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DB 601/x limitation of poweroutput

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Hello,  i see in the bf109g2 topic some disscusion to the limitation of the db 601 engines, espacilly Start und Notleistung. This documents speak about a 1 min time limit:

DB 601A  

http://www.deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Motoren/Daimler%20Benz/Handbuch%20DB%20601%20A-B.pdf

Page 21 Handbook

DB 601N

http://kurfurst.org/Engine/DB60x/DB601_datasheets_N.html

This doccument speaks of short time use:

http://www.deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Motoren/Daimler%20Benz/Motorhandbuch%20DB%20601%20E-G.pdf

Handbook Page 20: There are no strict PRESCRIBED information for temporal limitation of the power stages. Only the engine rpm is strict limited to 2700+2%

Handbook Page 73:  Bei Notleistung wird der Motor stark beansprucht, deshalb ist die Dauer dieser Leistungshebelstellung möglichst kurz zu begrenzen.

With emergency power , the motor is heavily used , therefore the duration of this power lever position is as short as possible to limit .

 

Because in the game all the machines are brand new,  the time limit for emergency power(db601E)  should be higher.

 

 

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Here an excerp form the "Kennblatt für das Flugzeugmuster Bf-109 Baureihe F-1 und F-2 mit DB601N Motor" (page 6):

 

ny3d89vx.jpg

Don't want to translate all of that, but summarized it says:

 

- 1.42 ata (Start und Notleistung) is limited to 3 minutes

- engine RPM can be increased to 2800 resulting in a speed gain of 10 - 15km/h at full pressure altitude

 

2700+2% is likely not the ultimate but the highest continues RPM limit for the DB601.

Edited by Stab/JG26_5tuka
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I test F4 with 1,42 ata, in Winter this morinig.. after 1 min technochat reports i reach the time limit for Notleistung. Documents for 601a/b and n write about time limit 1 min for Notleistung. According the manual for db 601e there is no strict time limit. As short as possible can be 5-3 min. 5 for a new engine and 3 for engine with some operating hours.

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This might prove interesting. These are run-in instruction for DB 605A, noting that Notleistung should be run several times for 5 minute duration when testing the newly made engine (using gas as fuel, hence the lower power outputs)

post-1271-0-25713500-1453397043_thumb.jpg

post-1271-0-18042300-1453397044_thumb.jpg

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Unfortunately all this is old news, the developers decided to not consider the information because the five minutes are run on a test rig. Also because it doesn't run with fuel.

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Don't be naive. Nothing will be changed. You all already be tagged as luftwhiner. You job is the providing good target to VVS heroes. That's all of your duty :lol: .

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Don't be naive. Nothing will be changed. You all already be tagged as luftwhiner. You job is the providing good target to VVS heroes. That's all of your duty :lol: .

 

Yes!!!! +1

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If 5 minutes is for runung test only i think 3 minutes would be resonable solution. But im not naive developers wouldnt change anything here probably

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Unfortunately all this is old news, the developers decided to not consider the information because the five minutes are run on a test rig. Also because it doesn't run with fuel.

You gotta be kidding. Surely you must. Is this truely their reasoning?

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I know it was presented and they said something along the lines of what I wrote, but not necessarily true to the letter. It was somewhere on the Russian forum and quite a while ago.

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As I understand it, the issue with the DB605 at least were weak pistons that would break, which is why use of 1.42 was discontinued:

 

Weak pistons wasn't that much of a reason (except for the very earliest examples) - if you read the document carefully, the reinforced pistons were already designed and fitted to engines at the time of service introduction.

 

The main reason for the 1.42ata limitation was that the bearing (ball bearings of the 601E changed to roller bearings) and lubrication (oil) system was changed, with more powerful oil pumps with resulted in the oil foaming, low oil pressures (DB also pointed fingers to the Mtt for the oil system as installed not living up to DB oil pressure specs, I am not sure though how much truth there was in this apart from pointing fingers) and reducing lubrication of the bearing to insufficient amounts. Lot of testing went into fixing this and the solution appears to be the fitting of oil de-aerators which functioned well, but it took until about October 1943 to finally clear the full rating.

