Silverwall wrote:The most important weapon who's development cycle was entirely withing the range of WW2 (even if not US involvement) is undoubtedly the P51 Mustang.
Designed with an Alison engine in 1940 specifically for the RAF it was transformed from mediocre to worldbeating when given the Merlin engine.
Nah. P47 already had the range, just needed larger drop tanks, was faster, had better spin performance except down low and better dive performance at all altitudes. So naturally the P47 got tasked with the stuff down low while the P51 got tasked with up high... Then again, the P51 would have been utterly ABYSMAL down low vrs the P47 and could not carry bombs/rockets like the 47. The reality is that while the top deck domination was very important, only one of the two aircraft could operate downlow in any reasonable manner due to the FLAK and the P47 was still tasked with high altitude superiority. You will note that the Tempest was also tasked with downlow ground pounding while the Spits pretended to dominate the high altitudes where there were no fighters anymore. What did both P47/Tempest have in common? Radial engines which can absorb damage.
PS: The P47 was faster than P51B/D because of the 150 octane fuel used from 1944 onwards which allowed much higher boost. P47D's were running at 460mph@altitude(You will note that the later Brit Sea Fury which did not see service during WWII has the exact same top speed with ~same HP). The numbers people quote all the time are under 100/130 octane fuel, even though they almost never flew with 100/130 octane fuel except during the early war years... and even then the P51 is a mere 7 mph faster at medium altitude and equal at or worse at high altitude. Because the P47 used a turbosupercharger compared to the P51 which used a dual staged geared supercharger which was optimized for ~6000m vrs the P47's optimum altitude of +8000m. Also, depending on the Mustang in question using the 1650-7 engine(or was it the -3), which had its supercharger optimized for 5000m just like the Spitfire IX.
It is also why the P51H with its 3 stage supercharger hits its amazing peak speed(same with the VERY late Spitfires). Yet if you read the operation reports the P51H was 450mph.... why? They went back to 130 octane as it required FAR less maintenance and better reliability. A more optimal design in its new engine did allow for the ability to truly USE the 150 octane fuel. Of course in 1943, P47J with a real nose cone/cowling hit over 500mph and the XP72 using the P&W 4360 with a "tidy" 50% increase in power was expected to top out at 540mph which was equal to that of the first jet aircraft. Of course everyone saw that the turbine, even in its infancy was only going to increase in power etc. Judging by the horrific turbine fuel efficiency, and reliability, might have been a much smarter idea to go with the XP-72 for carrier operations at least for the decade after WWII. Of course; who was going to go up against the USN and commit suicide during that decade or the next several? No one. Certainly not the Brits who were buying half their ships from the US... at the time and after that there was no other navy in the world. Of course today, China could literally bury the world in warships if they so chose(steel production kings). Now what systems are on the ships is the question
For more information go to
http://www.wwiiaircraftperformance.org and also on youtube, Greg's airplanes and automobiles channel where he completely knows his stuff regarding engines, but is a hopeless case when it comes to entry level aerodynamics. His latest goober in Aerodynamics, was to try stating that a constant speed prop has same efficiency at all airspeeds... oh yea... lets see, a square radial function obtaining velocity vrs a linear forward velocity function... yea, last I checked a squared function times a linear is still a squared function.