Water injection inconsistency between K-4 and P-47D

[Rebel_Scum]

Just now, =RvE=Windmills said:

 

Then the question is, how would one reasonably interpret the P47 manual. Would a pilot be expected to throttle back down to continuous after running emergency? Without this being directly stated, I doubt anyone could say for sure that it should be interpreted like that. If it was, wouldn't it be explicitly stated?

 

So here the devs tried to follow the instructions for the 109 to the letter, the workaround to achieving this being the creation of two separate limits. This is obviously works out to being extremely beneficial in combat. I don't think this is particularly disagreeable on its own, its a fine way to achieve exactly what the manual states. Though the rub is obviously in the fact here that we're kinda playing with words. While The P47 manual doesn't explicitly state that you can cool down from emergency in combat, it also doesn't state that it cannot. I don't think its reasonable to assume the latter as an implication of the former.

 

Obviously this partially stems from the fact that it wouldn't really make a difference in reality. The engine would never care about having an extra 15 mins of combat thrown on top of 5 mins of emergency. Though we're now dealing with a very real disadvantage ingame simply due to the precise way in which the P47 manual happens to be worded. With the 109 experiencing a clear advantage due to the way its manual happens to be worded.

 

I don't mind there being differences here, but it seems this is either being overly charitable to the 109 or overly pessimistic to the P47 depending on your perspective. The more I consider this the more separating engine timers seems like way too big of a difference in ingame performance to be justified by this simple wording in the manuals.

 

Excellent summary.  Agree 100%.

[Legioneod]

14 minutes ago, =RvE=Windmills said:

 

Then the question is, how would one reasonably interpret the P47 manual. Would a pilot be expected to throttle back down to continuous after running emergency? Without this being directly stated, I doubt anyone could say for sure that it should be interpreted like that. If it was, wouldn't it be explicitly stated?

 

So here the devs tried to follow the instructions for the 109 to the letter, the workaround to achieving this being the creation of two separate limits. This is obviously works out to being extremely beneficial in combat. I don't think this is particularly disagreeable on its own, its a fine way to achieve exactly what the manual states. Though the rub is obviously in the fact here that we're kinda playing with words. While The P47 manual doesn't explicitly state that you can cool down from emergency in combat, it also doesn't state that it cannot. I don't think its reasonable to assume the latter as an implication of the former.

 

Obviously this partially stems from the fact that it wouldn't really make a difference in reality. The engine would never care about having an extra 15 mins of combat thrown on top of 5 mins of emergency. Though we're now dealing with a very real disadvantage ingame simply due to the precise way in which the P47 manual happens to be worded. With the 109 experiencing a clear advantage due to the way its manual happens to be worded.

 

I don't mind there being differences here, but it seems this is either being overly charitable to the 109 or overly pessimistic to the P47 depending on your perspective. The more I consider this the more separating engine timers seems like way too big of a difference in ingame performance to be justified by this simple wording in the manuals.

 

One of the reasons we need more realistic engine models with more deciding factors than just a unrealistic time limit.

 

Heat, detonation, etc need to be the deciding factor when an engine quits due abuse, not a time limit.

[=362nd_FS=RoflSeal]

One of the P-47 manuals describes usage as WEP as ammunition, hoard it till necessary then use it unhesitatingly. This is a similar message to AP 2095 Pilot's General notes for the RAF where the time limits are general guidelines for reasonable use, in emergencies and combat considerations, there is justification for the pilot disregarding the time limits.

[LuftManu]

I think the system works at the moment as all the planes are modeled the same way and I am happy with it. The engine modeling is great and miles ahead of 1946.

If this is correct and water could be used 15 minutes straight, I would be happy if the Devs implement that as an extra timer meaning you can use the 15 minutes straight or in series. But this being it's own timer. Then you can go to the 5 minutes WEP and destroy your engine with lower settings than with Water cause you are not using it anymore. Something like the MW50 but this having it's own timer too of series of 10 minutes.

