The quest for more powerful propulsion systems is as old as the history of aviation. While development of the first turbojet engines began in the late 1920s, other designers were drawn by the potential of preexisting rocket technology. Unlike air-breathing turbojets, rocket motors rely operate solely on propellant, and can deliver greater thrust — with the limitation being that they burn through propellant really fast.
Prior to the start of World War II, Hellmuth Walter had started experimenting with the use of hydrogen peroxide as a fuel for various engines. The fuel was particularly useful as a rocket fuel, as it would “ignite” (although it was actually just decomposing) simply by being passed through a metal catalyst. That meant that one could build an engine with nothing more than a pump and a tube with a wire mesh in it. Hydrogen peroxide was also suited to being the oxidizer for a more conventional rocket engine, instead of just being solely a propellant.
Combustion instabilities in the chamber made it difficult to scale the engine to power outputs useful for an aircraft. Although a number of missiles and RATO systems would eventually be built using this design, any aircraft based on it would have to be very light weight. At the same time the fuel consumption was such that the plane would also require a large internal volume to be devoted to tankage.
Dr. Alexander Lippisch had been working for a number of years on tail-less glider designs, which he later suggested be used with the Walter engines. Although Lippisch had not invented the design with rocket power in mind, he argued that a tail-less aircraft could be built with much larger internal volume and still have the same drag as a smaller conventional design. Combining the Walter rocket with a larger Lippisch glider seemed to offer the potential to create a powerful short range rocket interceptor.
The German Messerschmitt Me 163 “Komet” was perhaps the most unique frontline, operational-level fighter design of World War II. German engineers, seemingly always on the cutting edge of evolving war technology, developed the rocket-powered aircraft based on early testing completed with an engine-less glider. The resulting research produced the single-seat, swept-wing fighter that was equally dangerous to both enemy bomber crews and the Me 163 pilot alike. The Me 163 first flew on September 1st, 1941 and was formally introduced in the Luftwaffe inventory in 1944. The idea of fast interceptors also soon gave way to ground-based homing/guided missile technologies.
The Komet remains the only rocket-powered fighter to have entered operational service.
The Me 163 was born from the mind of Dr. Alexander Lippisch who pioneered a great deal of data research of tailless glider designs dating back to the 1920s prior to joining the Messerschmitt concern in 1939. Work began on such a tailless design through the DFS 194 glider outfitted with a Walter rocket motor. The motor relied on a volatile, though potent combination, known as “C-Stoff” and “T-Stoff”. The new Messerschmitt design would utilize the chemical explosion to power the small fighter at break-neck speeds – able to outfly any bomber formation escort fighters with ease. More importantly, the design could be aloft in seconds in response to incoming waves of Allied bombers appearing through both day and night campaigns, wreaking havoc on German industry and supply lines. By 1944, the German initiative that was once held early in the war was all but lost and it began to fight more a defensive war for its very survival.
Testing occurred at the covert Peenemunde facility in June of 1940 to help prove the concept sound. Despite the motor failing to impress due to reliability issues, the airframe itself handled well in the hands of test pilot Heini Dittmar. Serial production of several prototype forms was ordered under the “Me 163” designation in the early part of 1941. At least five “V” based prototypes emerged beginning with V1. Some eight preproduction forms then followed in the Me 163 “A-0” format. Early prototypes managed to reach an impressive 340 miles per hour in recorded test flights.
The Messerschmitt Me 163 Komet, designed by Alexander Lippisch, was a world’s first rocket-powered fighter aircraft.
The diminutive Me 163 was piloted by a single crewman housed under a wide clear canopy. The design was given the then-revolutionary concept of swept-back wings mounted along each fuselage side. The fuselage was a stout, portly design intended to house the cockpit and necessary fuel stores. The empennage was capped by a simple vertical tail fin lacking any horizontal planes. Take-off for the Me 163 was achieved by way of a wheeled, unsprung “dolly” assembly with the rocket motor at full thrust. The dolly was then jettisoned immediately after take-off for it proved an unnecessary counter-aerodynamic element. The interceptor then climbed to the required attack altitude to meet the incoming enemy bomber formation, most likely expending all of its fuel supply by this time. From its lofty perch, the accepted tactic for the Me 163 became a high-speed swoop down into the bomber formation, engaging targets with cannon for as long as momentum allowed – usually two or three dives though each swipe at the target was managed through a quick three-second-or-less window of opportunity. Once spent of both fuel and ammunition, the Komet was then glided to the ground under basic physics, landing on a relatively smooth patch of earth atop the provided spring-loaded centerline skid.
