DB 605A-1 1.42 ata (WEP) duration

[Roland_HUNter]

https://www.asisbiz.com/il2/Bf-109E/Bf-109E/pages/Messerschmitt-Bf-109E-Cockpit-01.html

[=EXPEND=13SchwarzeHand]

Ok but this shows 3 min at 1.31 ata for the e model. Isn’t that what we have in game?

[JtD]

The DB601A as in the Bf109E isn't comparable anyway because it had an actual clockwork restricting the take-off setting to 1 minute.

[=EXPEND=13SchwarzeHand]

yes and I though this thread was about the Db605, has that changed? What is that picture supposed to show?

[Roland_HUNter]

 

[the_emperor]

On 8/5/2020 at 3:56 PM, 41Sqn_Skipper said:

If the use of 1.42 ata with B4 fuel was really uncritical for 3, 5 or 10 minutes (as is claimed here based on a bench test protocol using B4 fuel), why does the October 1944 manual state that the throttle must be moved to 1.3 ata? Why doesn't it allow the further use of 1.42 ata for "minimum amount when deemed operationally essential"?

Maybe because throttling to WEP without the MW50 engaged still would boost the engine to 1.7ata, at last below FTH.

(it reads like, "if the MW-50 is cut off or  empty?")

it also says, that above 8.5km height the AS-engine can be reved to WEP with 2800rpm, while the MW-50 is cut off. though it is not clear whether this is for C-3 or B-4 fuel.

Quite confusing.

Though still it would be nice to see any documents, that does ristrict the use of 1.42WEP for the DB605A, after ist was revised and the use of WEP was cleared in autumn of 1943.

If not, then maybe should be better restricted by the engines temperature limitations, which are known and force one to keep the speed above a certain value and keeps one from maneuvering in slow speed dogfights for a too long time.

 

Edited September 18, 2021 by the_emperor

[FTC_ChilliBalls]

On 9/18/2021 at 8:43 PM, the_emperor said:

it also says, that above 8.5km height the AS-engine can be reved to WEP with 2800rpm, while the MW-50 is cut off. though it is not clear whether this is for C-3 or B-4 fuel.

Quite confusing.

That may have to do with the fact that the AS-engine full-throttle height is 7.8km. 

 

[the_emperor]

 

45 minutes ago, So_ein_Feuerball said:

That may have to do with the fact that the AS-engine full-throttle height is 7.8km. 

Yes, that may be (7.8km FTH without ram and 8.8km FTH in level flight for th 1.3ata/2600rpm setting).

It seems that you could savely reve it up from from 2600rpm to 2800rpm at that height without the risk of overboosting. Though the AS-Engine FTH (with Ram) at the 1.42ata/2800rpm setting is 9km, so it seems you could savely run 1.42/2800rpm at that height (of course ata decreasing with increasing height).

Which still begs the questions:

Are there any documents that limit the use of 1.42ata/2800rpm after the engine was revised to 1 Minute?

IRRC the limit or ban of WEP was due to insufficient lubrication of the piston rod/crankshaft bearings. (change from ball bearing to plain bearing for cost reduction and smoother run) with hindsight is a dumb decision as  it blocks the DB605 from WEP usage from 1942 to late 1943, while the Brits start to intruduce the Merlin 6X two stage after cooled power charged engines series in their Spitfire MK IX series.

Funny side note:

it is an issue i have with my english motorcycle which was changed to plain bearings and which in theory should make it run smother (and of course lowers the costs) but the oil suply/filter system does not support that system ideally.

 

Cheers

 

 

 

 

[FTC_ChilliBalls]

20 hours ago, the_emperor said:

Yes, that may be (7.8km FTH without ram and 8.8km FTH in level flight for th 1.3ata/2600rpm setting).

It seems that you could savely reve it up from from 2600rpm to 2800rpm at that height without the risk of overboosting. Though the AS-Engine FTH (with Ram) at the 1.42ata/2800rpm setting is 9km, so it seems you could savely run 1.42/2800rpm at that height (of course ata decreasing with increasing height).

According to Versuchs-Bericht Nr. 109 20 L 43  full throttle height of the DB605 AS with RAM effect is 8.3km.

 

So to clear up this:

On 9/18/2021 at 8:43 PM, the_emperor said:

it also says, that above 8.5km height the AS-engine can be reved to WEP with 2800rpm, while the MW-50 is cut off. though it is not clear whether this is for C-3 or B-4 fuel.