 

See: http://kurfurst.org/Engine/Boostclearances/DB605A_GLmeeting_September1943.html

Edited by VO101Kurfurst

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Unfortunately all this is old news, the developers decided to not consider the information because the five minutes are run on a test rig. Also because it doesn't run with fuel.

 

If 5 minutes is for runung test only i think 3 minutes would be resonable solution. But im not naive developers wouldnt change anything here probably

 

 

Umm, just because it's test doesn't mean you cant do it operationally out in the plane/jet. Test, just means you're testing it to be a serviceable engine. The run-in is just like a break-in run for a jet engine. Cutting seals and wearing in the new parts and taking it through the array of operating limits it will see in the operational world. I use to TEST engines that would go to a spare line or straight to a jet. Pretty sure a pilot could do everything we did to test the engine, as long as they don't exceed the limits of the engine; oil temps, n1 and n2 speeds, vibe limits, EGT, etc. I don't see why 5 minutes couldn't be used. If they're development tests, that could be a different story.

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Just found this for the DB 601N for the F2:

 

http://kurfurst.org/Engine/DB60x/files/Flight_16April1942_DB601N_Engine.pdf

 

"At maximum emergency power of 1,270 b.h.p. at 2,600 r.p.m. a t 16,270ft., the boost pressure is 7.81 lb. / sq. in. For take-off, a t 2,600 r.p.m., 1,200 h.p is developed with 7.81 lb./sq . in. boost pressure. An in-genious mechanism allows for increased boost and power for take-off for the duratioruof one minute.When opening up, the pilot gives an increased movement to his throttle lever, which also operates a clockwork gear in the control mechanism. This clockwork device keeps the throttle at its extra opening until a small slipstream-operated windmill retards the opening at the end of a minute , and the engine then returns to its normal full-throttle power."

 

So from what I'm reading you shouldnt be able to burn up your engine in F2.

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The F-2 we have ingame has that mechanism removed and a clearance rating of 1.42 ata @ 2800 RPM for Start und Notleistung.. I know that because I checked & reported this until one of the devs pointed the source out (also on Kurfürsts site) saying that this change was done by the time the battle of Moscow took place.

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I have a couple of Questions about the Bodenlader and connected to that the 109Es performance.

 

What is the Bodenlader? My Guess it's an especially Low Revving Setting for the Supercharger, thus allowing for more power at the same settings at low altitude.

 

Was it an Automatic Setting or did it have to be actutated in the Cockpit?

 

Is the lack of (a functioning) Bodenlader the reason for the lacking Performance of captured 109Es at low altiudes, both in Speed and Climb in foreign tests?

At altitudes around 4000 and higher German Tests and Foreign ones tend to agree, but the results of 109Es close to the Ground were often around 10% less Top Speed and 25% in Climb Performance. Because quite often in the test Protocolls some kind of Supercharger Problems were quoted. d

 

(ca.500 in the all-out german test, against ca.460 for French, Russians and Brits. 16.5m/s in German Test against ca. 13m/s in French Tests)

 

Was the Bodenlader only a feature in the DB601Aa, or in the A-1 as well?

Would this be an explanation for the above?

What was the relation of DB601A-1 and Aa in terms of Produciton Numbers and Service use?

 

Does the ingame Model realistically lack the Bodenlader, would we get some more performance?

 

Edit:

This is the World as I experience right now:

 

RL Test of Emil with Aa engine, 1.35ata@2400RPM and Bodenlader: 498kph on the Ground, 570 at altitude Tested.

 

Other Tests, apparently using DB601A-1, 1.3ata@2400 apparently without Bodenlader achieving 476 at Ground Level

 

Another Test Claims Rate of Climb of 14.5m/s and Speed of 460 Ground and 555 at 4.5-5.5k (My Guess at Cont or 30 Min Setting), no other Info

 

Brits get 14.5m/s at 1.23ata and 465 on the Ground with a Captured Model with Sueprcharger Dufficulties. No other Info wether Aa or A-1

 

This is why I'm asking, a huge Speed and Climb Increase simply by use of different Supercharger Drives, and it appears to me only to be due to the Bodenlader setting used in the Aa. 

