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THE UNDERGROUND AIRPLANE

When Robert Bush saw a Heinkel He 162 Volksjäger (People’s Fighter) while flying a combat mission, he thought it was some sort of mysterious bomb or missile. The words aerial torpedo sprang into his mind.

“We’d been briefed on German jets and had a recognition chart showing what a Messerschmitt Me 262 jet fighter looked like. There were rumors the Germans were working on other strange and new gadgets. But nothing in our briefing covered a short, stub-winged jet that looked a little like an arrow shot from a quiver. No one had told us anything about this,” he said.

Early 1945

Bush was in a P-51 Mustang with a broken heater at twenty-eight thousand feet over Germany. He was cold. He’d never felt so cold. Below him, cloud banks interrupted the sky at intervals of altitude. The He 162 was at about sixteen thousand feet moving in a straight line. Bush saw puffs escaping from the back of the aircraft.

“I uncaged my K-14 gunsight, said something to my wingman, rolled over, and went after him,” Bush said. His wingman followed and two silvery Mustangs went into a forty-five-degree dive behind the He 162.

“My flight leader was pissed off and said something on the radio about flight discipline. That’s when I realized that my plan to get up close to this ‘thing’ wasn’t working. It continued to give off spurts of exhaust and to pull away from me,” Bush said.

Bush said he returned to formation, made his way home, and got an “ass chewing” for being curious about a flying object that was too far away, and too fast, to catch. He still didn’t know what it was. Rumors about mysterious and even magical German weapons were making the rounds, but no one seemed to have heard of this one. Bush sat down with a pair of flinty intelligence officers—not by choice, he was ordered to—and made sketches while giving his account. “They didn’t thank me, but about three weeks later, in the very final days of the war, we finally got a briefing and we all knew what it was,” Bush said.

The Heinkel He 162 Volksjäger, built under a program called Salamander, was a shoulder-wing monoplane of mostly wooden construction with retractable tricycle landing gear and a tailplane with twin fins astride an upwardly canted horizontal stabilizer. This design allowed its single turbojet to be positioned in an easy maintenance position atop the fuselage with the exhaust blowing straight back. It was supposed to be the aircraft any youngster could fly. It was also called the Emergency Fighter—a rushed attempt by the Reich’s battered armaments industry to provide a mass-produced fighter that would stem the Allied bombing offensive on Germany. In a perfect world, it would be incredibly cheap, anyone could fly it, and it could be disposed of easily if it suffered damage. It might have helped had there existed a ground simulator to train fledgling pilots, but the concept of a simulator still lay in the future.

Mustang pilot Bush, the ex–Boy Scout from Washington, D.C., came as close to shooting down a He 162 as any American in World War II. “I learned only years later that it was a very interesting and very formidable aircraft. I learned that I probably would never have caught it because it was so damned fast. Apparently, nobody ever came any closer to a He 162 than I did,” he said.

September 8, 1944

Minus Ernst Heinkel himself, the company bearing his name wanted a second chance—following its near success with the Heinkel He 280—to get an operational jet into service. The company submitted its design as part of an overall program called Salamander to fulfill a September 8, 1944, requirement for a simple, lightweight jet fighter that even a novice could operate—specifically, a teenage member of the Hitlerjugend (Hitler Youth).

The requirement amounted to an invitation to the German aircraft industry, which was in the process of vexing the Allies by continuing to develop and produce aircraft even while being bombed. Industry was happy to respond. At first glance, it appeared to be an opportunity to manufacture an enormous number of aircraft, possibly several thousands, paid for from the coffers of the Reich. The intended production goal was no fewer than four thousand airframes per month, to overwhelm the Allies with sheer numbers.

Focke-Wulf weighed in with a variation of designer Kurt Tank’s previous, and never built, Ta 183, a jet design with high-swept wings and a T tail. The Ta 183 itself would later exert enormous influence on the Soviet Union’s Mikoyan-Gurevich design bureau, with a curious and unforeseen result: in the 1950s, a fake photo of the Ta 183 emblazoned with red stars would appear everywhere in American fan magazines labeled as the MiG-19. In reality, no version of the Ta 183, even one with a MiG prefix, was ever built, although the design influenced the MiG-15 of Korean War fame.

