DB 605A-1 1.42 ata (WEP) duration

[Bremspropeller]

It's relevant for understanding what's written in the manual, as in "blocked WEP", which never existed in the first place.

 

5 hours ago, ZachariasX said:

An F1 car can go full bore for about 5 km straight, give it take. You can expect the engine to explode before you reached the 10 km mark. By not exceeding a timer corresponding to a 2.5 km straight, you can operate the engine for several (single digit though, like the later DB) hours. This equates to a 30 sec useable „WEP setting“ based on a 1 min destructive timer. That is what you can do if you have fancy computers aboard and telemetry that monitor every milisecond of engine life.

 

The F1 motor will be built for extreme lightness and as close to that destruction-margin as possible.

That's not quite similar to an aero engine, where this is precisely what's being tried to be avoided and where sufficient growth-potential is a serious consideration during the design-process.

 

Note that the manual excerpt does not mention Start- & Notleistung being a time-bomb. That's because it isn't. Per se.

As long as you stay within the temperature, torque and combustion-stability boundaries, you should be okay. For now. You'll rather quickly figure out, whether the engine was designed with the additional load in mind, though. Especially when that load is being applied frequently and liberally.

 

 

41 minutes ago, the_emperor said:

(max. rpm/max. boost = WEP or Notleistung to not confuse you)

 

Still incorrect.

There simply isn't any WEP on any german aircraft, unless MW50/ Sondernotleistung or Erhöhte Notleistung is installed.

That would be Special Ermercency Power or Increased Emergency Power.

 

Start- und Notleistung is the normal take-off rating. Similar to the take-off rating on amercian/ british aircraft.

How often did P-51s take-off with WEP?

[the_emperor]

well, in flight its just "Notleistung" ?

@Bremspropeller do you have any further information on the usage of "Notleistung" than taxonomy(btw you are correct, the G-10 manual states: "der Einbau der  MW 50-Anlage dient zur Erhöhung der Start- und Notleistung des Triebwerkes auf Sondernotleistung" so, 1.42/2800rpm= take off and emergency power and higher boost at 2800rpm with MW-50 use = special emergency power.)? Do you have some primary sources that yet not have been presented here? 

Edited December 11, 2021 by the_emperor

[ZachariasX]

1 hour ago, Bremspropeller said:

That's because it isn't. Per se.

As long as you stay within the temperature, torque and combustion-stability boundaries, you should be okay.

Yes, that is why they (must) last relatively long on maximum ratings on the bench.

 

In the real world, you will find how efficient your cooling is and what the engine is actually digesting in terms of atmosphere. 5-10% deviation of "reference input" may well determine wether you walk home or not ("densitiy altitude"). Pilot anectotes for sure reflect this way more than any speculative nominal power output. Also, I really do think WW2 fighter engines resemble F1 engines much more than they do compare to your average Lycoming. They were literally riding the very edge of what was reasonably possible.

 

Regarding temperatures, you might well burn your engine quickly whole not deviating much from what you want to see on your water temp gauge in the cockpit. When things start to go south, the engine tends not to heat up uniformly, but it does so in critical location such as the valves. (Especially if you have unsuitable unsuitable material.) It's not even just power output that may spell your doom, but the whole configuration as such. You can happily burn your engine quickly while having water temp in the green. If you see your water temp suddenly veering off, consider what you see a post mortem.

 

It is my impression that people today often think that engines just run. Because that is what we are buying today. That they can even shut off for no apparent reason is unthinkable. Reliability back then and today have nothing in common, nil. Same goes for aircraft engines. Especially those engines we are talking about. Mark Hanna didn't need to red line his rebuilt DB engine, but it still killed him after what is only a couple of flights compared to what you'd do in a Cessna. Merlins quit all the time and they trash those warbirds for that all the time. So that is the actual reliability we are talking about and yet there seems to be people who'd happily redline these engines. Buy yourself a good old Jag E-type V12, then use it to commute to work. Mark the days in your callendar where you actually reach your workplace. Be prepared for a close relationship with your specialized mechanic. Have your last will up to date. (It's not just about engines, but about brakes as well.)