Quite confusing.

As the DB605 ASM does not feature a different or more potent supercharger, it, like the DB605 AS, can not sustain 1.42 ata at 8.5km of altitude. 

So the manifold pressure would have fallen to so low a level at 8.5km that using 2800RPM for longer periods was considered harmless.

 

Thus, the ability to use the AS engine at 2800RPM at above 8.5km altitude has no significance to the question whether the DB605 could be used at 1.42 ata 2800 RPM without limit after this setting being unlocked in 1943.  

[the_emperor]

1 hour ago, So_ein_Feuerball said:

According to Versuchs-Bericht Nr. 109 20 L 43  full throttle height of the DB605 AS with RAM effect is 8.3km.

The FTH for the AS engines were rated at 8,8km for 1.3 ata and 9km for 1.42ata accourding to these documents:

 

 

 

1 hour ago, So_ein_Feuerball said:

Thus, the ability to use the AS engine at 2800RPM at above 8.5km altitude has no significance to the question whether the DB605 could be used at 1.42 ata 2800 RPM without limit after this setting being unlocked in 1943.  

Yes, you are absolutely right about that.  Currently we are still missung documents about the time limit of WEP usage of the DB605A(AS) after it was revised.

[the_emperor]

Ingame the Bf109 G-14 can run 1.42ata/2800rpm at FTH~6800m (there is no MW injection at that hight) for 10min.

So I following the ingame logic that should also apply to the later DB605 engine (Starting around fall ´43 where the ban of "Notleistung" is no longer mentioned)

[Eisenfaustus]

shouldn't MW50 still retain it's cooling effect without offering any additional MP at that height?

[Raven109]

2 hours ago, the_emperor said:

Ingame the Bf109 G-14 can run 1.42ata/2800rpm at FTH~6800m (there is no MW injection at that hight) for 10min.

So I following the ingame logic that should also apply to the later DB605 engine (Starting around fall ´43 where the ban of "Notleistung" is no longer mentioned)

 

At 6800m I'm still getting pressure in the MW50 system, which means it's still getting pumped into the compressor intake. This is because the throttle is fully pushed forward to hold 1.42 ata at that alt, which in turn energizes the MW system. Try it at a lower alt, so you you can run 1.42ata/2800rpm at a lower throttle position. At lower alts the engine breaks after ~1min at 1.4ata/2800rpm.

[the_emperor]

8 hours ago, Raven109 said:

At 6800m I'm still getting pressure in the MW50 system, which means it's still getting pumped into the compressor intake.

Shouldnt the MW-50 injection be shut off at that height? Well, if ingame the MW-50 is still working, then yes, My first assumption is not right.

Thanks ?

[JtD]

You had a manual switch on the dashboard to switch the system on and off. It was supposed to be switched off above full throttle height. If you didn't do it, the system would still activate at full throttle and inject MW50, which would essentially be wasted.

Edited November 4, 2021 by JtD

[Raven109]

18 hours ago, the_emperor said:

Shouldnt the MW-50 injection be shut off at that height? Well, if ingame the MW-50 is still working, then yes, My first assumption is not right.

Thanks ?

It should according to the manual. But the switching was done by the pilot as JtD described. The FW-190D has the switch modeled, not sure why the 109s didn't get theirs.

 

This test however shows an issue with the abstraction of engine timers. Basically, in-game, if you're using MW injection at FTH you're getting 10 minutes worth of running the engine at 1.42ata/2800rpm, so a benefit. While the real life manual advises you to turn off your MW50 system above FTH since it would be a waste if you didn't.

 

Here's the 109k cockpit with the MW50 switch highlighted (component 25), right of the magnetos switch, below the altimeter:

 

 

 

[ZachariasX]

4 hours ago, Raven109 said:

Here's the 109k

The "Fürer" in his 109...  ?

[the_emperor]

Thank you very much @Raven109

 

[Eisenfaustus]

6 hours ago, Raven109 said:

It should according to the manual. But the switching was done by the pilot as JtD described. The FW-190D has the switch modeled, not sure why the 109s didn't get theirs.

 

This test however shows an issue with the abstraction of engine timers. Basically, in-game, if you're using MW injection at FTH you're getting 10 minutes worth of running the engine at 1.42ata/2800rpm, so a benefit. While the real life manual advises you to turn off your MW50 system above FTH since it would be a waste if you didn't.

