Profile – Me 163 Komet

The Komet stemmed from a series of experimental tail-less (eliminating the conventional horizontal tailplane) aircraft evolved by Dr. Alexander Lippisch whose basic research began in 1921 when he, together with Gottlob Espenlaub, formed the small company of Weltensegler GmbH, and designed the initial tail-less model of the Storch (Stork) series of gliders. The second model followed in 1925 and led to the construction of the Storch I the company’s first manned tail-less glider. This was tested in 1927 by Fritz Stamer and Bubi Nehring and both reported that the glider had good flying characteristics and stability with the exception of manoeuvrability in turns. While working on this series Lippisch also developed the Ente (Duck), another tail less configuration. In May, 1928, the famous automobile manufacturer, Fritz von Opel and his designer, Max Valier, visited Lippisch and asked him to supply an aircraft for testing their ideas on rocket propulsion. After initial tests using models of the Storch, two 44Ib thrust rockets developed by Alexander Sander of Wessermunde were mounted on the rear of the fuselage nacelle of the tail-first configured Ente. Stamer made the first flight which lasted 35 seconds on June 11, 1928. He reported that stability and control were good and a second test flight was made using 55Ib thrust rockets. Stamer flew 4,000 feet (1220m) in 70 seconds, made a 180° turn and landed near his starting point. On a third flight, however, a rocket exploded setting the tail of the aircraft on fire and this accident ended test flying for some time.

Lippisch, in the meantime, joined the German Research Institute of Sailplanes (DFS) where the tail-less DFS 39 Delta IVb a light two-seater powered by a 75hp Pobjoy Niagara engine had proved the practicality of the unorthodox tail-less configuration. In 1937 the Research Department of the Reichsluftfahrtministerium (RLM), or German Air Ministry, ordered the construction of a second DFS 39 to feature a lengthened fuselage suitable for the accommodation of a special power unit. The new machine was immediately veiled in secrecy and given the title of ‘Project X’. Heinkel was given the responsibility of building the fuselage while DFS constructed the wings. Tests in the wind tunnel and of free flight models brought about drastic changes so that after some time ‘Project X’ differed completely from the DFS 39 upon which it had been based. Lippisch designed a small piston-engined aircraft of generally similar configuration to the changed design with the idea that it would furnish advanced data. This plane, the DFS 194, was intended to have a light air-cooled pusher engine installed in the rear fuselage driving an airscrew by means of an extension shaft behind the tail.

Meanwhile, the plan under which Heinkel was to build the ‘Project X’ fuselage proved unsuccessful and a frustrated Lippisch decided to take on the responsibility of building the entire aircraft himself. Because of the lack of facilities at the Research Institute and the infuriating security restrictions he, with a team of twelve co-workers, joined the Messerschmitt concern at Augsburg on January 2, 1939. This move brought the project under the wing of the Aircraft Development Department of the Luftwaffe and at this stage the designation Me 163 was allocated.

Developments at Heinkel continued separately and resulted in the He 176 which proved to be a miserable flop, causing the ALM to lose interest in experimental rocket research as a potential powerplant for aircraft.

Nor did Willi Messerschmitt show much interest, but at least Lippisch was allowed to carry on with his work. He modified the almost complete wooden airframe of the DFS 194 to take a rocket motor instead of the intended piston engine for which it had been originally intended. In early 1940 this machine was transferred to Karlshagen, the test airfield at Peenemunde, where a 661lb (300kg) thrust Walter HWK R. 1 rocket motor was installed. This powerplant was of the so-called ‘cold’ type using T-stoff (80% hydrogen peroxide plus oxyquinoline or phosphate as a stabilizer) and Z-stoff (a watery solution of calcium permanganate) as its fuel – an extremely volatile combination.

On June 3, 1940, with Heini Dittmar at the controls, the DFS 194 made its maiden flight. Dittmar reported superb handling characteristics and later this machine, which had been designed for 186 mph (300 km/h), actually achieved 341. 8 mph (550 km/h) in level flight and it also proved capable of impressive steep climbs. These successes renewed official interest in the Me 163 and the ALM-ordered work continued on the Me 163 V-1, V-2 and V-3 development prototypes. The first prototype was completed during the winter of 1940-41. This machine, coded KE+ SW, was given glider trials in March 1941 at Lechfeld using a Messerschmitt Bf 110 tow plane. After initial tail flutter and aileron flutter problems were corrected, Dittmar was again lavish with his praise of its handling characteristics. The newer Walter HWK Rll-2038 motor of 1,653Ibs (750kg) thrust was installed for powered trials which took place at Peenemunde. The first rocketpropelled flight took place on August 13.

