Shortround6
Major General
Verry true and I realize hindsight is 20/20 but by 1940 there was trouble brewing with Japan( they were already at war with China and from what I've read many saw the potential for conflict with the US) so seems like the need for more range would have been appearant and doesn't seem like youd loose alot of performance on a p47 by packing a little more fuel.
Maybe it just didn't look as obvious then as it looks now.
The P-47 started with 305 US gallons or over 1800lbs of fuel. Which is about the the same as a P-38 once the P-38 got self sealing tanks.
For perspective the fuel fraction for the P-47 was about 15.25% ( weight of fuel as a percentage of the normal gross weight) fir 12,000lb plane, production versions got heavier quickly and the fuel fraction shrank. Meanwhile the fuel fraction of the Spitfire MK I was about 11%.
As the planes got heavier the fuel fraction dropped. The Fuel Fraction tells you nothing about how plane performs (or it's range/endurace) it merely tells you what sort of choices the designer made or perhaps how clever he was in using weight. Bigger planes do have some advantages though. (Pilot fraction for a 12,000lb plane is 1/2 the pilot fraction for a 6000lb plane unless you get really big pilots
As to hindsight, the paddle blade props, water injection and WEP power settings that really turned the P-47 into a formidable fighter were several years away when initial design and prototype testing were going on. The bigger internal fuel tanks on the late P-47Ds weighed about 90 lbs more than the small tank set up. and held about 390 lbs more fuel.
Most early P-47s had trouble climbing better than 2500fpm and many of the test planes were not carrying full ammo (425rpg weighs about 1020lbs). one test plane was carrying 525lbs of ballast which is equal to about 218-220 rpg. a few test planes only had 6 guns.
Adding almost 500lbs to an early P-47 might not be what you want to do regardless of how well the P-47D-25 handled it
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