Thread by @USAS_WW1

#avgeek #aviation #RAF #USAF #P51 - The P-51 Mustang was built to a British spec for a new RAF fighter and later served in the USAAF. Let's tour the fighter, from its prototype NA-73X to P-51D, etc., its development and different versions... @kadonkey @Sylvia70485099 1/

2/ The British Purchasing Commission asked North American to license-build Curtiss P-40 Warhawks for the #RAF. Instead, North American designed a more modern NA-73X prototype fighter with the same 1,090 hp Allison V-1710 engine. It first flew September 9, 1940.

@AlexanderZPain @MartinKoenigsb2 @kingdomman66 @majestic_air @curlyboy1975 @deecanadian 3/ It was 25 mph faster than the P-40. Britain bought 320 NA-73 + 300 NA-83 (fishtail engine exhausts) and christened them Mustang I. This new RAF type was used for recon and fighter-bombing. It had a 12' wide landing track, simple production, etc. 4 x .50 cal; 4 x .30 cal.

4/ The A-36 Apache was a dive-bomber version of the NA-73 with a reinforced heavy-duty wing for bomb racks, and hydraulic dive brakes both above and below each wing. 6 x .50 cal and 1325 hp V-1710-87.↖️Cockpit at @AFmuseum ↗️. Note dive brakes↙️. @AHMuseum's A-36 by @airpigz↘️.

5/ The USAAF's first P-51, the P-51A was the RAF's Mustang II. It had a more powerful 1200 hp Allison V-1710-81 and the A-36's bomb capacity, low canopy and raised back but no dive brakes and only a pair of .50 cal M2 Brownings per wing. No .30 cals or nose guns.

6/ The Allison engines underperformed above 15,000'. RAF test pilots suggested using the Rolls Royce Merlin in the P-51. Packard started making license-building them as 1520 hp Packard V-1650. The result was the P-51B /Mustang III. 1,987 built at Inglewood, California.

7/ The P-51C was identical to the P-51B but made at North American's Dallas plant. 1,750 built, of which 636 sent via Lend-Lease to the RAF who logically named them Mustang IIIs, just like the P-51B fighters. P-51C Excalibur is at @NASM Udvar Hazy!