Messerschmitt Me 163B-1 2nd Staffel Jagdgeschwader 400 Luftwaffe - Germany 1945
 

There can be little doubt that if the Messerschmitt Me 163 rocket-powered fighter had been available to the Luftwaffe a year earlier, The Allied daylight bombing programme would have proven even costlier than it was. With an extra year of development behind it, the Me 163's problems, particularly those concerned with handling its unstable mixture of rocket fuels, might well have been solved, but the whole programme was at the edge of a new technology range, and time was not on Germany's side.

Research had been proceeding in Germany into the possibility of rocket-powered aircraft since the 1920's and Dr Alexander Lippisch, who had been working on tail-less sailplane designs, produced the DFS 194 glider in a basic layout which was to be developed into the Me 163. Lippisch and his team joined Messerschmitt in January 1939 and began to work on adapting the DFS 194 airframe to take an 882 lbs (400 kg) thrust Walter rocket motor. This motor had already flown in the experimental rocket-powered He 176, but that programme had been unsatisfactory. The DFS 194, on the other hand, reached a speed of 342 mph (550 km/h) and this lead to increased momentum in the programme, Messerschmitt receiving and order for six prototypes designated Me 163A.

The first prototype was originally tested as a glider, towed behind a Messerschmitt Bf 110, and its flying qualities were good, the few problems being easily ironed out. In the summer of 1941 two of the prototypes were taken to Peenemunde for powered trials with the new Walter HWK R11-203b rocket motor, which gave 1,653 lbs (750 kg) thrust, and the Me 163 was soon attaining speeds of up to 550 mph (885 km/h). Since only a small amount of rocket fuel could be carried there was a danger of running out before higher speeds could be attained but on one occasion, after being towed to a height of 13,125 ft (4000 m), test pilot Heini Dittmar cast off, fired the engine and reached the remarkable speed of 623.85 mph (1003.9 km/h) before suffering a loss of stability as a result of compressibility effects. This phenomenon was to become well known later as aircraft approached the speed of sound. Dittmar corrected the situation but a redesign of the wing was undertaken to combat this fault.

There was, in fact, more danger at this stage of the programme in the instability of the fuel, which was a mixture of 80 per cent hydrogen peroxide with oxyquinoline or phosphate (T-Stoff) and an aqueous solution of calcium permanganate (Z-Stoff). An imbalance of these fuels in the combustion chamber could cause an explosion and occasionally did; a replacement for Z-Stoff, using a different catalyst (30 per cent hydrazine hydrate solution in methanol) , was called C-Stoff and was developed for use in the Walter RII-211 which, in its production form for the later Me 163B was the HWK-109-509A.

Since the Me 163 had to be as light as possible, in order to get the maximum performance from its very limited fuel load, the weight penalty of retractable landing gear was not acceptable. Thus, the take-off was make using a jettisonable two-wheel dolly, the aircraft landing on a retractable skid beneath the forward fuselage plus a tailwheel. The method caused problems, since take-offs had to be made directly into the wind; if a concrete runway was to be used and there was a crosswind it was impossible to get airborne as the aircraft would not keep straight below the speed at which the rudder became operative. A subsequent modification to couple the rudder control to rocket ignition partially cured this.

Following the six Me 163A prototypes, a pre-production series of 10 Me 163A-0 aircraft was built by Wolf Hirth, the sailplane company, and these were used as training gliders, However, considerable redesign took place before the operational Me 163B Komet flew. Six prototypes and 70 production models were ordered, but troubles with the new rocket motor held up the programme, and fuel consumption was almost double the calculated figure. Production was subcontracted to a number of component manufacturers and the parts were assembled in a Black Forest factory under the supervision of Klemm Technik GmbH, although this company had many problems since sub-contractors were not accustomed to close-tolerance work.

First production deliveries of the Me 163B-1a interceptors began in May 1944, and the type saw action for the first time on 28 July, when five Me 163's from 1./JG 400, the first operational unit, ineffectively attacked a formation of Boeing B-17's near Merseburg. Their difficulties can be appreciated when it was realized that approaching the target at around 559 mph (900 km/h) when the bombers were travelling at 250 mph (402 km/h), the closing speed allowed the attacker only a three second burst from a slow firing cannon before he had to break away. Because of the poor performance with the MK 108 cannon an alternative weapon had to be found.

One answer was certainly unusual; the SG 500 Jagdfaust consisted of five vertically mounted firing tubes in each wing root, each containing a 50 mm shell. The system fired in a salvo and was activated the shadow of the target passing over a light cell (unfortunate if it happened to be your wingman) and the Me 163 merely had to fly at high speed beneath the bomber formation, when the armament was activated automatically. The Jagdfaust system was fitted to 12 Me 163's but, although these were not issued for operations, this unlikely weapon did manage to destroy one B-17 on occassion.

In 1944, to help convert the dwindling supply of pilots to the Me 163, a tandem trainer variant designated the Me 163S was developed, an adaptation of the Me 163B with ammunition, T-Stoff tanks and other items removed to make way for the extra seat. The Me 163S was flown only as a glider and few where converted.

