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  #1  
Old 03-04-2012, 11:54 AM
Mustang Mustang is offline
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Default MW50 -Secondary effects were cooling of the engine .

1) BF 109 could use full engine power (110%) with MW 50, 10 minutes with MW50 without engine damage.
But the Luftwaffe ONLY, not recommended that.

The pilot could use MW50 more time.. Maximum 20 minutes
It was his choice.

That does not mean, you got engine on fire after 13 minutes.
Ofcourse 15 minutes = cylinder heads developed micro-cracks, But the engine is still operating.


2) A friend uses water methanol in a car.
I can send them pictures of the engine

One Thing... I can assure
It cools the engine

I think I never saw represented in IL2, the effect of the engine cooling for MW 50.
I think ....





Quote:
MW 50 (Methanol-Wasser 50) was a 50-50 mixture of methanol and water (German: Wasser) that was often sprayed into the supercharger of World War II aircraft engines primarily for its anti-detonant 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.

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 additive.
The similar MW 30 increased the water to 69.5% and decreased methanol to 30%.[1]
[b]This increased the cooling performance[B] but made it easier to freeze, the mixture intended to be used for lower-altitude missions.

EW 30 and EW 50 mixtures also existed, which substituted methanol with ethanol; in emergency, pure water could be used.
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 100 hp (75 kW) on the BMW 801 and DB 605. However, the MW 50 also allowed the supercharger to be run at much higher boost levels as well, for a combined increase of 500 hp (370 kW).
At sea level, this allowed the 1,600 hp (1,200 kW) engine to run at over 2,000 hp (1,500 kW). MW 50 was fully effective up to about 6,000 m (20,000 ft), above which it added only about 4% extra power, due largely to charge cooling.

The increased power could be used for a maximum of 10 minutes at a time, much like the American war emergency power setting for their own aircraft, with at least five minutes between each application.[2]
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 missions. 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 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, which relied on it to reduce non-boosted performance and tune the supercharger for higher altitudes.

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[2] (the Erhöhte Notleistung [Increased Emergency Performance] system), 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, which was intended to add oxygen to the fuel/air mix by injecting nitrous oxide into the supercharger[2] instead of employing higher boost levels.
Quote:
Due to the cooling effect of the water, aircraft engines can run at much higher manifold pressures without detonating, creating more power. This is the primary advantage of a water injection system when used on an aircraft engine.
The extra weight and complexity added by a water injection system was considered worthwhile for military purposes, while it is usually not considered worthwhile for civil use. The one exception is racing aircraft, which are focused on making a tremendous amount of power for a short time; in this case the disadvantages of a water injection system are less important.


Quote:
Many water injection systems use a mixture of water and alcohol (approximately 50/50), with trace amounts of water-soluble oil. The water provides the primary cooling effect due to its great density and high heat absorption properties. The alcohol is combustible, and also serves as an antifreeze for the water. The purpose of the oil is to prevent corrosion of water injection and fuel system components. [2] Because the alcohol mixed into the injection solution is often methanol (CH3OH), the system is known as methanol-water injection, or MW50. In the United States, the system is commonly referred to as anti-detonant injection, or ADI.
[edit]Effects

In a piston engine, the initial injection of water cools the fuel-air mixture significantly, which increases its density and hence the amount of mixture that enters the cylinder. The water (if in small liquid droplets) may absorb heat (and lower the pressure) as the charge is compressed, thus reducing compression work.[1] An additional effect comes later during combustion when the water absorbs large amounts of heat as it vaporizes, reducing peak temperature and resultant NOx formation, and reducing the amount of heat energy absorbed into the cylinder walls. This also converts part of combustion energy from the form of heat to the form of pressure. As the water droplets vaporize by absorbing heat, it turns to high pressure steam (water vapor or steam mainly resulted from combustion chemical reaction). The alcohol in the mixture burns, but is also much more resistant to detonation than gasoline. The net result is a higher octane charge that will support very high compression ratios or significant forced induction pressures before onset of detonation.
Fuel economy can be improved with water injection. Depending on the engine, the effect of water injection, with no other modification, like leaning out the mixture, may be quite significant[1] or rather limited and in some cases negligible.
In some cases water may also reduce CO emissions, this might be attributable to the water-gas shift reaction, in which CO and H2O shift to form CO2 and H2.[1] However, water may also increase hydrocarbon emissions, possibly due to an increased quenching layer thickness.
Some degree of control over the water injection is important. It needs to be injected only when the engine is heavily loaded and the throttle is wide open. Otherwise injecting water cools the combustion process unnecessarily and reduces efficiency.