During the second flight, Dittmar easily exceeded the existing World Air Speed Record of 469. 22 mph and it was soon regularly attaining speeds of more than 500 mph (885 km/hr). On October 2, 1941, after casting off from a Me 110,at 13,000ft, starting the motor and accelerating, Dittmar established a new record of 623. 85 mph (1000 km/hr or Mach. 84) but in the same instant, he suddenly lost control as the nose dropped violently because of the onset of compressibility. Negative ‘g’ interrupted fuel flow to the motor which cut out but fortunately, as airspeed decreased Dittmar was able to regain control and land safely. Initially, officials refused to believe the performance figures but these were checked and verified. Dittmar was later given a Lilienthal Diploma for Aeronautical Research as also were Lippisch and a second test pilot, Rudolf Opitz.

Soon after the record flight, orders were received for the construction of more prototype Me 163As (totalling six altogether) for developing the fully operational version Me 1638, dubbed later the ‘Komet. The installation of special low-drag fixed slots, known as C-slots, stretching over the outer 40 per cent of the wing directly in front of the elevons on the Me 163 resulted in the remarkable characteristic that the aircraft could not spin. This machine’s more powerful rocket motor, the Walter HWK 109-509, which had throttle control offering an idling and three thrust stages, was of the ‘hot’ type, the Z-stoff being replaced by C-stoff, a 30% hydrazine hydrate solution in methyl alcohol. Nevertheless, the fuels remained a volatile combination and could easily cause an explosion.

On one occasion, test pilot Rudolf Opitz, who came into the test programme after Dittmar had suffered a spinal injury during a landing accident, was almost blinded by T-stoff fumes. While taking off, his Komet separated from its take-off dolly before flying speed had been reached and the aircraft shot forward on its landing skid but luckily Opitz managed to reef it off the ground before overshooting the airfield perimeter. As he started to climb, the cockpit filled with T-stoff steam which smarted and stung his eyes. Fortunately the prototype had only enough fuel for a two minute flight and once this was exhausted Opitz was able to land safely in spite of the fact that his eyes were burning painfully and streaming tears which impaired his vision.

The spinal injury suffered by Dittmar, which gave him a two year stay in hospital, had resulted from a fault which needed to be rectified. While landing he had stalled 12 feet (3. 6m) above the ground and bounced down heavily. Twelve months later, Opitz made a hard and bumpy landing when his skid mechanism seized up and he suffered similar, though less serious, injuries. Investigations revealed that both pilots had been subjected to an impact force of some twenty times that of gravity. It was technically impossible to construct a landing skid capable of absorbing such high stresses so a torsion-sprung seat which would create a cushioning effect was made for the pilot. This feature was subsequently adopted as standard on production Me 163s. While Opitz was in hospital, flight testing was carried on by Wolfgang Spate.

Work was now progressing on the six Me 163A prototypes plus ten Me 163A-0 pre-production aircraft and seventy pre-production versions of the Me 1638 interceptor. In its production form the aircraft was designated Me 1638-1a. It had a fuselage of light alloy covered mostly with panels which could be removed for access to the close-packed interior. The nose was packed with radio and other equipment including a generator driven by the small windmill propeller in front. Access to this was created by holding back the instrument panel in the cockpit. The cockpit itself was comfortable although the only pressurisation system available for it was a plain ram inlet in the front. Its canopy was a plexiglass moulding hinged on the right side and within it was a small hinged ventilation window on the opposite side. While it afforded good visibility, the ability of the hood to withstand severe weather such as hail or a collision with birds in flight was questionable. Nose and back armour was incorporated and the aircraft’s standard armament consisted of two 30mm Rheinmetall Mk 108 cannon in the wing roots each with 60 rounds, these replacing the original pair of 20mm MG 151/20 cannons which were considered to be too light to be effective against the US heavy bombers.

