Key point: Like many other over-hyped German wonder weapons, the Komet was revolutionary but not practical. Overengineered and full of problems, it was too fast and only had 7 minutes worth of fuel.
Nazi Germany pursued numerous ambitious and impractical weapon programs over the course of World War II. One of the few that saw action was the Messerschmitt Me 163 Komet, the only rocket-powered fighter to enter operational service. The stubby rocket planes were blindingly fast by the standards of World War II fighters—but were in as much danger of blowing up from their volatile rocket fuel as they were of being shot down by enemy fire.
This first appeared several years ago and is being reposted due to reader interest.
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.
The first aircraft to fly under rocket power was actually a modified tail-less glider, the Ente (“Duck”) produced by German designer Alexander Lippisch. Lippisch began working with glider-manufacturer DFS on a proper rocket fighter in the late 1930s, before transferring his DFS 194 prototype to the Messerschmitt airplane manufacturer. Because Messerschmitt had worked on an observation plane called the Bf 163 before switching to using “Me” aircraft designations, the designers figured using the Me 163 designation would trick Allied intelligence as to the rocket plane’s true nature.
The first Me 163A prototype was produced in 1941, sporting swept wings for improved high speed performance. Powered by an HWK 109 liquid-fuel rocket engine, it proved phenomenally fast, setting a world speed record of 624 miles per hour in level flight on October 2, 1941. Front-line fighters of the time rarely exceeded 350 miles per hour.
In 1944, a modified Me 163 reportedly achieved 702 miles per hour in a dive, nearly shearing off its vertical stabilizer in the process. This unofficial record was not exceeded until 1947, when Chuck Yeager broke the sound barrier in his Bell X-1.
However, the Komet burned through its fuel in just seven minutes of flight—giving it an operational range of just twenty-five miles. Nonetheless, the Luftwaffe decided it could use the Me 163 as a point-defense fighter, deploying it to airfields close to high-value targets subject to repeated attack.
The Komet’s design was revised for mass production in the Me 163B. A tiny propeller added on the tip of the nose generated electricity for the Komet’s avionics. The Me 163 had smooth handling characteristics and a superb rate of climb, but its unpressurized cockpit made it necessary for pilots to undergo special conditioning in high-pressure chambers to avoid passing out at high altitudes.
The first thirty preproduction B-0 aircraft were armed with MG-151 twenty-millimeter cannons, while the remaining four hundred B-1s had twin Mk 108 thirty-millimeter cannons. The heavy cannons could punch out a fighter plane with a single direct hit or a bomber with four or five shells. However, they lacked long-range accuracy due to their low muzzle velocity.
To save on weight, the Komet’s wheels were mounted on a trolley, which it jettisoned shortly after takeoff. For landing, the Me 163 relied on a skid retracting from the belly with an oil-hydraulic shock absorber. However, the Komet’s glider-like characteristics gave it so much lift that it was difficult to land—and because it had usually exhausted its fuel by the time it made its approach, it could not usually attempt a second pass if it overshot. Once an Me 163 skidded to a halt on its belly, it had to be hoisted up and towed by a modified agricultural tractor.
The Komet’s rocket engine used a propellant called C-Stoff, combining methanol and hydrazine hydrate. The C-Stoff was oxidized with a hydrogen peroxide–based solution called T-Stoff. Both chemicals were transparent, corrosive and toxic to the touch, and extremely volatile when mixed, even at room temperature. Ground crew in special protective suits employed separate fuel trucks to fill Me 163s with C-Stoff and T-Stoff, and of course the T-Stoff was stored behind and next to the cockpit. The chemicals were so dangerous that Me 163s sometimes combusted spontaneously on the tarmac. On other occasions, battle damage or collisions would result in midair explosions.
The first Me 163Bs were deployed to the Erprobungskommando 16 testing unit on January 1944, and first saw combat in an inconclusive B-17 intercept on July 28, 1944. By August, an entire wing of Komets, designated JG 400, commanded by Maj. Wolfgang Späte, deployed to Brandis and Stargard to defend the Leuna and Pölitz synthetic fuel plants, respectively. Allied planners had finally realized that fuel was the Achilles’ heel of Germany’s war economy, and shortages of C-Stoff caused by allied bombing would actually keep many of the Me 163 grounded for much of their time in service.
Nonetheless, some Me 163s did see action. Typically, one or two Komets would dive down on Allied bomber formations in a hit-and-run attack, before gliding back to base, their fuel spent.
It turned out the Me 163 was too fast to be a good bomber destroyer. Flying up to four hundred miles per hour faster than the bombers it was hunting, while using cannons accurate only at short range, a Komet pilot had about 2.5 seconds to aim and fire before he shot past his target. Allied fighters had no chance of keeping pace with the speedy Komets—but they learned to follow them back to their airfields and strafe them as they made landing approaches.
In an attempt to address the accuracy problem, the Luftwaffe fitted Me 163s with the experimental SG500 Jagdfaust, which involved six recoilless fifty-millimeter mortars fixed in the wings roots of the Komet. When the Me 163 flew under an enemy bomber, the bomber’s silhouette would trigger the SG500’s optical photocells, automatically launching the recoilless weapons vertically into the target’s belly. The Jagdfaust was used only once operationally to shoot down a Lancaster heavy bomber on April 10, 1945.
In all, Komet pilots claimed sixteen aerial victories—mostly B-17 and Mosquito bombers —though only nine can be confirmed with certainty from Allied records. In return, between six and nine Me 163s were shot down in combat, mostly by P-51 Mustangs, though one also fell victim to a B-17 tail gunner. Another nine were lost to accidents. It was not an impressive showing, given the resources invested in the Komet project.
Messerschmitt developed an Me 163C with a double-chambered rocket engine, expanded fuel tanks and a pressurized cockpit. However, only one of the three prototypes produced is believed to have flown. In the end, the Luftwaffe realized its slower Me 262 turbojet fighters were far more practical than the short-range Komets, which were withdrawn one month before the German surrender. Allied troops went onto capture many Me 163s intact and take them back home for testing—at least ten of which can be seen in museums in North America, Europe and Australia today.
The Me 163 story doesn’t end in Europe. Germany agreed to share Me 163 technology with Japan for twenty million reichsmarks—but both Japanese submarines carrying Komet parts back to Japan, as well as a German U-Boat, were sunk in transit in 1944 and 1945. However, an officer on one of the submarines disembarked at Singapore and flew back to Japan with the instruction manual. Japanese designers used the manual to create their own versions of the Me 163, the J8M Shushui (“Autumn Water”) for the Navy, as well as the Ki-200 for use by the Army Air Force.
A total of seven J8Ms were assembled using slightly less powerful rocket motors, but only one was ever flown. On its maiden flight on July 7, 1945, the J8M’s rocket motor quit after takeoff, and the airplane combusted after a minor collision during the emergency landing, mortally injuring the pilot. The remaining aircraft were grounded until the fuel system could be fixed and the war ended before plans for full-scale production were realized.
The Komet remains the only rocket-powered fighter to have entered operational service. Despite attaining speeds unsurpassed by any other airplane of its time, the Me 163 stands as an object lesson on the limitations of maximizing one attribute of a combat plane at the expense of all others.
Sébastien Roblin holds a Master’s Degree in Conflict Resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing, and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring. This first appeared several years ago and is being reposted due to reader interest.