GM- 1 was a method to increase the performance of aircraft engines above the full pressure head by injection of nitrous oxide (laughing gas), which was used by the Luftwaffe during the Second World War.
The injection of nitrous oxide as a means of improving the performance went back to a 1939 submitted to the German Research Institute for Aviation by Otto Lutz proposal. The first development and testing was carried out at the test site Rechlin E3 in cooperation with the Lower Saxony equipment construction company. First flight tests were conducted with a Bf 109 E with an engine DB 601 A. In the course of the tests proved the feasibility and good performance of the system.
The aim was to compensate for the lack of oxygen to the full pressure level by the injection of oxygen or even to achieve improved performance over the normal power addition. The injection of pure oxygen does not make sense, as this would quickly lead to overheating of the engine and a strong tendency to knock when burned. Developed in the German Reich and used in several German aircraft successfully process using an oxygen carrier has done outstanding work in the war effort. As an oxygen carrier in this case nitrous oxide ( chemical formula N2O, laughing gas) was used, the mixture was derived from first under the code - name " HA HA" out. It became known later as the so-called Goering Mix GM 1
The performance gain can be motor technically explained as follows: The nitrous oxide injection increased the amount of oxygen in the combustion chamber, and allowed complete combustion and above the full pressure altitude. Further, the injection caused by the heat of vaporization of the liquid gas, a cooling of the charging air and thus an increase in the amount of charge in the combustion chamber.
While initially pressurized liquefied N2O ( pressure necessary to liquefy 80 bar ) was used came from 1941/42, because of the fire sensitivity of the container kälteverflüssigtes nitrous oxide ( boiling point -90 ° C ) are used. For this purpose, first had to be developed thermally insulated container for the use and transport.
The injection pressure was 4 bar. The injection quantity could be controlled in some patterns, such as the s Jumo 213E in three stages of 60, 100 and 150 g /. At the maximum injection a performance gain could be achieved up to 400 hp depending on engine type in the insert height. With a Bf 109 G-1/R2 settled with GM-1 plant 100 km / h gain in speed in 12,000 m and a peak altitude of 13,800 m achieve. When used in altitude reconnaissance Ju 88T with BMW -801 -G -2 engines was the performance that fell in these machines in 10,000 m altitude of 1,730 to 880 hp, will be enhanced by GM-1 to 1,430 hp.