 

Here's the 109k cockpit with the MW50 switch highlighted (component 25), right of the magnetos switch, below the altimeter:

 

 

 

According to the manual (L.Dv.T 2109 G-14/Fl MW-50-Anlagen-Karte) on mw50 for the g14 it wasn’t used like that - it was turned on at engine start and after that activated with the throttle just like we have in game. 
The manual says because of this you should take off on combat power because emergency/take-off power isn’t available with mw50 installed. 

[the_emperor]

What is then the current justification for the limit of the WEP of the revised (reinforced pistons revisd oil librucation system) DB605A of 1 minute?

If the oil lubrication system does limit that engine to 1 minute, then why can the G6-MW50/G14 reliably run 2800rpm for 10min? Shouldnt the engine be able to run that before the instalation of the MW-50 system (of course with the lower boost of 1.42ata)?

 

Edited November 5, 2021 by the_emperor

[Raven109]

7 hours ago, Eisenfaustus said:

According to the manual (L.Dv.T 2109 G-14/Fl MW-50-Anlagen-Karte) on mw50 for the g14 it wasn’t used like that - it was turned on at engine start and after that activated with the throttle just like we have in game. 
The manual says because of this you should take off on combat power because emergency/take-off power isn’t available with mw50 installed. 

Yes, and my answer doesn't disagree with the manual, and I agree with your statement. However, the same manual also states that using MW50 above FTH was a waste, and it also states (for the AS engine):

 

"If the emergency speed (2800 rpm) is required in special cases above 8.5km altitude, then the throttle must be raised over the lock, while switching off the MW switch (no display on the pressure gauge!); When descending below 8.5 km, switch the switch on again!"

 

So, then I see that there are 2 ways not to use MW50 above FTH:

1. Pull the throttle back until you deactivate the MW50 system . 
2. Use the MW50 toggle button to turn the system off.

If the pilot is using the 1st method it would mean that he's not able to use 1.42 ata above FTH without wasting MW50, since pushing the engine past 1.3 ata will engage the MW50 system, and he'll go against the manual. I don't think pilots refraining from using the available power was the solution to not wasting MW50, hence why the manual states that if you really need the extra power above FTH, make sure you toggle off the MW50 system.

 

However, the other solution (2) also has its drawbacks, as I see it. Imagine a patrol above FTH. They turned off their MW50, using the toggle. They get jumped and need to dive. Of course if you get jump, you might forget to enable the MW50 and going below FTH will allow the engine to reach 1.7 ata, without MW.

 

In the end it was probably the pilots decision on how to operate the system, based on the specifics of that sortie. 

Edited November 5, 2021 by Raven109

[Raven109]

6 hours ago, the_emperor said:

What is then the current justification for the limit of the WEP of the revised (reinforced pistons revisd oil librucation system) DB605A of 1 minute?

If the oil lubrication system does limit that engine to 1 minute, then why can the G6-MW50/G14 reliably run 2800rpm for 10min? Shouldnt the engine be able to run that before the instalation of the MW-50 system (of course with the lower boost of 1.42ata)?

 

My assumption is that the game is modelling engine knock as the main cause of failure and engine overheat as the 2nd cause. By injecting MW50, the intake charge is cooled down, both reducing the likelihood of knock and also preventing the engine to overheat as fast when running at higher boost. 

 

Whether the 1 min was a hard limit I'm not entirely sure, there seem to be contradicting opinions/information. Would you allow your pilots to precisely estimate by themselves the passage of time while under the stress of combat? The 109E had a timer which was triggered once you went to full power. Once the 1 minute elapsed the throttle was pushed back. If for the DB605A the same 1 minute limit was so critical, why would they do away with the timer from the 109E and let pilots estimate something which was already automated.

 

But then again, also the question arises, if the operation of the MW50 system was so critical, why didn't they automate it and disable it above FTH, based on altitude and boost. 

[the_emperor]

1 hour ago, Raven109 said:

If the emergency speed (2800 rpm) is required in special cases above 8.5km altitude, then the throttle must be raised over the lock, while switching off the MW switch (no display on the pressure gauge!); When descending below 8.5 km, switch the switch on again!"

So using 2800rpm/1.42(+) is allowed  as the FTH for the AS engine without MW50 is 9km.

 

56 minutes ago, Raven109 said:

My assumption is that the game is modelling engine knock as the main cause of failure and engine overheat as the 2nd cause. By injecting MW50, the intake charge is cooled down, both reducing the likelihood of knock and also preventing the engine to overheat as fast when running at higher boost. 