 

If the alternative to "full forward" is imminent death, then then redlining the engine seems like a good idea, even if there's sharks or evil enemies below. For anything other than iminent death, both sharks and evile enemies below should represent a compelling reason to be careful.

Edited December 11, 2021 by ZachariasX

[Dakpilot]

Did you ever have the GM-1 boost or MW-50 in any of your planes? 

Oh yeah, we used it quite often…in combat you know.

How long did it last? 

Uhh…you were not allowed to have it at more than 5 min., you know…if you used it 10 minutes, then motor has to come out.

 It makes the engine worse?

It wrecks the motor.

 And this was for the higher altitude?

Higher…yes…

 And at what speed could you get up to?

Oh boy…I don’t remember…450 or 500 km…

 Like you said, you could only use it for 5 min. otherwise you would burn out the engine. How many 5 min. intervals could you use?  Did you have to shut it down for a period of time to let the engine cool?

That’s okay…that uh…it didn’t matter.  You…but you never used it for five minutes…a minute, minute and a half and that’s it.

 

Franz Stigler interview on 109 engine

 

Cheers, Dakpilot 

[Bremspropeller]

25 minutes ago, ZachariasX said:

If the alternative to "full forward" is imminent death, then then redlining the engine seems like a good idea, even if there's sharks or evil enemies below. For anything other than iminent death, both sharks and evile enemies below should represent a compelling reason to be careful.

 

But if there'd be "sure engine death" after 5 minutes, you'd think twice about going a full arm's length, too.

I think we can all agree on the topic being a bit more "shades of gray" rather than "black and white".

 

[the_emperor]

20 minutes ago, Bremspropeller said:

I think we can all agree on the topic being a bit more "shades of gray" rather than "black and white".

Yes, indeed. and that these aero-engines are much more complex than they are represented in the game and that there are many things missing.

Unforntunately the game/devs treat it more like black and white. So if there is time limit in the manuals, it is in the game and it is a definitiv limit that destroys your engine if you over step it. So I for myself do mainly make my points in regards to the in-game logic and its implementions of those limits, not how they might accured in real life.

Edited December 11, 2021 by the_emperor

[Bremspropeller]

FWIW, here's a great report on Erhöhte Notleistung long-term trials in the Fw 190:

http://www.wwiiaircraftperformance.org/fw190/Erprobung_2581.pdf

 

Bottlenecks weren't the motors themselves, but the oil-cooler performance and the propeller-reduction gears.

Five aircraft were used, three having demonstrated totals of 10hrs of Erhöhte Notleistung each. The remaining two had amassed 1.25 and 0.75hrs of EN each.

 

Tests were conducted with continuous EN runs for 20-25 minutes.

 

A relatively similar result for the increased boost-pressure method:

http://www.wwiiaircraftperformance.org/fw190/BMW-VB-126.html

 

Again, oil-cooler performance was the bottleneck during time-to-climb trials at full bore.

 

One can say that, at least for the mature Fw 190, the glass-engine theory is a fairy tale.

 

[the_emperor]

@Bremspropeller that is very interesting indeed.

So the test were by increasing Notleistung to Sondernotleistung (1.42ata -> 1.6ata)? so probably less problematic when kept at 1.42ata?

[Bremspropeller]

They tested two different systems - the first test was the Jabo system, injecting additional C3. This would run at a richer mixture, spo the additional cooling-requirements were low (the CHT only went up a couple of degrees).

Take it as a data point that running engines for prolonged timeframes at emergency power won't necessarily lead to engine failures. Don't assume it can be transferred over to other engine-airframe installations easily, though.

 

The second test is the boost-increase from 1.42 to 1.58 and 1.65 ata. The test included a climb test to 8km with Erhöhte Notleistung. Other than oil temps becoming critical, no other issues were found. One has to mention that this test wasn't as thorough as the one with C3 injection and they didn't test as many hours.

[the_emperor]

Thanks @Bremspropeller very interesting.

I guess there are no such tests regarding the 2800rp,/1.42ata setting for the DB605A engine?

[Bremspropeller]

38 minutes ago, the_emperor said:

I guess there are no such tests regarding the 2800rp,/1.42ata setting for the DB605A engine?

