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

[Talon_]

Both these engines use anti-detonant injection to get Emergency power, but the implementation is very different.

 

As it stands the P-47D can run ADI for 5 minutes followed by non-ADI Combat Power for 4 minutes before engine death: https://streamable.com/6s2ah

 

The Bf109K-4 with DC engine can run ADI for 10 minutes followed by Combat for 10, followed by ADI for 10, followed by Combat for 10 and just keep doing it until the water or fuel runs out. https://streamable.com/ay7rv

 

Do the laws of physics work differently for the P-47D? Does it make sense that the water cooled DB605 can make 2000hp on WEP for longer than the much larger, heavier and air-cooled R-2800 Double Wasp running at Combat?

 

Currently combined timer outside of continuous comparison, aircraft using ADI for WEP:

P-47D: 9 minutes before engine death

Bf109K-4: Unlimited

[PainGod85]

The P-47's manual explicitely doesn't state whether the combat power setting includes the 5 minutes of war emergency power.

 

That said, as long as 1C insists on modeling engines on (or even below) their manual limits instead of actual engine durability tests, there will always be cases where a nominally much more reliable and durable powerplant gets outlasted by one that the engineers struggled even getting into service.

 

We all know US manuals were written extremely conservatively while the Luftwaffe relaxed its engine limits as the war progressed - odds were the plane would get shot down before the engine wore out, might as well get the most out of it until then.

1C needs to stop modeling on the letter of the manual, and start modeling off of a durability model that has been normalized across all engines.

Edited November 24, 2018 by PainGod85

[Talon_]

Please note that I am not arguing that either the K-4 or P-47D are wrong, only that they use the same technology so the effects should be similar.

 

If the K-4 manual says the plane on ADI is in a separate engine mode with a separate timer to the plane at Combat Dry while the P-47D manual simply doesn't mention any link between the two timers, can we not assume that the ADI follows the same physics and can be "recharged" while at Combat power in the P-47D too? It's the same technology.

[LuftManu]

From AAFM 51-127-3, Page 13.

The water supply on the latest series (speaking of D-25 and later ) is sufficient for about 15 minutes of operation, so be sure an emergency is real before tapping the tank. Like ammunition, water should be hoarded until needed, and then used unhesitantingly.

 

My opinion is that the Water injection should last 15 minutes and when it runs out, the 5 min limit could be implemented but not with the Water injection ON. At least if we keep the actual parameters.

 

I hope that if it's wrong it's going to be fixed, I trust in @Gavrick and the rest of the team.

Edited November 24, 2018 by LF_Gallahad

[Talon_]

Just to clarify with the current physics the Bf109 can use the water injection this way:

 

WEP 1.98 10m

Combat 1.6 10m

WEP 1.98 10m

Combat 1.6 10m

WEP 1.98 5m

Total time spent outside Continuous: 45m

 

After this it runs out of water (but only has a few minutes of fuel left anyway).

 

This is shown in the Streamable link in the OP.

Edited November 24, 2018 by Talon_

[Ehret]

27 minutes ago, Talon_ said:

As it stands the P-47D can run ADI for 5 minutes followed by non-ADI Combat Power for 4 minutes before engine death: https://streamable.com/6s2ah

 

If you use the power modes in reverse (the combat power followed by the emergency) you will get longer times. Still, hilarious when compared to the K4.

[Talon_]

Just now, Ehret said:

 If you use the power modes in reverse (the combat power followed by the emergency) you will get longer times. Still, hilarious when compared to the K4.

 

The power is used this way to show that in the P-47D the WEP eats Combat timers as well as its own however it does not in the K4.

[LuftManu]

6 minutes ago, Talon_ said:

 

The power is used this way to show that in the P-47D the WEP eats Combat timers as well as its own however it does not in the K4.

I agree on the observations. Water should have an extra timer like it is on both 109s with MW50. In the manuals there is no "Use the water in series of 5 minutes" so I think the game modeled the WEP as 5 minutes even if you use or not the Water injection. 
The way I see it is that if you need to use it, push the button, you have 15 minutes till you run out. Then the actual limits should appear.

Edited November 24, 2018 by LF_Gallahad

[Ehret]

2 minutes ago, Talon_ said:

The power is used this way to show that in the P-47D the WEP eats Combat timers as well as its own however it does not in the K4.

 

It's the same way for the P-40 and the P-39.