Yes that is true for the boost over 1.4ata due to fuel limitation and the missing of an after cooler.

But the ban of 2800rpm was mainly due to a insufficient oil lubrication system, which was revised and the engine got reinforced pistons and the ban for 2800rpm was lifted in October '43.

If the better oil system and pistons had not been implemented you would not be able to use the higher power and rpms with MW50.

MW50 allows for higher boost due to cooling to a toleratable limit and preventing knocking,

but the pistons and oil system must also be able to coop with that. and if they can, why cant they handle 2800rpm with 1.42?

[Raven109]

Yes, for the AS engine FTH for 1.42ata/2800rpm is somewhere between 8.5-9.0km, depending which chart you're getting your info from. Related to this, from the same manual quoted above (A and AS engines - I added in brackets [] my notes):

 

"The additional MW can be injected into the DB605 AS up to an altitude of 8.5km; At altitudes over 8.5km, no increase in performance can be achieved by adding MW, and the MW mixture is unnecessarily consumed (methanol is scarce/high-priority material). 6km for the [DB605] A engine. [the engine in the G-14]"

 

Lower on the same page:

"if there is no pressure displayed [on the MW pressure gauge] (meaning that there's no MW support), then the throttle must be immediately taken back to the "climbing and fighting" power setting (1,3 ata)."

 

"Caution! When using B4 fuel [which our G14 is using], after switching off or stopping the MW add-on, under no circumstances may you continue to fly at the "special emergency" power setting [1.7ata/2800rpm]. Bring the throttle back immediately to the "climbing and fighting" power setting [1.3 ata], otherwise the engine will be damaged."

 

Now, these excerpts do say that you need to go back to the "climb and fighting" power setting when the MW mix isn't injected into the compressor eye. However they don't say what happens if you stay at 1.42 ata/2800 rpm (will damage occur in 1, 5, 10 minutes? - is this damage a complete and instant failure, or is it something you can still nurse home? Is the issue that the engine needs to be taken down at base and checked for small damage which might get ugly later?)

 

Considering that this is a manual for pilots, I'm guessing that the pilot didn't really need to know what happens with the engine. The engineers said "just don't do it", and I think it was easier to tell the pilot to just throttle back to 1.3ata and be on the safe side, rather than add a lot of complicated exceptions. By this moment in war, 109 veteran pilots/instructors would already be familiar with the DB605A and its limitations. So, perhaps there was no need to add additional information.

 

We can see from the manual that there was a concern with the scarcity of methanol, so perhaps they had the same concern about increased maintenance times on the engines.

 

1 hour ago, the_emperor said:

Yes that is true for the boost over 1.4ata due to fuel limitation and the missing of an after cooler.

But the ban of 2800rpm was mainly due to a insufficient oil lubrication system, which was revised and the engine got reinforced pistons and the ban for 2800rpm was lifted in October '43.

If the better oil system and pistons had not been implemented you would not be able to use the higher power and rpms with MW50.

MW50 allows for higher boost due to cooling to a toleratable limit and preventing knocking,

but the pistons and oil system must also be able to coop with that. and if they can, why cant they handle 2800rpm with 1.42?

 

The ban is modeled in game by limiting the engine to 1.3ata (for G-2). The 1.42ata setting with the 1min+10s-30s? time limit is modelling the engine after the ban was lifted. My point was that the engine is failing not because we're flying the G-14 in the ata range that is banned, but because we're boosting it (up to 1.42ata - post-ban) until knock and heat destroy the engine, even with the improved pistons/lubrication system.

[the_emperor]

46 minutes ago, Raven109 said:

The ban is modeled in game by limiting the engine to 1.3ata (for G-2). The 1.42ata setting with the 1min+10s-30s? time limit is modelling the engine after the ban was lifted. My point was that the engine is failing not because we're flying the G-14 in the ata range that is banned, but because we're boosting it (up to 1.42ata - post-ban) until knock and heat destroy the engine, even with the improved pistons/lubrication system.

Yes I think you are absolutely right about that. Which then closes the circle back to the original question: why?

What is the reason for that limitation? Where is the documentation that the revised engine could not or according to a manual (which is the route the devs chose) must not use WEP more than one minute? 
I know that engine timer issue is another topic in itself but if the manuals are what they are currently slaved to, why 1minute when the manuals give us no time limit after the lift of the WEP ban?

