Heinkel He 162 Volksjager
|He 162 120230 during post-war trials, USA.
||6 December 1944
The Heinkel He 162 Volksjäger (German, "People's Fighter"), the name of a project of the Emergency Fighter Program design competition, was a German single-engine, jet-powered fighter aircraft fielded by the Luftwaffe in World War II. Designed and built quickly, and made primarily of wood as metals were in very short supply and prioritised for other aircraft, the He 162 was nevertheless the fastest of the first generation of Axis and Allied jets. 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 construction program, and Spatz ("Sparrow"), which was the name given to the plane by Heinkel.
The crippling 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 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 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 had ordered a change in fighter tactics earlier in 1944, amounting to an air supremacy entry into German airspace far ahead of the bombers' combat box formations — when at the end of April, he added additional directives allowing the fighters, following the bombers' flight back home to England, to roam freely over Germany and 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. 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, with maintaining aircraft in fighting condition becoming almost impossible. Getting enough fuel was even more difficult because of a devastating Oil Campaign of World War II against German petroleum industry targets.
He 162 120077, surrendered to the British at Leck, pictured at Freeman Field, Indiana, 1945
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 der Jagdflieger ("General of Fighters") Adolf Galland, 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").
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 262A or the Ar 234B, 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 2,000 kg (4,400 lb),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 20 mm (0.79 in) MG 151/20 cannons with 100 rounds each, or two 30 mm (1.2 in) 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 8 m (26 ft 3 in) or 6 m (19 ft 8 in), 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.
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 Blohm + Voss's 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.
Heinkel had designed a relatively small, 'sporty'-looking aircraft, with a sleek, streamlined fuselage. Overall, the look of the plane was extremely modernistic for its time, appearing quite contemporary in terms of layout and angular arrangement even to today's eyes. The BMW 003 axial-flow turbojet was mounted in a pod nacelle uniquely situated atop the fuselage, just aft of the cockpit and centered directly over the wing's center section. Twin roughly rectangular vertical tailfins were perpendicularly mounted at the ends of highly dihedralled horizontal tailplanes - possessing dihedral of some 14º apiece - to clear the jet exhaust, a high-mounted straight wing (attached to the fuselage with just four bolts) with a forward-swept trailing edge and a noticeably marked degree of dihedral, with an ejection seat provided for the pilot — which the Heinkel firm had pioneered in a front-line combat aircraft, with the earlier He 219 night fighter in 1942. The He 162 airframe design featured an uncomplicated tricycle landing gear, the first such landing gear system to be present from the very start in any operational Axis Powers single-engined fighter design, that retracted into the fuselage, performed simply with extension springs, mechanical locks, cables and counterweights, and a minimum of any hydraulics employed in its design. 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. The Heinkel firm's previous experience with designing flightworthy, retractable tricycle undercarriage-equipped airframes extended as far back as late 1939 with the Heinkel He 280 jet fighter prototype, and further strengthened with the unexpectedly successful Heinkel He 219A night fighter, which also used a tricycle undercarriage.
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 was far too complicated for any but a highly experienced pilot. 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, did not begin any training, and it is doubtful that more than one or two He 162S gliders ever took to the air.
The Hinterbrühl underground production line for the He 162A was captured in April 1945
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 790 km/h (427 kn; 491 mph) at sea level and 839 km/h (453 kn; 521 mph) at 6,000 m (20,000 ft), but could reach 890 km/h (481 kn; 553 mph) at sea level and 905 km/h (489 kn; 562 mph) /h (562 mph) at 6,000 m (20,000 ft) using short burst extra thrust. The short flight duration of barely 30 minutes - only somewhat better than the even shorter 7.5-minute flight duration of the faster-flying Me 163B rocket fighter - 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 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 Mittlewerk plant began deliveries.
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 and it is frequently stated this unit was under the command of Heinz Bär. Bär, an experienced combat pilot credited with more than 200 kills, gained 16 of his victories with an Me 262 as commander of operational training unit III./Ergänzungs-Jagdgeschwader 2 (EJG 2). However, Bär's personal documents do not confirm his presence at Erprobungskommando 162 or if he ever flew He 162s.
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, all while the transportation network, aircraft production facilities and petroleum, oil, and lubrication (POL) product-making installations of the Third Reich had been collapsing under the pressure of continued Allied air attacks, which had begun to also target the Luftwaffe's jet and rocket fighter bases. On 7 April, the USAAF bombed the field at Parchim (an airfield used by JG 7) 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 Marienehe 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.