Last edited by Mustang; 03-04-2012 at 12:07 PM.
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  #2  
Old 03-04-2012, 03:57 PM
Letum Letum is offline
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Quote:
Due to the cooling effect of the water, aircraft engines can run at much higher manifold pressures without detonating, creating more power.
I think this is wrong.
My understanding is that it's the methanol that causes the engine to run cooler, not the water. The water is just there to prevent the methanol from causing premature detonation.

edit: Looks like I'm wrong.

Last edited by Letum; 03-04-2012 at 04:02 PM.
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Old 03-04-2012, 04:55 PM
K_Freddie K_Freddie is offline
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Of course this is going to create the Allied whiners club (as compared to the old Luft-Whiners), now that we have a superior booster.

ahhh! what the hell, ...DT let's do it.
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Old 03-05-2012, 01:43 AM
WTE_Galway WTE_Galway is offline
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Quote:
Originally Posted by Letum View Post
I think this is wrong.
My understanding is that it's the methanol that causes the engine to run cooler, not the water. The water is just there to prevent the methanol from causing premature detonation.

edit: Looks like I'm wrong.


Neither will cause the engine itself to run cooler.

The fuel air mix is cooler meaning combustion is cooler and thus detonation is avoided.

Any engine cooling would be negligible, people are just confused.
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Old 03-05-2012, 04:14 AM
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Crumpp Crumpp is offline
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Mustang,

None of the test of the BMW801D series list "micro-cracks" in the cylinder head as an issue. Where did you get that information from?

The first test in 1941 had an issue with the zinc lining of the tank peeling off. Other than that, Alkohol-Einspritzung was authorized but not adopted because it simply did not deliver the power gains that C3-Einspritzung.

C3-Einspritzung is were fuel was sprayed into the supercharger intake. Its major drawback was thin air made the mixture too rich and the power gains dropped substantially. An altitude restriction of 1Km or below was placed on the system and could be used for two ten minute intervals. The system was fitted to ground attack and bomber variants.

Erhöhte Notleistung in the fighters was just a simple manifold pressure increase and came about because of knock limited performance of the C3 fuel was raised. It did not develop as much power as the other boost systems but did not require heavy additional equipment such as an auxiliary tank. It could only be used once for 10 minutes.

GM-1 was lighter than a turbocharger and offered good power gains at altitude. Its drawback was the altitude restriction and the system was vulnerable to intake icing.
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Old 03-05-2012, 12:02 PM
Mustang Mustang is offline
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The MW50, began to operate at full power.

If Luftwaffe recommended for Bf 109, MW50 ON... for 10 minutes.

I think ..
Then I can fly at full power + MW50, 10 - 12 minutes minimum, without engine damage.

And you can only get that... if you are cooling the engine

That's my point

Last edited by Mustang; 03-05-2012 at 12:25 PM.
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Old 03-05-2012, 02:13 PM
HundertneunGustav HundertneunGustav is offline
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you said "i think"

and when you say that, you are canceling all your arguments, however good they may be.
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  #8  
Old 03-05-2012, 02:46 PM
Mustang Mustang is offline
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If Luftwaffe recommended for Bf 109, MW50 ON... for 10 minutes

This is a fact.

Then the BF 109 can fly for 10 minutes full power + MW 50

This is a fact.

And over that time, with risk of overheating and possible engine failure.

This is a fact.

I want see a BF 109 do that in IL2 1946 , and not see the engine on fire.

Only this.

It´s so difficult, see the reality.

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Old 03-05-2012, 08:41 PM
jameson jameson is offline
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Fatcat you have my heartfelt sympathy, having to deal with cut and paste experten. Maybe Gaston will be along shortly, to boldly go where no physics has gone before....
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  #10  
Old 03-05-2012, 10:50 PM
Mustang Mustang is offline
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I could not understand it.
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