Engine temperature in the 109s

[9./JG52_J-HAT]

Hi,

I have been noticing a correlation between speed and "radiator damage" in the 109E-3 and E-4 since the last patch. I don't remeber it being like this before.
I think what is great now is the limit on ata. Running full time with 1.35 ata wasn't realistic at all and now one needs to pay attention to it. Rpms have always been limited and I always assumed higher rpms would cause temperatures to rise. At a certain radiator setting the temperature would stay at an aceptable value (as it is). But increasing rpms with this same radiator setting will still make your radiator burst without the temperature rising (it still stays around 95 - 96°C). High rpms will seemingly burst your radiator regardless of temperature.
Is the temperature a function of rpms and airflow (which is a function of radiator setting and airflow, which relates to speed and angle of attack)? Or how does it really work?

And if you start pulling you nose up, maintaining rpms at 2500 and ata at 1.25, your speed will obviously drop. It usually drops to around 200 kph and you will still climb. But if you leave the water radiator at 3/4 the radiator will burst anyways, even with the temperature stays under 95°C. This was between 1k and 2,5k altitude. What I do is just open radiators fully and nothing goes wrong.
Oil radiator I always leave at around 70% and oil temperature is always within limits.

And the cooling system was a closed, pressurized system I am assuming, so boiling point will not decrease so drastically with altitude and temperature limits will still stay around the same up to the ceiling, correct? I can't imagine an open system for engine cooling in a machine that operates from sea level to 10k meters.

I can work around this and it doesn't pose any problems whatsoever. The nature of me asking this is to try to understand the reason behind this behavior.

Anyone noticed this too or has an (the) explanation?

[9./JG52 Jamz Dackel]

Hi,

I have been noticing a correlation between speed and "radiator damage" in the 109E-3 and E-4 since the last patch. I don't remeber it being like this before.
I think what is great now is the limit on ata. Running full time with 1.35 ata wasn't realistic at all and now one needs to pay attention to it. Rpms have always been limited and I always assumed higher rpms would cause temperatures to rise. At a certain radiator setting the temperature would stay at an aceptable value (as it is). But increasing rpms with this same radiator setting will still make your radiator burst without the temperature rising (it still stays around 95 - 96°C). High rpms will seemingly burst your radiator regardless of temperature.
Is the temperature a function of rpms and airflow (which is a function of radiator setting and airflow, which relates to speed and angle of attack)? Or how does it really work?

And what I have also noticed is, if you start pulling you nose up, maintaining rpms at 2500 and ata at 1.25, your speed will obviously drop. It usually drops to around 200 kph and you will still climb. But if you leave the water radiator at 3/4 the radiator will burst anyways, even with the temperature stays under 95°C. This was between 1k and 2,5k altitude. What I do is just open radiators fully and nothing goes wrong.
Oil radiator I always leave at around 70% and oil temperature is always within limits.

And the cooling system was a closed, pressurized system I am assuming, so boiling point will not decrease so drastically with altitude and temperature limits will still stay around the same up to the ceiling, correct? I can't imagine an open system for engine cooling in a machine that operates from sea level to 10k meters.

I can work around this and it doesn't pose any problems whatsoever. The nature of me asking this is to try to understand the reason behind this behavior.

Anyone noticed this too or has an (the) explanation?

Yes I have and only recently... It will be good to get an answer from someone in the know

[RAF74_Buzzsaw]

Temperature and engine failure in CLIFFS OF DOVER are a function of a number of elements:

1) Speed of the aircraft. Higher speeds generate more flow through the aircraft radiator/cooling shutters and therefore more cooling, lower speeds less.

2) Radiator/cooling shutter opening. Obviously the wider the opening, the more airflow, the more cooling.

3) Boost level. Higher boost means a larger volume of air/fuel mix is being forced into the compression chamber by the supercharger, therefore a larger explosion occurs on ignition, therefore more heat is generated. Sustained operation at high boost will generally generate more heat than the cooling system can deal with.

4) RPM's. The higher the rpms, the more explosions in the combustion chamber per second, therefore more heat generated. RPM's which exceed the recommended limits also affect the rods, crankshaft and bearings of the engine, these bearings are not built to sustain the frictional heat and forces generated beyond a certain RPM and can fail. Sustained operation at higher RPM's still within the acceptable limit generates more heat due to frictional causes.

