Heinkel He 162
The Heinkel He 162 "Volksjäger (German, "People's Fighter") was a German single-engine, jet-powered fighter aircraft fielded by the Luftwaffe in World War II. Developed under the Emergency Fighter Program, it was designed and built quickly and made primarily of wood as metals were in very short supply and prioritised for other aircraft. "Volksjäger" was the Reich Air Ministry's official name for the government design program competition won by the He 162 design. Other names given to the plane include "Salamander", which was the codename of its wing-construction program, and Spatz" ("Sparrow"), which  was the name given to the plane by the Heinkel aviation firm. The aircraft was notable for its small size; although almost the same length as a Bf 109, its wing was much shorter at vs. for the 109. Most distinctive was its top-mounted engine, which combined with the aircraft's ground-hugging landing gear allowed the engine to be easily accessed for maintenance. This made bailing out of the aircraft without hitting the engine difficult, and the 162 is thus also notable as the first single-engine aircraft to mount an ejection seat in an operational setting. The  small size left little room for fuel, which combined with the inefficient engine resulted in very low endurance on the order of 20 minutes, and it only had room to mount two autocannons, making it quite underarmed for the era. A series of fatal accidents during testing required a series of refinements that delayed the program, but it eventually emerged in January 1945 as an excellent light fighter. Although production lines were set up and deliveries began, the state of Germany by that time made the effort pointless. Of just less than 1,000 examples on the assembly lines, only about  120 were delivered to the airfields, and most of those never flew, lacking parts, fuel and pilots. Small numbers were used in development squadrons and these ultimately saw combat in a few cases in April 1945, but the plane proved more dangerous to its own pilots as its tiny fuel load lead to a number of planes crashing off field, along with additional cases of structural failure. Production was still ongoing when the war ended, and a number of examples were captured by the Allied forces along with ample supplies of parts from the production lines. Eric Brown flew one  just after the war and considered it a first-rate aircraft with few vices. A number remain in museum collections around the world. Development. State of the Luftwaffe fighter arm. Through 1943 the U.S. 8th Air Force and German "Luftwaffe" entered a period of rapid evolution as both forces attempted to gain an advantage. Having lost too many fighters to the bombers' defensive guns, the Germans invested in a series of heavy weapons that allowed them to attack from outside the American guns' effective range. The addition of heavy cannons like the 30mm calibre MK 108, and even heavier  Bordkanone autoloading weapons in 37mm and 50mm calibres on their "Zerstörer" heavy fighters, and the spring-1943 adoption of the "Werfer-Granate 21" unguided rockets, gave the German single and twin-engined defensive fighters a degree of firepower never seen previously by Allied fliers. Meanwhile, the single-engine aircraft like specially equipped Fw 190As added armor to protect their pilots from Allied bombers' defensive fire, allowing them to approach to distances where their heavy weapons could be used with some chance of hitting the bombers. All of this added greatly to the weight being carried by both the single  and twin-engine fighters, seriously affecting their performance. When the 8th Air Force re-opened its bombing campaign in early 1944 with the Big Week offensive, the bombers returned to the skies with the long-range P-51 Mustang in escort. Unencumbered with the heavy weapons needed to down a bomber, the Mustangs (and longer-ranged versions of other aircraft) were able to fend off the "Luftwaffe" with relative ease. The "Luftwaffe" responded by changing tactics, forming in front of the bombers and making a single pass through the formations, giving the defense little time to react. The 8th Air Force  responded with a change of its own; after Major General Jimmy Doolittle ordered the fighters to enter German airspace far ahead of the bomber formations and roam freely over Germany to hit the Luftwaffe's defensive fighters wherever they could be found. This change in tactics resulted in a sudden increase in the rate of irreplaceable losses to the Luftwaffe day fighter force, as their heavily laden aircraft were "bounced" long before reaching the bombers. Within weeks, many of their aces were dead, along with hundreds of other pilots, and the training program could not replace their casualties quickly enough . The Luftwaffe put up little fight during the summer of 1944, allowing the Allied landings