Nine
OFFICIALLY IT WAS CALLED the Messerschmitt Me 163B, the Komet, but unofficially this stumpy aircraft was known among its pilots as the ‘Powered Egg’, although ‘flying bomb’ might have been a better description. Either way, it promised a lightning-fast ride to hell or glory.
Everything about the Komet was dangerous, particularly the fuel. The later production versions from June 1944 had the improved ‘hot engine’, the Walter HWK 109-509, which used two liquid propellants: 20 per cent C-Stoff, a mixture of hydrazine hydrate, methanol, water and a small amount of potassium-copper-cyanide, and 80 per cent of oxidiser, T-Stoff, which consisted of concentrated hydrogen peroxide. Brought together these form a hypergolic fuel; in other words they ignite upon contact. Refuelling required special care with the C-Stoff tank filled first, and then the whole system would be washed down with water before the T-Stoff fuel came anywhere near the aircraft. T-Stoff was an extremely unpleasant substance. It would spontaneously combust on contact with organic material and, gruesomely, it actually dissolved human flesh. Accordingly the Me 163 pilots were issued with special non-organic flying suits including headgear, gloves and boots.
The rocket pilots came from wildly differing backgrounds; war-hardened fighter veterans and rookie student pilots who were taking to the air after a few lessons under tow. The good news is that the Me 163B flew superbly well and they were far more likely to be killed in an accident during the take-off and landing than in combat. Before starting the engine the motor and jet pipe were flushed out with water. A small quantity of the catalyst was introduced into the T-Stoff which decomposed into high-pressure steam to drive the two fuels into the combustion chamber. The cockpit would fill with an ear-splitting screech and the little aircraft began rocking. The Me 163B took off on a detachable wheel dolly to save the weight of an undercarriage. Take-off was always into wind and on a hard runway surface as the wheels were close together and any bumps or ruts could cause the aircraft to veer to one side. At about 80mph (130km/h) the airflow was sufficient for the aerodynamic controls to kick in and at 180mph (290km/h) it took off. Jettison the wheel dolly too high off the ground and there was a danger it would bounce back up to strike the underside of the aircraft. Within moments the Komet was roaring towards the airfield boundary. (Should the engine fail at this stage, the chances of surviving an emergency landing in the fully fuelled aircraft were zero.) The trick was to fly straight and level at around 420mph (675km/h), taking care not to exceed the critical Mach number, and then pull back hard on the stick for an almost vertical climb.
The German test pilot Hannah Reitsch flew both the Me 163A and 163B and she described the sensation as being, ‘Like thundering through the skies sitting on a cannonball, intoxicated with speed.’ The only Allied test pilot to try the Komet under rocket power was Captain Eric Brown, commanding officer of the Captured Aircraft Flight:
It was an aeroplane that made the adrenaline flow … I was normally used to a climb speed of 220mph (355km/h) and a climb rate of 3,000ft (915m) per minute, but when I flew this it had a climb speed of 450mph (725km/h) and a rate of climb of 16,000ft (490m). It was rather like being in charge of a runaway train.
Climbing at such incredible speeds the Komets could close in on the enemy bomber formations in a matter of minutes. The pilots didn’t have time to spare as the rocket fuel would run out after six minutes and then the Komet would revert to a glider. With adrenaline pumping and a closing speed of around 400mph (645km/h) the German pilots had only seconds to fire off their formidable Rheinmetall-Borsig MK108 30mm cannon. (Some later Komets were armed with 50mm rockets which pointed upwards and were triggered by a photocell when the outline of a bomber passed overhead.) At that fleeting moment of contact the Komet’s great speed was suddenly its greatest drawback. A pilot had to think and act fast. New tactics were tried. Some would attack from underneath the formation in a 45° climb, knowing that the turret gunners couldn’t follow them. But the escort fighter pilots soon learned that they could pursue and attack an Me 163B on its fuel-less glide back to the airfield.
The prototype Heinkel He 176 was the first aircraft to be powered by liquid-fuelled rocket motor when it flew on 20 June 1939.