Blohm und Voss, already well known for weird and wonderful aircraft designs, weighed in with a very sensible design for a fighter for the common man, but the Heinkel design team had too much of a head start. Since the designation of P.1073, Heinkel had been mulling small, single-engine jet fighter designs for years and had a solution ready on the drawing board. The Heinkel firm was given an order on September 15, 1944, only a week after the requirement was enunciated.*

Of course, the idea of a jet fighter for the common folk resulted from a motive stronger than egalitarianism. The Reich’s leaders were worried about real and anticipated shortages of strategic materials, and the Volksjäger was constructed primarily of wood. This concern about aluminum, rubber, plastic, and other materials was reflected on both sides and was seen in a small, prop-driven American fighter, the Bell XP-77. In the case of both sides, it was essentially a false alarm since supplies remained abundant; Germany was still manufacturing aircraft at a respectable rate on the last day of the war.

A more realistic motive behind the simplicity of the He 162: it could be assembled on a crude assembly line in the field, far from any building that might be easily identified as an aircraft factory, using unskilled or semi-skilled labor. While Ernst Heinkel, unlike Willy Messerschmitt, never made use of slave laborers, the Heinkel company after his departure suffered no such compunction. The He 162 was, to put it bluntly, a throwaway fighter, one that could be lost along with its hapless pilot at relatively little expense to the Reich. For all of that, it was fundamentally a solid design and was not, as often described, flimsy. It offered excellent aerodynamic properties and, once away from the airfield pattern, was a stable and reliable platform.

Generalleutnant (Maj. Gen.) Adolf Galland, the seasoned ace in command of the Luftwaffe’s fighter force, bitterly opposed the Volksjäger and the concept behind it since he felt it would divert resources from existing aircraft programs, particular the Messerschmitt Me 262 jet fighter. Galland objected with the support of Willy Messerschmitt and Focke-Wulf’s Kurt Tank. But the Volksjäger was a concept dear to the Führer himself and backed by Göring and Speer, so the objections went nowhere.

The Heinkel company was instructed to have a full-scale mockup ready by October 1, a finished aircraft by December 10, and the beginning of production on an unspecified date in January 1945. It met all of these goals. Wind tunnel tests, also completed in January, demonstrated some instability at high speeds and other control issues but proved that this was a workable, high-speed combat aircraft. The wind tunnel effort did not begin until after the aircraft was flying. It demonstrated, as an American technical report later explained, an aerodynamic need for a slight downward displacement of the wing or by drawing down the trailing edge of the landing flaps.

1943 and 1944

Throughout the Reich—in Germany, Austria, and Czechoslovakia—the Germans continued to produce “Ottos” (propeller-driven planes), jets, and other “wonder weapons,” despite Allied bombing because of a massive effort to move assembly plants underground. In August 1943, Hitler ordered assembly of the V-1 robot bomb and the V-2 rocket (the “V-weapons”) moved underground.

A broader effort to put production capacity beneath the surface came much later, with a February 1944 general order to disperse the aircraft industry.

One of the best-known subterranean plants was Mittelwerk, at Thüringen near Nordhausen, where slave laborers assembled V-weapons and Messerschmitt Me 262 jet fighters inside tunnels carved deep within a mountain. They also manufactured Taifun antiaircraft missiles and, near the end of the war, the He 162.* Three colossal underground facilities in Czechoslovakia were dubbed the Rabštejn Underground Factory (dug out of sandstone rock in northern Bohemia), Underground Factory Richard (inside a hill near the city of Litoměřice), and Underground Complex Výpustek (dug out of karst in the south of the country). Five thousand prisoners from the Terazin concentration camp died in constructing Richard, which is a series of low-ceilinged caves where many kinds of weapons were built.

Two groups of woodworking/furniture manufacturing companies were established in Erfurt and Stuttgart for the difficult task of assembling and bonding the He 162’s wooden tail section, wings, and other components. Metal fuselages and completed aircraft were to be produced at Aschersleben, Barth, Bernburg, Halberstadt, Leopodsall, Oranieburg, Pünitz, and Stassfurt, and in a former salt mine at Tarthun.

March and April 1945

Belatedly placed into operation in March 1945, the Tarthun underground facility (code name Maulwurf and also known as Egeln), near Magdeburg, occupied about two hundred thousand square feet in a salt mine. There, some 2,400 men performed subassembly work twelve hours a day, seven days a week, and final-assembled Focke-Wulf Fw 190s, Junkers Ju 88s, and especially the He 162. The workers lived in camps near the mine or in the adjacent town of Schönbeck.

