Messerschmitt Me 163 Komet

Specification (B-1)

Type: single-seat fighter / interceptor;
Powerplant: 1 x 3,750lbs (1,700kg) thrust Walter HWK 509A-2 bi-fuel rocket motor;
Performance: 596mph / 960kph at 32,810ft  / 10,000m (maximum speed), 39,700 ft / 12,100m (service ceiling), 3 minutes 30 seconds (time to ceiling), 7 minutes 30 seconds (maximum powered endurance);
Weight: 4,200lbs / 1,905kg (empty), 9,061lbs / 4,110kg (maximum take-off);
Dimensions: 30ft 7in / 9.32m (wing span), 19ft 2in / 5.84m (length), 9ft 1in / 2.77m (height), 199.14sq.ft / 18.5m.sq (wing area);
Armament: 2 x 20mm MG151 cannon or 2 x 30mm MK108 cannon in the wing roots;
Used: Germany.

History

Quirky though it was, there can be little doubt that if the Me163 Komet had been available to the Luftwaffe in reasonable numbers a year earlier, the Allied bombing campaign would have suffered even greater casualties in men and material than it did in actuality. With an extra year of development time behind it, it is very likely  that the problems the Me163 had, particularly those concerning its unstable fuel mixture, would have been fixed but the entire programme was then at the cutting edge of technology and time was a luxury that Germany didn't have. Research into the use of rocket propulsion in aircraft had been going on in Germany since the 1920s, with Dr Alexander Lippisch developing the DFS194 glider, which would form the basis of the Me163. Lippisch had built his first tailless glider, known a Storch (Stork) in 1926 and flown it the following year. The glider was progressively developed and eventually fitted with an 8hp engine coupled with a pusher propeller, becoming the Storch V, making its first powered flight on 17 September 1929. Lippisch was always keen on the delta-wing configuration and turned his attention to designing a glider in this form, having obtained some private financial backing. The glider, known as the Delta I, began flying in the summer of 1930 and was later fitted with a 30hp engine to fly at speed of up to 90mph (145kph) in early 1931. It has been said that the Horton brothers were inspired to work on tailless aircraft after seeing a flight of Delta I but official reaction was quite the opposite – the aircraft had no tail so no airworthiness certificate was issued. By 1932, Lippisch was working with both Focke-Wulf and collaborating with Fieseler on Delta III and the following year saw him move to DFS at Darmstadt where work continued on both the Delta III and IV. After both aircraft had crashed in the same fortnight, an order came from RLM banning further work on tailless designs. This was eventually removed, due to Dr W Georgii (the then Director of DFS) and work continued on modifying the design to the Delta IVa so it became the Delta IVb and received the RLM designation DFS39. The reconstructed aircraft had a modified wing platform, twin vertical surfaces instead of a wingtip anhedral and a 75hp engine driving a tractor propeller. In this form it received an airworthiness certificate as a two-seat sports aeroplane and in 1937, an RLM order came for a second DFS39 which was to be powered, as it eventually turned out, by a top secret rocket motor.

This was the beginning of Project X where DFS was to build the wing and Ernst Heinkel AG were to build the remainder of the airframe as they had the full spectrum of manufacturing facilities and had already started developing their own rocket aircraft, the He176. Although the RLM had already selected the DFS39 for conversion to rocket power and stipulated a modest 217mph (350kph) top speed, Lippisch started design work on the DFS 40 and DFS194, both intended to have conventional propulsion for research work. Using models and wind tunnel tests at AVA, Göttingen, Lippisch concluded that the DFS39's wingtip rudders would be a source of flutter from the sweptback wing and that future designs would require a central fin and rudder arrangement for improved control. Such an arrangement was needed (as in the case of the Horten designs) to balance the effect of the fuselage nose which protruded beyond the wing contour. The division of the production arrangements as well as the tight security surrounding the project hampered the progress of the project but Lippisch was able to have the work transferred from Heinkel and DFS into a single unit based at Messerschmitt AG, Augsburg where he and his team formed Section L on 20 January 1939 and immediately began work to adapt the more promising DFS194 airframe to take the 882lbs (400kg) thrust Walter rocket motor. This unit had already flown in the experimental He176 but the programme proved unsatisfactory. On the other hand, during tests the DFS194 managed to reach a top speed of 342mph (550kph) leading to the programme gaining momentum and Messerschmitt receiving an order for six prototypes, designated the Me163A.