 

What I mean?
I need extra power so I just push the Water injection. I know I have 15 minutes. I just push the plane as far as I can go and then the message of "Boost time exceeded" appears and I know I only have 5 minutes and I also take a look at the MAP and it's lower because the ADI has been depleted.

 

I think we all would be happy as it would work like it works with other ADIs, at least for the moment.

I am enjoying the Jug as a child, and I would like to reminder that this is just an small thing betweeen the other 1,000 that are great. I hope our documents make de devs take a decission and change it or not depending if it would be realistic.

Edited November 24, 2018 by LF_Gallahad

[Cpt_Siddy]

32 minutes ago, =RvE=Windmills said:

 

 

I don't mind there being differences here, but it seems this is either being overly charitable to the 109 or overly pessimistic to the P47 depending on your perspective. The more I consider this the more separating engine timers seems like way too big of a difference in ingame performance to be justified by this simple wording in the manuals.

 

 

 

If i ever get a time machine, ill go back and rewrite the manual just to troll with games in the year 2018, because computers and modern education system cant help model system used in 1940's or understand what principles governed them.  

Edited November 24, 2018 by Cpt_Siddy

[=362nd_FS=RoflSeal]

3 minutes ago, Cpt_Siddy said:

 

 

If i ever get a time machine, ill go back and rewrite the manual just to troll with games in the year 2018, because computers and modern education system cant help model system used in 1940's or understand what principles governed them.  

Yeah Americans didn't think for the future where video game companies would model their engines blowing up 1 minute after they exceeded the time limit stated in the manual.

[Cpt_Siddy]

3 minutes ago, LF_Gallahad said:

I think the system works at the moment as all the planes are modeled the same way and I am happy with it. The engine modeling is great and miles ahead of 1946.

  
If this is correct and water could be used 15 minutes straight, I would be happy if the Devs implement that as an extra timer meaning you can use the 15 minutes straight or in series. But this being it's own timer. Then you can go to the 5 minutes WEP and destroy your engine with lower settings than with Water cause you are not using it anymore.

 

 

It is my understanding, that the limiting factor of high manifold pressures on two stage intercooled systems were intercoolers ability to keep the air temperature below premature detonation point. 

 

The water injection system just raises the temperature threshold by providing additional cooling to compressed gasses. 

[Rebel_Scum]

Just now, Cpt_Siddy said:

 

 

If i ever get a time machine, ill go back and rewrite the manual just to troll with games in the year 2018, because people, with computers and modern education system, cant model system used in 1940's and need to read manuals. 

The problem is that they're modelling the manual, not the system.

[Cpt_Siddy]

Just now, RoflSeal said:

Yeah Americans didn't think for the future where video game companies would model their engines blowing up 1 minute after they exceeded the time limit stated in the manual.

 

This tragedy, if any, motivates me to invent time machine. (no i wont stop ww2, what games will we play then?)

Just now, Rebel_Scum said:

The problem is that they're modelling the manual, not the system.

 

Well, in that case, job well done 

[PainGod85]

Just now, Rebel_Scum said:

The problem is that they're modelling the manual, not the system.

 

This so much.

[LuftManu]

Just now, Cpt_Siddy said:

 

 

It is my understanding, that the limiting factor of high manifold pressures on two stage intercooled systems were intercoolers ability to keep the air temperature below premature detonation point. 

 

The water injection system just raises the temperature threshold by providing additional cooling to compressed gasses. 

I don't know the quircks, I am speaking about what would an average pilot like me see and what would be easy to understand seeing how the MW50 works on german planes (Maybe a different system)

 

I hope some day I can understand what all of you are talking about ?

[Rebel_Scum]

15 minutes ago, Cpt_Siddy said:

 

This tragedy, if any, motivates me to invent time machine. (no i wont stop ww2, what games will we play then?)

