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MW-50 at high altitude


vadupleix

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Hello,

 

Yesterday I did a test to see how high this bird can reach and in the process I find something unexpected regarding to the MW-50 system so I’m wondering what is happening.

At about 8k altitude I engaged max throttle and see the MW-50 pressure gauge showing a low 0.2-ish pressure and when I reach even higher the pressure is gone completely. Before that I have only used 5 minutes of MW-50 so it’s not because I’m running out of juice.

In my understanding the MW-50 injection does two things: it delays knocking thus enabling a higher boost pressure and then it cools the supercharger. So even at high altitudes it still serves the second propose of cooling, does it? Then my questions:

1. Is the reduced pressure a conscious design choice to save MW-50 fluid because even cooling is not required at that altitude? (True that the supercharger is not producing as much boost as down low but in the mean time the atomosphere pressure is low there as well and the air is much thinner up high to cool the engine/supercharger, so I’m not sure of the combined effect).

2. At those altitudes can I safely use full throttle even with low or no MW-50 pressure?

 

Thanks!

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MW system is pressurized by supercharger.

Above 7km supercharger starts losing power to keep 1,8ATA MAP, it is probably reason why MW pressurure starts falling down. There is not enough pressure from supercharger, i suppose.

This makes sense to me.

When use it, always when you go above 1,45ATA.

 

Why then Dora`s MW system holds MW pressure steady up to "space" is another story.

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Its possible the Dora uses a different system to pressurise MW injection. The original MW-50 modification kits for G-6s also used a separate bottle as a pressure source rather than draw it from the Supercharger. That changed with the introduction of the G-14. Either way MW-50 only really provides cooling above FTH, the increase in HP brought above that altitude is not really huge.

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The DB-605DB of our K4, did have a Full Throttel Altitude of 7,6km.

Thats means above this Altitude the Super Charger is not able to produce full Mainfold Pressure anymore, the ATA goes down and losing Power.

As consequenz MW50 doesnt provide any extra Power above around 8 Km with falling Mainfold Pressure + that what Saburo write.

Because that Reason the GM1 was used sometimes above this Altitudes, was providing Oxygen to keep the Mainfold Pressure up.

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I forgot that in MW50/3rd fuel Dora`s tank is a booster pump.

It is probably reason why is MW pressure steady. Booster pump seems to be used as a MW supplier and not air from supercharger. Without it (Off C/B) MW does not work.

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MW50

 

MW50 injection is not providing any power to the engine directly. Spraying mw50 in to intake wont change output power of the engine. MW50 works as a internal cooler allowing engine to work safly at highpower setting(higher boost or higher rpm)

 

The simplest way to provide anti knock protection for engien is done by riching air-fuel(a/f) mixture aditional fuel works as internal cooler as well but this hit it limit fast becouse when a/f mixture is too rich you will disrupt combustion to that extent that engine will start loosing power quick.

MW50 is much much more effective ofc you can't spray mw50 as much as you want.

MW50 is not for coooling supercharger i doubt that superacherger system like in bf109 needs any aditional cooling, air flow through supercharger is preaty massive it should cool it self without problem

P-51 is equiped with intercooler but this is for increasing density of air after first supercharger stage.

Another statment supercharger in bf109 is driven by hydraulic coupling it can change impeler speed of supercharger in order to reach set ATA(supercharger will spin faster and faster while bf109 is climbing) while bf109 dont suffer from supercharger throttling power loosses it will loose power every each meter it goes higher(supercharger in order to keep set ATA will spin faster that means it will drain more power from engine to provide boost) so bf109 supercharger hit its top power drain at altitude where ATA will start droping at this point supercharger works with the max power(load) So statment the supercharger works lighter at high alt becouse its not providing max boost is wrong ofc boost is lower but supercharger boosting air pressure from much lower ambient pressure than at sea level. when in bf109 ATA start droping it mean that supercharger impeler reach its max rpm its draining max power form engine .


Edited by grafspee

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Thanks for all the replies, now I get an idea of the pressure dropping

...so bf109 supercharger hit its top power drain at altitude where ATA will start droping at this point supercharger works with the max power(load) So statment the supercharger works lighter at high alt becouse its not providing max boost is wrong ofc boost is lower but supercharger boosting air pressure from much lower ambient pressure than at sea level. when in bf109 ATA start droping it mean that supercharger impeler reach its max rpm its draining max power form engine .