5. Detonation and Pre-ignition. All of the engines in the game have optimum RPM/boost/temperature levels at which the valves and pistons operate most effectively in combusting the engine's fuel type without detonation and pre-ignition. If an engine operation exceeds the recommended levels, then pre-ignition or detonation can occur, generating excess heat and potentially damaging the engine bearings or pistons.

https://www.savvyanalysis.com/articles/detonation-and-pre-ignition

[aus]

I have a university education in chemistry and physics, and was discussing these issues with JHAT today. We both decided there are some serious coolant questions worth talking about here. I'm going to do bullet points, as it is easiest to organize in that way. This is assuming pure 100% H20 which of course the coolant may not be in the winter. However, the maintenance manual states that pure water with minor anti corrosion additives is to be used, "unless freezing is a concern".

1. The BF109 has a very weakly pressurized, closed coolant system, per the German Bf109 Operator manual. It was necessary to run the DB601 at less than 100C coolant temperature at sea level. However, at higher altitudes, say 8km, the sim allows us to run at 90-92C coolant temperature without popping the radiator. See data lists below... Pure water with no pressurization boils at 71C when at 8km. We know that at this altitude, the BF109 is rated to tolerate, MAXIMUM, 82C coolant temperature (low-level coolant pressurization). However, the testing we have done (see below) shows that the Bf109 coolant system is actually modeled as being able to tolerate far higher temperatures. Furthermore, the higher the altitude we tested, the more the discrepancy.

We ran a test to verify our hypothesis... controlling for all factors other than coolant temperatures.

--JHAT made a run with a bf109 E-3/B to 6km altitude while I recorded... he achieved 400kph IAS, 1.0ata, 2200rpm, oil radiator half-open, and had 90C on his coolant temperature gauge without perforation. He then fully closed his water radiator to reach the temperature at which radiator perforation occured: 105C, and only took 10 seconds.
--He then made another run with a bf109 E-3/B to 6km altitude to duplicate... he achieved 400kph IAS, 1.0ata, 2200rpm, oil radiator half-open, and had 90C on his temp on his coolant gauge without perforation. He then closed his water radiator position to reach a temperature increase of 1C/10sec (water radiator position 1/4 open): 99C, took 30 seconds.
In other words, the water temperature the radiator burst at was at sea level temperature limits.



Per the Messerschmitt AG Bf109 Operation Manual, Db601 engine, ca. 1938, the temperature to not exceed at various altitudes (page 8, http://109lair.hobbyvista.com/techref/manuals/bf109e.pdf):

Sea Level = 100C
2km = 95C
4km = 91C
6km = 87C
8km = 82C
10km = 78C



Pure water boiling temperatures at various altitudes (http://www.csgnetwork.com/h2oboilcalc.html):

Sea Level = 100C
2km = 93C
4km = 86C
6km = 79C
8km = 71C
10km = 63C

Our conclusion is that the coolant temperatures which can be currently tolerated by the DB601/Bf109 are not modelled correctly for various altitudes. We recognize that were this to actually be remedied without changing anything else, there would be a serious problem, because in our experience, there is simply no way to reduce coolant temperature below 88C, regardless of altitude or radiator position. Thus, if the correct modelling was put into place, the Bf109 would be blowing radiators continuously when piloted at high altitudes, and the pilot simply couldn't do anything to avoid it.

This of course did not happen in real life, and we believe the reason why there was no historical problem, is because the BF109 engineers recognized that the AMBIENT AIR TEMPERATURES at high altitudes, being so much colder, would easily provide for sufficient cooling to prevent overpressurization of the coolant system. We therefore conclude that, in the sim, the coolant temperatures are not correctly being affected by ambient air temperature.

To put how large an effect ambient air temperature should have, one needs only to look at the temperature variation with altitude. On a day in which the temperature is 15C at sea level, at the same time and location, the temperature at 6km is -24C. You can see how such a low temperature could actually cause freezing of aircraft coolant at high altitudes, if full radiator was used without consideration of coolant temp. Indeed, this very issue was a problem at high altitudes for the operation of some US aircraft in the European theatre of operations in WWII (see P-38 cooling problems).