The 229 gal (1040-1) T-stoff tank filled the space between the rear cockpit bulkhead and the motor bay and two smaller self-sealing T-stoff tanks of 13 gal (601) capacity lined each side of the cockpit. C-stoff was also stored in two 38 gal (1731) tanks between the wing spars and two more 16 gal (731) tanks in the leading edges of the wings. The rocket motor comprised of a single chamber fed by two long pipes from the turbo-pump group and it, and the entire rear fuselage, was designed so that they could be easily detached for maintenance.

The structure of the wings was simple, consisting of two widely spaced cross-grained plywood spars covered by a skin of plywood and fabric. Although in appearance they looked swept-back, it was mostly their taper that gave the 23. 3° quarter- chord sweep angle. Besides the rudder, the only control surfaces were large manual fabric-covered elevons for pitch and roll out-board on the trailing edge. Closer to the fuselage were large hin- ged flaps operated hydraulically by screw-jacks at the same time as the main landing flaps in front on the underside of the wings and these compensated for the strong nose-up trim by creating equal nose-down trim. The flap hydraulics were energized by compressed-air bottles which in two separate circuits, served most of the on-board auxiliary power including cocking the guns, lowering the landing skid and tail wheel and operating the emergency dolly release. This wheeled dolly, which was used for take off, was supposed to be automatically released when the landing skid was retracted but numerous accidents occurred because of it hanging up or bouncing and smashing back into the aircraft.

The Komet’s maximum speed at all altitudes was restricted to 559 mph (900 km/hr) because of critical mach limitations and resulting compressibility effects-in other words, it would run into what was popularly called the ‘sound barrier’. The acceleration rate it boasted was phenomenal and its service ceiling was set at 39,400 feet (12,000 metres) because of the lack of a pressurised cockpit-it could climb to that height in 34 minutes from a standing start but its major limiting factor for operational use was its short range because of the quick burn-up of fuel.

Into Service

The transition from prototype and pre-production model to operational interceptor was not smooth. In November 1941, less than a month after he had approved the rocket fighter project, Generaloberst Ernst Udet, who was in charge of Luftwaffe equipment, committed suicide. Generalfeldmarschall Erhard Milch, who took over the position, gave the project a low priority because he saw that it was being too innovative to be useful to the Reich in the near future. Development of the rocket motor suffered from teething troubles to the extent that explosions twice destroyed the building in which it was being tested. Ground personnel and pilots were obliged to wear special non-organic asbestos and suits for protection. Nevertheless, in early 1943 a special Komet test squadron, Erpro 16 (Test Commando 16), was formed at Karlshagen under the command of Hauptmann Wolfgang Spate.

The Allies first became aware of the type’s existence on July 26th, 1943, when an RAF photographic reconnaissance Mosquito came home with evidence of a small aircraft with an unusual tail configuration being tested at the German research centre at Peenemunde. The British were already conscious of the experimental V weapons and this new find caused further alarm. At the time they labelled it the ‘Peenemunde 20’. A month later RAF Bomber Command sent over 597 bombers to destroy the facilities. This raid, and an American Eight Air Force attack on the Messerschmitt plant at Ragensburg, which destroyed many of the pre-production models, delayed Komet production several months. Consequently. EK 16 was transferred to Bad Zwischenahn where test flying and training was carried on for the next 12 months.

The first inkling that Me 163’s were in use came to the Allies on May 31st, 1944. A reconnaissance Spitfire was flying at 37,000 feet (11,278 metres) over Wilhelmshaven when the pilot noticed a contrail 7,000 feet (2,134 metres) lower down which was turning on an interception course. The trail disappeared and reappeared intermittently as the interceptor climbed. The Spitfire also began to climb and in several minutes was at 41,000 feet (12,496 metres) but at the same time the enemy plane, which the Spitfire pilot could now make out as being ‘nearly all wing’ had easily closed to 3,000 feet (914 metres) below and 1,000 yards (914 metres) behind. At this stage, he lost sight of it and there were no more contrails. The Spitfire returned home safely – its German opponent had apparently been on a training flight.