Does this mean that by pushing the throttle all the way forward I'm giving the supercharger the same workload as it is at sea level and hence I still need to restrain myself from keeping full power for more than 10-ish minutes?

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I would state that if you advance throttle forward you demanding more power from engine so yo uare puting more load on supercharger then via engine control unit

for example

you take off in bf109. Setting auto prop in bf 109 and 1.0ATA and start climbing. basicly at sea level supercharger only boost bearly up to 1 ATA its almost nothing providing that ambient pressure is around 1 ATA. ATA stand for standard atmospheric pressure.

then you start climbing higher and ambient pressure start droping(i dont know exact numbers its only example) at 10k ft (around 3000m) ambient pressure is droping to about 0.65 ATA so in proces of climbing ECU will increase rpm of spuercharger to maintain 1 ATA at this point supercharger is boosting 0.35 ATA not like at sea level where it was boosting almost nothing but remember we set 1 ATA and auto prop so propeler speed will be low maby even below 2000rpm it limits spuercharger ability to boost couse it cant spin faster then engine. Our bf 109 is still climbing but you can see that ATA gage is droping slowly to 0.99ATA this mean that supercharger reach max rpm for given engine rpm and it cant boost more. at this point you need to advance trottle further engien rpm will increase and supercharger speed will increase too allowing to boost up to 1ATA again

when you were talking that ATA start droping around 8km of alt so given this info i can tell that at 8km alt bf109 can run 1.8 ATA so at 8km ambient pressure is around 0.35ATA so supercharger is boosting from 0.35 ATA to 1.8ATA = 1.45ATA of boost at this alt so supercharger is working almost twice harder than at sea level where its boosting only 0.8ATA\

Ofcourse this only apply to bf-109. P-51 and spitfire have difrent supercahrging systems and difrent supercharger drive systems

 

Did some testing in dcs yeap what i said numbers are just for example bf109 set to 1.ATA start loosing manifold pressure much earlier at 1000m there is significant lose of boost but 1ata at sea level is almost iddle around 1400rpm so the supercharger cant do a lot with those rpm. probably 1.2 ata for example would be much more accurate but you have basic idea in 1ATA example

BTW you can run 1,8 ATA in bf109 k-4 as long as you can i tested it. i took off set full power and kept flying i run out of mw50 tank when my main fuel tank passed 150L mark. bf-109's engine(DB605) runs at very low boost levels even 1.8 ata is much less then p-51 or spitfire boost DB605 dont work as hard as his allied counterparts

when it comes to engine limitations it doesnt matter what your throttle position is only matters two thing manifold pressure and rpm if you are restricted to 15minutes in p-51 at 61/3000 power setting it doesnt matter at what altitude you are


Edited by grafspee

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I would state that if you advance throttle forward you demanding more power from engine so yo uare puting more load on supercharger then via engine control unit

for example

you take off in bf109. Setting auto prop in bf 109 and 1.0ATA and start climbing. basicly at sea level supercharger only boost bearly up to 1 ATA its almost nothing providing that ambient pressure is around 1 ATA. ATA stand for standard atmospheric pressure.

then you start climbing higher and ambient pressure start droping(i dont know exact numbers its only example) at 10k ft (around 3000m) ambient pressure is droping to about 0.65 ATA so in proces of climbing ECU will increase rpm of spuercharger to maintain 1 ATA at this point supercharger is boosting 0.35 ATA not like at sea level where it was boosting almost nothing but remember we set 1 ATA and auto prop so propeler speed will be low maby even below 2000rpm it limits spuercharger ability to boost couse it cant spin faster then engine. Our bf 109 is still climbing but you can see that ATA gage is droping slowly to 0.99ATA this mean that supercharger reach max rpm for given engine rpm and it cant boost more. at this point you need to advance trottle further engien rpm will increase and supercharger speed will increase too allowing to boost up to 1ATA again

when you were talking that ATA start droping around 8km of alt so given this info i can tell that at 8km alt bf109 can run 1.8 ATA so at 8km ambient pressure is around 0.35ATA so supercharger is boosting from 0.35 ATA to 1.8ATA = 1.45ATA of boost at this alt so supercharger is working almost twice harder than at sea level where its boosting only 0.8ATA\

Ofcourse this only apply to bf-109. P-51 and spitfire have difrent supercahrging systems and difrent supercharger drive systems