Most of this remained unknown to the Allies, until soldiers of the U.S. Ninth Army arrived at Egeln. On April 14, 1945, the New York Times reported: “Two curious American soldiers today unlocked the secrecy surrounding Adolf Hitler’s deadly jet-propelled plane by strolling through a salt mine and literally dropping into a vast underground factory.”

Private First Class James Prenger and Warrant Officer Joseph Crocker descended into the mineshaft, dropping 950 feet in a small elevator, and discovered a factory winding through miles of subterranean corridors—most of it dismantled and wrecked by the Germans the previous day. The corridors were paved with concrete, and there were motor-driven carts for key employees and inspectors to travel through the plant. Like so many of the subterranean plants, Tarthun/Egeln was not only untouched by bombing, but it also was apparently never detected while fighting was under way.

In the He 162 program, engines were to be produced in a salt mine in Urseburg, to which the Berlin-Spandau and Basdorf-Zülsdorf engine plants had transferred. Pre-production He 162s were produced at Schwechat, which was phased into the mass production effort. Many 162 fuselage units, the only component of the aircraft using more than a token amount of metal, were assembled at Seegrotte, a former chalk mine at Hinterbrühl on the outskirts of Vienna, also known as the Langusta (Lobster) assembly plant. This was also the site of final assembly of most of the He 162s built.

Seegrotte was the site of the largest underground lake in Europe, and it became a subterranean aircraft factory. To permit installation of production equipment—including jigs and holding fixtures needed to integrate and install structural parts, ribs, longerons, stiffeners, and aircraft skin—water had to be pumped out of the mine every day and warm air had to be pumped in. Much of the underground work on He 162 fuselages at Seegrotte was performed by slave labor from the Hinterbrühl satellite camp of the Mauthausen Concentration Camp, and some by Allied prisoners of war.*

Hastily developed, the He 162 had structural problems related to its wooden construction. It was nearly all wood (except for for principal fuselage components, which were all metal). It made extensive use of an adhesive that turned out to be harmfully acidic, failed to bond properly, and caused technical problems. Some attribute the Volksjäger’s infamous fin and rudder problems—the tail routinely broke off and fell away during maneuvering, with fatal results—to problems with the glue, at least in part.

The He 162 was designed to use Tego film, a casein adhesive similar to the Aerolite used on the British De Havilland Mosquito. The only factory that produced Tego film was destroyed in an Allied bombing raid. The Heinkel firm then resorted to what was later called ersatz glue, developed by Dynamit AG of Leverkusen. This was a cold resin glue that was straightforwardly applied, unlike the planned Tego adhesive, which was placed on the wood and then heated while the sheets were in a press. The ersatz glue left an acidic residue after curing, which ate at the very wood it was supposed to be bonding. The problem was well known to those who were building and fielding the He 162. They made improvements in the curing process and other changes, but they never completely resolved the glue-wood bonding issue.

From an aerodynamic and engineering standpoint, the He 162 was a sound aircraft. Its small size made the He 162 difficult for an adversary to see, an early form of stealth. The pilot of the He 162 had superb visibility straight ahead and to the side. However, the engine location blocked visibility to the rear, making it necessary for the pilot to maneuver from side to side in order to “check six”—observe the six o’clock position behind the plane.

Engine reliability was always a concern for all of the German jets. In the case of the Me 262, a complete failure of one engine would leave a second engine still functioning. But the He 162 had just one jet engine. All of the available German turbojet engines were tried on the He 162, including the BMW 003A-1 Sturm (Storm) and the Junkers Jumo 004. All had slow throttle response. All had high rates of flameouts and other failures. But when the engine worked, and when the pilot didn’t over-control the rudder, the He 162 had world-beating potential: some German officers envisioned swarms of He 162s engaging Allied fighters, freeing up the less nimble Me 262s to attack the bombers.

From nose to tail, the He 162 made economical use of all functions—lift, propulsion, yaw, roll, and bank. Its low weight, high-thrust engine (when it worked properly), and the small size of the aircraft combined with its sensibly sized wings and aerodynamically clean design to give the He 162 high speed, a high rate of climb, and a superb turn rate and roll characteristics. British test pilot Eric Brown, who evaluated the He 162 after the war, called it a first class fighter, fun, and a delight to fly. Brown was unique, having flown nearly all of the jet aircraft of the era—American, British, and German. He repeatedly said the He 162 was the easiest and most comfortable of the lot.

