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Installation of the
GM-1 System in the Bf 109
HISTORY
A thermally insulated tank was installed in the
fuselage behind the cockpit, filled at normal
pressure with liquefied nitrous oxide cooled to
a temperature of -90°C. Compressed air, stored
in pressure bottles in the outer part of the right
wing, was used to expel nitrous oxide from the
tank into the engine intake. To maintain the
aircraft's balance, pressurized oxygen bottles
for the pilot's breathing apparatus were moved
to the outer part of the left wing. Below the
right wing, a cap for filling compressed air (not
nitrous oxide!) was added, and on the right side
of the fuselage a cap for filling the cooled nitrous
oxide (in the same place as the cap for the
MW-50 system) was added. The cap for the GM-1
system was marked with a white triangle with
two blue stripes, possibly with the inscription
‘Sonderstoff’. Because the space in behind the
wheel wells remained vacant, it was possible to
mount cannon pods under the wings. This system
was not as vulnerable to hits from enemy fire and
at the same time had the advantage of even better
efficiency (increased engine power) than the
pressurized method, since the low temperature
of nitrous oxide cooled the fuel mixture further
before entering the engine cylinders. This
installation was designated U2 and was installed
in the Bf 109 G-5 and Bf 109 G-6. It is likely that
it was not used on earlier versions of the Bf 109
G, as it was not yet available at the time of their
production. Unfortunately, I have not been able
to find out if the early versions of the Bf 109 G
were equipped with the same GM-1 system as
the F-4/Z. I believe it wasn’t, which would mean
that the Bf 109 G equipped with the GM-1 did not
appear until after considerable delay. Douglas
E. Calum states that universal installation of the
INFO Eduard
25
November 2024