Production of the Me 163B-1a ended in February 1945 after almost 400 of all variants had been built. Projected developments included the Me 163C and Me 163D; the former was a modification of the Me 163B with an auxiliary cruising chamber to improve endurance, a new centre section and a more streamlined fuselage with a blister canopy. Three Me 163C-1a aircraft were built, but only one was flown. The Me 163D was further refined and had retractable tricycle landing gear. One prototype was built and, since Junkers had been tasked with development and series production of this model, it was for a while known as the Ju 248 before reverting it to a Messerschmitt designation as the Me 263. It did not enter production, the prototype being captured by the Russians who fitted it with new straight wings and modified tail surfaces, flying it in 1946 as the I-270(ZH), but it was soon abandoned.

Mention should be made of a licence-built version of the Me 163B, the Mitsubishi Ki-200 (J8M1), which was to be built in Japan with Mitsubishi and Yokosuta building the HWK 509A motor. Loss of the pattern aircraft on a ship en route to 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 Me 163B. The first aircraft flew in July 1945 but was destroyed when the motor failed. Several others were built but the programme was terminated by the end of the war.

Powerplant

The Me 163B was powered by a single Hellmuth Walter Werke R 11-211 rocket motor, with fuel for six minutes at full throttle. Derived from Von Braun's 2.89 kN (650 lb st) A 1 rocket engine of 1935, the engine was closely based on Walter's TP-1 and TP-2 'Cold' rockets using hydrogen peroxide (T-stoff) with an aqueous solution of sodium or calcium permanganate (Z-stoff) as a catalyst. Essentially the engine consisted of a steam generator into which the two fuels were sprayed using compressed air. This drove a turbine, which powered the pump that delivered T-stoff to the combustion chamber. The TP-2 was redesignated as the HWK (Hellmuth Walter Kiel) R I-203, and was developed progressively into the R II-203 which powered early Me 163 prototypes. Substitution of a solution of 30 per cent hydrazine hydrate, 57 percent methyl alcohol, 13 per cent water and 17 percent cupracyanide (C-stoff) for the Z-stoff resulted in a hot rocket engine with more thrust and greater reliability, which did not generate a white vapour trail. This was the R II-211, redesignated HWK 509A in production form.

Take-off Procedure

The Me 163 was usually started with the help of an external APU (Auxiliary Power Unit). The pilot placed the five-position throttle in the idle position, exposing the start button, which was then depressed. This activated the T-stoff steam turbine, which pumped t-stoff to the rocket motor. The starter button was released four to five seconds after the turbine started (at 40-50 per cent rpm). The throttle was then moved to the 1st Stage position, and then to the 2nd Stage position, instruments being carefully scrutinised at each stage. The 3rd Stage position caused the Komet to jump its tiny chocks and begin its take-off run. The dolly was jettisoned at a height of between 6 and 9m (20 and 30 ft), and a steep climb was initiated when the speed reached 643 km/h (400 mph). The climb to 12192 m (40,000 ft) was undertaken at an airspeed of 800 km/h (498 mph), and took just under four minutes. At 12192 m, full throttle allowed acceleration from 402 to 965 km/h (250 to 600 mph) within seconds. Tactics were to climb to altitude, then make unpowered diving attacks slashing down through the enemy bomber formations, relighting the rocket engine to climb and position for another attack or to evade enemy fighters. Two minutes had to elapse between shutting down and relighting the engine.

Variants

Me 163A

The remarkable Messerschmitt Me 163 Komet (Comet) rocket powered fighter was developed from the designs of Dr Alexander Lippisch who for many years had been working on tail-less sailplane designs. In January 1939 he and his design team joined the Messerschmitt company and began to work to adapt the DFS 194 tail-less research glider to be powered by a 882 lbs (400 kg) thrust Walter rocket motor. Successful testing of this aircraft, during which a speed of 342 mph (550 km/h) was attained, resulted in Messerschmitt receiving an order for six Me 163A prototypes.

The first prototype was initially tested as a glider, towed by a Messerschmitt Bf-110. Prototypes were tested at Peenemunde in the summer of 1941 powered by the Walter HWK R11-203b rocket motor of 1,653 lbs (750 kg) thrust, and demonstrated speeds of up to 550 mph (885 km/h). Flown by Heini Dittmar, and Me 163A towed to a height of 13,125 ft (4000 m) before the engine was fired, attained 623.85 mph (1003.9 km/h) before losing stability as a result of compressibility effects. Dittmar succeeded in regaining control, and the wing was re-designed to alleviate this problem. There were many development problems, those pose by the highly unstable liquid fuel for the rocket motor and by the jettisonable wheeled dolly/retractable skid landing gear being the most difficult to resolve. Me 163A-0

Following the Me 163A prototypes, a preproduction series of 10 Me 163A-0 aircraft was built by Wolf Hirth and used as training gliders.