in France to go almost unopposed from the air. With few planes coming up to fight, Allied fighters were let loose on the German airbases, railways and truck traffic. Logistics soon became a serious problem for the Luftwaffe, as maintaining aircraft in fighting condition became almost impossible. Getting enough fuel was even more difficult because of a devastating campaign against German petroleum industry targets. Origins. Addressing this posed a considerable problem for the Luftwaffe. Two camps quickly developed, both demanding the immediate introduction of large  numbers of jet fighter aircraft. One group, led by General Adolf Galland, the Inspector of Fighters, reasoned that superior numbers had to be countered with superior technology, and demanded that all possible effort be put into increasing the production of the Messerschmitt Me 262 in its A-1a fighter version, even if that meant reducing production of other aircraft in the meantime. The second group pointed out that this would likely do little to address the problem; the Me 262 had notoriously unreliable powerplants and landing gear, and the existing logistics problems would mean there would merely be more of them  on the ground waiting for parts that would never arrive, or for fuel that was not available. Instead, they suggested that a new design be built – one so inexpensive that if a machine was damaged or worn out, it could simply be discarded and replaced with a fresh plane straight off the assembly line. Thus was born the concept of the "throwaway fighter". Galland and other Luftwaffe senior officers expressed vehement opposition to the light fighter idea, while "Reichsmarschall" Hermann Göring and Armaments Minister Albert Speer fully supported the idea. Göring and Speer got their way, and a contract tender  for a single-engine jet fighter that was suited for cheap and rapid mass production was established under the name "Volksjäger" ("People's Fighter"). Volksjäger. The official RLM "Volksjäger" design competition parameters specified a single-seat fighter, powered by a single BMW 003, a slightly lower-thrust engine not in demand for either the Me 262 or the Ar 234, already in service. The main structure of the "Volksjäger" competing airframe designs would use cheap and unsophisticated parts made of wood and other non-strategic materials and, more importantly, could be assembled by semi- and non-skilled labor, including slave  labor. Specifications included a weight of no more than , with maximum speed specified as 750 km/h (470 mph) at sea level, operational endurance at least a half hour, and the takeoff run no more than 500 m (1,640 ft). Armament was specified as either two MG 151/20 cannons with 100 rounds each, or two MK 108 cannons with 50 rounds each. The "Volksjäger" needed to be easy to fly. Some suggested even glider or student pilots should be able to fly the jet effectively in combat, and indeed had the "Volksjäger" gone into full production, that is precisely what  would have happened. After the war, Ernst Heinkel would say, "[The] unrealistic notion that this plane should be a 'people's fighter,' in which the Hitler Youth, after a short training regimen with clipped-wing two-seater gliders like the DFS "Stummel-Habicht", could fly for the defense of Germany, displayed the unbalanced fanaticism of those days." The clipped-wingspan DFS Habicht models had varying wingspans of both or , and were used to prepare more experienced "Luftwaffe" pilots for the dangerous Me 163B "Komet" rocket fighter – the same sort of training approach would also be used for the Hitler Youth  aviators chosen to fly the jet-powered "Volksjäger" design competition's winning airframe design. The requirement was issued 10 September 1944, with basic designs to be returned within 10 days and to start large-scale production by 1 January 1945. Because the winner of the new lightweight fighter design competition would be building huge numbers of the planes, nearly every German aircraft manufacturer expressed interest in the project, such as Blohm & Voss, and Focke-Wulf, whose Focke-Wulf Volksjäger 1 design contender, likewise meant for BMW 003 turbojet power bore a resemblance to their slightly later Ta 183 "Huckebein" jet  fighter design. However, Heinkel had already been working on a series of "paper projects" for light single-engine fighters over the last year under the designation P.1073, with most design work being completed by Professor Benz, and had gone so far as to build and test several models and conduct some wind tunnel testing. Although some of the competing designs were technically superior (in particular to the Blohm & Voss P 211 submission), with Heinkel's head start the outcome was largely a foregone conclusion. The results of the competition were announced in October 1944, only three weeks after being announced , and to no