Documentation of 2000HP Bf 109s in 1945

[Kurfürst]

Note : Both Bf 109 G-10 and K-4 used the same type(s) of engines, namely :

DB 605DM
DB 605 DB/DC. The latter could be converted into each other, 605DB running on 87 octane 'B-4' fuel for 1.8ata and 1800/1850 PS at SL, 1600PS at 6km, as opposed the DC`s maximal boost of 1.98ata with 96 octane 'C-3' fuel, for 2000 PS at SL and 1800 at 4.9km, both achieved with the built-in MW 50 injection.

The output of the DB/DC engines were the same above 6000m, under which the DC was more power, if at higher boost.


Summary of the clearance 1.98ata/2000 HP for the DB 605DC and the Bf 109G-10/K-4 story - so far :



Early troubles.

So far we seem to know DB cleared the 1.98ata rating somewhere before Jan 1945, and released it to the troops and Gen Galland, probably in december 1944 : the first known, being the third edition already, DB 605 DB/DC manual was issued on the 5th December 1944, and already noted 1.98ata.

Furthermore, referecences to 1.98ata were made in various docs from December 1944 :

 

The clearance of 1.98ata p*ssed some guys at Rechlin out, since several tests done with 1.98ata in early January - such as one that tested four different VDM airscrews - showed the engines failed at the rating, to which DB replied to that their previous test runs at 1.98ata were positive.

It was agreed in mid-January, 1945, to test the rating at 'Gruppe 2/11' before released to troops, along with 1.8 and 1.9ata ratings :

"Nach Lage der Dinge wird denn festgelegt, dass vorläufig die Erprobung des Ladedruckes 1,98 ata nur bei der Gruppe 2/11 durchgeführt werden darf, und dass im übrigen nur die bereits angelaufenen Erprobungen mit 1,9 ata zu Ende geführt werden dürfen bis die entsprechenden Motoren ausgefallen sind. Der Nachschub für diese Motoren darf dann nur mit Motoren mit Einstellung 1,8 ata Ladedruck erfolgen. Bei Nichtbeachtung dieses Befehls wird strenge Bestrafung angedroht. Die Genehemigung zur Einstellung 1,98 ata darf ausschliesslich nur durch die Abtlg. VI des Generalstabes erteilt werden.

Seitens der Herren das Che*****. wird vorgeschlagen, evtl. auch einzelnen Aufklärer mit dem Ladedruck 1,98 ata auszurüsten. Eine Entscheidung hierüber ist jedoch nicht gafällt worden.

Zur thermischen Entlastung der mit 1,98 ata und 1,90 ata eingestellten Motoren wird festgelegt, dass auch diese das spätgestellte Zündprogramm erhalten. Somit werden also all Motoren, die mit der sogenannten Sondernotleistung geflogen werden, auf die späte Zündung umgestellt."


Translation :



"After the delays in the matter, it has been laid down, that testing of 1.98ata manifold pressure is foreseen to be proceeded with only with the Gruppe 2/11, otherwise only the already initiated tests in process with 1.9ata manifold pressure are to be completed,  until the the said  engines fail. The replacements for these engines should be with the 1.8ata setup only. Not following this order will result in severe punishment. Permission for adjusting for 1.98ata can only be given in cooperation with Department VI. of the General Staff.

On behalf of the Chief Engineer`s men it has been presented, that it may be possible to equip single fighter-recons to 1.98ata manifold presure. Decision has not been taken on this yet.

Delayed ignition is to be used with engines at 1.9ata and 1.98ata setups, as a result of the termal load that had been observed with them. Therefore all engines, that are flown with the abovementioned Sondernotleistungs, are to be set to delayed ignition."

See : Niderschrift Nr. 6730 Daimler-Benz AG,  Sektor Entwicklung. 20.1.45



Butch2k says the 1.98ata clearance came in late February, after the trials were successfull, but there was some delay, probably due to finding the correct spark plugs etc.

It is also known that a maintaince document was issued at that time, namely Reparatur-Anweisung 2. Nachtrag Nr. 191/345 from des Reichministers für Rüstung und Kriegproduktion, in 14 March 1945 which tells the details of converting the 1.8ata capabe 605DB into the 1.98ata capable DC version.

