MW50 -Secondary effects were cooling of the engine .

[RPS69]

Mustang, you have been attacked, but you answered back. That's your mistake.

And believe me, telling another people that they are nuts because they don't see THE truth, is not actually the way to better nothing, unless you are godsend to show mankind the light. And even then, only God will know, but you still have to convince mankind...

And really, in your case God is not going to throw lightning bolts and whatever on miscreants...

So why don't you try to offer the other chick as a more friendly approach?

TD have never appeared here, so which attack is important and which not?

More... everybody that matters here knows that MW50 is a cooling device. That was never the issue.

But even so, the general plane dynamics, need to take into account, in which situations it was meant to be used, and if there was a needed plane attitude...

So, the research is on the actual conditions in which it was engaged, not if the MW50 cooled the engine or not.

But... if you get engaged on low speed combat, with your engine at max revs, and MW50 engaged, I do expect your engine to overheat, because the cooling system in general will have a lowered efficiency.

This same concept applies to the SPits MkII with the 100 octane fuel.
WEP is emergency... not dogfight power...

So... why don't you start again from scratch and do the test of climbing with MW50 engaged and disengaged. And find if there is possible to reach higher altitudes faster with MW50 use, AND without overheating?

Maybe you can come back with a better case.

[Mustang]

Originally Posted by RPS69

But... if you get engaged on low speed combat, with your engine at max revs, and MW50 engaged, I do expect your engine to overheat, because the cooling system in general will have a lowered efficiency.

Let me explain.

You are in dogfight al low speed...you are in bad combat situation...
and you need emergency power,
You must push the throtle over 100%.

Without Water methanol:
You get some power close to max revs and the engine get overheat maybe soon.



You are in dogfight al low speed,you are in bad combat situation...
and you need emergency power,

You must push the throtle over 100%

With water methanol you get more power, injected a

mixture of methanol and water into the cylinders to cool the mix. Cooling causes the air to become denser.
Increase horsepower safely, Lower air temperatures, and Decrease cylinder temperatures.

Nobody can understand ?

In both situations the engines will overheat.
Without methanol water the engine get overheat more quickly.
I'll go find manuals P 51 H .

But with the injection of wather methanol (MW50) , the overheat takes longer time, you can run saflely 10 minutes, in any condition, that's what says the Luftwaffe.

In 4.11 you can get engine on fire with 10 minutes of MW 50 ON.

[41Sqn_Banks]

Originally Posted by Mustang

But with the injection of wather methanol (MW50) , the overheat takes longer time, you can run saflely 10 minutes, in any condition, that's what says the Luftwaffe.

No way. Even if MW50 is authorized for a 10 minutes duration the maximum allowed oil and coolant temperatures still apply.

For example Merlin emergency power was authorized for 5 minutes, but the oil and coolant temperature must remain in the specified limits, see: http://www.spitfireperformance.com/dowding.pdf

The time limit means that the stress on the engine is that high that it will take considerable damage even without overheat after that time.

[Mustang]

Each engine is different.

Can you explain me...

The FW 190 D9 had a tank for 39 minutes of water/ methanol.

The water methanol only work in emergency power. this is a fact.
Under 100% of throtle dont work.


The FW 190 D9 had a titanium engine ?

The answer is not the MW 50 (Water/methanol) is coolant mixture, the secondary effect is more horsepowers.

Or German engineers were crazy
And no sense a tank (MW50) for 39 minutes in FW 190 D9... or had a titanium engine?

Could resist 4 uses for 10-minutes?

What is more important for the luftwaffe ?
The damage to the engine or in dogfight the pilot's life?

The Ta 152 had MW50 and GM 1 (nitrous oxide) and can use the 2 together at the same time
The luftwaffe engineers built for the pilot a great fireball for fly ?

I see many things that only few can see.


Nobody could prove my "mistakes"
My job is done.
I do not say anything more
Good luck and enjoy the flight, IL2 is a great combat sim.

[RPS69]

I just tried it a bit. Picked a 190G6/AS and tried to climb with the MW50 at manual's speed.

Very bad results indeed...

But most surprising is that overheat message comes on 80º
Manual states, 85º as safety, 100º as practical limit, 110º engine damage.

Now, I could take big damage on an engine from overheat, but injecting the MW50 doesn't mean overheating the engine, it implies over-pressure. (overreving of it, is prevented by prop pitch)

The only reports about engine damage from MW50 use were micro cracks on piston heads. This could be because of high pressures, and more likely for the fast cooling MW50 could have on piston heads when untimely injected.

But I have never read, nor on books, nor in the web anything about engines taking on fire with MW50 use.

Now, testing a bit more, I get some uncomfortable results, being that climbing with 110% without MW50 is a bit slower, but your engine overheats later...

Something is wrong here gents... and I don't believe that the right solution should be limiting the 109 to 100% throttle when MW50 is not engaged...