Landing was another high-risk moment for the Me 163. The retractable landing skid offered little protection, and it was essential that no fuel was left in system as a bad landing in the fast-moving but powerless egg could spell disaster. In an incident during one of the early un-powered flights, test pilot Hannah Reitsch had just taken off on tow behind an Me 110 when the Me 163’s trolley failed to disengage and her aircraft began to shudder violently from the unexpected turbulence it created in the air-flow. After casting off from the tug at 10,000ft (3,050m) she desperately tried to shake the trolley off but it remained stuck. On the landing approach Reitsch made a crucial error, a side-slip which caused a stall, and the aircraft plunged into the ground before tumbling to a halt and leaving her with multiple fractures to her skull. Despite this incident she remained an enthusiastic fan of the Komet: ‘The Me 163B had excellent flying qualities, better than I had found in any other aircraft.’
THE OPEL-HATRY RAK-1
The Me 163 was not the first rocket-powered aircraft to have taken to the skies. During the 1930s there was something of a fashion for strapping rockets on to all manner of vehicles including cars, rail riders and even snow sledges. One of the most notable proponents of rocket-power was Fritz von Opel of the Opel car company. In 1928 Opel bought a Lippisch Ente glider from Alexander Lippisch, a young engineer with a fascination for aerodynamics. With two black powder rockets the Lippisch glider flew in 1928, although it was badly damaged on the second attempt when one of the rockets exploded. Undaunted, Opel bought a second purpose-built glider, this time from Julius Hatry. Christened as the Opel-Hatry RAK-1, it flew on 30 September 1929 at Frankfurt-am-Main with thrust provided by sixteen black powder rockets, but it was damaged beyond repair in a heavy landing.
KE+SW, the Messerschmitt Me-163 V-1 prototype has a far more rounded nose than later models and lacked the single-piece bubble canopy.
Although Opel lost interest after that, in the late 1930s some of the mainstream aircraft companies were also looking into rockets, among them Heinkel.
THE HEINKEL He 176
When Wernher von Braun’s rocketry team at Peenemünde needed aircraft for experiments with liquid-fuelled rockets Ernst Heinkel supplied them with an He 72 biplane and two He 112s; the latter a candidate for the Luftwaffe’s 1933 competition for a new fighter aircraft. In 1936 the He 72 was used to test a Walter rocket motor using hydrogen peroxide and a paste catalyst, and in April 1937 one of the He 112s flew with a von Braun liquid-fuel rocket, but crashed on landing. Undeterred, Heinkel began work on a purpose-built rocket-powered aircraft which, it was hoped, might surpass the 621mph (1,000km/h) mark. The result was the Heinkel He 176, an extraordinarily modern-looking design with a rounded nose, a totally enclosed cockpit, and forward tricycle undercarriage. Unusually the entire nose section could be jettisoned in the event of an emergency at high speed. It was also very small, just over 17ft (5.2m) long with a wingspan of 16ft 5in (5.0m) – barely big enough to take the test pilot Erich Warsitz – and was built almost entirely of wood to keep weight to an absolute minimum. Within the streamlined fuselage there were tanks for the hydrogen peroxide and methanol propellants, plus the Walter R1 rocket which produce a regulated level of thrust between 1,102 to 1,323lb (500 to 600kg).
The first official flight under liquid-fuelled rocket power took place on 20 June 1939. The following day a flight demonstration was put on for Ernst Udet and Erhard Milch of the RLM and on 1 July it flew in front of the Führer. These displays were met by a resounding lack of interest from the officials and the project was cancelled by the autumn.