 

Well, in that case, job well done 

 

Edited November 24, 2018 by Rebel_Scum

[PainGod85]

Just now, LF_Gallahad said:

I don't know the quircks, I am speaking about what would an average pilot like me see and what would be easy to understand seeing how the MW50 works on german planes (Maybe a different system)

 

I hope some day I can understand what all of you are talking about ?

 

The system is functionally the same. A cold mix of water and alcohol is injected into the cylinders alongside the fuel-air mixture, which absorbs heat from the compression cycle's adiabatic process. This delays detonation until the spark plug ignites the cylinder's contents at the proper time, thereby increasing engine cooling and knock resistance and causing a net stress reduction on the powerplant.

[Cpt_Siddy]

Just now, LF_Gallahad said:

I don't know the quircks, I am speaking about what would an average pilot like me see and what would be easy to understand seeing how the MW50 works on german planes (Maybe a different system)

 

I hope some day I can understand what all of you are talking about ?

 

Very simple way to look at this: 

 

It is physics with mixed in chemistry. In short, in the quest to cram as much oxygen and fuel in to confined space (cylinder) as humanly possible and then have it ignite in a timely fashion to produce a power stroke. 

 

Compressing gasses, when dealing with ideal gasses, tend to warm up: PV=nRT.  This can be changed by introducing an agent with high phase change enthalpy, (water has about 40Kj/mol) in a temperature range that is before the detonation occurs. This mean, spraying in water will soak up thermal energy (kinetic energy from every individual molecule) as the water will change phase from fine mist to water vapor. This will produce cooling effect that is greater than the added n value to the equation by the water. 

 

This mean, combining intercooler and water system allows you to cram in more stuff before the stuff auto detonates prematurely in the middle of compression stroke and causes you a world of trouble 

 

[LuftManu]

Thanks both of you, so it's the same system as the MW50 afaik. Does this water comes with Methanol?

Edited November 24, 2018 by LF_Gallahad

[Cpt_Siddy]

9 minutes ago, LF_Gallahad said:

Thanks both of you, so it's the same system as the MW50 afaik. Does this water comes with Methanol?

 

I have no idea what mixture did Americans use, the methanol, iirc, mainly serves as anti corrosion agent, but i could be wrong. There were cases where pure water was used, not sure about other additives. 

 

Oh and antifreeze, i always forget that they fly so high that water tends to freeze. Even when i live in country that suffers from this very problem half of the year

Edited November 24, 2018 by Cpt_Siddy

[Kurfurst]

Yes. Methanol is a cheap anti freeze in the system, although it has its own burning energy (far lower than gasoline though) and actually very high knocking resistance. Ethanol could be also used.

 

Water would work on its own but for both practical reasons (freeze) and due to that some mixtures yield slightly better powers the 50/50 ratio was used.

[PainGod85]

Just now, LF_Gallahad said:

Thanks both of you, so it's the same system as the MW50 afaik. Does this water comes with Methanol?

 

25% methanol, 25% ethanol, 50% water.

 

Note the alcohol is just in there to prevent the mixture from freezing up if the plane is kept in a ready state on the ground, at least where the P-47 is concerned. The manual says as much, stating that a greater cooling effect is achieved with 100% water, but that the tank should only be filled in subzero temperatures after the engine has been warmed up or that it be filled with the water-alcohol mix beforehand.

[Cpt_Siddy]

6 minutes ago, PainGod85 said:

 

25% methanol, 25% ethanol, 50% water.

 

Note the alcohol is just in there to prevent the mixture from freezing up if the plane is kept in a ready state on the ground, at least where the P-47 is concerned. The manual says as much, stating that a greater cooling effect is achieved with 100% water, but that the tank should only be filled in subzero temperatures after the engine has been warmed up or that it be filled with the water-alcohol mix beforehand.

 

Idd imagine that inert gas antifreeze system could be machined/cobbled up around the water system if the pure water was desirable, its not like we lack waste thermal energy on a P-47 power plant 

[PainGod85]

No, the issue is the water tank freezing solid on the ground. Once the engine is running, the ambient temperature inside the cowling prevents the water from freezing.

