In 1940 the prototype P-51 was developed by North American Aviation to British specifications.
The power plant for the prototype P-51 was an Allison V-1710 V-12 engine which produced 1200 HP.
The first production aircrafts (A-36A Apache) and (P-51A Mustang) used the Allison engines but later used the Packard built Rolls Royce Merlin engine.
The P-51B and the P-51C were the first of the Mustangs to use the Merlin Engine.
While adding more power to the P-51B and P51C they encountered a problem which created a limited view from the cockpit,but was later rectified with the development of the P-51D
The pilot was given a much greater view of the sky around him when a bubble canopy was developed .
The Mustang was made to be a long range fighter to match the German fighter aircraft.
This design resulted in an aircraft that was extremely fast,agile and easy for pilots to fly.
There were 15576 built and put into service and some were still on duty in the 1960's
The Mustang continued its services even after WWII even though many
other piston aircraft were no longer being used. During the Korean War they
provided valuble support. Many other nations elected to use the P-51's
in the 1960's and a few are still in service today.