(from http://usatoday30.usatoday.com/weather/wstdatmo.htm)

Height(m) Temperature(C)
0000 15.0
1000 8.5
2000 2.0
3000 -4.5
4000 -11.0
5000 -17.5
6000 -24.0
7000 -30.5
8000 -37.0
9000 -43.5
10000 -50.0



2. Per the maintenance manual, the DB601 coolant system in the Bf109 has a pressure relief valve that vents overheated coolant, just like a radiator cap on a modern car. This is not the case in the game, where a coolant overheat means the radiator is perforated just like a bullet went through it. In reality, the historical design has a relief valve which should open to vent excess pressure (and some coolant), and then close when that pressure is reduced (the pilot opens the radiators, slows the engine, etc). There should be sufficient cooling capacity at altitude and speed to reduce coolant temperature if the aircraft were to be put into a dive, radiators opened, and throttle lessened to nil. The coolant capacity of the aircraft is 65 Liters. This is a large coolant capacity and I believe that if the coolant overheat was caught and recified via the above methods in time, there should still be enough coolant to operate the aircraft at a reduced level without coolant vapor lock and engine destruction.

3. Per the maintenance manual, the DB601 should not be operated at less than 60C water temperature. This is in stark contrast to the current state of affairs where the coolant temp can be 30C and the aircraft will do a maximum power takeoff with no problem or consequences.


We are not trying to ruffle feathers, and realize the limitations that the Team Fusion works under regarding sim code, etc. However, without recognition of problems, there can be no solution.

[aus]

I have the maintenance manual on .pdf, but it is too large to attach here. Any TF members please feel free to contact me for a copy.

[ATAG_Colander]

I have a university education in chemistry and physics, and was discussing these issues with JHAT today. We both decided there are some serious coolant questions worth talking about here. I'm going to do bullet points, as it is easiest to organize in that way. This is assuming pure 100% H20 which of course the coolant may not be in the winter. However, the maintenance manual states that pure water with minor anti corrosion additives is to be used, "unless freezing is a concern".

1. The BF109 has a very weakly pressurized, closed coolant system, per the German Bf109 Operator manual. It was necessary to run the DB601 at less than 100C coolant temperature at sea level. However, at higher altitudes, say 8km, the sim allows us to run at 90-92C coolant temperature without popping the radiator. See data lists below... Pure water with no pressurization boils at 71C when at 8km. We know that at this altitude, the BF109 is rated to tolerate, MAXIMUM, 82C coolant temperature (low-level coolant pressurization). However, the testing we have done (see below) shows that the Bf109 coolant system is actually modeled as being able to tolerate far higher temperatures. Furthermore, the higher the altitude we tested, the more the discrepancy.

We ran a test to verify our hypothesis... controlling for all factors other than coolant temperatures.

--JHAT made a run with a bf109 E-3/B to 6km altitude while I recorded... he achieved 400kph IAS, 1.0ata, 2200rpm, oil radiator half-open, and had 90C on his coolant temperature gauge without perforation. He then fully closed his water radiator to reach the temperature at which radiator perforation occured: 105C, and only took 10 seconds.
--He then made another run with a bf109 E-3/B to 6km altitude to duplicate... he achieved 400kph IAS, 1.0ata, 2200rpm, oil radiator half-open, and had 90C on his temp on his coolant gauge without perforation. He then closed his water radiator position to reach a temperature increase of 1C/10sec (water radiator position 1/4 open): 99C, took 30 seconds.
In other words, the water temperature the radiator burst at was at sea level temperature limits.



Per the Messerschmitt AG Bf109 Operation Manual, Db601 engine, ca. 1938, the temperature to not exceed at various altitudes (page 8, http://109lair.hobbyvista.com/techref/manuals/bf109e.pdf):

Sea Level = 100C
2km = 95C
4km = 91C
6km = 87C
8km = 82C
10km = 78C



Pure water boiling temperatures at various altitudes (http://www.csgnetwork.com/h2oboilcalc.html):

Sea Level = 100C
2km = 93C
4km = 86C
6km = 79C
8km = 71C
10km = 63C

Our conclusion is that the coolant temperatures which can be currently tolerated by the DB601/Bf109 are not modelled correctly for various altitudes. We recognize that were this to actually be remedied without changing anything else, there would be a serious problem, because in our experience, there is simply no way to reduce coolant temperature below 88C, regardless of altitude or radiator position. Thus, if the correct modelling was put into place, the Bf109 would be blowing radiators continuously when piloted at high altitudes, and the pilot simply couldn't do anything to avoid it.