 

On ww2aircraftperformance, you'll see a lot of reports and passages of MAP-reduction (Start- and Notleistung being blocked), but there's little discussion on tests besides the need to prove the 109 had it's nails clipped.

 

Kurfürst might have more info about any similar tests.

[LukeFF]

On 11/6/2021 at 2:39 PM, 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.

 

Mmm, no, sorry, that's not the case:

 

(It's from a 1944 P-51B/C manual):

 

Edited December 13, 2021 by LukeFF

[the_emperor]

Thank you @LukeFF that is very interesting. It also says, that the engine is safe for a total use of 5h of WEP (this time correct ? ) I guess at least for the operation of the P-51 fuel consumption has also to be taken into consideration, since you have to make a trip back to England (mostly) on internal fuel load. in WEP mode the Merlin 60s series uses up ~ 150 gallons/h ~ 680l/h so 5min of WEP eats roughly 56l of your fuel.

But back to the topic: I dont reject the implementation of the time limits per se. They are part of the game and therefore I argue from that point.
Currently I am here:

the DB 605A manual from 1942 seems to be in effect till spring 44 -> it blocks the use of Start-Notleistung (1.42ata/2800rpm).

In Spring 44 (April) the new revised engine is released. Start-Notleistung is cleared but no time limits given.

Since this is probably the engine which also had to be able to handle the increased power with the MW-50 instalation, of which we know the limits (10min),I would say (and there are no documents for that, just my conclusion) that, 10min of Notleistung for the revised non MW-50 DB605A at 1.42ata/2800rpm seems reasonable to me.

If the engine can handle the stress of ~1700-1800hp for 10min, it should be able to handle ~1400-1500hp. The engines got an overhauled oil lubcriation system and an slightly improved cooling system. If "Notleistung" wasnt cleared for save use, the "Sondernotleistung" with MW-50 at its increased power and stress for the engine wouldnt probably be save either.

TLDR:

Start Notleistung block till March 1944.

Start Notleistung cleared April 1944 -> 10min limit (that is my assupmtion)

 

 

Edited December 13, 2021 by the_emperor

[the_emperor]

The unlocked Notleistung Rating would probably at that time mostly effect the G-6 version which is the only version I could find date for (just top speed, no climb perfomance):

Bf 109 G-6: 530kp at 0m; 640kph at 6600m fth (3,196kg)

Bf 109 G-6/AS: 520kp at 0M; 660kph at 9000m VDH (3,221kg) -> both from the Datenkennblatt 13.08.44

 

Another from 07.03.44:

BF 109 G-6 3350kg (with gondolas): 520@ 0m; 635 @ 6500m

BF 109 G-5/AS 3230kg: 530kph @0M; 670kph ata 8500m

 

 

 

 

 

 

[JtD]

7 hours ago, the_emperor said:

It also says, that the engine is safe for a total use of 5h of WEP

 

No, it says after 5h it has to be removed for inspection. No one would make a statement about "safe" use, because because that's not really a technical concept. Things can always break down. It's basically telling you that accumulated wear after this much time necessitates an inspection.

 

Same way for instance the DB605 says it has to be removed for inspection after over-revving the engine beyond 2850. This does neither mean it is safe up to 2850, nor does it mean it's going to break down beyond that point. (Just to get a little bit more back on topic.)

[the_emperor]

@JtD "safe use" is indeed a bit optimistic ? but it does say that the inspection after 5h of emergency use or does that mean total time used of emergency power?

for the DB 605 per manual:

in a dive you sould not rev over 2870rpm. In in exceptional cases (e.g. automatic damaged) your may rev up to 3000rpm ("dürfen für kurze Zeit erreicht werden") for a short period of time. Engines that exceeded the 3000rpm must be send back to the factory.

Edited December 13, 2021 by the_emperor

[41Sqn_Skipper]

9 hours ago, the_emperor said:

Thank you @LukeFF that is very interesting. It also says, that the engine is safe for a total use of 5h of WEP (this time correct ? ) I guess at least for the operation of the P-51 fuel consumption has also to be taken into consideration, since you have to make a trip back to England (mostly) on internal fuel load. in WEP mode the Merlin 60s series uses up ~ 150 gallons/h ~ 680l/h so 5min of WEP eats roughly 56l of your fuel.