[PainGod85]

Just now, Ehret said:

 

It's the same way for the P-40 and the P-39.

 

Even ignoring the fact that the V-1710s are modeled extremely conservatively, neither of those has ADI.

[Talon_]

2 minutes ago, Ehret said:

 

It's the same way for the P-40 and the P-39.

 

They do not use water injection. This thread is about the difference in physics at play between water injection in two aircraft.

[Ehret]

1 minute ago, Talon_ said:

They do not use water injection. This thread is about the difference in physics at play between water injection in two aircraft.

 

But it shows a pattern...

[LuftManu]

Just now, Ehret said:

 

But it shows a pattern...

109s with MW50 have a different pattern with ADI. P47 should have it too as it has ADI.

[Talon_]

We have two different engine types with water injection ingame.

 

On one the manual says water injection is recharged at combat power

On another the manual doesn't mention a link between combat or WEP "time" at all

 

Yet they are implemented differently and on the second WEP eats Combat time.

[Ehret]

1 minute ago, LF_Gallahad said:

109s with MW50 have a different pattern with ADI. P47 should have it too as it has ADI.

 

I meant a different pattern - that the western planes get worst possible limits.

[Sgt_Joch]

I cant link from my phone, but check the 11 oct. 1943 flight test of the P47-D10 on WW2 aircraft performance site. Par. C 1) says WEP with water injection could be used continuously for 10 minutes to climb from SL to 24,000 feet.

Edited November 24, 2018 by Sgt_Joch

[Talon_]

Please stay civil guys, hopefully we hear from the devs on this issue but there is clearly a major inconsistency at play. No point getting angry before the devs even know about it.

Just now, Sgt_Joch said:

1943 flight test of the P47-D10 on WW2 aircraft performance site. Par C 1) says WEP with water injection could be used continuously for 10 minutes to climd from SL to 24,000 feet.

 

That plane also only had enough water injection for 10 minutes at a time.

[Cpt_Siddy]

11 minutes ago, LF_Gallahad said:

Please, refrain yourself on the Anti-US Bias. Don't get the thread locked because of your opinions.

 

Opinions or demonstrable and documented facts?

 

I recall VVS pilots stating that they threw the recommended engine settings to the wind and wore out the engines under 200 hours, because other option was to get shot down. 

 

Also, this thread was about how the physics work. IIRC, the main limiter on WEP on american high altitude planes was inter cooler temperature climbing too high.

As long as the air coming to the second stage compressor is cool enough, there is nothing stopping for using WEP. 

Edited November 24, 2018 by Cpt_Siddy

[Talon_]

I appreciate your frustration but pilot accounts in planes without ADI aren't really the topic of this thread.

[PainGod85]

Just now, Sgt_Joch said:

I cant link from my phone, but check the 11 oct. 1943 flight test of the P47-D10 on WW2 aircraft performance site. Par. C 1) says WEP with water injection could be used continuously for 10 minutes to climb from SL to 24,000 feet.

 

Just now, Talon_ said:

Please stay civil guys, hopefully we hear from the devs on this issue but there is clearly a major inconsistency at play. No point getting angry before the devs even know about it.

 

That plane also only had enough water injection for 10 minutes at a time.

 

Correct: http://www.wwiiaircraftperformance.org/p-47/P-47D_43-75035_Eng-47-1652-A.pdf

[LuftManu]

5 minutes ago, Sgt_Joch said:

I cant link from my phone, but check the 11 oct. 1943 flight test of the P47-D10 on WW2 aircraft performance site. Par. C 1) says WEP with water injection could be used continuously for 10 minutes to climb from SL to 24,000 feet.

Please, if you can provide such information for the team it would be great. I have linked a document that states for series above D25 up to 15 mins. And use unhesitantingly.

 

Edit: found by PainGod

Edited November 24, 2018 by LF_Gallahad

[Sgt_Joch]

2 minutes ago, Talon_ said:

 

That plane also only had enough water injection for 10 minutes at a time.

 

You are missing the point. It is documentary proof that there was no 5 min. Time limit on using Water Injection. It should be modeled the same in game as MW50.

[Talon_]

I think either:

Make it like the K-4 (WEP recharges while on Combat)

Make it like the earlier tests (15 minutes of WEP and water in one hit)

 

Both go a long way towards getting close to reality.

Edited November 24, 2018 by Talon_

[=FEW=N3cRoo]

13 minutes ago, Cpt_Siddy said:

 

Opinions or demonstrable and documented facts?