 

Did some testing in dcs yeap what i said numbers are just for example bf109 set to 1.ATA start loosing manifold pressure much earlier at 1000m there is significant lose of boost but 1ata at sea level is almost iddle around 1400rpm so the supercharger cant do a lot with those rpm. probably 1.2 ata for example would be much more accurate but you have basic idea in 1ATA example

BTW you can run 1,8 ATA in bf109 k-4 as long as you can i tested it. i took off set full power and kept flying i run out of mw50 tank when my main fuel tank passed 150L mark. bf-109's engine(DB605) runs at very low boost levels even 1.8 ata is much less then p-51 or spitfire boost DB605 dont work as hard as his allied counterparts

when it comes to engine limitations it doesnt matter what your throttle position is only matters two thing manifold pressure and rpm if you are restricted to 15minutes in p-51 at 61/3000 power setting it doesnt matter at what altitude you are

Appreciate your explanation, thanks a lot!

Yes the max boost can be maintained as long as MW50 tank is not empty and airspeed is not too low, not sure if this has to do with the current cooling model and if it will change after they update it. Some says it’s historically accurate some says not, I was referring to the 10min limit as on the manual.

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for me MW50 works as it should be working. MW50 is only for anti knock protection if supercharger hit its limit it wont help anymore if you have acces to high octane fuel like allied planes had there was no need of using mw50 systems becouse germans with 87 octane fule were strugling to keep up with allied engines powers and hight alt preformance since merlin used 2 stage supercharger with intercooling and that was very effiecient solution.

Yeap at high speeds you can get some boost from ram air intake designe too. i think almost all planes from WW2 had that kind of intakes

If we assume the Germany and allied countries like USA UK had similar technologies engine of bf109 running ata 1.8 ATA at 2800rpm with adition of MW50 which providin aditional internal cooling for engine, compared to v-1650-7 from p-51 wich runs 61inch/3000rpm which is something around 2.0ATA at higher rpm i would say that engine from bf109 can run much longer then p-51 engine.

Whats bothering me in bf109 is low speed efficiency of radiators you can fly at stall speed and still bf109 manages to cool engine down while p-51 or spitfire are blowing gasket imidietly, wonder is this some inaccuracy or the cooling system in bf109 was so good


Edited by grafspee

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for me MW50 works as it should be working. MW50 is only for anti knock protection if supercharger hit its limit it wont help anymore if you have acces to high octane fuel like allied planes had there was no need of using mw50 systems becouse germans with 87 octane fule were strugling to keep up with allied engines powers and hight alt preformance since merlin used 2 stage supercharger with intercooling and that was very effiecient solution.

 

Nonsense, the charge cooling effect persists even above rated altitude. As long as the supercharger tap can provide higher than ambient pressure to the tank, the MW system will increase power output. With high octane fuel such as allies or germans in form of C3 had (145 grade fuel in the allied rating scheme) you will be able to run your engine with even higher boosts. If you understand the effect of MW50 charge cooling as it was injected into the supercharger you may be able to recognize why a heavy intercooler makes no sense at all in this configuration and just how similiar the effect is.

 

The germans used lean ratings to describe their fuels and the allied used rich ratings. The B fuels were made from natural hydrocarbons (eg from Ploesti) and were complete crap by the end of the war. While the C fuels were made by coal hydration (eg in Leuna) and were completely synthetic with controlled aromatic additives that made for very high octane ratings and constant quality fuel production. The eastern front was supplied mainly with B4 fuel while the western front was mainly supplied with C3 fuel. Considering logistics and demand that made a lot of sense.

 

Eg DB605 in DC config with C3 fuel at 2.0 ata or the P&W R2800 with water injection. Same engines just higher octane fuel + MW50 = further increased boost ratings.

 

 

PS: It makes absolutely no sense to compare boost ratings without looking at least at engine compression as well, it tells you nothing.


Edited by rel4y

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Nonsense, the charge cooling effect persists even above rated altitude. As long as the supercharger tap can provide higher than ambient pressure to the tank, the MW system will increase power output. With high octane fuel such as allies or germans in form of C3 had (145 grade fuel in the allied rating scheme) you will be able to run your engine with even higher boosts. If you understand the effect of MW50 charge cooling as it was injected into the supercharger you may be able to recognize why a heavy intercooler makes no sense at all in this configuration and just how similiar the effect is.