The first prototype was flown as a glider, towed behind a Bf110, to test its flying characteristics (which were good – a few problems being easily sorted out). In the summer of 1941, two prototypes were taken to Peenemünde for powered trials using the new Walter HWK RII-203b rocket motor that gave out 1,653lbs (750kg) of thrust, propelling the Me163 to 550mph (885kph). As only a small amount of fuel could be carried, there was a risk that the aircraft would run out of fuel before higher speeds could be obtained but on one occasion, test pilot Heini Dittmar was towed to a height of 13,125ft (4,000m) and after casting off, accelerated to a speed of 623.85mph (1,003.9kph) before suffering a loss of stability due to compressability effects. Such a phenomenon became well known in later years as aircraft approached the speed of sound, as it was Dittmar managed to control the situation and a redesign of the wing was undertaken to combat the problem. There was in fact a greater danger posed by the instability of the fuel which consisted of hydrogen peroxide (80%) with oxyquinoline or phosphate (T-Stoff) and an aqueous solution of calcium permanganate (Z-Stoff). An inbalance in this fuel mixture could lead to instability in the combustion chamber and lead to an explosion – which occasionally did happen. A replacement for Z-Stoff using a different catalyst was developed (30% hydrazine hydrate solution in methanol) called C-Stoff, for use in the Walter RII-211, which in its production form equipped the Me163B and was designated the HWK 109-509A. Since the aircraft had to be as light as possible to take advantage of its limited fuel load, the weight penalty involved with a retractable landing gear was unacceptable and so the aircraft took off using a two-wheel dolly (that was jettisoned on take-off) and landed using a retractable skid beneath the forward fuselage plus the rear landing wheel. The method caused problems however as take-offs had to be directly into the wind and if a concrete runway was being used and a crosswind was present, the aircraft would not stay straight below the speed at which the rudder became operational. A subsequent modification partially fixed this.

On the back of the six prototypes, a batch of ten Me163A-0 aircraft was built by Wolf Hirth, the sailplane company, and the aircraft were used as training gliders. Considerable redesign had to take place however, before the production version (Me163B Komet) flew. Six prototypes and seventy production models were ordered, but there was trouble with the rocket motor which held up the programme and fuel consumption was almost double the calculated figure. Production was then subcontracted to a number of component manufacturers and the aircraft were assembled in the Black Forest by Klemm Technik GmbH, although again, there were many problems as the component manufacturers were unused to the close tolerance work that was required. Initial deliveries of the Me163B-1a began in May 1944 and the aircraft made it combat debut on 28 July 1944 when five Me163s from 1/JG400 attacked a formation of B-17s near Merseburg. They failed to bring any bombers down but the difficulties can be appreciated in taking into account that the fighters would be closing on the bombers at around 559mph (900kph) and the bombers themselves would be moving at 250mph (402kph), the combined closing speed allowing only a three second burst from the slow firing MK108 cannon. An alternate weapon therefore had to be found. In fact the SG500 Jagdfaust, which consisted of five vertically mounted firing tubes mounted in each wing root, each containing a 50mm shell. The system fired a salvo when a shadow passed over a light-sensitive cell and so the Me163 just had to fly at high speed underneath a target for the system to be activated. The system was fitted to twelve Me163Bs but was never issued for operations, although it did manage to destroy a B-17 on one occasion.

To help convert a number of the dwindling supply of pilots to the Me163, a tandem trainer was developed, designated Me163S, with various internal components including ammunition and T-Stoff tanks removed to make way for the extra seat. It was flown as a glider but only a few were converted. Production of the Me163B-1a ceased in February 1945 after almost 400 aircraft were built. Projected developments included the Me163C and Me163D, the former being a development of the Me163 with an auxiliary cruising chamber to enhance endurance, a new centre section and a streamlined fuselage with a blister canopy. Three Me163C-1a aircraft were built but only one was flown. The Me163D was a further refinement with a retractable, tricycle landing gear. One prototype was built and since Junkers had been responsible for its development and series production, it was known as the Ju248 before reverting to a Messerschmitt designation. It did not enter production and the prototype was captured by the Soviets who fitted it with straight wings and modified tail surfaces and flew it in 1946 under the designation I-270(ZH). Lastly, there was a license built version of the Me163B, the Mitsubishi Ki-200 (J8M1) which was to be built in Japan with Mitsubishi and Yokosuka building the HWK 509A rocket motor. Loss of the aircraft on a ship bound for Japan left the Japanese with only an instruction manual and it is to their credit that they began design of an airframe based on the Me163B. The first aircraft flew in July 1945 but crashed after its motor failed. Several others were built but the programme was terminated by the end of the war.

Bibliography

Gunston, Bill. The Illustrated Encyclopedia of Combat Aircraft of World War II, Salamander, London, 1978.
Kay, A L & Smith, J R. German Aircraft of the Second World War, Putnam Aeronautical Books, London, 2002.
Mondey, David. The Hamlyn Concise Guide to Axis Aircraft of World War II, Bounty Books, London, 2006.

Photos and additional information courtesy of:
http://tanks45.tripod.com/Jets45/Histories/Me163/Me163.htm
http://www.danielsww2.com/page12.html
http://ronpenndorf.com/rnspl5.html
http://meshula.net/photos/chino/index.html

Books on the First World War | Subject Index: First World War

How to cite this article: Antill, P. (29 August 2007), Messerschmitt Me163 Komet, http://www.historyofwar.org/articles/weapons_me_163.html

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