But back to the topic: I dont reject the implementation of the time limits per se. They are part of the game and therefore I argue from that point.
Currently I am here:

the DB 605A manual from 1942 seems to be in effect till spring 44 -> it blocks the use of Start-Notleistung (1.42ata/2800rpm).

In Spring 44 (April) the new revised engine is released. Start-Notleistung is cleared but no time limits given.

Since this is probably the engine which also had to be able to handle the increased power with the MW-50 instalation, of which we know the limits (10min),I would say (and there are no documents for that, just my conclusion) that, 10min of Notleistung for the revised non MW-50 DB605A at 1.42ata/2800rpm seems reasonable to me.

If the engine can handle the stress of ~1700-1800hp for 10min, it should be able to handle ~1400-1500hp. The engines got an overhauled oil lubcriation system and an slightly improved cooling system. If "Notleistung" wasnt cleared for save use, the "Sondernotleistung" with MW-50 at its increased power and stress for the engine wouldnt probably be save either.

TLDR:

Start Notleistung block till March 1944.

Start Notleistung cleared April 1944 -> 10min limit (that is my assupmtion)

 

 

 

No not really. We know from the MW50 manual for Bf 109 G (iirc dated Nov 1944) that engines with MW50 installation were only cleared for climb power (steigleistung) when MW50 was disabled or empty. So effectively "start- und notleistung" was also blocked/not auhorized for these engines. The manual also warns about immediate destruction of the engine if the engine is not throttled back to climb power when running out of MW50.

 

 

 

[the_emperor]

@41Sqn_Skipper was that due to a different interconnection of the throttle of rpm/boost for the MW50 instalation and the risk of overboosting? so if your rev above 2600rpm the engine starts to boost above 1.42 ata even when MW50 is turned off or empty? didnt that manual mention that above a certain altitude (at and above FTH) you could again start reving up to 2800 (no more risk overboosting)?

So if not 10 minutes limit? what would be reasonable? in game logic would dictate no limit, since there is non mentioned -> again for the DB605A cleared in April 44 (but that seems not right). I still consider the Notleistung blocked till then and the current one minute weird as it is only mentioned in manuals where Notleistung ist blocked and couldnt used anyway.

As we do have a late version of the G-6 in game, where a revised DB605A could be easily implemented and fit to a certain time frame substituting older G-6 veriants.

Edited December 13, 2021 by the_emperor

[41Sqn_Skipper]

9 minutes ago, the_emperor said:

@41Sqn_Skipperwas that due to the interconnection of the throttle of rpm/boost and the risk of overboosting? so if your rev above 2600rpm the engine starts to boost above 1.42 ata even when MW50 is turned off or empty?

 

Certainly. Moving the throttle to 2800 RPM would give 1.7 ata with or without MW50. It would technically be possible to move the throttle carefully to ~2650-2700 RPM and 1.42 ata to get something similar to "Start- und Notleistung". But this method is not mentioned or authorized in the manual. In my opinion this indicates that anything above 1.3 ata without MW50 is either blocked or limited to a very short duration.

 

[the_emperor]

10 minutes ago, 41Sqn_Skipper said:

Certainly. Moving the throttle to 2800 RPM would give 1.7 ata with or without MW50. It would technically be possible to move the throttle carefully to ~2650-2700 RPM and 1.42 ata to get something similar to "Start- und Notleistung". But this method is not mentioned or authorized in the manual. In my opinion this indicates that anything above 1.3 ata without MW50 is either blocked or limited to a very short duration.

Probably to prevent the pilot from trying such things and damaging the engine due accidentially overboost without MW-50. Pilot training at that stage of the war in the Luftwaffe was not of the highest quality.

And this only refers to the engine with MW-50 installation.

I am not quite sure if you could translate that to the regular DB605A without MW-50 were the boost ist limited to 1.42ata

Edited December 13, 2021 by the_emperor

[Roland_HUNter]

G-6/AS should be faster than the G-6, no? More aerodynamic Nose?