 

The germans used lean ratings to describe their fuels and the allied used rich ratings. The B fuels were made from natural hydrocarbons (eg from Ploesti) and were complete crap by the end of the war. While the C fuels were made by coal hydration (eg in Leuna) and were completely synthetic with controlled aromatic additives that made for very high octane ratings and constant quality fuel production. The eastern front was supplied mainly with B4 fuel while the western front was mainly supplied with C3 fuel. Considering logistics and demand that made a lot of sense.

 

Eg DB605 in DC config with C3 fuel at 2.0 ata or the P&W R2800 with water injection. Same engines just higher octane fuel + MW50 = further increased boost ratings.

 

 

 

PS: It makes absolutely no sense to compare boost ratings without looking at least at engine compression as well, it tells you nothing.

 

Yes allies used 100/130 first is for lean mixture second is for rich germas used 87 if i recall corectly.

I did write that way to focus on what primary job is for MW50. MW50 will cool charge in some extent providing extra power true but this gain is very very small

Basicly this thing looks like that

MW50 will provide a lot anti knock protection and little increase in charge density

INTERCOOLERS/AFTERCOOLERS will provide very little anti knock protection and big increase in charge density

Take note when you injecting MW50 in to intake of the engine you are taking away some volume from charge volume which is not involved in combustion but you gain a lot anti knock protection soe you can boost much higher overcoming this effect by far far.

that's why in p-47 both intercooler and mw50 injection were used.

Germans used MW50 to bypass low grade of their fuel allowing engines runs higher boost.

Boost it self is not made by any of those neither MW50 neither intercoolers do this

Boost comes from supercharging system or ram air system.

Supercharger will alwayes give you higher pressure at supercharger discharge hose then ambient.

Comparing compresion ration of the engine is problematic becouse i dont have any data on this.Compression ratio isnt some global thing which is the same everywhere germas could have difrent requirements for determining compresion ratios then british. So i cant compare it.

Higher boosted engines will have lower compression ratios you want to lower peak combustion pressure in you engine if you want boost your engine much more you need to lower its compreassion ratio so engine designed for high boost will have lower compresion ratio than engine with low boost.

But i will agree 100% with you to campare engines it is require a lot more data then boost ratings rpms.

On another hand take a look at DCS FW190 this one blowing engien after a couple of seconds of running MW50 at not much higher boost then bf109 something around 1.9ATA with low supercharger speed engaged

Take note the bf109 oil tem can go up to 130 celcius degree that is a lot more then p-51. Fw190 oil can go up to 130 if i remember good that must mean something

 

Yest 2.0ata bf109 my dream :) same as 75inch boost p-51


Edited by grafspee

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Yes allies used 100/130 first is for lean mixture second is for rich germas used 87 if i recall corectly.

I did write that way to focus on what primary job is for MW50. MW50 will cool charge in some extent providing extra power true but this gain is very very small

Basicly this thing looks like that

MW50 will provide a lot anti knock protection and little increase in charge density

INTERCOOLERS/AFTERCOOLERS will provide very little anti knock protection and big increase in charge density

Take note when you injecting MW50 in to intake of the engine you are taking away some volume from charge volume which is not involved in combustion but you gain a lot anti knock protection soe you can boost much higher overcoming this effect by far far.

that's why in p-47 both intercooler and mw50 injection were used.

Germans used MW50 to bypass low grade of their fuel allowing engines runs higher boost.

Boost it self is not made by any of those neither MW50 neither intercoolers do this

Boost comes from supercharging system or ram air system.

Supercharger will alwayes give you higher pressure at supercharger discharge hose then ambient.

Comparing compresion ration of the engine is problematic becouse i dont have any data on this.Compression ratio isnt some global thing which is the same everywhere germas could have difrent requirements for determining compresion ratios then british. So i cant compare it.

Higher boosted engines will have lower compression ratios you want to lower peak combustion pressure in you engine if you want boost your engine much more you need to lower its compreassion ratio so engine designed for high boost will have lower compresion ratio than engine with low boost.

But i will agree 100% with you to campare engines it is require a lot more data then boost ratings rpms.