 

I recall VVS pilots stating that they threw the recommended engine settings to the wind and wore out the engines under 200 hours, because other option was to get shot down. 

 

I'm pretty sure after 200 hours of combat flying chances are the plane had to be rebuild and the pilot was an ACE or dead and the date was 1945 :-P 

Lets be real there where some more souped up engines in service with 25-50 hour lifespans like the VK-107s, oh and did i mention jumo-004s that will be facing this one?

Sth like 200-300 hours was given for BMW-801s.

 

While the US had their planes in interwar mode with regulations and durability requirements

Edited November 24, 2018 by =FEW=N3croo

[Cpt_Siddy]

1 minute ago, =FEW=N3croo said:

 

I'm pretty sure after 200 hours of combat flying chances are the plane had to be rebuild and the pilot was an ACE or dead and the date was 1945 :-P 

 

 

Not combat but a normal use + combat. 

 

You have to remember that lion shares of the engine gunning happened before combat. In combat, the pedal was to the metal no questions asked, i doubt any pilot was thinking about his engineer whining at him if he wore out the piston seals. . 

[PainGod85]

Just now, =FEW=N3croo said:

 

I'm pretty sure after 200 hours of combat flying chances are the plane had to be rebuild and the pilot was an ACE or dead and the date was 1945 ?

Lets be real there where some more souped up engines in service with 25-50 hour lifespans like the VK-107s, oh and did i mention jumo-004s that will be facing this one?

Sth like 200-300 hours was given for BMW-801s.

 

While the US had their planes in interwar mode with regulations and durability requirements

 

Did line pilots in the VVS even have their own planes?

[Legioneod]

8 minutes ago, Talon_ said:

I think either:

Make it like the K-4 (WEP recharges while on Combat)

Make it like the earlier tests (15 minutes of WEP and water in one hit)

 

Both go a long way towards getting close to reality.

Exactly this. WEP should be the full 15min in one go as the test reports show is completely possible. 

[Sgt_Joch]

20 minutes ago, PainGod85 said:

 

 

Correct: http://www.wwiiaircraftperformance.org/p-47/P-47D_43-75035_Eng-47-1652-A.pdf

 

Thanks for posting.

 

What is the next step? Will someone write it up and submit to the Devs?

[LuftManu]

Just now, Sgt_Joch said:

 

Thanks for posting.

 

What is the next step? Will someone write it up and submit to the Devs?

I think yes, I am not english native so I hope anybody can do a nice writeup for them

[Sgt_Joch]

I could do it, but wont have access to my computer for a few days.

[Tony_Kito]

27 minutes ago, PainGod85 said:

 

Did line pilots in the VVS even have their own planes?

 

IIRC, from what I read in Kozhedub's autobiography, which unfortunately is only available in either Russian or Portuguese, he was only given his own personal airplane a long ways into his career in the VVS in 1944, I recall he received an La-5FN #14. From what the book seemed to imply, a personal plane was probably only awarded to notable aircrew and/or unit commanders/element leaders.

[=RvE=Windmills]

2 hours ago, Talon_ said:

Please note that I am not arguing that either the K-4 or P-47D are wrong, only that they use the same technology so the effects should be similar.

 

If the K-4 manual says the plane on ADI is in a separate engine mode with a separate timer to the plane at Combat Dry while the P-47D manual simply doesn't mention any link between the two timers, can we not assume that the ADI follows the same physics and can be "recharged" while at Combat power in the P-47D too? It's the same technology.

 

I don't think any link is mentioned because this is the standard way in which the engine limits seem to work in Il2. There is a gauge that steadily climbs until destruction that climbs whenever you go past continuous mode, the rate at which it climbs determined by how much it exceeds continuous. 

 

The K4 (and G14) ingame wording explicitly states that it does not work that way, going against this rule by allowing either mode to 'cool down' while the other is active.

 

It seems to be against the idea of the whole timer system, I'm somewhat impartial on the system as a whole, but I do feel this breaks the rules in a very odd way.

 

Logically when you turn off of emergency+MW50 when the engine is on the edge of destruction, why would combat power not push it further towards destruction? Combat power is limited, so it should be pushing the engine over the edge when the engine is already at its limit from emergency boost.