[Cpt_Siddy]

Just now, PainGod85 said:

No, the issue is the water tank freezing solid on the ground. Once the engine is running, the ambient temperature inside the cowling prevents the water from freezing.

 

Installing a drain gate on the tank to empty it?

Dunno, but the ground maintenance is a greek tragedy of "doh, why did we not think of that". 

[PainGod85]

Just now, Cpt_Siddy said:

 

Installing a drain gate on the tank to empty it?

Dunno, but the ground maintenance is a greek tragedy of "doh, why did we not think of that". 

 

You're missing the point.

 

As the plane is kept in a ready state in subzero temperatures, you either fuel with the alcohol/water mix or you fill the tank with water after the engine is warmed up.

[Cpt_Siddy]

7 minutes ago, PainGod85 said:

 

You're missing the point. 

 

As the plane is kept in a ready state in subzero temperatures, you either fuel with the alcohol/water mix or you fill the tank with water after the engine is warmed up.

 

Didint the scramble ready fighters have heaters attached to them to keep the oil runny? 

Edited November 24, 2018 by Cpt_Siddy

[PainGod85]

Just now, Cpt_Siddy said:

 

Didint the scramble ready fighters have heaters attached tot hem to keep the oil runny? 

 

Don't think that was pertaining to scramble fighters. You won't have the whole air wing on heaters because you usually weren't issued enough for all your planes.

 

E: Anyways, we're getting off topic here.

Edited November 24, 2018 by PainGod85

[Sgt_Joch]

As I recall, early in the war the Russians had a serious shortage of antifreeze and used plain water in AC radiator even in winter. SOP was to drain the radiators every night since water freezing would expand and destroy the radiator. 

[Cpt_Siddy]

27 minutes ago, VO101Kurfurst said:

Ethanol could be also used.

 

 

Soviet experimental MV*50 system (1939, colorized)(*Much Vodka)

[Kurfurst]

Actually MW50 could be substituted by EW50 or EW30 (or pure water in emergency).

 

EW50 stands for Ethanol Water 50/50, so it was basically a pretty stout Vodka. With Schutzöl 39 for flavour. ? 

[Cpt_Siddy]

2 minutes ago, VO101Kurfurst said:

Actually MW50 could be substituted by EW50 or EW30 (or pure water in emergency).

 

EW50 stands for Ethanol Water 50/50, so it was basically a pretty stout Vodka. With Schutzöl 39 for flavour. ? 

 

Little bit of anti corrosive additive never hurt no one. 

[Ehret]

1 hour ago, LF_Gallahad said:

If this is correct and water could be used 15 minutes straight, I would be happy if the Devs implement that as an extra timer meaning you can use the 15 minutes straight or in series.

 

You can use 15m straight of water injection in the P-47 now. Only caveat is it will not be at maximum boost; you will have to limit the MP to the 58". Then the engine stays in the "combat mode" and allows whole 15m in one go.

[Legioneod]

5 minutes ago, Ehret said:

 

You can use 15m straight of water injection in the P-47 now. Only caveat is it will not be at maximum boost; you will have to limit the MP to the 58". Then the engine stays in the "combat mode" and allows whole 15m in one go.

That's not WEP though, just wasting water at a lower power imo. Water was for WEP not combat, so using it at combat settings is still insufficient imo.

Edited November 24, 2018 by Legioneod

[Ehret]

Just now, Legioneod said:

That's not WEP though, just wasting water at a lower power imo.

 

Yet the practical difference isn't insignificant... like 550km/h at the deck for 15m instead of 510km/h for the same time. Or 10m at 550km/h and then full emergency for the remaining 5m.

 

But I agree - it should be straight 15m of water injection without any hassle.

[LuftManu]

1 hour ago, Ehret said:

 

You can use 15m straight of water injection in the P-47 now. Only caveat is it will not be at maximum boost; you will have to limit the MP to the 58". Then the engine stays in the "combat mode" and allows whole 15m in one go.