During the summer of 1944, Jagdgeschwader 400 was formed at Bad Zwischenahn from personnel of EK 16. Its first operational Staffel 1/JG 400 was created at Wittmundhaven. In order to utilize the aircraft’s incredible speed and minimize the problem of its pitifully short range, Spate suggested that it should be deployed on a string of airfields along the western bord of the Reich so that it could take off to engage the USAAF boms and would not have difficulty finding landing areas. However, his idea was not adopted because a new General of Jet Aircraft, Oberst Gordon Gollob, favoured the concentration of all Me 163s in one area. He ordered that they be stationed at Brandis airfield which was 30 miles (50 km) to the west of the strategic Leuna synthetic fuel refineries near Leipzig.

The choice was not a good one because the refineries were at the very edge of the Komet’s range so the USAAF could easily navigate around Brandis and approach them from a different direction, Furthermore, the airfield itself was not really suitable because of its lack of proper storage facilities for the unstable fuels and these had to kept in the same railway cars which had delivered them. The runway was too short, the air-control system was too poor and repair facilities were inadequate.

Combat

In its role of fast-climbing interceptor against the marauding day bombers, the Komet’s main opponents were the formidable Boeing B-17 Flying Fortresses and their escorting North American [‘-51D Mustangs of the US Eighth Air Force. It had a margin of river 120 mph (193 km/hr) over the P-51 Mustang, the best escort fighter in the Allied arsenal and, using this speed advantage it could outstrip the escorts, swoop down on the bombers, attack and be gone before the American gunners could return fire. At least that was the theory.

Wolfgang Spate, newly promoted to Major, flew the first Me 163 combat sortie on May 13, 1944, but was unable to attack a number of P-47 Thunderbolts which he intercepted. The first encounters with the US bombers came on July 28th, 1944, with indecisive results for both sides. Teething troubles with engine flame-outs and misjudgment of closing speeds during attacks caused all seven Komet pilots who took off to miss their chances. For the Americans, the speed of the German planes was a shock. Closing speed while attacking the bombers continued to cause problems because of the difficulty of aiming and firing before over-shooting the target.

The Me 163’s cannons only had an effective range of (600m) and during a rear attack at an approach speed in the vicinity of 340 mph (550 km/hr) the pilot had about 3 seconds to aim, fire and break away at about 220 yards (200m) in order to avoid a collision. This meant that there was only time to discharge 40-45 rounds, while during a frontal attack, in the one second firing time as the aircraft closed at their combined speeds, only about 15 shells could be fired, hardly enough to bring down a Fortress. Consequently, the German pilots had to slow down in order to score an effective number of hits and whenever the Me 163’s did slow down, it gave the escorting P-51’s a chance. Records indicate that by the end of the war, P-51 pilots of the US 8th and 15th Air Forces had shot down five Me 163’s in air-to-air combat, and the gunners on the bombers claimed several others. On the other side of the coin, Komet pilots accounted for a total of 16 Allied planes and damaged many others.

While the Allies considered the Me 163 to be a highly dangerous opponent, its reputation among the German airmen was exactly the same – it was dangerous! The chemical fuels the machine used for propulsion remained a highly volatile and unstable cocktail and too often exploded into flames while landing. Incinerating the pilot. Many more Me 163’s were lost in takeoff and landing accidents than through enemy action.

To try and solve the problem of bringing effective firepower to bear on the enemy, various ideas were explored. Probably the most ingenious of these being the Jaegerfaust (fighter-fist) automatic firing system. Ten upward-firing 50mm gun barrels were built into the aircraft’s wing roots, five on each side and a photo-electric cell was installed to trigger them when the shadow of the target aircraft was overhead. To balance out the heavy recoil an equivalent counterweight was fired downwards for each 50mm high explosive shell fired upwards. The device was tested using as its target a cloth the size of a B-17’s wing stretched between two tethered barrage balloons and out of three attempts three direct hits were scored. Using a wide variety of approaches and speeds, the system retained its accuracy and it seemed now that even a relatively inexperienced pilot could be guaranteed a hit and probable kill. On April 10, 1945, Lieutenant Fritz Kelb of EK 16 used it on a formation of B-17s and quickly brought one down, the big bomber disintegrating as it fell. Thus the potency of the new weapon was clearly demonstrated but it was too late, less than a dozen Me 163s were converted before the war was over.