[41Sqn_Skipper]

1 hour ago, the_emperor said:

I am not quite sure if you could translate that to the regular DB605A without MW-50 were the boost ist limited to 1.42ata

 

Exactly that's my point. The 10 minute time limit of a MW50 engines says nothing about the time limit for 1.42 ata when no MW50 is used.

[the_emperor]

43 minutes ago, 41Sqn_Skipper said:

Exactly that's my point. The 10 minute time limit of a MW50 engines says nothing about the time limit for 1.42 ata when no MW50 is used.

Indeed. that is just my proposal (extrapolated Íf you will) instead of unlimited use as the manual does not mention a time limit (again, that is the game mechanic if there is a time limit mentioned its in the game,  if there is none there is none. That does not of course reflect real live as we already concluded, its just the road that what chosen for the game) and that is what this thread is ultimately about. when and how long should the G-6 with the DB605A should have access.

The current 1 Minute limit is highly doubfull as it is only mentioned in a time frame/manuals when its blocked and the DB605A got a new manual/overhaul in April ´44 with the Notleistung unlocked and beeing able to take the stress of 2800rpm and~1700hp for 10min with MW50. Again:

Start Notleistung blocked till March 1944.

Start Notleistung cleared April 1944 -> 10min limit (that is my assupmtion, "extrapolated" from the 10min use of 1.7ata with MW50 at 2800rpm and ~1700hp), but that is of course up for debate. maybe 5min as for the allied Spit/Mustang, P-40E, La-5fn (yes, the game says 10min, but the manuals say 5min) would be more suited.

Edited December 13, 2021 by the_emperor

[iFoxRomeo]

On 12/11/2021 at 4:46 PM, ZachariasX said:

Mark Hanna didn't need to red line his rebuilt DB engine, but it still killed him after what is only a couple of flights compared to what you'd do in a Cessna

Out of curiosity I wanted to look for an accident report for this. Perhaps the investigation reveals the cause for the engine failure. But...

Mark Hanna crashed in a Buchon, with a Merlin engine. And the engine didn't fail.

Perhaps you confused this accident with a different one?

 

https://aviation-safety.net/wikibase/18874

 

Spanish civil aviation accident commission report in english:

https://www.fomento.es/NR/rdonlyres/3BD150EE-9B94-4C27-8820-06B5CD8928AD/2428/1999_059_A_ENG.pdf

[ZachariasX]

1 hour ago, iFoxRomeo said:

Out of curiosity I wanted to look for an accident report for this. Perhaps the investigation reveals the cause for the engine failure. But...

Mark Hanna crashed in a Buchon, with a Merlin engine. And the engine didn't fail.

Perhaps you confused this accident with a different one?

 

https://aviation-safety.net/wikibase/18874

 

Spanish civil aviation accident commission report in english:

https://www.fomento.es/NR/rdonlyres/3BD150EE-9B94-4C27-8820-06B5CD8928AD/2428/1999_059_A_ENG.pdf

You are quiet right and thank you for the links. I indeed remembered wrongly. I thought at that time ihe flew the "refurbished" G6 and the engine quit on him on landing. Seems he stalled it out on approach without any further help. These crates (not just the 109!) are obscenely dangerous to operate and things like that do happen. Even with the relatively well known and thus "realiable" Merlin.

 

I confused Mark hannas Buchon with the 109 G10 that was rebuilt in 1982 with a Buchon as base and some 109 K4 parts and a DB605D-1. It was labeled "Black 2" and Mark Hanna made the first flight with that one on March 23., 1995. The aircraft was registered as D-FDME. I mistook his crash upon landing with the 1998 incident, where "Black 2" got damaged during ground operations. The aircraft had constant engine troubles, during a landing one gear unlocked with all the consequnces.

 

Here is a (German) article about those 109:

https://www.flugrevue.de/klassiker/deutscher-jaeger-flugfaehige-messerschmitt-bf-109/

 

What they mainly do with the aircaft is rebuilding after crashes of warious kinds or when it just blows up on it's own. But that is the charm of operating vintage high performance machines. You have to like that.