I agree with @Legioneod on this. If the chart is correct we should be getting 15m straigth with it's own timer.

 

By the way, has anybody sent the data from this thread to the devs yet?

[Cpt_Siddy]

The limiting factor of how long can you use combat/WEP should be for the same reason as in RL, the temperature of inter cooler. The engine the P-47 had, had no problem to WEP and combat power on test stands with "infinite endurance" intercooler for long times with no adverse effects. Once the discharge air was too hot or you ran out of water, you had to reduce throttle to get back inside the safe range for the rated fuel (150oct when???). 

 

Therefore the WEP and other engine modes durations should be modeled by the inter cooler discharge temperature and not some arbitrary value that is based on secret arts of timers. 

Edited November 24, 2018 by Cpt_Siddy

[-=PHX=-SuperEtendard]

I tested how the Emergency Power affects the Combat Power remaining time and found that it affects most planes, but mostly the planes that share the same RPM settings for both modes:

P-39L1: After using 5 minutes of 51" at 3000 RPM only, it is left with just 1 (!!!) minute of combat power at 42" at 3000 RPM (rated for 15 min), after that damage to the engine happens around 2 mins later.

P-40E: After using 2 minutes of 45.5" at 3000 RPM only, it is left with around just 30-40 seconds of combat power at 42" 3000 RPM (rated for 5 min).

Spitfire Mk Vb: After using 3 minutes of +16 boost at 3000 RPM, it is left with 20 minutes of combat power at +9 boost 2850 RPM (rated for 30 min).

Fw 190 A-8: After using 10 minutes of 1.58 ata at 2700 RPM, it is left with 15 minutes of combat power at 1.32 ata 2400 RPM (rated for 30 min).

I don't remember this was like this in previous versions. I have played with the P-39, using plenty of 51" power during fights, then switching back to 42" without much trouble, never got an engine damage because of consumed engine timer... could this be a bug that came with this 3.007 update?

Not only is troublesome for the P-47, but for planes like the P-39 or P-40 this is much worse.

Edited November 24, 2018 by -=PHX=-SuperEtendard

[Baron_Von_Mosler]

I would say although both 605 dc and r 2800with similar mw50 or water injection comparing them has to be done carefully, the engines where tested and the numbers given in the manuals come from the testings they did. This numbers are always somehow conservatives, so they give the pilot the ability to not to worry that much if they had the engine in wep for some time longer than the manual says.

 If the p47 has a tank of water injection that could be enough for 15 mins that doenst means it could be 15 in wep, that means provided the engine culd hold those 15 mins in wep the water injection tank would be emptied, maybe it couldnt hold more than those 9 mins becasue stress on the cylinders, or the heads i dont know it should say in some documents, also if the water injection empties theres no more wep so no extra 5 mins.

 

The dc engine was made with mw 50 + c3 in mind so the compresseion ratio and chamber volume is adapted to it as is the r 2800 to its fuel + water inj, but they are much different engines maybe the db 605 doesnt suffers that much from that stress. 

 

I will mention the benefits of mw 50 or water injection ( they are not the same composition but they are close )

- Cooling effect of the water in the intake and compression strokes

- Methanol and etanol increases octne of the mixture

- cooling effect in the power stroke, as the water turns into vapor it absorbs heat

- water cant be compressed so its volume is subtracted from the combustion chamber making a higher effective compression ratio 

- Methanol and etanol are also fuel so they also burn 

- All this prevents Knocking and detonation unlike gm 1 in german aircraft or nitrous oxide in usa 

 

Edited November 25, 2018 by Mosler

[LuftManu]

44 minutes ago, -=PHX=-SuperEtendard said:

I tested how the Emergency Power affects the Combat Power remaining time and found that it affects most planes, but mostly the planes that share the same RPM settings for both modes:

P-39L1: After using 5 minutes of 51" at 3000 RPM only, it is left with just 1 (!!!) minute of combat power at 42" at 3000 RPM (rated for 15 min), after that damage to the engine happens around 2 mins later.