Edited by 6./ZG26_Klaus_Mann

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Bodenlader simply means low level supercharging gear, its literally "Ground Supercharger", or in other words, the first gear of the supercharger that run at lower speeds and thus consumed less power from the engine. Equivalent to MS gear, or "Moderate Supercharging" in British technical terms. There is nothing fancy or special in it.

 

Now, in context of the DB 601 and Emil tests, it simply refers to running the supercharging in low (1st) gear, which is what the automatically controlled (via two different delivery rate oil pumps) DB 601 would do anyways under about 1500-2000 meters. The first gear rate (pump rate) on the 601/605 was fixed, so unlike the second gear, which had a gradual slip to run the supercharger at higher and higher revs (and provide more air and consume more engine power) it worked pretty much your avarage WW2 aircraft engine supercharger - providing a lot more air than actually needed and then throttling it down to the nominal boost rates.

 

Normally there was no manual override for it, but given that we are speaking of adjustable flow oil pumps, it could be set by mechanics on the ground almost certainly to just give full 1st gear or 2nd gear speed, for testing purposes for instance (to eliminate variance in supercharger speeds in flight trials for example). Hence the straight lines. There are a couple of later G-6 test flight test that show the same phenomenon and "sawtooth" curves.

 

Some variance of cource could be expected between individual engine runs, due to varying specs of the engine and the airframe. Hence why the manufacturing limit was +/- 5% for speed. For example the V15a tested was also noted to be down about 40 HP in engine power, established in bench tests. Also, one has to be careful about various Emil tests, because they were measured at a great variaty of ratings, sometimes on 30-min power or less. Given that the testing documentation is often incomplete, its hard to say with absolute certainity what the testing conditions were in most test - the V15a test is the exception, as its very through, and also, the low level speeds were run at a test course, so there is no instrument error possibility for instance.

 

As for A-1 vs Aa, Olivier once said that about 1/3 of the 601 production consisted of the latter, so there were definietely a lot of Aa around, and, it appears the Aa was always fitted to /B Jabo variants and the E-7 (not the E-7/N of course, that had 601N).

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Some people claim that making the time limit longer does not reflect the real situation, because pilots do not use notliestung so frequently in RL. but this is not the truth, the real situation is that the pilot will not meet the enemy plane in every sortie. but in game each virtual pilot shoots down someone or get shot down in every mission. In real life a pilot can use notliestung longer if he is in risk, but in BOX you will never get a chance to fight for you life by this way. 1 minute limit is up your engine blows up instantly.

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Hey, I just wanted to say, you guys are doing a terrific job here. I am kind of negatively surprised by how they have artificially undermodeled the German inline engines. So are the guys in my squadron. 1 minute straight vs 5 minutes cannot even be called "inaccurate" or "within tolerance" anymore. :(

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It's not just the German aircraft sir.

 

Fly a P40 and get back to me.

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Shut up you Luftwhiners. :D (joke)

 

I am for no limitations but i have no voice. But it would be nice if we had more realistic relative performances.

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anyone has books of J. Prien and G. Stemmer about Messerschmitt 109 in JG 3 (or other similar books)? - http://www.schifferbooks.com/jagdgeschwader-3-udet-in-world-war-ii-stab-and-i-jg3-in-action-with-the-messerschmitt-bf-109-2673.html

well, i asked about these books, just because there is must be lot of photos,

 

like this photo of Bf 109 F-4 of Walther Hagenah - http://forum.il2sturmovik.ru/uploads/monthly_05_2013/post-36-0-47016400-1369558233.jpg + https://me109.info/display.php?from=site&lang=de&auth=e&name=suchen&fotonummer=6089

 

plus another F-4 from same book (bottom left) - http://forum.il2sturmovik.ru/uploads/monthly_05_2013/post-36-0-10772000-1369395384.jpg

 

(meanwhile, it is F-2? - http://forum.il2sturmovik.ru/uploads/monthly_05_2013/post-36-0-47113000-1369558234.jpg )

 

 

and further i found these photos -

 

