P-51 Mustang (fighter)

The P-51 Mustang was the dominant bomber escort of the U.S. Air Force in World War II, air war World War II. Its main mission was defending bomber formations over Germany. It outperformed and largely destroyed the Luftwaffe. The fastest of all piston-planes, it also served as a light bomber, and reconnaissance aircraft, but was vulnerable in ground attack. Slower than a jet, it was displaced by jets after 1945, but saw service in the Korean War.

Origins

In spring 1940, the RAF, eager to take up President Franklin D. Roosevelt's invitation to use American factories and aeronautical expertise, challenged North American Aviation to build a model in 120 days if it wanted a contract. 117 frantic days later, the design team led by Edgar Schmued rolled out the first prototype. France had just fallen. Britain, standing alone against Hitler, hurriedly ordered 620 planes. After Lend-Lease passed Congress in 1941, the US purchased the planes and gave them to Britain.

Characteristics

The Mustang was a strikingly handsome plane. It boasted a revolutionary new smoothly polished laminar-flow wing that reduced turbulence. It was aerodynamically highly efficient, as demonstrated in wind-tunnel tests at the University of Washington. Fast-acting ailerons gave it a high rate of turn. The self-sealing nonmetallic fuel tank held 184 gallons gasoline, giving a radius of action of 300 miles, twice that of other single-engine fighters like the British Hawker Hurricanes and Supermarine Spitfires.

At low altitude Mustangs handled perfectly. The problem was that the original General Motors Allison V-1700 V-12 cylinder air-cooled engine, at 1550 horsepower, was not powerful enough at high altitudes, where it was outmatched by the Messerschmitt Me-109. The Mustang was therefore restricted close to the ground. The RAF used them for photographic reconnaissance in 1942. Six or eight machine guns were provided in case some likely ground target appeared. By 1943 the AAF was using 150 Mustangs for reconnaissance, and several hundred as dive bombers in the Mediterranean.

Merlin engine

In 1942 the British experimented by replacing the Allison with their own more powerful liquid-cooled Rolls-Royce Merlin supercharged engine; the P-51 suddenly became the fastest operational piston-engine plane of the Second World War. While it took a great deal of training to handle this "hot" plane properly, it could outperform anything but a jet. The new P-51B and P-51C models could fly 453 mph at 28,800 feet (versus 250 mph that high with the old Allison engines) and could climb to 20,000 feet in 6 minutes instead of 11. Washington now ordered all-out production. With Packard Corporation making the Merlin engine under license, the P-51B started rolling off North American's assembly lines in Los Angeles and Dallas in June, 1943.

Escort role

Equipped with auxiliary fuel tanks that were jettisoned when empty, the combat radius widened to 850 miles. Mustangs in March, 1944, began escorting B-17 heavy bombers at high altitude to all European targets and back, repelling any Luftwaffe fighters that dared to challenge. Actually shooting down an enemy fighter required rare skills that even the best pilots seldom had. Of the 5,100 fighter pilots who escorted the bombers of the 8th Air Force, only 300 shot down 5 or more planes and became "aces"; however, these 300 aces accounted for half of the 5,300 kills made by escorts.

Some 15,600 P-51s were produced at an average cost of $50,000--versus $80,000 for the bigger Thunderbolt and $150,000 for the B-17. The slower, shorter-range P-47 was already escorting bombers part of the way into Germany; in a reversal of roles, that mission in January 1944 went to the P-51 while the P-47 was assigned to tactical targets on the ground. The Thunderbolt's air-cooled engine was less vulnerable to ground flak; one bullet hole in the plumbing of a water-cooled Merlin engine would drain off the coolant and crash the Mustang. In early 1944 the Mustangs cleared the skies of the Luftwaffe--it was 30-70 mph faster than the Focke-Wolfe FW-190 and Messerschmitt Me-109, could climb at the same rate, dive faster, and turn more sharply. From mid-1944, American pilots began wearing the Berger G-suit, which automatically constricted blood flow to the lower body during high rate maneuvers, enabling the pilots to engage in more extreme maneuvers without blacking out. Mustangs claimed 4,950 kills in the air and 4,100 on the ground (plus some V-1s), while losing 2,520 planes in combat. The Messerschmitt Me-262 jets were faster and more maneuverable than the Mustangs, but they were few in number and their pilots were inexperienced--and never were permitted to acquire much experience. They rarely challenged the Mustangs. Most of the jets were destroyed while they were taking off, landing, or parked on the ground. Luftwaffe boss Herman Goering admitted that when he saw the American bombers over Berlin in March, 1944, escorted by fighters he knew the war was lost.