[6./ZG26_Klaus_Mann]

10 hours ago, the_emperor said:

What is then the current justification for the limit of the WEP of the revised (reinforced pistons revisd oil librucation system) DB605A of 1 minute?

If the oil lubrication system does limit that engine to 1 minute, then why can the G6-MW50/G14 reliably run 2800rpm for 10min? Shouldnt the engine be able to run that before the instalation of the MW-50 system (of course with the lower boost of 1.42ata)?

 

Look at the early Gustavs including G-6 early and compare to the late Model G-6. 
The Oil Cooler on the late Model G-6 is far bigger, and my guess is, that it would be able to take 1.42ata far longer than the older Models. 

So at least for that Model G-6 I also think the 1 Minute Limit is faaar to strict. 

 

But then, I also think that we should be allowed to Rev the Engine higher above 6km to maintain 1.3 ata in the G-4 and early G-6 without the strict limit on 2800rpm. 

And using 1.42a at in a straight line should be fine as well as well as the Oil keeps Cool. 

It's basically in a Climb where heat becomes an Issue.

[the_emperor]

12 minutes ago, 6./ZG26_Klaus_Mann said:

Look at the early Gustavs including G-6 early and compare to the late Model G-6. 
The Oil Cooler on the late Model G-6 is far bigger, and my guess is, that it would be able to take 1.42ata far longer than the older Models. 

Yes, a bigger oil cooler is part of the revised oil system. So late G6 models ( starting in October 43) should handle WEP much better.

 

[Raven109]

1 hour ago, the_emperor said:

Yes I think you are absolutely right about that. Which then closes the circle back to the original question: why?

What is the reason for that limitation? Where is the documentation that the revised engine could not or according to a manual (which is the route the devs chose) must not use WEP more than one minute? 
I know that engine timer issue is another topic in itself but if the manuals are what they are currently slaved to, why 1minute when the manuals give us no time limit after the lift of the WEP ban?

 

Well, I'm guessing that the 1min limit is still there since there is no document which explicitly states that there should be another limit. There are only extrapolations and assumptions. Surely there must be a time limit since even the 1.3ata/2600rmp setting has a 30' time limit in the manuals. However, it's not even clear what the purpose of the time limits was (as in a DB document explaining them), and the opinions range from your engine should implode after 30' - so an immediate effect that has consequences on gameplay, or your TBO should be reduced - no consequence on gameplay since there is no logistic layer.

 

The Repair docs from 1943 list a run period of 5 min at 1.42ata/2800rpm for a DB605A that has been repaired; of course the engine is on a test bench. The test run procedure for a new engine shows the same 5 minutes.

 

In the end this discussion might be pointless from the perspective of air combat for most of the time. The 1.3ata/2600rpm setting was called "Climb & Combat". The 1.42ata/2800rpm setting was called "Take-off & Emergency". I have a feeling that in the real world the Combat setting was used much more than the Emergency setting. If one finds himself relying on the Emergency engine setting all the time, I assume that he/she must be doing something wrong by putting themselves into situations where they shouldn't be.

 

What I'd like to see modeled is more nuanced feedback from the engine e.g. vibrations from hits, or from abusing it (you can read about these in pilot memoirs), engine knocking that doesn't outright blow your engine to bits, rising temperatures, dropping pressures, etc, so that one can diagnose the engine better. Right now I think it's the lack of this feedback that is leading to some of the frustrations that we see with the time limits.

[Raven109]

By the way, in-game the time limit at 1.42ata is not 1 min exactly. The behavior I've noticed is this (talking here about the G-6 collector plane): you can get a failure at 1 min and 10-20s, after going full throttle; in this case the engine will not be radically damaged. After the engine damage message appears, if you throttle back quickly to something like 0.8ata/2100rpm you can still fly around at 300km/h for about 10min. On the other hand, there are cases where you can run 1.42ata/2800rpm for almost 3 minutes (2 min over the 1 min limit we keep talking about). However, in this case the damage is extreme, and the engine is much more damaged, to the point it shuts down. In both these cases there is no indication that the engine will go, no change in oil pressure, no increase in coolant temperature, no vibration, no odd sounds before the failure. 

 

Most likely that the failure period is randomised and in can probably fail between 1 and 3 minutes of run-time. With a few more tests, we could know if the distribution is linear and also if there is a correlation between running at 1.42 ata for ~3 minutes and catastrophic failure.