[Robo.]

Originally Posted by RPS69

But most surprising is that overheat message comes on 80º
Manual states, 85º as safety, 100º as practical limit, 110º engine damage

Oil or Water temperature?

[RPS69]

Originally Posted by Robo.

Oil or Water temperature?

Funny question! If it was oil, it will be extremely cool!! Actually that will be Normal oil temperature, not the overheat mark.

Actually, according to the German test reports I've seen, the power increase due to water ALONE was only about 4%. They did get a temp reduction at the same time but I don't recall the particulars of that so I won't throw out numbers (it was a fair amount but not dramatic). 4% isn't the type of WEP I think is being discussed here, though. Normal max power is achieved when you reach the detonation limit*. Where the real power increase comes from with water injection is extra fuel/air can be fed in until you re-reach the detonation limit. So, now you're starting combustion at about the same cylinder inlet temp as non-water but your peak combustion temp is higher because of the additional fuel/air pumped in with the water.


* rpm + compression ratio raises temp a fixed amount.
a given fuel will detonate in a particular combustion chamber and rpm at a specific temperature.

[Shardur]

I see the main problem with this thread is that one of the main posters, Mustang, seems to have a somewhat low competence in the English language that seems to prevent him form actually discussing anything or properly understanding posts made by other users. The fact that he seems to be unfamiliar with the concept of how to properly present sources complicates the matter further.

To the topic:

Originally Posted by RPS69

This same concept applies to the SPits MkII with the 100 octane fuel.
WEP is emergency... not dogfight power...

I think that the Spitfire is a bad comparison here since its boost does not come from a Water/Methanol injection system but from supercharger air compression. Creating additional boost with the help of a supercharger might be effective, but unlike a water injection does not help with heat management and actually creates a lot of additional heat. This also explains why the RAF recommends the WEP boost to be used only for 5min while the MW50 was recommended by the Luftwaffe to be used for 10min at a time.

[Mustang]

I hope that someone can understand this

And the reason For the FW 190 D9 has tank ( 39 minutes for water/methanol)


http://horsepowercalculators.net/tun...er-performance

Why is this important for cooling ?
"
The first-order phase transitions are those that involve a latent heat . During such a transition, a system either absorbs or releases a fixed (and typically large) amount of energy. During this process, the temperature of the system will stay constant as heat is added.” … read more

Which means that the water or methanol will try to keep the air / fuel mixture at a fixed temperature of 65*C for the methanol phase change, and 100*C for the water phase change, for a long time (until the entire fuel has changed state) while absorbing a very large amount of heat energy out of the compressed air.

Since the air entering into the water/methanol spray’s path (especially with a lack of an intercooler) can be as high as 100*C above ambient (so with an ambient temperature of about 40*C for under hood temps we’re talking about an air inlet temperature of around 140*C in the intake piping).

Once this 140*C air meets the water & methanol mixture both the water and methanol will attempt to bring down the air / fuel mixture down to 100*C (the boiling point of water) and if all the water has vaporized into steam, then further down to 65*C the boiling point of methanol. If both operations are successful then the final temperature of our mixture is 65*C or 25*C above ambient which is great for any intercooler, and even more impressive for a higher octane non-intercooled system like ours relying on water methanol injection.

Now there are two possible applications for water / methanol injection:

1- The typical added cooling application:

a. In this setup, the water / methanol mix is usually mixed in a 50/50 mix of water and methanol.

b. The jetting is usually about 10-15% the total fuel flow of the system:

For example a 300hp four cylinder car needs four 450cc/min fuel injectors to produce that power figure. Our total fuel flow at peak power is 450cc/min 4 = 1800cc/min or 1.8 liters per minute of fuel.

1 gallon is four liters and 1 hour is sixty minutes so our total fuel consumption is equivalent to 27 gallons per hour of fuel (if you were able to stay at peak hp and rpm for a whole hour).

The reason we’re doing this math is that water / methanol jets are rated in gallons per hour.

So 10 to 15% of 27 gallons per hour = 2.7 to 4.05 GPH injection nozzle.

Now remember that 50% of our mixture is methanol, which is a high octane gasoline. So when injection 15% water methanol mixture with 50% of that being methanol, then our final air fuel ration will be richer by 7% or about 1 AFR point. This means that to reach optimum power again and our optimum air fuel ration we need to either increase boost pressure or retune our car to optimize it for the added high octane fuel.

2- Using methanol as a fuel

In light of what we just mentioned about methanol being a fuel, you could possibly use water /methanol injection as a supplementary stand alone high octane fuel system. The trick here is to keep in mind that the amount of water you spray in the system must be controlled to prevent the engine from hydro lock.

So in using water / methanol as a supplemental fuel as well as a cooling agent, limit the water content to 5 to 7% of your fuel injector flow, and compensate for your added fuel demands with methanol.