P-40E: After using 2 minutes of 45.5" at 3000 RPM only, it is left with around just 30-40 seconds of combat power at 42" 3000 RPM (rated for 5 min).

Spitfire Mk Vb: After using 3 minutes of +16 boost at 3000 RPM, it is left with 20 minutes of combat power at +9 boost 2850 RPM (rated for 30 min).

Fw 190 A-8: After using 10 minutes of 1.58 ata at 2700 RPM, it is left with 15 minutes of combat power at 1.32 ata 2400 RPM (rated for 30 min).

I don't remember this was like this in previous versions. I have played with the P-39, using plenty of 51" power during fights, then switching back to 42" without much trouble, never got an engine damage because of consumed engine timer... could this be a bug that came with this 3.007 update?

Not only is troublesome for the P-47, but for planes like the P-39 or P-40 this is much worse.

If this is true this is a serious issue, might be a bug? Could please the devs answer?

[=RvE=Windmills]

As far as I know this is always how it has worked, there is one unified timer and you cant switch to a different mode to cool another down. It will just drain faster or slower.

 

And yes it mostly screws over stuff like P40/39 due to them having short timers and very limited engine power on continuous. If you want to do anything but lazily cruise you have to be on a timer, and if you have used it on emergency its gone.

[Baron_Von_Mosler]

1 hour ago, -=PHX=-SuperEtendard said:

I tested how the Emergency Power affects the Combat Power remaining time and found that it affects most planes, but mostly the planes that share the same RPM settings for both modes:

P-39L1: After using 5 minutes of 51" at 3000 RPM only, it is left with just 1 (!!!) minute of combat power at 42" at 3000 RPM (rated for 15 min), after that damage to the engine happens around 2 mins later.

P-40E: After using 2 minutes of 45.5" at 3000 RPM only, it is left with around just 30-40 seconds of combat power at 42" 3000 RPM (rated for 5 min).

Spitfire Mk Vb: After using 3 minutes of +16 boost at 3000 RPM, it is left with 20 minutes of combat power at +9 boost 2850 RPM (rated for 30 min).

Fw 190 A-8: After using 10 minutes of 1.58 ata at 2700 RPM, it is left with 15 minutes of combat power at 1.32 ata 2400 RPM (rated for 30 min).

I don't remember this was like this in previous versions. I have played with the P-39, using plenty of 51" power during fights, then switching back to 42" without much trouble, never got an engine damage because of consumed engine timer... could this be a bug that came with this 3.007 update?

Not only is troublesome for the P-47, but for planes like the P-39 or P-40 this is much worse.

i think those ratings are from a fresh start, so you are in cruise mode then you go inte combat power, the engine is cool before, but if you come from a hot start (wep) it makes sense they cant hold the same, coming from wep with mw50/water injection its not the same that coming from wep without it since mw50/water injection helps cooling, should be detonation/knocking what kills this engines you listed. I dont think its a bug.

 

 

Edited November 25, 2018 by Mosler

[Talon_]

1 hour ago, Mosler said:

it should say in some documents

 

We have documents saying a P-47 with a 10 minute tank drained the whole 10 minutes in one go on climb, and another with an engine on a test stand sustaining 70 hours of WEP continuous.

[Baron_Von_Mosler]

What i want to say is that theres a lot of factors in play in an engine, detonation and knocking are only the two most common but a piston engine at its maximum capabilities colud be destroyed in seconds 

 

this is what an engine testing looks like, in ww2 they did the same, from test like this comes the engine ratings.

i let you here some more info

http://www.theijes.com/papers/v5-i1/E0501030035.pdf

 

there are lots out there

7 minutes ago, Talon_ said:

 

We have documents saying a P-47 with a 10 minute tank drained the whole 10 minutes in one go on climb, and another with an engine on a test stand sustaining 70 hours of WEP continuous.

oh i havent seen them, same engine we have in il?

Edited November 25, 2018 by Mosler