MW 50 (Methanol-''Wasser'' 50) was a 50-50 mixture of
methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...
and
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
(German: ''Wasser'') that was often sprayed into the
supercharger
In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement.
The current categorisation is that a supercharger is a form of forced induct ...
of
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
aircraft engines
An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many ...
primarily for its
anti-detonation effect, allowing the use of increased boost pressures. Secondary effects were cooling of the engine and charge cooling. Higher boost was only effective at altitudes below the
full-throttle height, where the supercharger could still provide additional boost pressure that was otherwise wasted, while the smaller secondary effects were useful even above that altitude.
Composition
MW 50 is something of a misnomer, as it is actually a mixture of three fluids: 50% methanol acting primarily to achieve optimum anti-detonant effect, secondarily as an anti-freeze; 49.5% water; and 0.5% ''Schutzöl'' 39, an oil-based
anti-corrosion
In chemistry, a corrosion inhibitor or anti-corrosive is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy, that comes into contact with the fluid. The effectiveness ...
additive. The similar MW 30 increased the water to 69.5% and decreased methanol to 30%.
[Bridgeman 1989, p. 296.] This increased the cooling performance but made it easier to freeze at -18 degrees C as opposed to -50 C for MW 50). As a result, this mixture was intended to be used for lower-altitude missions. EW 30 and EW 50 mixtures also existed, which substituted methanol with
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
; in emergency, pure water could be used.
Effect
The effect of MW 50 injection could be dramatic. Simply turning on the system allowed the engine to pull in more air due to the charge cooling effect, boosting performance by about on the
BMW 801
The BMW 801 was a powerful German air-cooled 14-cylinder-radial aircraft engine built by BMW and used in a number of German Luftwaffe aircraft of World War II. Production versions of the twin-row engine generated between 1,560 and 2,000 PS ( ...
and
DB 605
The Daimler-Benz DB 605 is a German aircraft engine built during World War II. Developed from the DB 601, the DB 605 was used from 1942 to 1945 in the Messerschmitt Bf 109 fighter, and the Bf 110 and Me 210C heavy fighters.
The DB 610, a p ...
. However, the MW 50 also allowed the supercharger to be run at much higher boost levels as well, for a combined increase of . At
sea level
Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...
, this allowed the engine to run at over . MW 50 was fully effective up to about , above which it added only about 4% extra power, due largely to charge cooling.
Time limits
The increased power could be used for a maximum of 10 minutes at a time, much like the American
war emergency power
War emergency power (WEP) is a throttle setting that was present on some American World War II military aircraft engines. For use in emergency situations, it produced more than 100% of the engine's normal rated power for a limited amount of time ...
setting for their own aircraft, with at least five minutes between each application.
[Bridgeman 1989, p. 297.] Aircraft generally carried enough MW 50 for about two ten-minute periods of use, allowing them to increase their climb rate and level speed in combat for
interception
In ball-playing competitive team sports, an interception or pick is a move by a player involving a pass of the ball—whether by foot or hand, depending on the rules of the sport—in which the ball is intended for a player of the same team b ...
missions.
Applications
Fittings for MW 50 first appeared on the BMW 801D in 1942, but it never went into production for this engine because the cylinder heads developed micro-cracks when MW 50 was used. Instead, the DB 605-engined later versions of the
Messerschmitt Bf 109
The Messerschmitt Bf 109 is a German World War II fighter aircraft that was, along with the Focke-Wulf Fw 190, the backbone of the Luftwaffe's fighter force. The Bf 109 first saw operational service in 1937 during the Spanish Civil War an ...
were fitted with an MW 50 injection system, beginning in early 1944. Later engine designs all included the fittings as well, notably the
Junkers Jumo 213
The Junkers Jumo 213 was a World War II-era V-12 liquid-cooled aircraft engine, a development of Junkers Motoren's earlier design, the Jumo 211. The design added two features, a pressurized cooling system that required considerably less cooling ...
, which relied on it to increase non-boosted performance and tune the supercharger for higher altitudes.
Other systems
MW 50 was not the only charge cooling system to be used by the Germans. Some engines dedicated to high altitude included an intercooler instead, as they would be needing the cooling for longer periods of time. The 801D also included the ability to spray gasoline into the supercharger
[ (the ''Erhöhte Notleistung'' ncreased Emergency Performancesystem), in place of the MW 50. While this was not as effective, it did increase boost without the complexity of the additional tanking and plumbing. Additionally, many of the late-war engines also included a system for high-altitude boost, ]GM-1
{{unreferenced, date=September 2008
GM-1 (''Göring Mischung'' 1) was a system for injecting nitrous oxide (laughing gas) into aircraft engines that was used by the ''Luftwaffe'' in World War II. This increased the amount of oxygen in the fuel mi ...
, which was intended to add oxygen to the fuel/air mix by injecting nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has a ...
into the supercharger[ instead of employing higher boost levels – the Jumo 213E inverted V12 on the Ta 152H could "sprint" with both boost systems engaged to airspeeds of well over at low altitudes.
]
See also
*Water injection (engines)
In internal combustion engines, water injection, also known as anti-detonant injection (ADI), can spray water into the incoming air or fuel- air mixture, or directly into the combustion chamber to cool certain parts of the induction system where "h ...
*War emergency power
War emergency power (WEP) is a throttle setting that was present on some American World War II military aircraft engines. For use in emergency situations, it produced more than 100% of the engine's normal rated power for a limited amount of time ...
References
Notes
Bibliography
* Bridgman, L, (ed.) (1989) ''Jane's fighting aircraft of World War II.'' Crescent.
{{refend
Aircraft engines
fr:Injection d'eau-méthanol