significant advantage for bomber escort, as what it was designed to do.