On another hand take a look at DCS FW190 this one blowing engien after a couple of seconds of running MW50 at not much higher boost then bf109 something around 1.9ATA with low supercharger speed engaged

Take note the bf109 oil tem can go up to 130 celcius degree that is a lot more then p-51. Fw190 oil can go up to 130 if i remember good that must mean something

 

Yest 2.0ata bf109 my dream :) same as 75inch boost p-51

 

MW50 does not have a primary job, it is injected into the supercharger for a reason and its effects are twofold. If charge cooling wasnt a major expected effect you could inject it into the carb (not in case of the DB since DI) or into the charge air duct or into the cylinders directly. But you dont. You inject it into the supercharger with all the detrimental effects due to droplet damage to the very high RPM supercharger. Why is that you ask?

 

Water and methanol injected into the charge air cause a big enthalpy delta due to vaporization. And no, you take away no volume at all, on the contrary you increase the oxygen supply when measured at same temp because the charge air is densified through cooling. Around a 100 HP increase can be expected due to MW charge cooling alone, keeping boost pressure constant. So thats 5,4% of total engine output at SL.

 

The charge temp rise of the Merlin 61 was 205°C at max F.S. revs and intercooler efficiency was ~35%. That is a delta of 72°C. So, rule of thumb ~13% engine output gain at FTH. That means MW charge cooling alone provides 42% of the benefit of a heavy intercooler. It is a bit of apples to oranges because we are comparing SL vs FTH and at low ambient temperature an intercooler gives better performance. Also a single stage blower will not heat up the air as drastically in the first place.

 

I just tried to explain that german "low grade" fuel was the same as allied fuel on the western front, because germans classified their fuel in lean rating and allies in rich! At the end of the war the german C3 fuel was pushing a 145/100 rating.

 

Whatever boost the 109, Dora and Mustang are running is not comparable because they run different compression ratios. The DB605 runs at 7.5:1 and the Jumo at 6.5:1 with B4 fuel. Both higher with C3 fuel. The Dora blowing its engines after a few seconds at 1.9 ata is a bug and not an engine design feature. With the lower compression ratio it can obviously sustain higher boost pressure than a DB605 engined 109.


Edited by rel4y

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first mw50 injection systems in bf109 were just field kits so the easiest way was to inject mw50 in to supercharger inlet.

check this out

https://www.rbracing-rsr.com/downloads/NACA_H2O_2.pdf

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091835.pdf

this one is about char air cooling https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093159.pdf

this raport is testing water/fuel ratios up to 2.0 and in bf109 there is no way that mw50 system injecting wather/methanol at this ratio it would require bigger mw50 tank then fuel tank

So you teling me that mw50 in bf109 isnt for knock protection ?? or what becouse a lots track a little

i though that allies got 100/130 fuel and it was better then 87 german counterpart. Fuel rated 100/130 is for both lean and rich i think and this is waht allies were using

but you must agree that this sudden jump in ATA form 1.45 to 1.8 is because the ECU is increasing supercharger impeler speed nothing more

finaly found this proper NACA raport

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093582.pdf

i noticed that in game when you engage mw50 at high alt in bf109 you can see that prop gage snaps forward it mean that engine want to speed up so there is some power increase at hight alt is it 100hp i dont know at high alt it maby less but it is definetly modeled in game :)

so mw50 engaged above critical alt it will increase power output of the engine due to cooling air charge introduced to engine so ECU must take it to account to introduce more fuel too actualy make it happen. but what power increase are we talking about ?? and what evaporation level are we talking about at high alt since inlet air tem will be very low

so thae power increase of increased density of charge air will be present through all altitude of plane but power gain because increased knock limit of fuel will fade away since supercharger wont be able to put ata above 1.45.

but i will hold up to that german fuel had less octane number then allied one but if this not true i dont see any reason to use mw50 in bf it could just run 1.8 ata without mw50. as i said earlier compresion of engine can be tested in difrent way givign difrent numbers so i will not take it as legit comparison

B4 and c3 fuel was captured and tested by allies dont know about db engines


Edited by grafspee

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MW50 does not have a primary job, it is injected into the supercharger for a reason and its effects are twofold.

 

I dont believe you understand most of what I am saying... You commented some partly correct stuff in another thread where I explained in high detail how MW50 actually works. I am pretty sure I know how it works. Of course it acts as antidetonant, but charge cooling is the second major desired effect! I have been saying that the whole time.

 

first mw50 injection systems in bf109 were just field kits so the easiest way was to inject mw50 in to supercharger inlet.

 

Why is it easier for a "field kit" to inject into the supercharger than through the cylinder injection nozzles which are there anyway in a DI engine?