one's surprise, the Heinkel entry was selected for production. In order to confuse Allied intelligence, the RLM chose to reuse the 8-162 airframe designation (formerly that of a Messerschmitt fast bomber) rather than the other considered designation He 500. Design. Heinkel had carried out some design work of a new twin-engine fighter with one engine placed on top of the aircraft and another under the nose, the highest point on the bottom of the fuselage. For the single-engine development, the removed the lower engine and repositioned the remaining upper engine just aft of  the cockpit and centered directly over the wing's center section. This made the overal ballance of the aircraft simple and placed the engine in a convinient point for removal as it could be removed upward with a small crane. This also meant the jet exhaust was over the fuselage and across the tail area. For this reason, the tail was constructed with two small vertical stabilizers positioned to either side of the exhaust path, and the horizontal elevator mounted below it. The horizontal section had considerable dihedral at 14º, raising the vertical stabilizers inline with the wing. The small  wing was high mounted, and held on with four bolts. The leading edge was straight while the trailing edge had a significant forward sweep. The combination of the engine being directly above the pilot and the wings on either side would make a conventional bailout very risky, so the aircraft was designed from the start to feature an ejection seat like the one used in the Heinkel He 219 night fighter. The main landing gear retracted into the fuselage below the wing and were of the tricycle layout. Heinkel had significant previous experience with this layout on earlier designs including  the Heinkel He 280, but this was the first of their designs to use this layout from the start. A small window in the lower cockpit between the rudder pedals allowed the pilot to visually check whether the gear was down. Partly due to the late-war period it was designed within, some of the He 162's landing gear components were "recycled" existing landing gear components from a contemporary German military aircraft to save development time: the main landing gear's oleo struts and wheel/brake units came from the Messerschmitt Bf 109K, as well as the double -acting hydraulic cylinders, one per side, used to raise and lower each maingear leg. Prototypes. The He 162 V1 first prototype flew within an astoundingly short period of time: the design was chosen on 25 September 1944 and first flew on 6 December, less than 90 days later. This was despite the fact that the factory in Wuppertal making Tego film plywood glue — used in a substantial number of late-war German aviation designs whose airframes and/or major airframe components were meant to be constructed mostly from wood — had been bombed by the Royal Air Force and a replacement had  to be quickly substituted, without realizing that the replacement adhesive was highly acidic and would disintegrate the wooden parts it was intended to be fastening. The first flight of the He 162 V1, by "Flugkapitän" Gotthold Peter – the first German jet fighter aircraft design to be jet-powered from its maiden flight onward – was fairly successful, but during a high-speed run at 840 km/h (520 mph), the highly acidic replacement glue attaching the nose gear strut door failed and the pilot was forced to land. Other problems were noted as well, notably a pitch instability and problems with  sideslip due to the rudder design. None were considered important enough to hold up the production schedule for even a day. On a second flight on 10 December, again with Peter at the controls, in front of various Nazi officials, the glue again caused a structural failure. This allowed the aileron to separate from the wing, causing the plane to roll over and crash, killing Peter. An investigation into the failure revealed that the wing structure had to be strengthened and some redesign was needed, as the glue bonding required for the wood parts was in many cases defective. However , the schedule was so tight that testing was forced to continue with the current design. Speeds were limited to 500 km/h (310 mph) when the second prototype flew on 22 December. This time, the stability problems proved to be more serious, and were found to be related to Dutch roll, which could be solved by reducing the dihedral. However, with the plane supposed to enter production within weeks, there was no time to change the design. A number of small changes were made instead, including adding lead ballast to the nose to move the centre of gravity more to  the front of the plane, and slightly increasing the size of the tail surfaces. The third and fourth prototypes, which now used an "M" for "Muster" (model) number instead of "V" for "Versuchs" (experimental) number, as