| Without a doubt, the Messerschmitt Me 163 Komet was the most unconventional fighting plane to see service in World War II. By war's end, it was the fastest manned aircraft in existence, and still stands as the only successful military rocket-plane ever to see service. Despite the ingenuity behind its design, the Me 163 had neither the numbers nor the development time to delay the advance of the Allies on the Fatherland.
Development - In the mid-1930s, engineers across the world had begun to perfect the liquid-fuel rocket. Starting in 1936, the the Reichsluftfahrtministerium (German Air Ministry) issued a series of contracts to the Hellmuth Walter company to develop rockets for military uses. Walter's efforts attracted the attention of Dr. Alexander Lippisch from the Deutsches Forschunginstitut fär Segelflug (DFS, the German Gliding Research Institute), who thought that early Walter rockets could be adapted to a tailless glider design. Lippisch got his wish, and was appointed head of Projekt X (not to be confused with Project X, the Matthew Broderick movie).
The radical design rapidly took shape. It was thought that encasing volatile fuels in a highly-flammable wood fuselage may be a bad idea, requiring an all-metal fuselage. The original straight-wing concept was scrapped for a swept-wing design. Overall, the tailless profile, large rudder and thick fuselage give the plane a striking resemblance to a butt-plug. By late 1938, the team moved to the Messerschmitt facility and the project was rechristened the Me 163.
The first six Me 163A prototypes entered trials in 1941, with the initial powered tests demonstrating speeds upwards of 550 mph (885 km/h) from conventional takeoff and 625 mph (1000 km/h) when first towed aloft. Unlike all aircraft of its day, the Me 163's maximum speed was limited only by its maddeningly-high rates of fuel consumption.
Modifications made to the design to improve fuel efficiency, as well as a new powerplant, led to the development of the Me 163B. The upgraded engine, the HWK 109-509A, used a less-volatile combination of fuels, but was fraught with developmental problems. The Me 163B, complete with its drop-away take-off dolly and retractable landing skid, didn't begin powered trials until mid-1943.
Performance - The production model of the Me 163B, now called the "Komet," didn't begin reaching the Luftwaffe until March 1944, and even then the aircraft was still buggy. Only one Me 163 unit, the I Gruppe of Jagdgeschwader 400, ever was brought to full strength due to shortages of war materiel (caused by Allied bombing campaigns) and skilled pilots.
Those Komets that were deployed against Allied bomber formations met with mixed success. The limited operational range -- the HWK 109-509A engine proved only half as efficient as expected -- often led to aborted missions after flights failed to locate the enemy planes. When combat did occur, it was usually too brief and lopsided; groups of a dozen Me 163s strafing bomber formations of more than 1000 planes for three minute spates will not change the tide of a war. Komet pilots tallied a mere 9 kills for their efforts, losing 14 planes in return (about half of those during landing accidents).
In total, almost 400 Me 163s were built, with 279 of that number seeing service with the Luftwaffe. A limited number of those built were of the Me 163S trainer variant.
Specifications (for Me 163B-1a):
Weight (empty): 4,200 lbs (1,900 kg)
Weight (maxmimum): 9,500 lbs (4,300 kg)
Powerplant: 1 Walter HWK 109-509A-1/2 rocket motor
Maximum speed: 593 mph (955 km/h)
Ceiling: 39,400 ft (12,000 m)
Maximum range: up to 60 miles (100 km)*
Wingspan: 30' 7" (9.32 m)
Length: 19' 2" (5.84 m)
Armament: 2 30mm MK108 cannon with 60 rds per gun -or- 2 20mm MG151/20 cannon with 100 rds per gun. (Some variants were armed with five SG 500 Jadfaust launchers on each wing, which fired a single-shot 50 mm projectile downwards. Others were armed with 24 R4M rockets, mounted under the wings.)
* - Best measured in maximum flighttime (7 min, 30 sec), rather than distance. Range depended heavily on weight at takeoff.
Sources:
Chant, Chris; German Warplanes of World War II (2001); Barnes & Noble Books; 176 pp.
Messerschmitt Me 163 Komet - http://www.kotfsc.com/aircraft/me-163.htm (site only available through Google's cache)
Me 163B Komet - http://www.sml.lr.tudelft.nl/~home/rob/me163.htm | 