Because RAF bombers operated primarily at night, encounters with German jet and rocket fighters were rare. One such meeting took place though late on the same day that Kelb had used the Jagdfaust for the first and, fortunately for the Allies, last time. Bomber Command had sent a force of 290 Lancaster and Halifax bombers on a daylight mission to Leipzig and the bombers were escorted by several squadrons of Mustang Ills, the British designation for the P-51 B/C series used by the RAF. One unit was 165 Squadron containing “Slops’ Haslope who, at 6. 05 pm found himself well positioned to attack a Me 163 which had appeared just below.

Both planes hurtled groundwards from 28,000 feet (8,514 metres). The Mustang was superb in a dive and consequently, the Australian ignored his airspeed indicator as he concentrated on squeezing the Komet into his sights. There would only be one chance as he closed before the Me 163’s superior speed would take it away. When he was certain it was in range he fired a short burst and the German rocket fighter pulled up sharply. It could pull out of a vertical dive faster than a Mustang. Nevertheless, Haslope hauled violently on the controls and attempted to follow. The resulting ‘G’ force was too much he blacked out. As his vision changed from black to grey he could hardly make out his own instruments. Was the altimeter registering 8,000 or 28,000? There was excruciating pain in his ears and he swallowed hard to ease it. He felt odd and his plane’s controls felt strange-something wrong. . . his eyes cleared. The reading was 8,000 feet and there was no one else in sight – no bombers, no fighters and no Me 163!

Haslope’s Mustang was still not flying normally as he gingerly nursed it home. After a long, tense flight he landed it very carefully back at Bentwaters, Suffolk, half an hour after the rest of 165 Squadron had returned. He was promptly mobbed by the other pilots who had lost sight of him and believed that he may have ‘gone in’. An examination of his plane soon revealed why it had felt strange. It had been badly “bent’. The wings were wrinkled and their dihedral angle had been changed by several degrees. The wing tips were now much higher off the ground. But the good news was that the Komet was his! After Haslope had lost contact the German machine had gone into a series of out-of-control looping manoeuvres to finally dive into the ground and explode. The entire incident had been witnessed by the other pilots. John Haslope completed two operational tours altogether and was awarded the DFC for this and his victory over the Me 163. His was the only rocket fighter to be shot down by a member of the RAF or RAAF.

Improved Versions

Prior to the war’s end there were several projects under way to improve and develop the Komet’s design. The Me 163s was a dual trainer with the instructor’s cockpit above the centre fuselage. Several were built but none were actually flown under rocket power. The Me 163C was an improved version with an HWK 509C-1 rocket motor, with main and cruise thrust chambers. Only two prototypes and three production aircraft were constructed. The Ju 248/Me 263VI featured numerous improvements including a motor with both main and cruise thrust chambers and a tricycle undercarriage which eliminated one of the most serious causes of accidents-the impact from a bouncing dolly. The type was flight-tested as a glider but the war ended before powered flight trials could be undertaken.

On the other side of the world the Japanese showed an interest in the Komet particularly after B-29 Superfortresses began raiding the home islands. Mitsubishi Jukogyo KK was instructed to build the fighter and the Yokosuka Naval Aeronautical Engineering Arsenal was given the task of constructing the engine. A complete Me 1638 plus an example of the Walter HWK 109 509A engine and detailed blueprints were shipped to Japan in mid-1944 but the submarine carrying this precious cargo was sunk en route. A second submarine managed to get through but this only brought a rocket engine and an Me 163 instruction manual, no detailed plans or blueprints. The Japanese decided to go ahead and build a copy of the Komet from the scant material on hand and this was given the designation of JBM1 Shusui (Rigorous Sword) for the Navy and Ki 200 for the Army. In the long run only one Shusui was flown and this crashed on July 7, 1945.

About 360 Messerschmitt Me 163s had been built by VE day and with the hostilities ended, 48 Komets fell into Allied hands while numerous others, including an example of the two-seat trainer, were seized by the Russians. In terms of aircraft development, the Me 163, because of its lethal and unforgiving, although spectacular, flight characteristics, represented a dead end and neither the Allies nor the Soviets proceeded any further in developing an exclusively rocket-propelled fighter.