Me 163B Komet/Ba-1/B-1a

Considerable redesign preceded the order for six prototypes and 70 production Me 163B Komet point interceptors, the preproduction prototypes having the designation Me 163B-a1, and the first production deliveries of the Me 163B-1a interceptors began in May 1944. The type saw action for the first time on 28 July 1944 when 5 Me 163s from 1./JG 400, the first operational unit, attacked a formation of B-17s. This proved ineffective, for the closing speed of about 808 mph (1300 km/h) meant that the slow firing 30 mm Mk 108 cannons could be fired for only three seconds before the pilot had to break off his attack. At this stage of the war the provision of an effective weapon was to prove an insoluble problem, and production of the Me 163B-1a ended in February 1945 after nearly 400 of all variants had been built.

Me 163S

A few examples were built of the tandem two seat trainer which, with ammunition and fuel tanks removed to provide space for a second seat, had to be flown as a glider.

Me 163C-1a

Three aircraft were built but only one was flown. This was an improved version of the Me 163B, with a revised airframe and a modified powerplant to increase powered endurance.

Me 163D

Projected developments included the Me 163D with further refinements and retractable tricycle landing gear. One prototype was built, and because Junkers would have developed and produced this version it gained the temporary designation Junkers Ju 248 before reverting to a Messerschmitt designation as the Me 263. It did not enter production and the only prototype was captured by the Soviets.

Mitsubishi Ki-200 (J8M1)

This was a licence built Japanese version with Yokasuka building the HWK 509A motor and Mitsubishi building the airframe. The single example that Germany sent to Japan by ship, was lost in transit, but the Japanese did manage to build a few examples with only the instruction manual to aid them. One flew but crashed and the war ended before anymore progress could be made.

MiG I-270(ZH)

The Soviets captured the sole example of the Me 163D and based on this, designed their version with modified wing and tail surfaces. It flew in 1946 but was soon abandoned. 

Specifications (Messerschmitt Me 163B-1 Komet "Comet")

Type: Single Seat Interceptor

Design: Dr Alexander Lippisch

Manufacturer: Messerschmitt AG

Powerplant: One 3,748 hp (1700 kW / 16.67 kN) thrust Walter HWK 109-509A-2 bi-liquid propellant rocket motor burning concentrated hydrogen peroxide (T-stoff) and hydrazine/methanol (C-stoff).

Performance: Maximum speed 596 mph (960 km/h) at 32,810 ft (10000 m); absolute ceiling 54,000 ft (16500 m) with an operational (service) ceiling of 39,700 ft (12100 m) taking 3 minutes 30 seconds to reach. Initial climb rate of 15,951 ft (4862 m) per minute.

Fuel Capacity: 336.6 Imperial Gallons or 404.2 US Gallons (1530 litres).

Range: Range varied greatly from 22 miles (35 km) to an extreme of 62 miles (100 km) but all limited to a maximum powered endurance 7 minutes 30 seconds.

Fuel Type: The Z-stoff (calcium permanganate) originally used as a catalyst in the Me 163A was prone to clogging the feed pipes, but the T-stoff fuel (80 per cent hydrogen peroxide with oxyquinoline or phosphate) had even worse characteristics. Highly unstable, and prone to spontaneous combustion when exposed to organic material (such as human flesh), T-stoff was also highly corrosive. The Me 163 pilot was surrounded by T-stoff tanks in flight, and had to wear a non-organic flying suit made of asbestos-Mipolamfibre. The C-stoff catalyst (30 per cent hydrazine hydrate solution in methanol) used in the Me 163 (replacing Z-stoff) was also highly reactive, and had be stored in glass or enamelled containers.

Weight: Empty 4,206 lbs (1908 kg) with a maximum take-off weight of 9,502 lbs (4310 kg).

Dimensions: Span 30 ft 7 in (9.32 m); length 19 ft 2 in (5.84 m); height 9 ft 1 in (2.77 m) on take off dolly; wing area 199.14 sq ft (18.50 sq m).

Armament: Two 20 mm MG 151 cannon with 100 rounds per gun or usually two 30 mm MK 108 cannon with 60 rounds each mounted in the wing roots. Twelve Me-163Bs were fitted with the SG 500 Jadfaust consisting of five vertically mounted firing tubes in each wing root, each containing a 50 mm shell and was fired by a light sensitive cell.

Variants: Me 163A (six prototypes, Me 163A-0 (training gliders), Me 163B, Me 163Ba-1/B-1a, Me 163C/3C-1a (three built, but only one flown), Me 163D/263/Junkers 248 (single aircraft only), Me 163S (tandem training gliders), Mitsubishi Ki-200 (J8M1) was to be a licenced built Japanese version with Yokasuka building the HWK 509A motor, MiG 1-270(ZH) Soviet designation for their version of the captured Me 163D.

Equipment/Avionics: Standard communication and navigation equipment plus a Revi 16/B reflector gun sight.

History: First flight (Me 163V-1) spring 1941 as a glider, August 1941 under power; (Me 163B) August 1943; first operational unit (1/JG 400) May 1944.

Operators: Germany (Luftwaffe), Japan (under license)