But Brown also warned that the He 162 had too much rudder response and that its twin fins could fall off if overhandled. This well-known issue is probably overstated in literature about the Heinkel jet: pilots tend to control fighter aircraft aggressively. The He 162 was designed in an era when pilots used a lot of rudder. But in a jet, the pilot doesn’t need to use a lot of rudder, just enough to coordinate a turn or correct for a crosswind when landing. The rudder handling issue would have been resolved in time with training, practice, and greater institutional knowledge.

Reactions were different in France, where half a dozen test pilots tested the He 162 in the postwar era. They found it pleasant to fly but difficult to maneuver. When a He 162 landed with a landing gear door torn partway off the aircraft, indicating that the He 162 could be unpredictable, the French discontinued their test flights.

Only one version appeared in numbers before the war ended, the He 162A. It had two variations: the He 162A-1 was armed with two 30mm Rheinmetall MK108 cannons with one hundred rounds per gun and with their short barrels entirely enclosed within the fuselage; empty shell casings were extracted by the belts that fed the gun, rendering an ejection port unnecessary on the A-1 model. The He 162A-2 dispensed with these big guns and offered two lighter high-velocity Mauser MG 151 20mm cannons with 120 rounds per weapon and with their longer barrels protruding from the fuselage and with portals for ejected shell casings below and beyond the nose wheel. Both the A-1 and A-2 variants were flown with all of the Reich’s models of jet engines.

A distinguishing feature of the He 162 was the turbojet engine mounted in a housing atop the fuselage on the centerline. The oil tank and other supporting equipment were positioned atop the engine housing, giving it a distinct bulge. Just forward of the engine air intake was the hinged, bubble-type canopy.

Some features of the He 162 were remarkable. Together with the propeller-driven Dornier Do 335 Pfeil (Arrow) tandem tractor-pusher and Heinkel He 219 Uhu (Eagle-Owl) twin-engine night fighter—each a very advanced aircraft in its own right—the He 162 had an ejection seat similar to all that would be used on future jet aircraft for decades to come. The parachute was stored in the seat pan. An explosive cartridge fired the seat vertically up two rails. This made it different in kind from the compressed-air ejection seat of the Heinkel He 280 and more like the seats used on jet aircraft in postwar years. In a curious sidelight, ejection seats were tried on the Me 262 but were not used operationally.

December 6, 1944

Haste was the keynote with the He 162. Rushing the aircraft into production, the Heinkel firm relied on a landing gear design copied with minor variations from the Messerschmitt Bf 109. Officials at the company claimed that because their aircraft was so simple and light, it would achieve with one engine the same performance the Me 262 attained with two.

Rushed into production with less than one hundred days elapsing from production order to actual flight, the He 162 first took to the air on December 6, 1944. On its second flight, the leading edge of its unswept wing collapsed and the prototype broke up in the air. The crash was mysterious: it may have been caused by a phenomenon known later as inertia coupling. This is a potentially deadly phenomenon in high-speed flight in which the inertia of the heavier fuselage overpowers the aerodynamic stabilizing forces of the wing and tail section. The problem became apparent as single-engine jet fighter aircraft were developed with narrow wingspans that had relatively low roll inertia, relative to the pitch and yaw inertia dominated by the long slender high-density fuselage.

Intentionally flimsy in design, the He 162 turned out to be structurally too weak to accommodate the two 30mm cannons installed on the He 162A-1 variant. This was the reason for the shift in armament that resulted in two lighter and somewhat smaller 20mm cannons being substituted on the He 162A-2 version.

Some 116 He 162s were built. The aircraft came from the facilities named above, plus plants operated by Heinkel and separately by Junkers in Vienna. In January 1945, the Luftwaffe formed a special Erprobungskommando 162 He 162 test pilot evaluation group to which the first forty-six aircraft were delivered. The group was based at the Luftwaffe test center at Rechlin under the command of Heinz Bär. Bär, an experienced combat pilot credited with two hundred kills, familiarized himself and his group with the new airplanes.

February saw deliveries of the He 162 to its first operational unit, Jagdgeschwader 1 (No. 1 Fighter Wing). After JG 1, two additional units were slated to be equipped with the type, but the war ended before they could receive aircraft. The He-162A-2 was the main production variant. However, several prototypes of different versions were built with various engine types installed.