Moreover this document tells that "C-3 fuel is available for use in unreduced quality", as opposed to B-4:

"Sämtliche Änderungen sind durch die Forderung bedingt, für die leistungsgesteigerten Motoren auch B4 Kraftstoff minderer Qualität ohne Gefahr verwenden zu können. Da kraftstoff C3 in unverminderter Qualität zur Verfügung steht, werden Motoren 605 ASC und 605 DC, falls sie in dieser Ausführung aufgebaut werden, unverändert wie bisher abgegeben;"



... which makes claims about specific shortage of C-3 fuel, that was required for 1.98ata operation, doubtful, C-3 was appearantly not any more on short supply than any other fuel in 1945.

Furthermore, it is proven that C-3 was not some kind of ultra-rare fuel curiosity, but a major volume of aviation produced in Germany in the 2nd half of the war.

From the "TECHNICAL REPORT NO. 145-45, MANUFACTURE OF AVIATION GASOLINE IN GERMANY, 2. Supply and Composition of Aviation Gasolines, "prepeared by the U.S. Naval Mission to Germany after the surrender. The original can be found at the Fishcer-Tropsch archives :

http://www.fischer-tropsch.org/primary_doc..._145_45_toc.htm

http://www.fischer-tropsch.org/primary_doc...20and%20sources.


"(B) Composition and Specifications

There were two (2) grades of aviation gasoline produced in volume in Germany one the B-4 or blue grade and the other the C-3 or green grade. Both grades were loaded with the equivalent of 4.35 cubic centimeters tetraethyl lead per gallon. The B-4 grade was simply a fraction of the gasoline product from coal and coal tar hydrogenation. It contained normally 10 to 15 percent volume aromatics, 45 percent volume naphthenes, and the remainder paraffins. The octane number was 89 by a measurement corresponding to the C.F.R. motor method. The C-3 grade was a mixture of 10 to 15 percent volume of synthetic isoparaffins (alkylates and isooctanes) and 85 percent of an aromatized base stock produced by hydroforming types of operation on coal and coal tar hydrogenation gasolines. The C-3 grade was permitted to contain not more than 45 percent volume aromatics. This aromatic limitation sometimes required that the base stock component include some diluents other than the aromatic fraction, which could then be balanced if necessary by the inclusion of slightly more isoparaffin. (The C-3 grade corresponded roughly to the U. S. grade 130 gasoline, although the octane number of C-3 was specified to be only 95 and its lean mixture performance was somewhat poorer.)

The components of the two grades were therefore simple and few in number. The isoparaffins were produced by standard, well known methods and there was nothing abnormal found in their compositions. The base stocks were fractionated to and points of 300 to 320 degrees Fahrenheit. No normal isopentane separation was carried out and the pentane and butane contents were adjusted simply for vapor pressure control. Small amounts of specially synthesized aromatic compounds were included from time to time but no regular large scale use of such materials was practiced. No aromatic olefines or other special additives were used.

Oxidation inhibitors were not used in the regular blended aviation gasolines. It will be seen that the components were in general of such nature that addition inhibition should not have been necessary. Lead depositions from fuels was an operating problem, however, but no inhibitors were used for its prevention. This lead instability was believed to be related to aromatic content and fear of lead deposits was a reason for the limitation of the aromatic contents of the two grades.

The relative volumes of production of the two grades cannot be accurately given, but in the last war years the major volume, perhaps two-thirds (2/3) of this total has the C-3 grade. Every effort was being made toward the end of the war to increase isoparaffin production so that C-3 volume could be increased for fighter plane use. The isoparaffin usage in that grade had already been cut to a minimum."

Some details of the actual supplies of C-3 fuel to the Bf 109 units in 1945 :

The following relates to the use of C-3 fuel by the Axis-Italian air force in the last stages of the war. I guess they were not preferred over genuie Luftwaffe units in being supplied with high octane fuel.

