Installation of the GM-1 System in the Bf 109
It is widely known that the GM-1 was a system devised to increase engine power at high altitude by injecting liquid nitrous oxide into the engine's intake compressor. Here, I will explain how the system was installed in the Bf 109 and the principle on which it was based.
HISTORY
Installation of the
GM-1 System in the Bf 109
Pavel Raška
It is widely known that the GM-1 was a system devised to increase engine
power at high altitude by injecting liquid nitrous oxide into the engine's
intake compressor. Here, I will explain how the system was installed
in the Bf 109 and the principle on which it was based.
Nitrous oxide, commonly referred to as laughing
gas, can be stored in liquid state in two ways:
1. at room temperature in special bottles under
a pressure of 80 bar or about 1160psi.
2. at normal atmospheric pressure at
a temperature of -90°C.
Both of these methods were used in the following
versions of the Bf 109:
1. Bf 109 E-7/Z. The first ever GM-1 installation in
the Bf 109 employed the first method using three
pressure cylinders installed in the fuselage
behind the pilot. It was called ‘MONA’, but it is
not clear what the acronym stood for. I can only
assume that this is a typical German abbreviation,
and may stand for ‘MOtorleistungsNAchschub’.
Externally, the aircraft differed from the
standard E version by the presence of two filler
caps for filling the pressure bottles on the left
side of the fuselage behind the cockpit.
2. Bf 109 F-4/Z. Here, the pressure bottles were
moved from the fuselage to the wing. It should
be mentioned that the Bf 109 from the F version
on had newly designed wings that had two
free spaces for the installation of additional
equipment, one just behind the landing gear
bays and the other further towards the wing
tip. Four nitrous oxide pressure bottles were
installed just behind the wheel wells with access
to filling these from within them. The F-4/Z
carried a total of eight pressure bottles. It was
distinguished from the outside by a deeper oil
cooler, and apparently most of these aircraft
had wider propeller blades. It must be noted
that this installation eliminated the possibility of
underwing cannon pods.
3. Bf 109G/U2. Because the pressurized nitrous
oxide cylinders were vulnerable to enemy
fire and tended to explode when hit, the GM-1
system was redesigned for the Bf 109 G version.
INFO Eduard24
November 2024