THE MESSERSCHMITT Me 163
Meanwhile Alexander Lippisch had been continuing to explore new aerodynamic forms under the aegis of the German institute for the study of glider flight, the Deutsche Forschungsanstalt Segelflug (DFS), and his tail-less Storch (‘stork’) was first flown in 1927. Further models on this theme led to the Delta I, which began flight testing in 1930 and saw a 30hp engine added in the following year. Development with the tail-less form continued with the DFS, on and off, but eventually culminated with the announcement of a rocket-powered version, the DFS 194, with an airframe built by Heinkel. This division of responsibilities proved untenable and in 1939 work on the DFS 194 was reorganised under one team under Lippisch’s leadership and within the Messerschmitt company at Augsburg to create what became the Me 163.
In 1940 the first of the Me 163A prototypes was shipped to Peenemünde West where it was fitted with a Walter HWK RI-203 rocket motor, an improved version to the one on the He 176. In test flights the aircraft achieved speeds of up to 342mph (500km/h). The Me 163A V4 received the HWK RII-203 motor which used T-Stoff and Z-Stoff propellants on the cold principle, and in October 1941 it attained a new world speed record of 624mph (1,005km/h). This record was entirely unofficial as the project was so shrouded in secrecy that even the Me 163 designation had been taken from an earlier light aircraft. Five prototype Me 163 A-series were built, followed by eight pre-production aircraft designated as the Me 163 A-0. The flight testing wasn’t without incident. There were problems with the detachable wheel trolley rebounding into the aircraft, and malfunctions of the hydraulic dampers in the landing skid resulted in pilot injuries. Nevertheless, the aircraft’s performance couldn’t fail to impress and, equipped with the newer HWK 109-509A 0-1 hot engine fuelled by a deadly cocktail of T-Stoff and C-Stoff propellants, the Me 163B Kometemerged in late 1941.
The Komet entered active service in May 1944, operating initially from the airfield at Brandis, near Leipzig, to defend the Leuna oil refineries to the south-west. The specifications for the Me 163B-1 were: length 18ft 8in (5.7m), wingspan 30ft 7in (9.33m). The Walter HWK 109-509A-2 motor gave a maximum speed of 596mph (1,060km/h), and the aircraft had a service ceiling of 39,700ft (12,100m). Improved endurance came with the HWK 109-509B and HWK 109-509C motors, although the latter was fitted to only a handful of aircraft. The final version, the Me 163C, featured a pressurised cockpit, enlarged wings and a lengthened fuselage with bubble canopy. There was also the Me 163S, an un-powered tandem conversion with the second seat for an instructor in the space normally occupied by the rocket motor. This was used for glider landing training.
Me 263 SCHOLLE
Due to the pressure already on Messerschmitt to supply Bf 109s and Me 262s, production of the Komet was dispersed among a number of locations and control of the work was handed firstly to Klemm and then to Junkers. The engineers at Dessau thought they could improve on Messerschmitt’s work and their Ju 248 retained the pressurised cockpit of the 163C on a longer fuselage, to carry more fuel, which featured a retractable tricycle undercarriage. Only one prototype was built of the Ju 248 which reverted to a Messerschmitt designation as the Me 263 Scholle(‘plaice’). Un-powered test flights were made in February 1945, but time ran out before it could be flown under rocket power. The Americans overran the Junkers plant in April 1945 and with the reallocation of territory within the Allied zones of occupation it fell into the hands of the Russians. The Me 263 is said to have been the inspiration for Russia’s short-lived Mikoyan-Gurevich I-270 rocket power interceptor, of which two prototypes were built immediately after the war.
The Japanese also constructed several versions of the Me 163 from plans supplied by the Germans. The Mitsubishi Ki-200 Shusui (‘autumn water’) was the equivalent of the Me 163B and was armed with two 30mm Ho 155-II cannon. A version produced for the Japanese Navy known as the J8M1 saw the Ho 155 cannon replaced with the navy’s 30mm Type 5 cannon. Lacking the parts to complete their own motors, the Japanese aircraft could only be flown experimentally as gliders.
With only sixteen Allied aircraft credited to the Me 163B Komet, the operational record never lived up to expectations. In the end it was a glorious experiment in a type of propulsion that was not to enjoy a more widespread application. Just like its namesake, it had burst across the sky on a column of flame for only the most fleeting of moments. As Sir Roy Fedden stated:
The Me 163, the only rocket-propelled fighter of the war, was a remarkable experiment capable of great development, and indicated the German plan of things to come for high-speed aircraft had the war continued.