This of course did not happen in real life, and we believe the reason why there was no historical problem, is because the BF109 engineers recognized that the AMBIENT AIR TEMPERATURES at high altitudes, being so much colder, would easily provide for sufficient cooling to prevent overpressurization of the coolant system. We therefore conclude that, in the sim, the coolant temperatures are not correctly being affected by ambient air temperature.

To put how large an effect ambient air temperature should have, one needs only to look at the temperature variation with altitude. On a day in which the temperature is 15C at sea level, at the same time and location, the temperature at 6km is -24C. You can see how such a low temperature could actually cause freezing of aircraft coolant at high altitudes, if full radiator was used without consideration of coolant temp. Indeed, this very issue was a problem at high altitudes for the operation of some US aircraft in the European theatre of operations in WWII (see P-38 cooling problems).

(from http://usatoday30.usatoday.com/weather/wstdatmo.htm)

Height(m) Temperature(C)
0000 15.0
1000 8.5
2000 2.0
3000 -4.5
4000 -11.0
5000 -17.5
6000 -24.0
7000 -30.5
8000 -37.0
9000 -43.5
10000 -50.0



2. Per the maintenance manual, the DB601 coolant system in the Bf109 has a pressure relief valve that vents overheated coolant, just like a radiator cap on a modern car. This is not the case in the game, where a coolant overheat means the radiator is perforated just like a bullet went through it. In reality, the historical design has a relief valve which should open to vent excess pressure (and some coolant), and then close when that pressure is reduced (the pilot opens the radiators, slows the engine, etc). There should be sufficient cooling capacity at altitude and speed to reduce coolant temperature if the aircraft were to be put into a dive, radiators opened, and throttle lessened to nil. The coolant capacity of the aircraft is 65 Liters. This is a large coolant capacity and I believe that if the coolant overheat was caught and recified via the above methods in time, there should still be enough coolant to operate the aircraft at a reduced level without coolant vapor lock and engine destruction.

3. Per the maintenance manual, the DB601 should not be operated at less than 60C water temperature. This is in stark contrast to the current state of affairs where the coolant temp can be 30C and the aircraft will do a maximum power takeoff with no problem or consequences.


We are not trying to ruffle feathers, and realize the limitations that the Team Fusion works under regarding sim code, etc. However, without recognition of problems, there can be no solution.


TF will change the damage to "generic engine damage" instead of "water radiator perforated". Problem solved!

[aus]

I am not quite that cynical, Colander, and believe that a Team which has gone to such great lengths to improve this beloved red-headed stepchild of ours will be interested in the evidence put forth above, to improve upon their already great improvements in COD.

[RAF74_Buzzsaw]

There was no modelling in the original game for the difference between fully pressurized versus partially-pressurized systems. All systems were considered fully pressurized.

This means altitude difference is not taken into account when determining what temperature an non-pressurized engine will overheat.

Sea level or 9000 meters, there is no difference.

This is particularly noticeable if you are looking at the historical 109 system versus what we have in the game.

Although we could, it is not worthwhile at this point for us to spend the very large amount of time and effort to re-write the code to model differences between fully pressurized and limited pressure systems. There are far more important issues and additions to the game for us to invest our time in.

So comparisons between historical and game are not relevant for game purposes.

We have tried to model the existing systems to provide a functional overheat system. It is not perfect, we would be the first to admit this, the issue is again a flaw within the game's core physics system, and its modelling of atmospheric density through the altitude range, and the properties of reduced density at higher altitudes. We have applied fixes for this issue, but they are as yet, not perfect as we are still in the process of decrypting the core elements of the code and our knowledge is limited.

Our development of this mod is always a tradeoff between spending forever trying to get something perfect, or getting a functional fix in place so the players can enjoy the game, and in the meantime working on more permanent and more accurate fixes to be applied later.

TF 3.0 was an improvement on the vanilla game, and TF 4.0 is an improvement on TF 3.0. We hope to move forwards with further improvements in the future.