The Me 163B design then emerged in December of 1941 as a simplified production-quality form intended for wartime mass production and outfitted with an improved form of rocket motor. Two V prototypes were generated and these were followed by at least thirty pre-production series aircraft. Initial models were designated as “Me 163 B-0” and fitted with 2 x 20mm MG 151/20 series cannons. These were followed by the Me 163 B-1 marks which incorporated 2 x 30mm Rheinmetall Borsig Mk 108 series cannons. The B-1 mark was powered by a Walter HWK 109-509A-2 liquid-fueled rocket motor providing 3,800lbs of continuous thrust. Its maximum speed was 596 miles per hour with a range of just 25 miles and service ceiling of 39,700 feet. The Me 163 B-1 held an amazing 31,500 feet-per-minute rate-of-climb.
In theory, the idea of a small, one-man interceptor tearing holes in unsuspecting bomber formations was a sound one as defending Allied escort fighter aircraft could only hope to catch the Me 163, a target reaching speeds of nearly 600 miles per hour. However, the reality of the design provided an array of dangers for the pilot. The fuel mixture itself was known to self-combust as both elements were highly volatile, proven by the fact that such an event killed a test pilot – the aircraft had the possibility of exploding in the air or on the ground. The airframe could also become highly uncontrollable at the provided extreme speeds for swept wings were still an infant concept concerning high-speed flight. Powered flight was essentially limited to just 7.5 minutes through the available fuel stores and the freefall glide to the ground during landing placed the pilot and his aircraft in a precariously vulnerable position when Allied fighters were about. Unpowered landings also held its own share of inherent dangers as only a single attempt was essentially allowed. The operational range of the Me 163 also proved extremely limited and restricted the German response. Additionally, the armament array of 2 x cannons (mounted in the wing roots) was afforded up to 60 rounds of ammunition per weapon installation.
Initial combat sorties in July of 1944 attempted to showcase the Me 163 as a true fighter breed, able to fly twice as fast as any available Allied fighter type. However, it was found that the aircraft approached a flight of Boeing B-17 Flying Fortresses much too fast, thus not allowing the Me 163 pilots a chance to properly aim their guns and engage, consequently overshooting the targets and claiming no kills. It was only then discovered that the Me 163 could be used more effectively by conducting the aforementioned steep climb upon takeoff, achieving the desired attack altitude until the rocket motor fuel was expended and diving down to engage under control – relying on gravity and drag in the process.
Me 163 interceptors were credited with destroying just nine enemy aircraft (some sources state as many as sixteen kills) during the latter part of the war, this against the 370 Me 163s produced. Another Axis member nation, the Empire of Japan, also tried (somewhat successfully) to copy the Me 163 design. However, one of two submarines transferring the Me 163 design and associated plans from German hands to Japan was sunk by the Allies. The Japanese did manage to develop their own working variant of the Me 163 (as the Mitsubishi J8M “Shusui”) with the surviving set of plans but the aircraft never went into operational service.
The Mitsubishi J8M Shūsui was a Japanese World War II rocket-powered interceptor aircraft closely based on the German Messerschmitt Me 163 Komet.
For the Germans, the base Me 163 design was also planned to be reworked into a two-seat trainer form known as the “Me 163S”, these born from the streamlined Me 163B production model.
Operations began in 1944. As expected, the plane was extremely fast, and for a time the Allied fighters were at a complete loss as what to do about it. The plane often climbed to the bombers faster than the opposing fighters could dive in an attempt to intercept it. A typical Me 163 tactic was to zoom through the bomber formations at 30,000 ft (9,000 m), up to an altitude of 35,000-40,000 ft (10,700-12,000 m), then dive down through the formation again. With luck, this would afford the pilot two brief chances to fire off a few rounds from his cannons before he had to glide back to his airfield. That high speed was to prove a problem in that the builders were never able to make a truly effective weapon for the plane, one that could fire fast enough to allow it to kill a bomber before passing it.
As the cockpit was unpressurized, the operational ceiling was limited by what the pilot could endure for several minutes while breathing oxygen from a mask, without having his blood boil or losing consciousness. Me 163 Pilots underwent altitude chamber training to harden them against the rigors of operating in the thin air of the stratosphere without a pressure suit.
One fighter wing, Jagdgeschwader 400 (J.G. 400), was equipped with the craft in two groups, with the mission of defending synthetic gasoline installations during May 1944. First actions occurred at the end of July, attacking two USAAF B-17s without confirmed kills and continuing in combat from May 1944 to spring 1945.
The Jagdfaust was used only once operationally to shoot down a Lancaster heavy bomber on April 10, 1945.
Me 163 “Komet” was a successful design in pointing the way to the future. It was one more piece of strong evidence that the day of the propeller fighter was over, and it also spawned improved weapons like the Bachem Ba 349 Natter and Convair XF-92.