Messerschmitt 163B, the ‘Komet’, the first and only operational rocket-powered interceptor.
THE ENZIAN
There is, however, an interesting adjunct to the Me 163 story. The Enzian, named after a type of mountain flower, was a guided surface-to-air missile designed to emulate the Me 163’s mode of attacking the high-altitude Allied bomber formations, but without its inherent operational difficulties or risk to pilots, and at a much lower cost. The problem with the Komet was its short flight duration and even briefer opportunity to engage with the enemy. When it did encounter the B-17s and B-29s it lacked the means to aim and hit the targets at a closing speed of around 100mph (160km/h). Originally known as the Flak Rakete when proposed by Dr Wurster at Messerschmitt, the Enzian would be flown in front of the bombers and then the massive 500kg charge would be detonated creating a blast that could, in theory, bring down several aircraft in one go. In appearance the EnzianE-4 certainly looked like a scaled-down version of the Komet. The 7ft 10in (2.4m) fuselage had a low aspect ration and featured swept wings with trailing-edge elevons for manoeuvring, plus upper and lower fins at the rear. The airframes were designed for simple mass production and made as much use of wood as possible. Launched from an 88mm gun mounting, four Schmidding 109-553 solid-fuel boosters grouped around the fuselage gave a combined boost thrust of 15,400lb (7,000kg) and a far greater rate of climb than any human pilot could endure. The sustainer motor was to have been the Walter RI-10B which used SV-Stoff (mixed acids) and Br-Stoff (petrol) propellants, with a small quantity of T-Stoff as the catalyst. In flight the thrust decreased from 4,410 to 2,205lb (2,000 to 1,000kg), enabling the controller to more readily fly it headlong into the bomber formations
The shape of the unmanned Enzian surface-to-air missile bears more than a passing resemblance to the Me 163. (JC)
Guiding such an approach remotely from the ground was the tricky part. It would be far more difficult than the straight line trajectory of competing missiles, such as Rheintochter, and initially the intention was to install a self-contained Elsass radar unit in the Enzian’s nose together with a proximity fuse. In tests the proximity fuse proved troublesome and an infrared system, known as Madrid, was proposed instead. This used several telescope mirrors to visually fix on the target. However, after thirty-eight test firings the Enzian programme was cancelled before Madrid could be made operational.
THE EMERGENCY FIGHTER PROGRAMME
Unknown to Sir Roy Fedden until after the end of the war, a copy of the secret report on his 1942-3 mission to examine American aircraft production had been leaked to the Germans shortly after its publication. In all likelihood this had been done quite deliberately to convince them that they could not possibly win the war in the face of such overwhelming industrial might. And that was Germany’s greatest dilemma. Its war machine was being battered and starved of vital resources while the Allied bombers just kept on coming by the thousands.
In the summer of 1944 the Emergency Fighter Programme saw all aircraft production focussed on defensive fighters, in particular the Messerschmitt Me 262A fighter versions, and the only bombers allowed to continue in production were those powered by jets. But it was becoming clear that neither the Me 163B or the Me 262 could be expected to protect the Reich on their own. In August 1944 a design competition was launched by the RLM to create a jet-powered Volksjäger (‘people’s fighter’) to deal with the Allied bombers. It must have only a single engine (the BMW 003 was specified), weigh no more than 4,410lb (2,000kg), should be readily manufactured by semi-skilled or even unskilled labour using only minimal resources, and had to be easy to fly by relatively inexperienced pilots. One suggestion was that members of the Hitler Youth could fly them after some preliminary training on gliders – a notion dismissed as ‘unrealistic’ by Ernst Heinkel after the war and symptomatic of the ‘unbalanced fanaticism of those days’.
