Originally posted by Widewing
You never cease to impress us with your selective data.
That document states that the F7F-1 had a sea level rate of climb of 5,230 fpm. Wow, that's a whole lot better than the Navy's official performance data for climb, which states it as 4,310 fpm.
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All depends on context, ie what power rating they were using for the figures.
I worked up figures for the F7F-1 a couple years ago.
At a loaded weight of 21,476 lbs I get a climb rate of 3900 fpm @ 2100 hp x 2 mil power.
WEP climb rate all depends on what rating they used. I have seen figures of 2250 hp, 2380 hp, 2600 hp and 2800 hp for the R-2800-22/32W.
Giving climb rates of:
2250 x 2 = 4025 fpm
2380 x 2 = 4575 fpm
2600 x 2 = 5125 fpm
2800 x 2 = 5600 fpm
I have seen climb figures as high as 6500 fpm for the F7F-1, which is probably doable lightly loaded on 2800 hp.
What about the XF8F-1 at 5,850 fpm? Again, officially, the Navy reports sea level climb for the XF8F-1 at 4,800 fpm.
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Well considering a stock, loaded F8F-2 set a climb record of standing start to 10,000 ft in 94 seconds in 1947 at the Cleveland air races, that doesn't sound to implausible.
Again, it all depends on the power ratings. 2100 hp would probably give right about 4800 fpm. I will see if I can find some starting data to do a workup on the F8F-1/2, but 5850 fpm is probably reachable on about 2500 hp.
I'm still trying to get a handle on the R-2800-22/32W. It looks like they were single-stage/two-speed blowers, vice the two-stage/two-speed blower in the -18W in the F4U-4.
Looks like low blower should match up with neutral blower in the -18W, which hits right about 2380 hp @ SL max.
My guess is that 2380 hp was the maximum possible in low blower, but high blower could be engaged to generate higher manifold pressures and power. If I can get info on the blower ratios and diameters I can get more solid power figures for both low and high blower.
Did the Navy fail to mention the JATO bottles, or is this what we in Naval Aviation referred to as "gundecking" the paperwork?
What about their 441 mph speed for the P-47D-11? That's 6 mph faster than what Republic claimed, and 8 more than the USAAF reported. Moreover, this P-47 apparently was fitted with under-wing pylons. These were known to reduce speed by another 6 to 8 mph.
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Again test conditions and ratings are everything. A P-47D-30 managed 450 mph on 2535 hp when tested against a P-47N in '44. Yet that is still officially rated as a 426 mph airplane IIRC.
Given that R-2800-21/63/59 ratings varied from 2000, 2100, 2300, 2400 and 2535 hp depending on date, 441 mph for a razorback with pylons isn't unreasonable.
If the razorbacks can manage 420 mph on 2000 hp, which initial models were rated at:
2100 hp = 428 mph
2200 hp = 437 mph
2300 hp = 450 mph
2400 hp = 457 mph
2535 hp = 470 mph
Subtract about 15-20 mph for those godawfull pylons that Republic burdened the TBolt with, and you get right about 437 - 442 mph on 2400 hp.
When we look at range issues, we see that this document states that the P-38J had an internal capacity of 300 gallons. This is incorrect. The P-38J and L had an internal capacity of 410 gallons.
That's fact and even the Navy can't alter facts. If they only calculated based upon 300 gallons, then you can expect a reduction in combat radius. This document also uses the typical Navy combat profile, not that of the AAF or 8th AF. P-47s typically flew at altitudes between 30,000 and 35,000 feet for escort duty. Not 15,000 feet, especially since the P-47's performance at 15k was less than stellar.
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The P-38J didn't get the 55 US gallon leading edge tanks in the initial production blocks. It was either the J-10 or J-15 that got the tanks.
If it was an early production P-38J then the USN figures are correct.
Greg Shaw