Bf 109 F-4 from 6/JG 53 (Comiso 1942) - https://reibert.info/threads/jg53-tuz-pik-jagdgeschwader-53-pik-as.45705/page-6#post-6128680 + http://me109.info/display.php?lang=en&auth=e&name=ergebnis_suche&fotonummer=8903

 

one of swiss Bf 109 F-4's - http://www.squadron.com/Messerschmitt-Bf-109-In-Action-SC-Squadron-Sig-p/ss10243.htm

 

 

plus page from "Flugzeug Classic" №3 2011 - https://forum.il2sturmovik.ru/uploads/monthly_10_2015/post-17024-0-50271500-1444865554.jpg

 

 

and "He 177 А-1 Exerzier-Karte" (April 1943) - http://www.avialogs.com/index.php/en/aircraft/germany/heinkel/he177greif/ldvt2177-a-fi-he-177a-exerzier-karte.html

Edited by bivalov
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and during last 1+ year i found not so much useful photos of Bf 109 G in 1942-1943, so, at this moment i only can state that...

 

 

at first, here is photo of tachometer with 1 (?) minute from "Bf 109 G-5 und G-6 Schusswaffenanlage Bedienungsvorschrift/Wa" (Stand März 1943, Ausgabe April 1943) - http://germancontrolsticks.blogspot.ru/2011/04/messerschmitt-bf-109-g-6.html
 
i.e. just like in "Bf 109 G-2, G-4, G-6 Bedienungsvorschrift-F1" (Stand April 1943, Ausgabe Juni 1943) - http://www.wwiiaircraftperformance.org/me109/BF109_G-2-4-6_Bedienungsvorschrift_June43.pdf

 
and in addition to at least DB 610 A/B with 3 minutes in end of 1943 - http://forum.il2sturmovik.com/topic/33381-db-605a-1-142-ata-wep-duration/page-2?do=findComment&comment=556262


here is photo of Bf 109 G-6 from "Aero Detail 5 Messerschmitt Bf 109G" (p. 64) - https://forum.il2sturmovik.ru/uploads/monthly_02_2016/post-17024-0-60934900-1454571925.png

which dated "1943" here - http://www.bild.bundesarchiv.de/dev06/barchpic/2010/07-13/15/c8/eb/athene-5v9sbn7e8ko1hdwm133t_layout.jpg
 

plus -
 
1) in "Aero Journal Horse-Serie №1" on p. 62 was posted photo from "Bf 109 G-5 Teil 8 D Sonderwaffenanlage Heft 1: 21 cm BR" (may/july 1944) with 5 (?) minutes of 2800 rpm (see below or in journal)

2) one of swiss Bf 109 G-6's from "Squadron-Signal 5543 - Walk Around 43 - Messerschmitt Bf 109G" - https://html1-f.scribdassets.com/13s7a5voow4rugx9/images/35-fd8b53c052.jpg

3) Bf 109 G-6/R3 of Elias Kuehlein - https://forum.il2sturmovik.ru/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1868 + https://me109.info/web.php?lang=de&auth=e&name=ueberlebende-ausgabe&flugzeug=433

4) tachometer FL 20286, which was "Transferred from the U.S. Air Force" - https://airandspace.si.edu/collection-objects/tachometer-german-fl-20286-1

5) description of Bf 109 G-14 of Jakob Vogel - http://109lair.hobbyvista.com/articles/airframes/413601/413601_report.htm

post-17028-0-57412600-1519171244_thumb.png

Edited by bivalov
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It's curious to note that there seems to have been no time limit whilst using MW50 at 1.7-1.8ata, apparently the cooling effect of this system was substantial. Explains why there was a supply for a whole 40 min. 

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It's curious to note that there seems to have been no time limit whilst using MW50 at 1.7-1.8ata, apparently the cooling effect of this system was substantial. Explains why there was a supply for a whole 40 min. 

In DCS the K-4 only can be run a few minutes on full power without MW50. With MW50 pretty much without limit. The cooling effect is indeed hughe there. While I have no clue how accurate that is, the DCS devs are usually quite good with aicraft systems tho.