It was already very late in the day but Heinkel rose to the challenge and dusted down an existing design, designated P.1073, to create the He 162 Spatz, or ‘sparrow’. The 162 designation was chosen from an earlier Heinkel project, and codenamed Salamander, to throw the Allies off the scent. Made primarily of wood with a sheet steel monocoque fuselage, the Heinkel He 162 wore its single BMW 003 jet engine on its back. Twin vertical tail fins were mounted on either side of a dihedral tailplane to provide clearance for the jet exhaust. It had high-mounted straight wings which were attached to the fuselage by four bolts, a tricycle retractable landing gear and an ejector seat for the pilot (vital to clear that big turbojet directly behind the cockpit bubble canopy).
Heinkel He 162, Volksjäger, captured at an airfield in France. (USAF)
Such was the urgency for the new fighter that Heinkel had a prototype in the sky on 6 December 1944, less than ninety days after the design had been selected. On the first test flight there was a problem with the wood glue on the nose cone and a number of other issues with pitch instability and side-slip due to the rudder configuration. On the second test flight the glue failed again, causing a fatal crash. There was no time for major design changes, so Heinkel made do with strengthening the wing structure and tweaking the tail design. On the third and fourth prototypes they introduced small aluminium wing tip droops in an attempt to improve stability.
The eventual production series, the He 162A-2, was armed with two 22mm MG 151 guns. Fuel duration was around thirty minutes and the aircraft could achieve a respectable 522mph (840km/h) at 19,700ft (6,000m); possibly a little more using short bursts of extra thrust although this ate into the BMW motor’s already short service life. Assembly facilities were established at three main sites, at Marienehe, in a former chalk mine at Mödling, and at the Junkers plant in Bernberg, with components and sub-assemblies coming from all over Germany. Some of the wooden components, for example, were produced by furniture makers. An output of 1,000 aircraft a month was predicted by April 1945, and double that when production facilities at the Mittelwerk came on stream later on.
An active evaluation unit, Erprobungskommando 162, was formed in January 1945 at Rechlin. Then in February He 162s were delivered to the first operational unit, I./JG 1 at Parchim, to the south-west of the Heinkel factory. Officially the He 162 never entered active service as the paperwork wasn’t ready in time but, unofficially, they were known to have engaged with Allied aircraft from late April 1945, only weeks before Germany’s capitulation.
Another aircraft that bore a strong resemblance to the He 162, with a single turbojet mounted on the top of the fuselage and a dihedral tail, was the Henschel Hs 132. This design actually pre-dates the He 162 as its origins lie in a 1943 specification issued by the RLM for a single-seat dive bomber to attack shipping in the anticipated Allied invasion of Europe. The original RLM specification had called for a piston-engined aircraft, but Henschel believed that the performance requirement could only be met by jet power, in this case a BMW 003A. The 29ft 2.5in (8.9m) fuselage of the Hs 132 was a streamlined cigar shape having a rounded clear nose with the glazing extended almost as far as the wing roots. This was to provide a wider view for the pilot who was positioned slightly back from the nose behind a plate of armoured glass, lying on his stomach with his head right in the nose. The apparent advantages of this prone position were a reduced frontal area to minimise both drag and the risk of being hit by defensive guns, plus it was thought to improve the pilot’s ability to withstand high pull-out forces. The thinner fuselage tube lacking any protuberances would also be easier to pressurise. The aircraft’s wings were tapered slightly and, as with the He 162, the tail had a dihedral layout with end-plate twin fins to give clearance for the jet exhaust. The payload was to be a single 1,100lb (500kg) bomb, to be dropped in a shallow dive with the aircraft pulling out sharply just beyond the enemy ship’s range of fire.
Other variations considered included the Hs 132B with a Jumo 004 engine and two 20mm MG 151/20 cannon. The Hs 132C was even beefier with the more powerful Heinkel HeS-011 and additional fire power.
Construction work on several prototypes, possibly four, was started in March 1945 with the first flight slated for June. Obviously events scuppered these plans and the Russians captured the Henschel’s Schönefeld factory in May 1945. By that time the wings and fuselage had not been mated and the only surviving photograph of the Hs 132 V1 prototype, standing outside the works, might only be a mock-up according to some sources.