[Bert_Foster]

On 12/12/2021 at 2:46 AM, ZachariasX said:

Mark Hanna didn't need to red line his rebuilt DB engine, but it still killed him after what is only a couple of flights compared to what you'd do in a Cessna

For the record Mark Hanna was flying a Buchon with merlin, and his crash had nothing to do with the engine it was Loss of control on approach

https://www.fomento.es/NR/rdonlyres/3BD150EE-9B94-4C27-8820-06B5CD8928AD/2428/1999_059_A_ENG.pdf

[DD_Arthur]

6 hours ago, Bert_Foster said:

 

 

?

[LColony_Kong]

On 12/12/2021 at 6:30 PM, LukeFF said:

 

Mmm, no, sorry, that's not the case:

 

(It's from a 1944 P-51B/C manual):

 

This has been brought up before, and rightfully disregarded. If you read the entire section, it is ultimately just referencing TBO. Especially in the greater context of manuals we have for this exact same engine, and even the same plane. In some of those, for the Spitfire, later P-51 manuals, etc...there is no ambiguous phrasing and it is in fact explicitly stated that there is no concern of immediate failure just for violating the time limit. We also have the run in tests and RR tests that show anywhere from 8-27 hours at WEP. Reading this the way you are is just confirmation bias and throws out the entire rest of the body of evidence.

 

 

 

 

On 12/11/2021 at 10:50 AM, Dakpilot said:

Did you ever have the GM-1 boost or MW-50 in any of your planes? 

Oh yeah, we used it quite often…in combat you know.

How long did it last? 

Uhh…you were not allowed to have it at more than 5 min., you know…if you used it 10 minutes, then motor has to come out.

 It makes the engine worse?

It wrecks the motor.

 And this was for the higher altitude?

Higher…yes…

 And at what speed could you get up to?

Oh boy…I don’t remember…450 or 500 km…

 Like you said, you could only use it for 5 min. otherwise you would burn out the engine. How many 5 min. intervals could you use?  Did you have to shut it down for a period of time to let the engine cool?

That’s okay…that uh…it didn’t matter.  You…but you never used it for five minutes…a minute, minute and a half and that’s it.

 

Franz Stigler interview on 109 engine

 

Cheers, Dakpilot 

Its always amusing that you disregard all of the other technical data, as well the the anecdotes that have been posted about P-38s having an SOP to run at full power until the fight was over, or several other anecdotes of Mustang and other aircraft claiming to run WEP for 15min or more, or people even running settings above and beyond the official MAP limits for time periods greatly exceeding the time limits even for the approved MAP settings.....

 

So you can post this one anecdote over and over that is just someone reporting the experience they had of following the procedure they were given. Which is evidence of nothing.

 

 

Edited December 30, 2021 by LColony_Red_Comet

[CUJO_1970]

Yes he says for 15 minutes he was indicating 600 mph at 1,000ft altitude?

 

At least now we know what the new P-51B FM is based on.

 

 

[CountZero]

1 hour ago, LColony_Red_Comet said:

This has been brought up before, and rightfully disregarded. If you read the entire section, it is ultimately just referencing TBO. Especially in the greater context of manuals we have for this exact same engine, and even the same plane. In some of those, for the Spitfire, later P-51 manuals, etc...there is no ambiguous phrasing and it is in fact explicitly stated that there is no concern of immediate failure just for violating the time limit. We also have the run in tests and RR tests that show anywhere from 8-27 hours at WEP. Reading this the way you are is just confirmation bias and throws out the entire rest of the body of evidence.

 

 

 

 

Its always amusing that you disregard all of the other technical data, as well the the anecdotes that have been posted about P-38s having an SOP to run at full power until the fight was over, or several other anecdotes of Mustang and other aircraft claiming to run WEP for 15min or more, or people even running settings above and beyond the official MAP limits for time periods greatly exceeding the time limits even for the approved MAP settings.....

 

So you can post this one anecdote over and over that is just someone reporting the experience they had of following the procedure they were given. Which is evidence of nothing.