Overheat systems are applied across the board to ALL AIRCRAFT consistently. There is no favouritism in modelling.

There will be no changes for these systems till at least TF 5.0.

Thanks Buzzsaw Chief Flight/Damage/Weapons modelling

[9./JG52_J-HAT]

Thanks for the definite answer, Buzzsaw! :thumbsup:

And it is nice to know there are indeed a series of parameters taken in account to induce damage to the cooling system. And the radiator damage is just the representation of all these problems occuring.

[ATAG_Colander]

I see you didn't like my joke :(

[RAF74_Buzzsaw]

Ahhh... it was ok... Not up to your usual high standards... but not bad. :P

[ATAG_Lolsav]

I see you didn't like my joke :(

This one?


TF will change the damage to "generic engine damage" instead of "water radiator perforated". Problem solved!

I loled, but at same time i had a grin smile in my face, imagining you had just spilled your coffee all over your keyboard.:devilish:

[ATAG_Colander]

I loled, but at same time i had a grin smile in my face, imagining you had just spilled your coffee all over your keyboard.:devilish:

At this time of day and on a Friday, is more likely to be a beer than coffee :D

[aus]

There was no modelling in the original game for the difference between fully pressurized versus partially-pressurized systems. All systems were considered fully pressurized.

This means altitude difference is not taken into account when determining what temperature an non-pressurized engine will overheat.

Sea level or 9000 meters, there is no difference.

This is particularly noticeable if you are looking at the historical 109 system versus what we have in the game.

Although we could, it is not worthwhile at this point for us to spend the very large amount of time and effort to re-write the code to model differences between fully pressurized and limited pressure systems. There are far more important issues and additions to the game for us to invest our time in.

So comparisons between historical and game are not relevant for game purposes.

We have tried to model the existing systems to provide a functional overheat system. It is not perfect, we would be the first to admit this, the issue is again a flaw within the game's core physics system, and its modelling of atmospheric density through the altitude range, and the properties of reduced density at higher altitudes. We have applied fixes for this issue, but they are as yet, not perfect as we are still in the process of decrypting the core elements of the code and our knowledge is limited.

Our development of this mod is always a tradeoff between spending forever trying to get something perfect, or getting a functional fix in place so the players can enjoy the game, and in the meantime working on more permanent and more accurate fixes to be applied later.

TF 3.0 was an improvement on the vanilla game, and TF 4.0 is an improvement on TF 3.0. We hope to move forwards with further improvements in the future.

Overheat systems are applied across the board to ALL AIRCRAFT consistently. There is no favouritism in modelling.

There will be no changes for these systems till at least TF 5.0.

Thanks Buzzsaw Chief Flight/Damage/Weapons modelling

At least I can see that it is being considered. It is another element of immersion in the game, that at high altitudes things get... different. Engine cooling is vastly different, contrails show up (which shows how cold things are, truly), mixture settings are radically different (on some A/C), ATAs fall off, and if coders were to start putting frost setting in on some surfaces as alt increases... this all would really immerse the player in the idea that "I am really *ucking high up, and it is really *ucking cold". Those of us who have been to high altitudes can attest that everything is different, even the lighting and shadows are very different. It is truly a different world up there, and I have yet to see a ww2 sim model this effectively. Everything always seems to be as if the cockpit were pressurized and warm like on a modern jet liner. In reality, these guys froze their balls off and had to deal with real high altitude considerations, even above 15,000ft. It would be nice to feel as a simmer, that this trusty machine you have taken up to these heights, have done battle in, have nearly been killed and have killed in, and takes you back home again, has truly been through some very different environments. Engine management is a part of that and I do love the ATA issues, I have had many supercharger discussions with simmers, so I know that people are noticing and truly paying attention to the details... the details are important... and this game is the closest so far to get them all right... so I would have to say that, although maybe there are other important systems yes, certainly these are not unimportant. I look forward to future updates. :)

[vranac]

Aus, just listen to your engine( or watch RPMs )

I'm still flying at full ATA( throttle) and oil rad at 50 %, air at 3/4 but I'm not overreving my engine and I can fly all the way with WEP on.