Designed as a dive bomber the Henschel Hs 132 looks very similar to the He 162.
THE LEONIDAS ‘SUICIDE’ SQUADRON
By early 1944 serious consideration was being given to the possibility of German airmen carrying out Selbstopfer or ‘suicide missions’ against important strategic targets. This proposal, which came originally from Otto Skorzeny and Hajo Hermann, had the enthusiastic support of the influential Hannah Reitsch, who had the ear of Adolf Hitler. At first he was dismissive of the idea, believing that it was not the right psychological moment for it to be acceptable to the German public, but he did agree to the formation of the Leonidas Squadron as the 5th Staffel of the Luftwaffe’s Kampfgeschwader 200. The squadron derived its distinctive name from the King Leonidas of Sparta, who in 480 BC had resisted the invading Persian army with 300 warriors who fought to the last man.
The plan was to arm an aircraft with a 2,000lb (900kg) bomb in order to attack shipping in the Allied landings. The prime candidate for the role was a specially converted manned version of the Fieseler 103 V-1 flying bomb, but another design, the Me 328, was chosen instead. This diminutive aircraft was originally conceived by Messerschmitt in 1941 as the P.1073 as a cheap escort fighter, either towed by a heavy bomber or carried aloft, parasite fashion, on the back of an Me 264. Constructed almost entirely of wood, development of the Me 328 had been handled by the DFS and two versions were proposed originally, the Me 328A fighter and the Me 328B bomber. The fuselage was 27ft 7in (6.4m) long and it had a wingspan of 20ft 6in (6.4m). There were three options for propulsion; un-powered glide, Argus pulsejets or even jet power with a Jumo 004 engine. Test flights commenced with the glider version being released from a tow aircraft or sometimes carried piggy-back on a Dornier Do 217. Testing of seven prototypes fitted with two Argus As 014 pulsejets was started but soon abandoned, probably due to the excessive vibration the pulsejets caused. (An illustration of the pulsejet version is shown on page 127.) However, the Me 328 programme had already been suspended by this time and in order to save development time attention reverted to the manned version of the V-1, the Fieseler Fi 103R, known by its codename as the Reichenberg.
To accommodate the pilot a cramped cockpit was added immediately in front of the intake for the Argus As 014 pulsejet in the space where the compressed-air cylinders would have been on the unmanned V-1 missile. These cylinders were replaced by a single one positioned further back in place of the autopilot. The cockpit had only the most basic instruments. The wings were fitted with hardened edges to slice through the cables of any defensive balloon barrage. The idea was to carry either one or two Reichenbergs beneath the wings of a Heinkel He 111, releasing them near the intended target. In theory the pilots were to bail out shortly before impact, but the likelihood of doing that safely just inches away from the intake of the Argus ramjet were very remote.
Training commenced with ordinary gliders at first, and then progressed to specially altered gliders with shortened wings, and concluded with instruction on the dual-control Fi 103R-II trainer. There was no shortage of volunteers and seventy young recruits, Hannah Reitsch among them, signed a declaration stating; ‘I hereby voluntarily apply to be enrolled in the suicide group as part of the human-glider bomb. I fully understand that employment in this capacity will entail my own death.’
Glider version of the Messerschmitt Me 328 considered as a candidate for suicide missions.
Test flights of the Reichenberg commenced in September 1944, with glider drops from a Heinkel He 111 at first, followed by fully powered tests. (It had become already standard procedure to drop the conventional V-1s from the bomber since the Allies had captured the missile’s launch ramps in the Pas de Calais area.) But by this time the Allied advance upon Germany was in full swing and the original purpose of the suicide missions, to attack the invasion fleets, was no longer valid.
By October 1944 official interest in the Reichenberg had shifted in favour of the Mistel composite aircraft as a means of striking against Russian targets.