Only experienced line pilots flew the He 162. The dream of an aerial army of young Hitler Youth pilots was never realistic. The learning curve was too steep, and, as it turned out, time was too short. Although the He 162 had some qualities that would have made it user-friendly in the hands of a fledgling pilot with minimal training—it was almost impossible to mishandle on final approach and extremely gentle during a landing—potential Hitler Youth He 162 pilots never advanced beyond initial flight training using towed gliders.

April 19, 1945

With the He 162 belatedly in combat, on April 19, 1945, a British fighter pilot who had been captured told his German interrogators that he had been shot down by a jet fighter whose description was clearly that of a He 162. The Heinkel and its pilot were lost during the same fray, shot down by a Hawker Tempest fighter while returning to base.

The only American to claim a He 162 in combat was 2nd Lt. Guy F. Cary of the 15th Tactical Reconnaissance Squadron on March 18, 1945. But the U.S. aerial victories credits list does not identify the type of aircraft flown by the shooter or the type shot down, and evidence suggests that Cary actually shot down an Me 262.

Pilot Leutnant (2nd Lt.) Rudolf Schmitt had the only successful use of an ejection seat in a He 162 on April 20, 1945. Having lived to fight again, on May 4, 1945, Schmitt was credited with shooting down a Tempest. This may have been the Reich’s last air-to-air victory because the war ended four days later. Schmitt was said to have been a relative novice, so his air-to-air victory is evidence of the He 162’s mostly unrealized potential. The literature about Schmitt is confusing and contradictory, and one source asserts that while Schmitt claimed a He 162, the German side credited the kill to an antiaircraft battery.

Many planned versions of the Volksjäger never progressed beyond the drawing board. One version had swept-back wings (He 162C), another swept-forward wings (He 162D), and yet another (He 162E) a butterfly or V tail of the kind seen in postwar years on the Beech Bonanza. The BMW 109-003R turbojet propulsion unit with rocket boost was tested just once on an Me 262C-2b, but plans to fly an He 162E with this power unit didn’t materialize before war’s end.

Watson’s Whizzers, the American team that evaluated captured German aircraft after the war, got their hands on a He 162. They spent several weeks wringing it out at Landsberg, Germany, in the summer of 1945 before taking it to the United States.

The Soviets also gathered up major parts of three unfinished Heinkel He 280s as well as two Me 262s found fully intact at a nearby airfield. Both the Americans and the Soviets conducted exhaustive postwar testing of their Nazi booty, including the He 162. Robert A. “Bob” Hoover, who spent sixteen months as a prisoner of war in German hands and was later a famous air show pilot, made a single flight in the He 162A-2 at Muroc, California (site of the future Edwards Air Force Base), in July 1946. Hoover commented that because the controls lacked any kind of power boost, he had to use both hands to put the Heinkel jet into a turn. Hoover called the aircraft “very risky” and reported, as any German pilot could have told him, that the landing speed of the He 162 was too high. This captured example apparently never flew again. Today, the aircraft Hoover flew is a display artifact in the Planes of Fame Museum in Chino, California, wearing authentic markings including the name Nervenklau (Nerve Stealer), the nickname of its last German pilot, Leutnant (2nd Lt.) Gerhard Hanf.

*The idea of a simple, cheap “wonder weapon,” a “people’s fighter” that could be operated by just about anyone, must have been influenced by the Volkswagen, the “people’s car” concept. In a country where few owned automobiles, Adolf Hitler wanted anybody to be able to own a car, and the Führer’s wishes coincided with a proposal by car designer Ferdinand Porsche—although much of this design was inspired by the advanced Tatra cars of Hans Ledwinka. The concept dates to the 1920s, became a 1937 project by a German trade union, and produced several designs before evolving into the postwar Beetle. The Volkswagen may have evolved into a trendy personal get-about in the 1960s for American college girls who wouldn’t give the time of day to the author of this book, but the Volkswagen began as the Volksjäger did, in a quest for simple construction, low cost, and wide availability.

*The underground camp at Oberammergau is discussed in chapter 16 and is where Willy Messerschmitt ended his war.

*Soviet troops captured two He 162s at Seegrotte that were sent back to Moscow for testing. Today, a small museum-style display at Seegrotte preserves two He 162 instrument panels, a set of landing gear, and other bits and pieces of the aircraft.

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