Edited by DerSheriff
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and during last 1+ year i found not so much useful photos of Bf 109 G, although, there is also have very interesting examples

 

 

at first, here is photo of tachometer with 1 (?) minute from "Bf 109 G-5 und G-6 Schusswaffenanlage Bedienungsvorschrift/Wa" (Stand März 1943, Ausgabe April 1943) - http://germancontrolsticks.blogspot.ru/2011/04/messerschmitt-bf-109-g-6.html

 

i.e. just like in "Bf 109 G-2, G-4, G-6 Bedienungsvorschrift-F1" (Stand April 1943, Ausgabe Juni 1943) - http://www.wwiiaircraftperformance.org/me109/BF109_G-2-4-6_Bedienungsvorschrift_June43.pdf

 

 

and in addition to at least DB 610 A/B with 3 minutes in end of 1943 - http://forum.il2sturmovik.com/topic/33381-db-605a-1-142-ata-wep-duration/page-2?do=findComment&comment=556262

 

 

here is photo of Bf 109 G-6 from "Aero Detail 5 Messerschmitt Bf 109G" (p. 64) - https://forum.il2sturmovik.ru/uploads/monthly_02_2016/post-17024-0-60934900-1454571925.png

 

which was dated "1943" - http://www.bild.bundesarchiv.de/dev06/barchpic/2010/07-13/15/c8/eb/athene-5v9sbn7e8ko1hdwm133t_layout.jpg

 

 

plus -

 

1) in "Aero Journal Horse-Serie №1" on p. 62 was posted photo from "Bf 109 G-5 Teil 8 D Sonderwaffenanlage Heft 1: 21 cm BR" (may/july 1944) with 5 (?) minutes of 2800 rpm (see below or in journal)

 

2) photo of one of swiss Bf 109 G-6's from "Squadron-Signal 5543 - Walk Around 43 - Messerschmitt Bf 109G" - https://html1-f.scribdassets.com/13s7a5voow4rugx9/images/35-fd8b53c052.jpg

 

3) Bf 109 G-6/R3 of Elias Kuehlein - https://forum.il2sturmovik.ru/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=1868 + https://me109.info/web.php?lang=de&auth=e&name=ueberlebende-ausgabe&flugzeug=433

 

4) tachometer FL 20286, which was "Transferred from the U.S. Air Force" - https://airandspace.si.edu/collection-objects/tachometer-german-fl-20286-1

 

5) description of Bf 109 G-14 of Jakob Vogel - http://109lair.hobbyvista.com/articles/airframes/413601/413601_report.htm

 

Good find bivalov.

 

So its looks thats 3 minutes emergency power for 109 F and G is confirmed by historical photos at least.

 

Are devs aware about these?

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In DCS the K-4 only can be run a few minutes on full power without MW50. With MW50 pretty much without limit. The cooling effect is indeed hughe there. While I have no clue how accurate that is, the DCS devs are usually quite good with aicraft systems tho.

 

Makes sense, would've otherwise also been quite an odd idea flying around with 40 min worth of water methanol if you could only use it for a couple min :P

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I think I saw someone say that the devs increased the dive speed of the lagg3 over the "book specified one" on a basis of a recorded account of a single aircraft able to withstand it? 

 

 Its a pity that the LW side of things gets overlooked.

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39 minutes ago, JaffaCake said:

I think I saw someone say 

 

LoL  :biggrin:

 

Cheers, Dakpilot

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5 hours ago, JaffaCake said:

I think I saw someone say that the devs increased the dive speed of the lagg3 over the "book specified one" on a basis of a recorded account of a single aircraft able to withstand it? 

 

Not even close. It was increased by factoring in a margin of safety to what was written in the pilot's manual.

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Does not make much sense, does it? Dive speed has limits in the manual that can be factored in. AFAIK Damage resistance calculation is based mainly on anecdotal accounts by surviving pilots (apart from studying the airframes, systems etc...).

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The LaGG-3 dive speed limit in game is based on a dive test report for a LaGG-3, showing that a LaGG-3 could safely dive to that speed.

 

The margins over the speeds listed in the manual were just a common sense comparison to show that the LaGG-3 is nothing special, all aircraft in game have limits somewhat higher than the limits given in the manuals.

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