The first modern research into military
solid-propellant rockets in the United States was conducted by Colonel
Leslie Skinner at the
Aberdeen Proving Ground in 1932. Little interest was shown by the US Armed Forces however, until the introduction of a British
anti-aircraft rocket; both nations exchanged their research data before the United States entered World War II. The M8 rocket was developed by the
National Defense Research Committee and the
Army Ordnance Department in the early 1940s at
Picatinny Arsenal. The specifications were agreed in the summer of 1941 after examining equivalent British rockets. Skinner produced the first prototypes which were tested at Aberdeen that fall, improvised from old
fire extinguisher tanks for rocket casings, thereby determining the 4.5 inch diameter. It was
stabilized by base-hinged flip-out fins on the tail, a system patented by
Edgar Brandt in 1930 (and also used on German
R4M rocket), which proved less than satisfactory for ground-launched rockets as their initial low velocity and resulting low fin forces led to wandering in the first moments of flight. (Modern implementations of this system like the
RPG-7 grenade launcher spin the projectile before leaving the tube to prevent similar wandering) Original priority was given to an air-to-ground version. Confidence in the initial results was so high that the
USAAF had ordered 3,500 rockets before any had been actually fitted to an aircraft and it was hoped to have them operational in time for
Operation Torch, the invasion of North Africa, in October 1942. The successful launch of an M8 from a
Curtiss P-40E fighter on 6 July 1942 resulted in a procurement order for 600,000 units. Development began on a reloadable
launcher that could be fitted in the bomb bay of a
Douglas A-20 bomber, but this never became operational. There were considerable problems with the propellant, the fuses and the underwing launching tubes, all of which considerably delayed operational deployment. The initial production model was given the Army designation of M8; improvements resulted in the M8A3, with a more powerful rocket engine and enlarged fins, and the T22, which had improved reliability and modifications to make the rocket safer. ==Operational history==