[9./JG52_J-HAT]

Really, Vranac? Are you sure you can fly WEP all day long? I keep busting my engine if I fly with manifold pressure too high, even if I don't overrev. I am going to try that.

[aus]

Aus, just listen to your engine( or watch RPMs )

I'm still flying at full ATA( throttle) and oil rad at 50 %, air at 3/4 but I'm not overreving my engine and I can fly all the way with WEP on.

Gee, I guess I'll have to try that... :coolio:

[vranac]

Really, Vranac? Are you sure you can fly WEP all day long? I keep busting my engine if I fly with manifold pressure too high, even if I don't overrev. I am going to try that.

Yes. Just watch this track with outside views disabled at the beginning where you'll see rad settings. Later you can enable outside views.
Look close to the end of the track ( you can speed up 2x, 4x, 8x ). It was just test with friend but other pilots joined )).

http://www12.zippyshare.com/v/52032979/file.html

[aus]

...I rest my case :salute:

[VO101_Tom]

I have a university education in chemistry and physics, and was discussing these issues with JHAT today. We both decided there are some serious coolant questions worth talking about here. I'm going to do bullet points, as it is easiest to organize in that way. This is assuming pure 100% H20 which of course the coolant may not be in the winter. However, the maintenance manual states that pure water with minor anti corrosion additives is to be used, "unless freezing is a concern".

...

Our conclusion is that the coolant temperatures which can be currently tolerated by the DB601/Bf109 are not modelled correctly for various altitudes. We recognize that were this to actually be remedied without changing anything else, there would be a serious problem, because in our experience, there is simply no way to reduce coolant temperature below 88C, regardless of altitude or radiator position. Thus, if the correct modelling was put into place, the Bf109 would be blowing radiators continuously when piloted at high altitudes, and the pilot simply couldn't do anything to avoid it.

This of course did not happen in real life, and we believe the reason why there was no historical problem, is because the BF109 engineers recognized that the AMBIENT AIR TEMPERATURES at high altitudes, being so much colder, would easily provide for sufficient cooling to prevent overpressurization of the coolant system. We therefore conclude that, in the sim, the coolant temperatures are not correctly being affected by ambient air temperature.

Hi.

The DB 601 engine manual writes, that the cooling mixture should be (regardless of season):
47 unit water
50 unit glycol
4.5 unit water-oil mix in 2:1 ratio

(The 109 E pilot manual states 30-70% Glycol-Water ratio)

The glycol prevent the icing, and increasing the boil temperature too. The manual not recommend the use of pure water.

[aus]

30:70 ethylene glycol raises boiling temp by 4C, 50:50 raises by 7C. The major effect is seen in freezing temps. I will contact you via PM.

[Stig1207]

[QUOTE=aus;72111Everything always seems to be as if the cockpit were pressurized and warm like on a modern jet liner. In reality, these guys froze their balls off......[/QUOTE]


This could possibly be simulated DIY with some ice from the freezer.:D

[9./JG52_J-HAT]

Hi.

The DB 601 engine manual writes, that the cooling mixture should be (regardless of season):
47 unit water
50 unit glycol
4.5 unit water-oil mix in 2:1 ratio

(The 109 E pilot manual states 30-70% Glycol-Water ratio)

The glycol prevent the icing, and increasing the boil temperature too. The manual not recommend the use of pure water.


This manual: 5532 says this: 5533. It refers to the DB601 manual for corrosion and water softner additives. Nothing about "Frostschutzmittel". And right on page 2 it sways in cold weather, add 30% Glysantin to 70% water warmed up to 65ºC.

But this manual could have been revised, and probably was. Your source is the engine manual and the information in it actually makes more sense, indeed.

[VO101_Tom]

This could possibly be simulated DIY with some ice from the freezer.:D

It's no joke, if the pilot forgot to wear leather gloves, He easily get frostbite on his hands.

[VO101_Tom]

This manual: 5532 says this: 5533. It refers to the DB601 manual for corrosion and water softner additives. Nothing about "Frostschutzmittel". And right on page 2 it sways in cold weather, add 30% Glysantin to 70% water warmed up to 65ºC.

But this manual could have been revised, and probably was. Your source is the engine manual and the information in it actually makes more sense, indeed.