Edited November 6, 2021 by Raven109

[the_emperor]

16 hours ago, Raven109 said:

The 1.3ata/2600rpm setting was called "Climb & Combat". The 1.42ata/2800rpm setting was called "Take-off & Emergency". I have a feeling that in the real world the Combat setting was used much more than the Emergency setting. If one finds himself relying on the Emergency engine setting all the time, I assume that he/she must be doing something wrong by putting themselves into situations where they shouldn't be.

My assumption would be that the manuals give a time limit where one can in fact have an eye on the watch, while in an emergency situation it is full throttle and try to get out of the pickle (also what many British statements say about their WEP usage).

if the limits were as strict in real live as in the game the britisch/US fighter cover missions over the continent where much more hazardous as the they were already. The game devs choose to run the WEP usage by the manuals. So if the manuals dont state a specific time limit, then there should be none.

of course the time limits are also there to prevent to much wear and tear on the engine, to keep the overhaul intervals als long as possible. But that did only matter in real live. In game we always get a brand new engine and airframe when we start. Wear and tear is not modelled and probably shouldnt (as it would over proportional effect late luftwaffe and soviet aircrafts with their shorter engine lifespan which then would start a whole other discussion….)

Edited November 6, 2021 by the_emperor

[6./ZG26_Klaus_Mann]

14 hours ago, Raven109 said:

Most likely that the failure period is randomised and in can probably fail between 1 and 3 minutes of run-time. With a few more tests, we could know if the distribution is linear and also if there is a correlation between running at 1.42 ata for ~3 minutes and catastrophic failure.

I took a Stop Clock to all Aircraft with Limits. Exactly 30 Seconds over for all of them is when the Engine is doomed. I don't care about time to complete stoppage, because in a Chase, once you lose Power even a little, you die. 

 

This applies even to the 30 Minute Setting. At exactly 30m:30s you get the Engine Damaged and fluctuating RPM and the Engine starts losing HP (HP in this Case meaning both Horsepower and Hitpoints)
Yes, the Engines have Hitpoints (when I say HP from now on, that's what I mean). There are three Factors in Engine Damage Calculation. Hitpoint Bleed, Power Setting and Hitpoint loss. 

 

If your Engine is hit by a large Shell, the hit will reduce your Engine HP from lets say 100% to 50% immediately and the Hit Point Bleed will be very fast, so that after another Minute the other 50% will be drained as well and the Engine is dead. Hit Point Bleed is at that point dependent on the initial damage taken and the Powersetting and the relationship is pretty direct. Use 50% Throttle instead of 100% and you get double the Engine Life. Of course, you lose Power all the time as well, so you have to increase throttle just to keep airborne, so the longer you fly damaged, the faster damage is accumulated. 

 

If you only damage the Engine by flying 31 Seconds over the time limit and then reducing, you can get 30 Minutes out of it until it dies flying at normal settings, but all the time it will lose Power and get worse by the slow HP drain. 

 

In any Case, ingame you can't fly with a damaged Engine if you fly an actual Mission that takes you away from your Homebase any sort of Distance. 

[Raven109]

Have been running some tests, results attached.

 

 

 

 

Test methodology:

All tests were performed in a Bf109 G-6 "early", powered by the DB605 A-1 engine. Prop pitch: auto, coolant radiators: auto, level flight (auto-hold). The throttle was pushed fully forward and held there until the "engine damage" technochat message popped-up. Immediately afterwards, the throttle was reduced to 0.8ata/2100RPM, and if the engine still worked, the throttle position was changed to evaluate how easy it is to nurse the plane, how long the engine can still hold on and what power modes were still available.

The stopwatch was turned on at the moment the ATA and RPM needles stabilised and indicated 1.41ATA/2800RPM. The value of the stopwatch was saved when the "engine damage" technochat message has been displayed and also saved again once the engine quite/player ended the mission. 

5 tests were run on a map during a certain season at the same altitude. 5 different map/season/altitude combinations were used, leading to a total of 25 test runs.