Paperwork issues meant none of the He 162 formations officially became operational, but the He 162 finally saw combat in mid-April. 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 he'd been downed by a He 162 during interrogation. The Heinkel and its pilot were lost as well, shot down by an RAF Hawker Tempest while on approach to land (a point when German jets were at their most vulnerable). Though still in training, I./JG 1 had scored a number of kills beginning in mid-April, but had also lost 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.
Captured He 162 120230 in France
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." This opinion was mirrored by Eric "Winkle" Brown of the Fleet Air Arm (FAA), who flew it not only during post-war evaluations, but went on to fly it for fun after testing had completed. He considered it delightful to fly, although the very light controls made it suitable only for experienced pilots. He wrote about his He 162A flights in Wings of the Luftwaffe, a description that has been reprinted in many media over the years. 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 A-0 — first ten pre-production aircraft.
- He 162 A-1 — armed with two 30 mm (1.18 in) MK 108 cannons with 50 rounds per gun.
- He 162 A-2 — armed with two 20 mm MG 151/20 cannons with 120 rounds per gun.
- He 162 A-3 — proposed upgrade with reinforced nose mounting twin 30 mm MK 108 cannons.
- He 162 A-8 — proposed upgrade with the more powerful Jumo 004D-4 engine of 10.3 kN (2,300 lbf) top thrust levels. Muster (model) prototype airframes M11 and M12's testing revealed a top speed of 885 km/h (550 mph) at sea level at normal thrust and 960 km/h (597 mph) with maximum thrust, close to the Me 163B rocket fighter's top velocity figures.
- He 162 B-1 — a proposed follow on planned for 1946, meant to use the Heinkel firm's own, more powerful 12 kN (2,700 lb) thrust Heinkel HeS 011A turbojet, a stretched fuselage to provide more fuel and endurance as well as increased wingspan, with reduced dihedral which allowed the omission of the anhedral wingtip devices. To be armed with twin 30 mm (1.18 in) MK 108s.
- The He 162B airframe was also used as the basis for the Miniature Fighter Project design competition powered by one or two "square-intake" Argus As 044 pulsejet engines. The pulsejet, however didn't provide enough thrust for takeoff and neither Heinkel nor the OKL showed much enthusiasm for the project.
- He 162C — proposed upgrade featuring the B-series fuselage, Heinkel HeS 011A engine, swept-back, anhedraled outer wing panels forming a gull wing, a new V-tail stabilizing surface assembly, and upward-aimed twin 30 mm (1.18 in) MK 108s as a Schräge Musik weapons fitment, located right behind the cockpit.
- He 162D — proposed upgrade with a configuration similar to C-series but a dihedraled forward-swept wing.
- He 162E — He 162A fitted with the BMW 003R mixed power plant, a BMW 003A turbojet with an integrated BMW 718 liquid-fuel rocket engine — mounted just above the exhaust orifice of the turbojet — for boost power. At least one prototype was built and flight-tested for a short time.
- He 162S — two-seat training glider.
- Tachikawa Ki 162 — proposed license-built version of He 162A in Japan, projected with Lorin ramjet and Argus pulsejet for first design.
Wk. Nr. 120227, RAF Museum, London
Wk. Nr. 120235, Imperial War Museum, London (now moved to Duxford)
Wk. Nr. 120086, Canada Aviation and Space Museum, Ottawa
Specifications (He 162A)
- Crew: 1, pilot with ejection seat
- Length: 9.05 m (29 ft 8 in)
- Wingspan: 7.2 m (23 ft 7 in)
- Height: 2.6 m (8 ft 6 in)
- Wing area: 11.16 m² (120 ft²)
- Empty weight: 1,660 kg (3,660 lb)
- Max. takeoff weight: 2,800 kg (6,180 lb)
- Powerplant: 1 × BMW 003E-1 or E-2 (meant for dorsal fuselage attachment) axial flow turbojet, 7.85 kN (1,760 lbf)
- Fuel capacity of 695 litres (183 US gallons), allowing maximum 30 minute mission profile
- Maximum speed: 790 km/h (491 mph) at normal thrust at sea level; 840 km/h (522 mph) at 6000 m (19,680 ft); using short burst extra thrust 890 km/h (553 mph) at sea level and 905 km/h (562 mph) at 6000 m (19,680 ft).
- Range: 975 km (606 mi)
- Service ceiling: 12,000 m (39,400 ft)
- Rate of climb: 1,405 m/min (4,615 ft/min)
- Guns: 2 × 20 mm MG 151/20 autocannons with 120 rpg (He 162 A-2) OR 2 × 30 mm MK 108 cannons with 50 rpg (He 162 A-0, A-1)