 

 

cccc we all know that pilot counted secounds and minutes as his primary ocupation when in combat, if manual say 5min then its no more then 5 min, no mather situation LOL

[gimpy117]

51 minutes ago, CountZero said:

cccc we all know that pilot counted secounds and minutes as his primary ocupation when in combat, if manual say 5min then its no more then 5 min, no mather situation LOL

the Alison memo comes to mind....

 

http://www.wwiiaircraftperformance.org/P-40/V-1710_Service_Use_of_High_Power_Outputs.pdf

Edited December 30, 2021 by gimpy117

[LColony_Kong]

2 hours ago, CUJO_1970 said:

Yes he says for 15 minutes he was indicating 600 mph at 1,000ft altitude?

 

At least now we know what the new P-51B FM is based on.

 

 

Come off it.

You know full well that reading a MAP gauge is not the same as the issues with measurement errors that occurred in pitot tube as mach numbers increased. Not to mention that by your own logic we should also disregard pilot anecdotes of operating the engines within the limits...in fact, if you think the MAP guages were unreliable, its a wonder how anyone could think the pilots maintained MAP timers or even MAP limits since the gauges were too unreliable to tell lol! I mean how do we know their clocks even worked?

Edited December 30, 2021 by LColony_Red_Comet

[Dakpilot]

4 hours ago, LColony_Red_Comet said:

Its always amusing that you disregard all of the other technical data, as well the the anecdotes that have been posted about P-38s having an SOP to run at full power until the fight was over, or several other anecdotes of Mustang and other aircraft claiming to run WEP for 15min or more, or people even running settings above and beyond the official MAP limits for time periods greatly exceeding the time limits even for the approved MAP settings.....

 

So you can post this one anecdote over and over that is just someone reporting the experience they had of following the procedure they were given. Which is evidence of nothing.

 

I don't  really understand why you think all engines are exactly the same and what P-38's and Mustangs have to do with operating a DB605 

 

Cheers, Dakpilot 

[the_emperor]

That is all very interesting regarding the Packard/Merlin engine and the engine timers there should defenetely looked upon . but back to the late revised DB605A (April ´44):

Why should that engine be limit to 1min @ 2800rpm at 1.42 ata with ~1450hp Notleistung/emergency

while

a) the engine manual thus far does not mention such a limit

b) that engine can "safely" take the stress of 2800rpm at 1.7ata (with MW-50 instalatlion to prevent knocking/premature detonation for the low octane fuel and cooling due to increased aie fuel mixture by the faster spinning chargere) with ~1750hp for 10min erhöhte Notleistung/increased emergency power

 

RPM limit does not seem to  factor since the engine is safe 2870rpm and even allows for up to 3000rpm in exceptional cases. and can be run "safely" for at least 10min.

If MAP of 1.42ata (causes knocking or premature detonation) is the limiting factor it has thus far not been mentioned anywhere (or mabye i have overlooked it in this thread, then apologies ? ). At least the manual does not state it. (the problems of earlier engines seem to be a week/construction in the piston department and insufficiant oil lubrication for the new plain crankshaft bearing -> a construction failure which limits the engine from mid 42 til April 44 and blocks the use of emergency power)

The limits per manual for level and climb of the engine are the coolant/oil temperature and pressure limits.

and the increased wear and tear.

Edited December 30, 2021 by the_emperor

[41Sqn_Skipper]

2 hours ago, the_emperor said:

 

If MAP of 1.42ata (causes knocking or premature detonation) is the limiting factor it has thus far not been mentioned anywhere (or mabye i have overlooked it in this thread, then apologies ? ).

 

We have documentation in the MW50 manual that the engine can't handle more than 1.3 ata without MW50 or the engine is immediately destroyed, so 1.42 ata (or "more than 1.3 ata") clearly is the limiting factor. 

Edited December 30, 2021 by 41Sqn_Skipper

[LColony_Kong]

10 hours ago, Dakpilot said:

 

I don't  really understand why you think all engines are exactly the same and what P-38's and Mustangs have to do with operating a DB605 

 

Cheers, Dakpilot 

Thats an odd comment to make, considering that you seemed to be using the DB605 anecdote to apply to all engines the other way round.

