North American P-51 Mustang History Part II - Variants

Mustang MkI
The first production Mustang aircraft delivered to the RAF. Two of this type were delivered to the USAAF as XP-51s. Most of this type was powered by the 1150 hp Allison engine and was armed with four .50 cal and four .30 cal machine guns.

A36

The dive bomber version of the Mustang, the A36 was powered by the Allison engine and entered service in 1942. It was armed with six .50 cal machine guns or four 20mm cannons, had provisions to carry two 500-lb bombs and was equipped with dive brakes, though many of this variant had the dive brakes disabled due to stress problems. Confusion surrounds the name designation of this aircraft. Some sources refer to it as the "Apache", "Invader" or both before it adopted the name "Mustang".