Looking for Bf 109 G Start&Notleistung duration

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As I`ve pointed out on other threads when people have been asking for the "dates" when the power wasnt allowed and what it was all ok again, you can find papers which have the full rating on, which are dated, but be careful about what you imagine this means.

All it actually means, is that a pilot COULD select that power setting at that time, and not be in contravention of the manufacturers guidelines, it does however NOT mean that he could select that setting and that it would actually WORK.

For example: June 18th 1942:



So, if you have in your game that the pilot can select this rating at any date BEFORE this
and not experience an engine failure its all good ?

Not so simple....

Lets go back nearly a YEAR... right back into 1941:



This was all due to the C3 fuel incompatibility with the new 109 F series
rubber "bag fuel tanks" which replaced the previous welded aluminium sheet
metal tanks. It caused a huge spate of engine failures and subsequent crashes.

I`m not suggesting not to bother attempting to add in the dates from the ratings
paperwork, as it does make it "more" accurate, but as Engineman has said,
these ratings varied throughout the war almost continuously, and many times
widespread failures were occurring months before any of the official
"banning" of full ratings were actually published. Sometimes it took a
very long time to work out what was going wrong during the chaos of war.

So I would say try to not get too exact about accuracy as unless you want your
109 or 190 occasionally randomly blowing up for almost no reason apparent to the game-player, your game isn't accurate.

(2nd Nov 1942: Letter from Milch): at the time these engines were both so bad
the mechanics named them the "pig" and "flowerpot"

 
Yew Staff said:
Many thanks E Engineman

D Deleted member 68059 thanks, but I am specifically looking for the duration for the cleared Start&Notleistung starting from mid 1943. I would consider that power rating blocked till then.
Cheers
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As per data from Engineman, I do not think such a definitive thing exists as one bit of paper which tells you the duration for emergency power at all points after the emergency power was gradually reintroduced (it certainly was not reintroduced for ALL planes and engines at once, as the refits for new valves and so on took months, even after they decided upon the solution).

The actual DB papers after June 43 do not give limits, I suspect strongly that the situation after that was so complex, (various engines in various states of refit and so on, etc etc) that it probably depended on the aircraft it was being used in, as each had quite different issues, for example the Bf-109 was only given the oil centrifige very late as it was extremely difficult to fit it, in the small nose cowling. Stuff like He177 got that earlier.

I simply do not think there is, or ever was, a bit of paper saying after THIS date, THIS set of operating circumstances applied to ALL DB605s and whatever aircraft they were in. (maybe it will be found, I know some books reference such a letter, but I`ve never seen it, and from the other records I think if such a letter did exist, it would be covered in a dozen cavets and other conditions, which would likely make it no more accurate than the general conditions we`ve already been discussing).

I can tell you (because I`ve read them) there is no "eureaka" moment in the RLM top level meetings about this, it was a slow process of solution which was very convoluted and time consuming. On many occasions you can read they thought they`d fixed it, and the next month its back to square one. I suspect localised memos went out to certain units as they got these new engines saying they were cleared for such a and such a setting. As Engineman says, you probably need to find something at the local level not a single letter from the RLM saying its all fixed and here are the limits for everything.
 
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Yes, Calum and I are in agreement about the difficult status of the DB 605 engine WRT the power restriction and the restoration of the 2800/1.42 rating. The big difficulty is that the documentation does not seem to be clearly written or completely available. There is no doubt that many engines were built and overhauled with the restricted limitations. It is possible that some restricted engines were overhauled to a higher standard after the main problems were fixed, but the proof is not there, well, I don't have it.
Cheers

Eng
 
E Engineman and D Deleted member 68059
yeah, that is what I thought, too.
I guess many information might also have been lost and are not as completely available as they are for e.g. western allied fighter planes.
thank you both very much for your insight.
Many Thanks
 
As a aside, the technical memo mentioning burned pistons was also translated into Finnish. I recall that it (or a follow-up) memo listed serial numbers with "reinforced pistons" which should at least in theory allow the higher rating.

Perhaps Calum/Engineman have measured data to confirm this, but multiple sources* on ADI suggest that with ADI, the thermal loads imposed are greatly reduced despite higher powers that it might explain why the MW 50 rating allowance was 10 minutes.

*E.g. Maxwell Smith's "Aviation Fuels".
 
Trilisser said:
As a aside, the technical memo mentioning burned pistons was also translated into Finnish. I recall that it (or a follow-up) memo listed serial numbers with "reinforced pistons" which should at least in theory allow the higher rating.
Click to expand...

R.L.M. message GL/C-TT No.1374/42 of 12.6.42 as translated by British Air Intelligence states "In engines with reinforced pistons the danger of their burning through is not so great as in the older version of the piston, but the take-off and emergency output may still not be used.
 
