Hatchery of Salamander - underground factory of heinkel He162 at Hinterbrühl

Heinkel He162 during production process in underground
factory at Hinterbrühl

In 1944 Ernst Heinkel went on a search for a bombproof production site for the  He162 "Salamander", the choice fell on the lake grotto. The underground lake was drained, the floor filled with concrete and the necessary equipment installed (lighting, heating, ...)
Despite the terrible situation as a whole in 1944/45 could be made in the tunnels 198 fuselages of the "People's hunter". Employees were over 2000 people, including 1700 KZ prisoners from KZ Hinterbrühl. The final assembly was carried out in Schwechat - Heidfeld in Heinkel factory at today's airport



"On August 4, 1943 a satellite camp of Mauthausen concentration camp was built in the city. The prisoners there built parts, sub-assemblies and BMW 003 turbojet engines for the He 162 jet fighter in a hastily converted underground factory during late autumn and spring 1945. The 162, known as the Emergency Fighter or People's Fighter (Volksjäger) was an extremely lightweight, cheap and fast plane that could be discarded if it suffered any damage. Hinterbrühl was just part of a vast crash production program where

Location in Austria

dozens of factories of varying sizes would make parts for the jet, then send them to sites like Hinterbrühl for final assembly and transshipment to flight test centers — or even directly to airbases, such was the desperate last-minute nature of the enterprise.

In the last days of the war in 1945, the inmates of other camps had to make a 200 km-long march to the concentration camp Mauthausen in Hinterbrühl. Virtually none of them survived. Fifty-one inmates were killed even before the march by a gasoline injections or strangled by SS officers. In 1988 a monument was erected above the Subterranean Lake to honor the 51 victims of this massacre."

 parts of planes produced in the underground factory
exhibited in the tunnel

"In Autumn 1943 a sub-camp of the Mauthausen concentration camp had been built at the Hinterbrühl mine. The camp would house 1.800 forced laborers who were building an underground factory in the mine, with the subsequent work to be the production of parts for airplanes. The factory was codenamed Languste, or crayfish. After all the water was pumped out of the old mine, a new floor was laid in what was now to become the production hall. Work started quickly and the 1.800 forced laborers and 300 skilled workers started turning out airframes for Heinkel He 162. A total of 198 of these airframe were produced before the factory was closed in the spring of 1945. During the evacuation, 51 forced laborers were executed and the rest sent on a death march back to Mauthausen. Almost no one survived. The Germans had plan to blow up the entire underground facility, but an Austrian soldier in the German army managed to prevent it and only a few of the charges detonated. However, the pumps that kept water from refilling the mine were destroyed during the explosion and the mine again filled with water. After the war a major clean-up began and in the spring of 1949 the underground lake was again opened to the public with boat trips."

The prototype of the Heinkel He 162 was lost by a dramatic crash on 10 December 1944th Photo KL documentation

The underground factory Hinterbruhl, Austria.This factory was tasked with building Heinkel 162s, a jet fighter built of cheap materials near the end of the war. The fighters were referred to as “Volksjaeger” with the idea that the aircraft would be easy to fly for new pilots, though in reality the aircraft was very difficult to handle. This photograph shows tens of fuselages awaiting wings and engines.Only a few Heinkel 162s ever saw active service due to its late war introduction

On of the assembly hall in Hinterbrühl complex

The fuselages of Heinkel He162 Salamander under the production process at  Hinterbrühl, Austria.

Partially completed Heinkel He-162 fighter jets sit on the assembly line in the underground factory at  Hinterbrühl, Austria.

Sources:

https://en.wikipedia.org/wiki/Hinterbr%C3%BChl

http://www.battlefieldsww2.com/Aircraft_factory_Seegrotte.html