the He 162 M3 and M4, after being fitted with the strengthened wings, flew in mid-January 1945. These versions also included – as possibly the pioneering example of their use on a production-line, military jet aircraft – small, anhedraled aluminium "drooped" wingtips, reportedly designed by Alexander Lippisch and known in German as "Lippisch-Ohren" ("Lippisch Ears"), in an attempt to cure the stability problems  via effectively "decreasing" the main wing panels' marked three degree dihedral angle. Both prototypes were equipped with two 30 mm (1.18 in) MK 108 cannons in the He 162 A-1 anti-bomber variant; in testing, the recoil from these guns proved to be too much for the lightweight fuselage to handle, and plans for production turned to the A-2 fighter with two 20 mm MG 151/20 cannons instead while a redesign for added strength started as the A-3. The shift to 20 mm guns was also undertaken because the smaller-calibre weapons would allow a much greater amount of ammunition  to be carried. The He 162 was originally built with the intention of being flown by the Hitler Youth, as the Luftwaffe was fast running out of pilots. However, the aircraft's complexity required more experienced pilots. Both a standard-fuselage length, unarmed BMW 003E-powered two-seat version (with the rear pilot's seat planned to have a ventral access hatch to access the cockpit) and an unpowered two-seat glider version, designated the He 162S ("Schulen"), were developed for training purposes. Only a small number were built, and even fewer delivered to the sole He 162 Hitler Youth  training unit to be activated (in March 1945) at an airbase at Sagan. The unit was in the process of formation when the war ended, and did not begin any training; it is doubtful that more than one or two He 162S gliders ever took to the air. Various changes had raised the weight over the original 2,000 kg (4,410 lb) limit, but even at 2,800 kg (6,170 lb), the aircraft was still among the fastest aircraft in the air with a maximum airspeed of at sea level and at , but could reach at sea level and at using short  burst extra thrust. The short flight duration of barely 30 minutes was due to only having a single 695-litre (183 US gallon) capacity flexible-bladder fuel tank in the fuselage directly under the engine's intake. The original "Baubeschreibung" document submittal for the He 162 dated mid-October 1944 showed a pair of fuel tanks for the original version of the "Spatz's" airframe as-designed: a single, smaller capacity 640 litre (169 US gal) fuselage main tank in approximately the same location as the later 695 litre tank was placed, with an additional wing centre-section tank just  above and behind it, never produced for the production run, of some 325 litres (86 US gal) feeding by gravity into the main fuselage tank. The A-2 version, in some examples (as the one flown by RN Captain Eric Brown postwar) had an emplacement of a pair of "impregnated" 180 litre (47.5 US gal) wing tanks, one built into each inner wing panel, within the first four wing ribs out from the root and between the spars, that fed into the main 695 litre fuselage tank in a similar manner to what the earlier 325 litre center-section tank had  been proposed to do; but were themselves ungauged, their exhaustion of fuel only marked when the main fuel gauge began to fall during flight. The production He 162A-2 was armed with a pair of 20mm MG 151/20 cannon. He 162 construction facilities were at Salzburg, the Hinterbrühl, and the Mittelwerk. Output was expected to be 1,000 a month by April 1945, double that when the Mittelwerk plant began deliveries. Operations. In January 1945, the Luftwaffe formed an "Erprobungskommando 162" ("Test Unit 162") evaluation group to which the first 46 aircraft were delivered. The group was based at the Luftwaffe  main test center, or "Erprobungsstelle" at Rechlin. February saw deliveries of the He 162 to its first operational unit, I./JG 1 (1st Group of "Jagdgeschwader" 1 "Oesau" — "1st Fighter Wing"), which had previously flown the Focke-Wulf Fw 190A. I./JG 1 was transferred to Parchim, which, at the time, was also a base for the Me 262-equipped "Jagdgeschwader" 7, some 80 km south-southwest of the Heinkel factory's coastal airfield at "Marienehe" (today known as Rostock-Schmarl, northwest of the Rostock city centre), where the pilots could pick up their new jets and start intensive training beginning in  March 1945. This was all happening simultaneously with unrelenting Allied air attacks on the transportation network, aircraft production facilities and petroleum, oil, and lubrication (POL) product-making installations of the Third Reich – these had now begun to also target the Luftwaffe's jet and rocket fighter bases as well. On 7 April, the USAAF bombed the field at Parchim with 134 B-17 Flying Fortresses, inflicting serious losses and