Yes, the text is the same because the Finnish were maintaining their engines in collaboration with their agreements with Germany and issued translated documents. It was only later understood that the real issue with piston failure was more to do with the problems with poor materials for valves, problems with sparkplugs and problems with fuel injectors. The whole development of these engines was complex and the restrictions were a poor result. However, all WW2 engines required huge modifications during their operational use.

Eng
 
My point was that the translation was so exactly the same despite the source being different (RLM message vs. a technical bulletin). The Finnish note does state that it has been translated from a German bulletin (and gives the original title).

In Finnish service the engine was considered to lack durability so much as to make it totally unsuitable for fighter training. Especially harsh dive recoveries stressed it's weak construction and lubrication system.
 

Well, the problems that the DB 605 had are now well understood and accurately described in Callum Douglas' great book TSHR. As the premier fighter in Finnish operation during the period and with short engine life, I would suggest that use of the Bf 109 G for training by Finland was possibly limited to conserve resources for actual Combat operations. However, it would be good if you gave a comprehensive description of all the problems the Finnish Air Force had and what other options they had?

Eng
 
If any one is still interested:
Bisher gesperrte Start- und Notleistung DB 605 kann nach Durchführung des Einfliegens von 10 Stunden entsprechend TAGTTIC 6., Nr. *, lfd. Nr. 705/43, entnommen ist jedoch nur in äussersten Notfällen und keinesfalls länger als drei Minuten zu entnehmen. Voraussetzung ist Vorhandensein des Überdruckventilles auf Schmierstofftank / Aenderung Bf 109G, Nr. 297. Drahtzug für Start- und Notleistung am Ladedruckregler ist einzuhängen und nötigenfalls Ladedruckregler auf 1,42 ata einzuregulieren. [...] Auf Ladedruck- und Drehzahlmesser sind für Notleistung die entsprechende Markierungen anzubringen. Zum Einstellen möglichts Spezialisten heranziehen. F.S. Gen. TT, Abt. G, vom 28.5.1943. betr. Start- und Notleistung DB 605 in Bf 109G is ausser Kraft gesetzt und zu vernichten.'

TMGL Nr. 44 07 019 vom 14.3.1944., S. 49.,
BArch RL 3/1293.
Via M. Baumgartl.

Previously restricted takeoff and emergency power DB 605 can be utilized after completing a run-in of 10 hours according to TAGTTIC 6., No. *, consecutive [lfd. meaning laufend] No. 705/43. However, it should only be taken in extreme emergencies and under no circumstances for longer than three minutes. A prerequisite is the presence of the pressure relief valve on the lubricant tank / Modification Bf 109G, No. 297. The wire rope for takeoff and emergency power on the throttle lever is to be hooked in and if necessary the throttle lever is to be set to 1.42 ata. [...] Markings corresponding to emergency power are to be applied to the boost and RPM indicators. For adjustment, consult specialists if possible. F.S. Gen. TT, Dept. G, dated May 28, 1943, regarding takeoff and emergency power DB 605 in Bf 109G is hereby revoked and to be destroyed.

Installation of the pressure valve starte in Spring of 1943 for individual aircrafts


That would explain why the 3min marking appears in the BF 109 G-5 und G-6 Schusswaffenanlage Bedienvorschrift-Wa (March/April of 1943)


and all manuals for the standard fighter version as of August 1943 do have Start&Notleistung cleared.

as for the Bf 109 G4-R3, G6-R3 Bedienungsvorshrift-Fl Feb 1944. that is a specialized long race recon version with a different oil circuit.
 
Many thanks for copying this instruction via Herr Baumgartl. As always, it would be great to see the documents, but I am certain the given info is correct.
The requirement for the oil tank pressurising valve does seem to fall in-between DB605/Bf109 developments in 1943/44.
Many thanks!

Eng
 
Additional comments.
The Messerschmitt AG overview list of change instructions, page 70 is dated 1. 7. 43 which would be 1st July 1943, NOT 7th January 1943. Also, if I read the attributions correctly, the de-restriction notice is TMGL Nr. 44 07 019 vom 14.3.1944 and it includes the cancellation of a previous restriction dated May 28th 1943.
The Messerschmitt change instruction seems to list all Bf 109 G production up to about July 1943, and is very interesting. It shows the priority of fitting the pressure valve (modification Bf 109 Nr. 297) as "1" and the responsibility of doing the work as being at the units with the aircraft on charge. Also, the "RLM agreed date" for mod Nr. 297 is shown as 24. 3. 43. It would seem that Bf 109 G aircraft built after the listed aircraft would have the modification (or similar) incorporated.
Thanks again!

Eng
 
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special ed said:
A question please. How is the 10 hour brake in time to be achieved?
Click to expand...
Hi,
There is a whole lot of instructions for the break-in of the DB 605. The procedures include test stand running with, normal fuel, Propane/Butane gas and electric drive options! Then there are the in-flight orders. I will try and get a bit of a resume together.

Eng
 
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Thanks. I couldn't believe a new engine, with only a few hours, would make takeoffs and still try to keep a good brake in.
 
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