I followed your intervention about this topic out of curiosity on (
http://www.arcforums.com/forums/air...hoto-reconnaissance-p-51-mustang-january-1943 /) and Here is what Martin Bowman writes in - "P-51 Mustang versus Fw 190 - Osprey. p.10".
"The first 20 P-51s to follow the last Mustang IAs off the line in July 1942 were taken on charge by the US Army Air Force (USAAF), fitted with two cameras for tactical reconnaissance duties and redesignated F-6As. When this contract was completed two months later, the RAF had received 93 Mustang IAs and the USAAF 55 F-6A photo-reconnaissance aircraft. Two airframes were diverted to the XP-78 project."
"The Allison powerplant was not designed to perform at high altitude, so the British decided to operate the Mustang in the armed tactical reconnaissance role with a camera fitted behind the pilot. Although restricted to ceilings below 16,000ft, the Mustang I's speed of almost 353mph at 8,000ft made it ideal for ground attack and tactical reconnaissance,"
"...Five Mustang Is were subsequently delivered to Rolls-Royce for conversion into Mustang Xs through the fitment ofa Merlin 65 to each airframe. At the same time the two surplus Mustang IAs retained by North American in California were modified to take license-built Packard Merlin engines in place of their Allison powerplants. Initially designated the XP-78, the aircraft had become the XP-51B by the time the first example completed its maiden flight on November 30, 1942."