 

Column description:

Map and season - the map and season on which the test has been flown

Test altitude [m] - the altitude at which the tests have been flown

Test no. - the number of the test for a given map/season/altitude combination

Time to "engine damage" message [mm:ss] - this is probably the most relevant column to this thread - time from when the 1.41ata/2800rpm setting was engaged till the engine damage message showed up

Engine state - the state of the engine immediately after the "engine message" has popped-up; these states are pretty subjective and are based on how much the cockpit vibrated, how much did the ATA and RPM needles oscillated, abnormal engine noises, etc:

• very mild damage - barely any vibration noticed, slight, barely noticeable oscillation of the RPM needle (less than ~+/-50RPM), most of the power range is available, no observable decrease in power
• mild damage - cockpit vibration, noticeable oscillation of the RPM needle (less than ~+/-200RPM), noticeable oscillation of the ATA needle, most of the power range is available
• heavy damage - heavy cockpit vibration, heavy RPM needle (less than ~+/-500RPM) oscillation, heavy ATA needle oscillation, going above 0.8ata/2100RPM will lead to the engine seizing up shortly after
• destroyed - the engine stops almost immediately

Time to end of mission [mm:ss] - the period of time from when the "engine damage" message appeared until total destruction of the engine, or the moment the mission was ended by the player

Reason for ending the mission - the reason why the mission was ended: either the engine was destroyed during the "nursing" process, or the player left since the engine didn't show any sign of giving up in the allotted time.

Max achievable speeds in level flight while nursing [km/h] - self explanatory

Notes about the behavior post "engine damage" message - author's notes about the engine behavior after the "engine damage" pop-up message showed up

 

Author's notes about the test results (some of these are well know, but I'm listing them for the sake of completeness):

1. Min recorded duration till the engine damage message popped-up: 1min:13s
2. Max recorded duration till the engine damage message popped-up: 3min:44s
3. Average duration across all tests: 2min:10s
4. Test results seem to indicate that the emergency power duration is randomized and so is the damage level incurred after the engine damage message appeared.
5. There doesn't seem to be a relation between season, altitude, map and the duration of the emergency power setting. I was expecting that situations where the compressor has to work more and the temperatures are higher to lead to shorter times till engine damage.
6. Since the tests were run in level flight at max speed, no conclusion can be drawn regarding the duration of the timer while flying at lower speeds (turn and burn).
7. There is no feedback from the instruments that the engine is going to be damaged soon. After the engine is damaged the only feedback is cockpit/ata needle/rpm needle shake. Sometimes this post-damage feedback is so subtle that players not using technochat will have a hard time noticing the damage.
8. The in-game Bf109 G-6 early cannot be pushed to 1.42ata, the needle stopping short before 1.41ata (~1.408ata). Not sure if this is a bug, or if it's supposed to model instrument error, etc - I assume that it's the former.
9. There is a technochat message which pops at ~1min after running at emergency power which states that the the time limit for this power setting has been exceeded. Engine damage hasn't been noticed after this message, until after the "engine damage" message has popped-up.

 

Edited November 7, 2021 by Raven109
Removed point 8 from Author's notes - 1.42 ata can be set just fine

[LColony_Kong]

There should be no time limits so long as water supply lasts.

[CountZero]

Techchat messages that tell player when engine timer safe time of use is over dont work if you also dont turn on Instrument panel in realisam.

Thouse messages will show up exactly when in game spec say they should,if emergancy is 1min then message show up exactly after 1min of use, extra time you can use it without damaging engine is random, its on player risk if he uses it, thats why they should fix this bug of this messages not showing up with only techchat on.

Also Instrument panel will turn on recovering time message, when timer is full recharged. You can have techchat turned on, but if this other option is not turned on you wont get that messages. Afcorce instrument panel have 0 conection to engine timers or techcat messages and this is clear bug in game, but they still cant fuiger out how to fix it to make their arcade engine timers easyer to understand for players.

12 minutes ago, LColony_Red_Comet said:

There should be no time limits so long as water supply lasts.

Yes, the pinicel of this stupidity of this arcade engine timer system, and you could see how it is on P-47D22, you can use wep for 5min but you have watter supply for it for 7min,  so you have only 7min of water but you can use it in one go only for 5min, that extra 2 min is so dangerous lol what a BS of system

Edited November 6, 2021 by CountZero

[LColony_Kong]

26 minutes ago, CountZero said:

Yes, the pinicel of this stupidity of this arcade engine timer system, and you could see how it is on P-47D22, you can use wep for 5min but you have watter supply for it for 7min,  so you have only 7min of water but you can use it in one go only for 5min, that extra 2 min is so dangerous lol what a BS of system

Yeah the P-47 is easily the best example of how stupid this system is. On top of the stuff you mentioned it also eats into your combat timer if you use WEP so you get double screwed in a plane that already is at a performance disadvantage and only fights halfway decently at full power.