Yep, I saw this, I know this document. There is a contradiction between the aircraft manual (which was made for pilots, edited by the Messerschmitt AG) and the engine manual (which was made for ground crew, edited the Daimler Benz AG). The DB document describes more accurate ratios. Later the DB 605 manual describes the tools and the whole mixing process in different temperatures. Clearly more reliable source, if you are looking for information about the engine.

You can see this ratio on page -20- :
http://www.pumaszallas.hu/Private/VO101_Tom/docs/DB601_AuB_MM_1940_08.pdf

The other thing, that the internal pressure of the cooling system was not higher than the pressure on the sea level (maybe this is why mentioned as "not pressurized"), but the system was closed. There was an overpressure valve, which prevent the damage if the water boil. This would have been obviously unnecessary if the pressure is equalized to the external pressure anyway (in your document, page 101 and 102, Anlage 15. The Überdruckventil on the front of the engine. That is the "overpressure-valve").

Apart from this, the ingame temperatures are higher than it should, but this is the error of the clod temperature modell. If we need to choose between the correct temperatures or the correct working, obvious which one the more important. Buzzsaw working a lot to make the engine overheat modell more accurate.

[9./JG52 Ziegler]

I would add that in real life, in a complex single engined airplanes, over reving (past 3000rpms) can be a problem but the bigger problem is low revs at high manifold pressures. Pilots are taught to fly "over square" or slightly higher revs than MP (ata). Example 25"mp and 2500 (or better) rpms. 35"mp at 2000rpm's would be highly stressful and akin to having your car in 5th gear uphill or at to slow a pace with full throttle. Modern planes use constant speed hydraulic props (versus the electric variable on the 109's) but the concept is the same except that constant speed props have set parameters and generally will not exceed top and bottom limits. also it's worth stating that proper technique is to reduce power, you want to reduce the MP first then the RPM. When you add power, RPM first then MP.

[9./JG52_J-HAT]

Yep, I saw this, I know this document. There is a contradiction between the aircraft manual (which was made for pilots, edited by the Messerschmitt AG) and the engine manual (which was made for ground crew, edited the Daimler Benz AG). The DB document describes more accurate ratios. Later the DB 605 manual describes the tools and the whole mixing process in different temperatures. Clearly more reliable source, if you are looking for information about the engine.

You can see this ratio on page -20- :
http://www.pumaszallas.hu/Private/VO101_Tom/docs/DB601_AuB_MM_1940_08.pdf

The other thing, that the internal pressure of the cooling system was not higher than the pressure on the sea level (maybe this is why mentioned as "not pressurized"), but the system was closed. There was an overpressure valve, which prevent the damage if the water boil. This would have been obviously unnecessary if the pressure is equalized to the external pressure anyway (in your document, page 101 and 102, Anlage 15. The Überdruckventil on the front of the engine. That is the "overpressure-valve").

Apart from this, the ingame temperatures are higher than it should, but this is the error of the clod temperature modell. If we need to choose between the correct temperatures or the correct working, obvious which one the more important. Buzzsaw working a lot to make the engine overheat modell more accurate.

Hey Tom,

Cool manual, thanks!
I noticed the pressure releave valve in the drawing too and from the manual's limit temperatures I realized it was a closed system pressurized to sea level pressure. Of course it would add another nice immersion factor having different temperatures, but I really don't think it is that important. The game engine models it the way Buzzsaw described and that's ok. If it gets done, great, if not, ok too.

From what I understood the game just models different damage to the engine as the radiator bursting, not just bullet hits. It is probably why one could fly endlessly with a venting radiator in the vanilla version but your engine would still stop if you had other problems (shaking, oil on your windscreen and so on).

I wish it were feasable to model the pressure releave valve for boiling water in the 109, and not just losing your engine after a couple of minutes because it boiled. Engine damge is another matter though. It should be damaged permanently. Having your gasket blow because you ran with manifold pressure too high would be nice, for example.

Colander's suggestion is actually a good one to stop people from thinking the venting radiators are just boiling related. If my assumption above is correct, of course.

And I am very grateful of Team Fusion and Buzzsaw for the patches and the upfront attitude regarding questions, by the way! This is no way a wish list or a demands list, of course. Just suggestion that could be taken in account for future development if resources allow. Keep up the good work!