THE MISTEL
The concept of piggy-back aircraft, or pick-a-back as they were sometimes called, was nothing new. Shortly before the war Britain’s Imperial Airways had begun experiments with the Short Mayo Composite which consisted of the S.20 Mercury twin-float seaplane riding atop the bigger S.21 Maia, a variant of the C-Class Empire flying boat. The plan was to use this combination to extend the range of the aircraft in order to establish a reliable long-range transatlantic service. In-flight separations, including one transatlantic flight, took place in 1938, but this line of development ended with the coming of war.
The German piggy-back, Mistel, was named after mistletoe for its obvious parasitic associations, although it was sometimes referred to as Vati und Sohn, (‘father and son’), or more officially by the codename Beethoven-Gerät (‘Beethoven device’). At first it was explored as a means of increasing the range of the Luftwaffe’s big paratroop-carrying gliders, with either a Focke-Wulf Fw 56 or Messerschmitt Bf 109E as the upper element. However, it was also apparent that the Mistel could be adapted to deliver a very heavy bomb load to a strategic target. The biggest bomb any existing aircraft could deliver was 5,500lb (2,500kg), but the Mistel composite aircraft could raise this to around 8,400lb (3,800kg) which was sufficient to seriously damage even the biggest and most heavily protected installation. Around 250 Mistels were built during the war, mostly a combination with various models of the Focke-Wulf Fw 190 or the Messerschmitt Bf 109 on top, and an unmanned Junkers Ju 88 to carry the bomb-load, although other variants were proposed including an all-jet Me 262 and Ju 287 combination. Contrary to expectations, the bombers were not well-used aircraft, but purpose-built for the task.
This ‘Bakka’, a Japanese equivalent of the Fieseler Fi 103R manned flying-bomb, was discovered by US troops at Kadena Airfield, Okinawa. (NARA)
Mistel piggyback combination, with Fw 190 above an unmanned Ju 88, captured by the Allies at Bernberg, Germany. (USAF)
The Bachem Ba 349 ‘Natter’ rocket-propelled interceptor shown on its vertical launch tower. (NARA)
The method of operation called for the pilot in the parasite aircraft to fly towards the target and when at relatively close range to set the bomber on automatic pilot before firing the explosive bolts that held them together. In practice pilot losses were heavy and the slow-moving bombers were easy prey to the anti-aircraft defences. Mistels were used against the Mulberry harbours during the Allied landings at Normandy, although with little effect. In Operation Eisenhammer (‘iron hammer’) they were to have attacked the more lightly defended power stations around Moscow and Gorky, but the Russians were already pushing into Germany before the plan could be implemented. In a final act of desperation in April 1945 Mistels were deployed as bridge-busters against the Russian bridgehead at Küstrin, but yet again they failed to cause any significant damage.
On 4 May 1945 Allied troops caught up with the Bachem team as they attempted to escape to the Austrian Alps. (NARA)
THE OHKA
American interest in the Reichenbergs in particular was concerned with the possibility of the Japanese deploying similar weapons in the continuing Pacific War. The Japanese culture was more familiar with the tradition of suicide missions and their equivalent of the Fieseler Fi 103R was the Yokosuka MXY7, known as the Ohka (‘cherry blossom’), but nicknamed by American servicemen as Baka, the Japanese word for fool. At first sight Ohka looks much like the Fi 301R. In essence it was a 2,646lb (1,200kg) bomb with a 19ft 11in (6.06m) cylindrical fuselage, a pair of short wings, a double-tail and a cockpit, but it lacked the Reichenberg’s rear pulsejet. Instead the Ohka was powered by three Type 4 Model 20 solid-fuel rockets fitted within the end of the fuselage. In operation the Ohka would be dropped from beneath a Mitsubishi G4M2e Model 24J bomber and then glide towards its target, usually an American ship. As it got closer the pilot would fire the three rockets, either one at a time or in unison, to increase the range and speed. On final approach the small aircraft was almost unstoppable as it closed in on the target at speeds over 400mph (650km/h), even more if in a dive.