damage to the infrastructure. Two days later, I./JG 1 moved to an airfield at nearby Ludwigslust and, less than a week later, moved again to an airfield at Leck, near the Danish  border. On 8 April, II./JG 1 moved to Heinkel's aforementioned Rostock northwestern coastal suburban factory airfield and started converting from Fw 190As to He 162s. III./JG 1 was also scheduled to convert to the He 162, but the "Gruppe" disbanded on 24 April and its personnel were used to fill in the vacancies in other units. The He 162 first saw combat in mid-April 1945. On 19 April, Feldwebel Günther Kirchner shot down a Royal Air Force fighter, and although the victory was credited to a flak unit, the British pilot confirmed during interrogation that he had been  downed by an He 162. The Heinkel and its pilot were then lost as well, shot down at Husum on the same day by Flying Officer Geoffrey Walkington, piloting an RAF Hawker Tempest. Though still in training, I./JG 1 began to score kills in mid-April, but went on to lose 13 He 162s and 10 pilots. Ten of the aircraft were operational losses, caused by flameouts and sporadic structural failures. Only two of the 13 aircraft were actually shot down. The He 162's 30-minute fuel capacity also caused problems, as at least two of JG 1's  pilots were killed attempting emergency deadstick landings after exhausting their fuel. During its exceedingly brief operational service career, the 162's cartridge-type ejector seat was employed under combat conditions by JG 1's pilots at least four times. Fw. Günther Kirchner was the first to attempt an ejection on April 19, but he was too low and was killed when his parachute failed to open. The second recorded use was by Lt Rudolf Schmidt on April 20, with Fw. Erwin Steeb ejecting from his 162 the following day. Finally, Hptm. Paul-Heinrich Dähne attempted an ejection on April 24 , but was killed when the aircraft's cockpit canopy failed to detach. In the last days of April, as the Soviet troops approached, II./JG 1 evacuated from Marienehe and on 2 May joined the I./JG 1 at Leck. On 3 May, all of JG 1's surviving He 162s were restructured into two groups, I. "Einsatz" ("Combat") and II. "Sammel" ("Collection"). All JG 1's aircraft were grounded on 5 May, when General Admiral Hans-Georg von Friedeburg signed the surrender of all German armed forces in the Netherlands, Northwest Germany and Denmark. On 6 May, when the British reached  their airfields, JG 1 turned their He 162s over to the Allies, and examples were shipped to the U.S., Britain, France, and the Soviet Union for further evaluation. "Erprobungskommando" 162 fighters, which had been passed on to JV 44, an elite jet unit under Adolf Galland a few weeks earlier, were all destroyed by their crews to keep them from falling into Allied hands. By the time of the German unconditional surrender on 8 May 1945, 120 He 162s had been delivered; a further 200 had been completed and were awaiting collection or flight-testing; and about 600 more were  in various stages of production. The difficulties experienced by the He 162 were caused mainly by its rush into production, not by any inherent design flaws. One experienced "Luftwaffe" pilot who flew it called it a "first-class combat aircraft." Eric "Winkle" Brown of the Fleet Air Arm, who flew a record 486 different types of aircraft, said the He 162 had "the lightest and most effective aerodynamically balanced controls" he had experienced. Brown had been warned to treat the rudder with suspicion due to a number of in-flight failures. This warning was passed on by Brown to RAF  pilot Flt Lt R A Marks, but was apparently not heeded. On 9 November 1945, during a demonstration flight from RAE Farnborough, one of the fin and rudder assemblies broke off at the start of a low-level roll causing the aircraft to crash into Oudenarde Barracks, Aldershot, killing Marks and a soldier on the ground. He 162 "Mistel". The Mistel series of fighter/powered bomb composite ground-attack aircraft pre-dated the He 162 by over two years, and the "Mistel" 5 project study in early 1945 proposed the mating of an He 162A-2 to the Arado E.377A flying  bomb. The fighter would sit atop the bomb, which would itself be equipped with two underwing-mounted BMW 003 turbojets. This ungainly combination would take off on a sprung trolley fitted with tandem wheels on each side for the "main gear" equivalent, derived from that used on the first eight Arado Ar 234 prototypes, with all three jets running. Immediately after take-off, the trolley would be jettisoned, and the "Mistel" would then fly to within strike range of the designated target. Upon reaching this point, the bomb would be aimed squarely at the target and then released, with the  jet turning back for home. The "Mistel" 5 remained a "paper project", as the Arado bomb never progressed beyond the blueprint stage.