 

The last time this got discussed in detail the developers said they wanted to fix this problem but hinted at doing some kind of full fledged engine model. Quite frankly, I think that is a royal waste of time that will likely be a over-complicated boondoggle. And if it ever actually gets done it will likely take away from the development of other things.

 

We don't need to wait another 3 years for nothing to happen. We just need these inane timers removed so that all planes in game and run indefinitely at their max rated power, or until water runs out on planes where that applies.

Edited November 6, 2021 by LColony_Red_Comet

[Raven109]

1 hour ago, LColony_Red_Comet said:

There should be no time limits so long as water supply lasts.

Are you referring the the MW50 supply? If so, the G-14 manual states that the "Special emergency" power setting should be used for 10 minutes at a time, with a break of 5 minutes in between. 

 

The reason for the 5min break is not apparent. Were the oil/coolant temperatures too high and did the engine need some cooling? Why not say so in the manual then, it would be a much better tip to the pilot. Where there other reasons for engine stress which would be reduced by the 5min break? Would engine knock be an issue after 10minutes of running at full power even though MW50 is being injected? I think not, but then again I'm not an expert in DB engines.

Edited November 6, 2021 by Raven109

[LColony_Kong]

41 minutes ago, Raven109 said:

Where there other reasons for engine stress which would be reduced by the 5min break?

There is only one reason for non-water limited time limits in planes. It is well known. It has to do with time before overhaul. By limiting time spend at high power settings, the engine can be made to last the number of hours intended to TBO.

 

It has nothing to do with temperature or detonation.

Edited November 6, 2021 by LColony_Red_Comet

[Raven109]

22 minutes ago, LColony_Red_Comet said:

There is only one reason for non-water limited time limits in planes. It is well known. It has to do with time before overhaul. By limiting time spend at high power settings, the engine can be made to last the number of hours intended to TBO.

 

Yes, the TBO has already been discussed when it comes to timers. If TBO was the reason, then I'd expect the 109 manual to say something like "run the engine at full boost for a maximum of 20 minutes, as you see fit", rather than "run for a maximum of 10 minutes, take a 5 min break, than run for another maximum of 10 minutes if needed". The effect should be the same on TBO, theoretically, if overheat/knock didn't become a problem towards the end of the 1st 10 min period. Perhaps I'm reading too much into the manual, but there must be a reason why the writer considered it important to add complicated instructions and tell a pilot who might be in a life and death situation that he should keep an eye on his watch and take a 5 min break. Then again, it wouldn't be the first manual that would provide questionable instructions which no one followed in practice.

 

On the other hand, if the 5min break was so important to the immediate operation of the engine, I would also expect the manual to mark it as an important note (Achtung!) as they did with other paragraphs.

 

 

Edited November 6, 2021 by Raven109

[the_emperor]

f@Raven109

thank you very much for your work and extensive testing.

Does the damage also happen when above FTH where boost is around 1.2-1.3 and rpm at 2800?   

Edited November 7, 2021 by the_emperor

[LColony_Kong]

6 hours ago, Raven109 said:

rather than "run for a maximum of 10 minutes, take a 5 min break, than run for another maximum of 10 minutes if needed". The effect should be the same on TBO, theoretically, if overheat/knock didn't become a problem towards the end of the 1st 10 min period.

No this is just a generalized procedure to get the pilot to not run the engine a high power without need. If there really was a thermal problem, a silly procedure like this would do you zero good. What speed are you flying at? What altitude? What engine power were you using before you initiated WEP? How hot is it outside? Etc. You cant just stamp on some rubbish 10 min limit and think that will keep you in parameters if indeed there was such a thermal problem. Not to mention that the idea that the engine heated up over 10min to a critical condition, but is somehow ready for another 10min after only 5 minutes is some fairly absurd sounding thermodynamics. Odd isnt it, that this hypothesized thermal problem has such exact parameters across numerous 109 variants using different engines?  And on top of all this, what condition of engine are we assuming for this procedure? If a new engine lasts 10 minutes, what about a worn out one? Do you think the pilot is really going to take a 5 minute break with a Mustang up its ass?

 

There is a simple explanation. This is not war thunder. They did not have thermal time limits.

 

There is only one reason these limits exist on  ww2 aircraft: Time Before Overhaul. That is it. Nothing else. And there is tons of explicit and implicit proof of this that has been posted by myself and others on this forum regarding many different aircraft over the years.

 

 

Edited November 7, 2021 by LColony_Red_Comet