 

If we want to apply limits, they need to be applied consistently. It does seem very odd that the P47 has 15 mins of water yet would struggle to employ that during a fight. If there was a real 5 minute limit at a time wouldn't that be made explicitly clear? If the manual apparently doesn't imply any danger beyond running out of its 15 minute usage limit, is it reasonable to impose it? Especially when similar systems bypass it?

 

Overhauling the system to make everything work like the K4 seems unreasonable, but within BoBP I do see value in keeping this consistency. Atm this does not seem logical.

[Talon_]

Blanket rules don't work for everything at this late stage - for example the +100kph dive bonus all planes get will literally allow supersonic flight for Me262s.

[PainGod85]

24 minutes ago, =RvE=Windmills said:

 

I don't think any link is mentioned because this is the standard way in which the engine limits seem to work in Il2. There is a gauge that steadily climbs until destruction that climbs whenever you go past continuous mode, the rate at which it climbs determined by how much it exceeds continuous. 

 

The K4 (and G14) ingame wording explicitly states that it does not work that way, going against this rule by allowing either mode to 'cool down' while the other is active.

 

It seems to be against the idea of the whole timer system, I'm somewhat impartial on the system as a whole, but I do feel this breaks the rules in a very odd way.

 

Logically when you turn off of emergency+MW50 when the engine is on the edge of destruction, why would combat power not push it further towards destruction? Combat power is limited, so it should be pushing the engine over the edge when the engine is already at its limit from emergency boost.

 

If we want to apply limits, they need to be applied consistently. It does seem very odd that the P47 has 15 mins of water yet would struggle to employ that during a fight. If there was a real 5 minute limit at a time wouldn't that be made explicitly clear? If the manual apparently doesn't imply any danger beyond running out of its 15 minute usage limit, is it reasonable to impose it? Especially when similar systems bypass it?

 

Overhauling the system to make everything work like the K4 seems unreasonable, but within BoBP I do see value in keeping this consistency. Atm this does not seem logical.

 

The 109's pilot manual states that no less than 5 minute intervals of combat power should be used between 10 minute intervals of war emergency power.

Engine limitations need to be normalized across all airframes and powerplants. Simply taking the pilot's manual as gospel just won't do if the goal is to get a faithful recreation.

[Matt]

32 minutes ago, =RvE=Windmills said:

If there was a real 5 minute limit at a time wouldn't that be made explicitly clear?

The document the devs used specifically limits WEP to 5 minutes. So there's a reason, why it currently works like that ingame.

 

I do agree though, that the "WEP reset" inconsistency between the P-47 and K-4, aswell as the fact that you can only use 5 minutes of combat power after using WEP on the P-47 (which is also working as intended) doesn't make much sense to me.

[Legioneod]

9 minutes ago, Matt said:

The document the devs used specifically limits WEP to 5 minutes. So there's a reason, why it currently works like that ingame.

 

Fact is it shouldn't work like that in-game, engine failure shouldn't happen after 5min of WEP. 

WEP limitations are to preserve the life of the engine over the course of a long period of time, not two minutes after going over WEP.

 

The R2800 passed the 7 1/2 hour testing at 65" WEP and did not fail, there is literally no reason for the engine to fail in-game besides some sort of balance and simplified engine model.

 

Either give us the full 15 min of WEP or decrease the time required between uses to a useable level, currently I waste most of my water due to the fact I can't even use it due to engine failure.

 

American aircraft suffer the most from the gamey engine model of this sim.

[Sgt_Joch]

19 minutes ago, Matt said:

The document the devs used specifically limits WEP to 5 minutes. So there's a reason, why it currently works like that ingame.

 

 

Could we know what that document is?

[PainGod85]

Just now, Sgt_Joch said:

 

Could we know what that document is?

 

Pilot's flight operating instructions, online on Avialogs: http://www.avialogs.com/index.php/en/aircraft/usa/republic/p-47thunderbolt/an-01-65bc-1a-pilots-flight-operating-instructions-for-p-47d-25-26-27-28-30-and-35-airplanes.html

 

That said, the very same document gives us a 15 minute limit for non-combat emergency power @52".

[Sgt_Joch]

So that settles it then. In game data matches the pilot manual.

 

 

[=RvE=Windmills]

56 minutes ago, PainGod85 said:

The 109's pilot manual states that no less than 5 minute intervals of combat power should be used between 10 minute intervals of war emergency power.

 

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.

 

Edited November 24, 2018 by =RvE=Windmills