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APPENDIX : THE BOOST SYSTEMS
The above texts widely mention the GM-1 and
MW50 systems. Of course, I assume that all
of you will know what these items were, what
each system was used for and how they worked.
Despite that, I would like to return to these
features and give a brief description of their
function and use. Without this mention, I feel
that this article would lack a little something.
The GM-1 (for which Goering Mischung 1 and
Ha-ha Geraet were slang terms) system was
one that injected nitrous oxide into the engine
pistons. With the DB 605AS engine, its use
was permitted at an altitude of 10,000m and
climbing, and from 10,500m in level flight.
In the DB 605A, use was permitted in a climb
from 8,000m. The GM-1 system could be used
for between 11 and 22 minutes, depending on
the time of year, outside temperature and time
since filling the system.
For increasing engine performance at low and
medium altitudes up to 6,000m, a methanol-
water supercharger intake injection system
was used in the form of MW50 (methanol/water
50:50, as the designation suggests mixing
equal parts of methanol and water, plus 0.5%
Schutzol 39, an anti-corrosion additive). There
variations on the MW50 theme, designated
by the mixture: MW30 (methanol/water at
70:30), EW50 (ethanol/water 50:50) and EW30
(ethanol/water 70:30). The MW50 system
was able to increase engine performance by
20 to 25%, depending on altitude and other
relevant conditions. It’s use was permitted to
a maximum of twice for ten minutes during
a single flight (other sources differ on these
values, such as a maximum length of time of
use of 5 minutes).At altitudes over 6,000m,
the effectiveness of the system fell off
dramatically, and is said that it only provided
a 4% increase in performance above 6,000m.
The differences in the GM-1 and MW50 systems
did not include, as is sometimes claimed,
a lower usefulness or obsolescence of the
GM-1 compared to the MW50. In practical
terms, there was no replacement of one by the
other. Each was technically different and was
intended for use under different conditions,
although both worked on the principle of
internal cooling of the engine combustion
chambers.
The MW50 worked by lowering the temperature
by injecting water into the supercharger, and so
also the volume of compressed air on entering
it, which allowed an increase in air (oxygen)
content of the fuel/air mix that was injected
into the cylinders. The system was, of course,
dependant on the local air pressure to begin
with, and at higher altitudes, the effectiveness
dropped off simply because in thin air, there
was less oxygen.
With the GM-1 system, nitrous oxide was
injected into the cylinders, which, under high
temperatures, broke down into nitrogen and
oxygen. The nitrogen lowered the temperature
of the mix and its volume in the cylinder,
which, in turn, allowed a higher amount of the
gas, and the oxygen supported combustion.
As a result, the GM-1 system was not dependant
on the outside air pressure, and that’s why it
was intended for use at higher altitudes (the
minimum permitted altitude for its use in the
DB 605D was 10,000m). The more widespread
use of the MW50 system and its basically
standard installation in the Bf 109G-14, G-14/AS
and G-10 was dictated by the tactical conditions
that prevailed over the European battlegrounds,
where most air combat took place at low
and middle altitudes, below or up to 6,000m.
The GM-1 system was utilized for specific
tasks at high altitudes, during reconnaissance
flights and fighters.
Installation of the GM-1 in the Bf 109 was
indicated by the suffix U2, and with the MW50,
by U3. That means that the, for example,
Bf 109G-6/AS/U2 or Bf 109 G-6/U2/AS was
a Bf 109G-6 airframe powered by the DB 605AS
and carried the GM-1 system. Both systems
were used not only in connection with the
DB 605, but with other types of German engines
as well, such as the BMW 801.
Sources:
MESSERSCHMITT Bf 109 F, G, & K Series,
An Illustrated Study. Jochen Prien & Peter
Rodeike, Schiffer Military History, 1995
Bf 109 Late versions Camouflage & markings.
Krzysztof W.Wolowski. Mushroom model
publications, 2010
Messerschmitt Bf 109G-10/U4 Production
& operational service. Aleš Janda, Tomáš
Poruba. JaPo.
Die Jagdfliegerverbande der Deutschen
Luftwaffe 1934 bis 1945, Teil 13/IV, Einsatz in
der Reichsverteidigung und im Westen 1.1. bis
31.12.1944. Jochen Prien, Gerhard Stemmer,
Winfried Bock. Buchverlag Rogge GmbH, 2018
ME SS ERS CH MI T T B F 109 J A SA KS A N SO TATA LOU S.
Keski-Suomen Ilmailumuseonjulkaisuja
8. Hannu Valtonen. Gummerus Kirjapaino Oy,
1999.
ERLAWERK VII ANTWERPEN
-
MORTSEL 1940-44.
Jean Dillen. Uitgeverij De Krijger.
Messerschmitt Bf 109 – EINSATZMASCHINEN –
DAS NACHTSCHLAGWERK. Harald Helmut vogt.
VDM
-
Heinz Nickel, 2012.
Das Jagdflugzeug Messerschmitt Bf 109.
Michael Baumgartl. 2022
HISTORY
INFO Eduard
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September 2024