Its range was 20 nautical miles (37km). Later models were designed to be launched from coastal airbases or even from catapults on board ships or submarines. Around 850 Ohka were built and they were used throughout the spring of 1945, mostly against American ships at Okinawa, where they sank or damaged seven vessels including the destroyer USS Mannert L. Abele. Other variations included the Model 22 fitted with a Campini-type thermojet, and also the Model 33 with Ishikawajima Ne-20 turbojet, but neither appears to have taken part in combat. The Ohka K-1 was a two-person trainer.
THE BACHEM Ba 349
The most radical design to emerge from Germany’s Emergency Fighter Programme was the extraordinary Bachem Ba 349, otherwise known as the Bachem Natter (‘viper’). Not a suicide weapon, it was the nearest thing the Germans had to an actual manned anti-aircraft missile. The Natter had evolved from Erich Bachem’s earlier and unrealised designs for the Fieseler Fi 166, a twin-engined jet fighter launched upright piggy-back, almost Space Shuttle-style, on a liquid-fuel rocket. His submission in response to the 1944 call for fighter designs was equally radical. It didn’t meet all of the Luftwaffe’s requirements although, crucially, it caught the eye of the SS leader Heinrich Himmler. Consequently its development continued under the patronage of the SS.
The Bachem Natter was small, vertically launched and rocket-powered. IT could be flown by an untrained operator/pilot. ‘Pilot’ seems too grand a term as it would be taken into the flight path of the Allied bombers on autopilot; all the occupant was required to do was aim and fire the air-to-air rockets at the bombers. After an encounter the pilot would then point the nose downwards and descend to a lower altitude before levelling out. A latch released the canopy, which would flick backward in the slipstream on its hinges. The pilot would jettison the nose section, and both pilot and aircraft would float to earth under individual parachutes. It sounded so simple and yet so complicated. In its favour this system did away with airfield runways for both the launch and the landing, making it possible to locate the Natter wherever it was needed, reducing vulnerability to attack by Allied fighters.
The Ba 349 wasn’t much to look at. A squat 20ft (6m) long, it had short straight wings with a wingspan of 12ft (9m), and a conventional-looking tail with control ailerons. The airframe was mostly constructed of wood, nailed or glued, and could be assembled by unskilled labour. The Natter’sdriving force came from the Walter HWK 109-509 A2 rocket motor, the same unit as on the Me 163, plus four Schmidding SG34 solid-fuel boosters strapped to the sides providing an additional 4,800kg of thrust for ten seconds before being jettisoned. It was armed with nineteen R4M air-to-air rockets, possibly increased to twenty-eight on later models, or 75mm Fohn assault rockets.
The first of the experimental prototypes was completed in October 1944, and test flights were undertaken towed behind a Heinkel 111 and also free-flying in glider mode. The first unmanned vertical launch took place on 22 December 1944 using only the solid-fuel boosters, and in late February 1945 a Natter was launched with the HWK 109-509 installed and it made a near-perfect flight. Near-perfect because the dummy pilot was returned safely enough but residual propellant ignited when the fuselage hit the ground, destroying the aircraft. Then on 1 March 1945 a young test pilot named Lothar Sieber bravely climbed into the cockpit for the first manned flight. In a cloud of steam the Natter rose out of the guiding rails on the launch tower with all rockets firing. Suddenly it pitched backwards and then continued to climb inverted at an angle about 30° to the vertical. At 1,650ft or so (500m) the cockpit canopy prematurely tore away and the Natter disappeared into low cloud. When the Walter motor stalled, at launch +15 seconds, the Natter nose-dived all the way to the ground. It is thought that Sieber had involuntarily pulled back on the stick because of the G-forces of acceleration, and he had probably broken his neck when the canopy holding the headrest flew off.
Development work continued, the rockets were upgraded, but claims that the Natter ever flew in anger are uncorroborated. It is thought that thirty-six Natters had been built by the time Allied troops had caught up with the Bachem team.