Friday, April 10, 2015


Jet and Rocket Aircraft

Aircraft propelled by gas turbines or rocket engines. Compared to the piston engine, the gas turbine (or jet engine) promised to offer unrivaled power-to-weight ratios, provided that the metallurgical, mechanical, and aerodynamic design problems could be solved. While still a Royal Air Force (RAF) cadet in 1928, Frank Whittle argued that the gas turbine was a practical power unit. He continued to work on the idea and formed his own company, Power Jets, in 1935. In Germany, Hans- Joachim Pabst von Ohain developed a jet engine that first ran in 1937, flying it in a Heinkel 178 test aircraft in August 1939. Whittle's prototype engine flew in the Gloster E28/39 in May 1941. The Germans also experimented with rocket fighters, with the Messerschmitt Me-163 entering service in June 1944 against U. S. bombers. The Me-163 had an incredible climb but used a highly corrosive fuel that was inclined toward instability, and many pilots were lost in landing accidents. Less than 50 Me-163s were operational at any one time; they had limited success, but their effect was mainly psychological.

The first operational jet fighter was the British Gloster Meteor, which entered service in July 1944. The Meteor I was distinctly underpowered and had serious limitations as a fighter, being difficult to control at speeds over Mach 0.67. It was armed with four 20 mm cannons. All World War II jet and rocket aircraft had compressibility problems at high speeds and were generally slow to accelerate at low speeds, but they were much better than propeller-driven rivals at high speed, easily outclassing them in acceleration and zoom climb.

The German Messerschmitt Me-262 first flew on jet power in July 1942 and also entered operational service in July 1944, but it was a much better fighter than the Meteor. In common with most jets, it was vulnerable during the landing and takeoff phases. It was armed with four 30 mm cannons. A total of 1,200 were built, but only about 200 entered squadron service. The Heinkel He-162 jet fighter utilized nonstrategic materials and required an experienced pilot during the takeoff and landing phases. Armed with two 20 mm cannons, the He-162 was prone to catastrophic structural failure if carelessly handled. A handful of He-162s became operational in April 1945.

The German Arado 234 "Blitz" was the world's first jet bomber. A prototype flew for the first time in June 1943, but delays in securing its engines meant that it did not enter service- and then, in only very limited numbers as a reconnaissance variant-until August 1944. The first bomber version was operational in December 1944. A total of 210 were built.

The Japanese also built such aircraft. Their Yokosuka Ohka MXY 7 Oka ("Cherry Blossom"), built at the Yokosuka Naval Arsenal, was essentially a rocket-propelled, manguided missile, carried to the target area under a specially converted Mitsubishi G4M Betty bomber. Once the pilot was in position, the canopy was sealed shut. Employed in combat from March 1945, most of these planes were shot down by Allied navy fighters, although one did sink the U. S. destroyer Monnert L. Abele in April.

The Bell P-59 Airacomet was the only jet aircraft of the U. S. Army Air Forces (USAAF) to see combat in the war. The twin-engine, straight-wing P-59 flew for the first time in October 1942. It had a top speed of only 400 mph and offered few advantages over the piston-powered U. S. aircraft then in service. Fifty production models were initially deployed with the 412th Fighter Group in 1945. Although the P-59 proved a valuable testing platform, the first mass-produced U. S. jet fighter was the Lockheed P-80 Shooting Star. Utilizing the British H-1 turbojet engine, it first flew in January 1944 and exceeded 500 mph on its first flight. The U. S. Army ordered 5,000 P-80s, but with the end of the war, production was scaled back to 917 aircraft. Ultimately, 1,714 were built.

References Brown, Eric M. Wings of the Luftwaffe. Shrewsbury, UK: Airlife, 1993. Ethell, Jeffrey, and Alfred Price. World War II Fighting Jets. Shrewsbury, UK: Airlife, 1994. Jarrett, Philip, ed. Aircraft of the Second World War. London: G. P. Putnam, 1997.

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