 

Where on earth was I talking about water fuel ratios? But since you brought it up, please show me the water/fuel ratio to charge temp graphs in that NACA doc, because I cant find it (and dont know what it could possibly tell me about inlet charge temp). MW50 consists of methanol and water btw.

 

How could a sudden charge pressure increase not be from the blower? Where else is it supposed to come from? But the temperature of this air is hugely important and that is independent of what pressure you inject it into the cylinders. Do you realize that in a highly supercharged engine ambient temperature and charge air temperature differ by a vast amount? Why do you think a intercooler gives you no benefit in natural aspirated engine? I tried to give you an example with the Merlin 61, but I am not sure you read that part.

 

The charge temp rise of the Merlin 61 was 205°C at max F.S. revs..

 

and what evaporation level are we talking about at high alt since inlet air tem will be very low

 

Let me explain to you the basics. If ambient temp is -50°C then after compression the charge air has a temperature 155°C. What levels of Methanol evaporation could possibly be expected by a temperature of 155°C with its (sea level) boiling point of 65°C? Or water?

 

Do you know how the fuel ratio is calculated by the ECU in 109?


Edited by rel4y

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i am very aware of temp increase while compresing air.

It very depends on what pressure is in supercharger discharge house if it is around 1.8 ata and what water/methanol solution temperature is so at 155 celcius degree evaporation maby limited i think. but supercharge up high may increase temp more then at SL it will boost much more. Since we know that mw50 system is lifting knock limitation for DB605 engine that i can tell for sure that evaporation isnt completed 100% part of injected mw50 have to evaporate in combustion chamber to lift knock limitation of fuel used in engine

I m not sure if using cylinder nozzles would be easier than just single spray bar at supercharger intake.


Edited by grafspee

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i am very aware of temp increase while compresing air.

It very depends on what pressure is in supercharger discharge house if it is around 1.8 ata and what water/methanol solution temperature is so at 155 celcius degree evaporation maby limited i think. but supercharge up high may increase temp more then at SL it will boost much more. Since we know that mw50 system is lifting knock limitation for DB605 engine that i can tell for sure that evaporation isnt completed 100% part of injected mw50 have to evaporate in combustion chamber to lift knock limitation of fuel used in engine

I m not sure if using cylinder nozzles would be easier than just single spray bar at supercharger intake.

 

True, at lower altitude the supercharger isnt heating up the charge air as much, but the ambient temperature also isnt -50°C. That means that the resulting charge air temps will still be more than enough to boil Methanol.

 

So you are saying that gaseous Methanol does not provide ADI effects because suddenly its octane rating changes, am I understanding that correctly? Why would you need 100% evaporation to cool the charge air?

 

A direct injection engine already has a bunch of cylinder nozzles for, well, direct injection. So why not put the Methanol into the fuel like in racing fuel? Instant higher octane rating, no detonation, done! Thats not easier than a bunch of piping and a MW tank and pressured gas tanks and a supercharger injection nozzle and an extra throttle mechanism and a seperate pump etc.?

Cougar, CH and Saitek PnP hall sensor kits + shift registers: https://forums.eagle.ru/showthread.php?t=220916

 

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i think we can expect lower temp increase in bf109 at SL than in merlin 61

as far as i know merlin 61 is dual stage supercharger diven by crank shaft

at SL at 3000rpm supercharger system in merlin 61 is doing crazy staff like

1st stage of proces is lowering incoming pressure via throttle this rapidly decreasign inlet air temp may couse icing in some scenarios then air is entering 1st supercharger and 2nd supercharger boosting inlet pressure to max rated manifold pressure this kind of setup will bump air intake temp a lot more then bf109 supercharger setup. At hight alt dual stage supercharger will take ahead position.

But any way you are probably right methanol will likly vaporise in almost 100% so only water will work as ant knock and combustion chamber coolant

mixing methanol with fuel inst good idea because fuel systems are very sensitive to methanol

at least p-51 engine cant run fuel with methanol addition.

Another reason is that they wanted it as emergency system that can be engaged and disengaged at any time. And mixing methanl with fuel would require aditional tanks and aditional housing and fuel pumps too.

Difrent story is r-2800. this one is air cooled so combustion chamber is much hotter in this engine so without water injection engine could not run any near boost levels as in p-51.

but air cooled engines is whole difrent world


Edited by grafspee

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