 

In any case engines do not have to be the same. Whether engines were mechanically identical has very little to do with whether anyone was applying time limits to engines in the manner we have in this game. Just like there is very little in common with Merlins and Allisons, or even those two and a R2800 but they all have the same sort of TBO limits.

 

Largely, this all has very little to do with the specifics of each engine. It has to do with the logic applied by manufacturers and air forces to time constraints on engines generally.

Edited December 30, 2021 by LColony_Red_Comet

[the_emperor]

1 hour ago, 41Sqn_Skipper said:

We have documentation in the MW50 manual that the engine can't handle more than 1.3 ata without MW50 or the engine is immediately destroyed, so 1.42 ata (or "more than 1.3 ata") clearly is the limiting factor. 

That document says (for the AS-eingine) you must not throttle up to 2800rpm without MW-50 supply in the tank or MW-50 Shut off it will destroy the engine (1.7 ata without MW-50 is undoubtly not a good idea). It also allows to throttle to 2800rpm at 8,5km which is roughly the FTH (9km in level flight) for the AS engine and so it allows 2800rpm and ~1,42ata. so it further hints that 1.42/2800rpm is not really as problematic as the game portrays it (in real life of course the increased tear and wear, but that does not apply for the game).

 

 

But again, this is for an engine with MW-50 instalation And with different thottle/boost setting, and we need documention on the regular DB605A.

So what would be better? unlimited Notleistung für the late DB605A, since there is no time limit documented (that is not my personal opinion, just how the game works), or extrapolate the 10min from the use of inreceased emergency power, which the engine can handle without problem?

Edited December 30, 2021 by the_emperor

[JtD]

The manual says emergency power is to be limited to emergencies.

 

So I'd say the game monitors the players stress level (pupils, puplse & sweating should do), and if it detects stress, you can use emergency power without time limit and if it doesn't detect stress, the engine breaks down immediately.

 

Alternatively, you can use unlimited emergency power when your plane is on fire or a wing is missing, because that definitely qualifies as an emergency.

[Kurfurst]

5 hours ago, 41Sqn_Skipper said:

 

We have documentation in the MW50 manual that the engine can't handle more than 1.3 ata without MW50 or the engine is immediately destroyed, so 1.42 ata (or "more than 1.3 ata") clearly is the limiting factor. 

 

 

[LColony_Kong]

In my view the way to solve this, would be just to remove time limits entirely.

 

But the compromise solution I have mentioned before gives everyone on both sides, at least as I understand it, what they want. That compromise would be to give every plane in the game 15 minutes of time at whatever is considered "emergency" power, or until water is exhausted whichever comes first. The gives every plane enough "WEP" that there is plenty for most conceivable in game combat situations while still limiting it so that it is unlikely players will wantonly cruise around at max power. If a player cruises around at WEP, they will eat into their time and wont have enough when they run into a fight. Considering it takes about 5 minutes to get to altitude and you could be playing spot the dot for anywhere from 5-40minutes, most decent players wont be wasting their WEP like this. Under this scheme, military/combat power settings would be unlimited on all aircraft. Cruising around at WEP will also eat into fuel extremely quickly, so players that fly constantly at these settings will either have to take very fuel heavy aircraft and/or cut their sortie very short. This solution gives everyone most of what they want, and also makes all the planes in the game equal in this regard, ending the issue that the time limits from the manuals have alot to do with the different TBO requirements of the various nations involved. Aircraft without MAP regulators like the P-40 would need some kind of special solution on top of this, as the current power restrictions are clearly too conservative but we dont want 1700bhp warhawks flying around.

 

So for a 109G it would work like this:

 

Pre 1.42 ata being authorized:

 

1.3 ata unlimited. 1.42ata restricted to 1 min since this was only authorized to assist in takeoff due to this power setting actually being too much for the engine until the problems were sorted out.

 

Post 1.42 authorization:

 

1.42 ata for 15min

 

1.3 ata unlimited.

 

For comparison:

 

K-4 would be unlimited 1.45ata and 15min at 1.8/1.98 ata

 

P-51 would be unlimited 61inches and 15min at 67/75inches

 

P-47 unlimited military power, 15min WEP or until water ran out. (I cant recall how much water 47 has of top of my head)