Via the Hungarian edition of :
Beale-D`Amico-Valentini : "Air War Italy, 1944-45: The Axis Air Forces from the Liberation of Rome to the Surrender"
Airlife Publishing, Ltd. (January, 1996) ISBN: 1853102520

     


Aircrafts on hand,the Order of Battle of the ANR (the Axis-allied northern italian airforce) during 22nd April 1945 :

Bf 109s
7 x G-6s
27 x G-14s
39 x G-10
3 x K-4s
2 x G-12 trainers

Futher 12 S.79 transports, I take these operated on B-4.

[Kurfürst]

-continued-

As seen, the most important engine was the DB 605D in the 109K and G-10, developing 1850 PS w. B-4 fuel and 2000 HP w. C-3 fuel.

The DB 605 A and AM engines of the G-6/G-14 could run on either fuel, but the output would remain the same.

The fuel stocks were as the following during the same period, during April 1945, and suggest that the primary fuel used by the Italian 109s was C-3.

 

It`s doubtful that the Italians would enjoy some kind of 'special treatment' and priority in being supplied with high quality fuel over the own Luftwaffe units.


Introduction of 1.98ata into service occured during March 1945 :


Orders issued to units to increase boost pressure to 1.98ata, according to a classified order dated 20th March 1945 from the LW high command (OKL, Lw.-Führüngstab, Nr. 937/45 gKdos.(op) 20.03.45) :

http://www.onpoi.net/ah/pics/users/715_1126475124_p43.jpg http://www.onpoi.net/ah/pics/users/715_1126475218_p45.jpg
via :
Fritz X. Kober - Jakob Maria Mathmann : The Messerschmitt Bf 109 Vol.2. Schiffer Publishing, 1996.

"The development in the equipment status of day fighter units is based on the standard types laid down in the emergency program and anticipates :

 

for Bf 109 units    : K-4

for FW 190 units : D-9, D-12 with changeover to Ta 152 H and C

 

The arrival of the Ta 152 and it`s assignment to FW 190 units will result in an improvement in the equipment status of these units.

Essentially Bf 109 development will conclude with the K-4 an will inevitably lead to the conversion of Bf 109 units - those not scheduled for disbandment - to TL (jet fighters). Homogeneity of the equipment is to be strived for, combination of similar types is temporary and to be accepted based on levels of production."
 

The proposed changes to units equipped with Bf 109 were as follows :

 

OKL, Lw.-Führüngstab, Nr. 937/45 gKdos.(op) 20.03.45
 
No. Unit Present type Convert to Notes
1. III./ JG 1 Bf 109 G-10 He 162 (April/May) -
2.  II. / JG Bf 109 G-10 K-4 when deliveries permit -
3. III. / JG 3 Bf 109 K-4 no change -
4. III. / JG 4 Bf 109 K-4 no change -
5. IV. / JG 4 Bf 109 K-4 K-4 -
6. III. / JG 5 Bf 109 G-14 K-4 when deliveries permit -
7. IV. / JG 5 Bf 109 G-14 K-4 when deliveries permit -
8. III. / JG 6 Bf 109 G-14/AS K-4 when deliveries permit -
9. II. / JG 11 Bf 109 G-10 K-4 when deliveries permit -
10. I. / JG 27 Bf 109 K-4 no change boost increase to 1.98 ata
11. II. / JG 27 Bf 109 G-10 K-4 when deliveries permit -
12. III. / JG 27 Bf 109 G-10 no change boost increase to 1.98 ata
13. I. / JG 51 Bf 109 G-14 K-4 when deliveries permit -
14. III. / JG 51 Bf 109 G-14 K-4 when deliveries permit -
15. IV. / JG 51 Bf 109 G-14 K-4 when deliveries permit -
16. II. / JG 52 Bf 109 G-14/U4 K-4 when deliveries permit -
17. III. / JG 52 Bf 109 G-14 K-4 when deliveries permit -
18. II. / JG 53 Bf 109 K-4 no change -
19. III. / JG 53 Bf 109 K-4 no change boost increase to 1.98 ata
20. IV. / JG 53 Bf 109 K-4 no change boost increase to 1.98 ata
21. I. / JG 77 Bf 109 G-14/U4 K-4 when deliveries permit -
22. II. / JG 77 Bf 109 G-10 K-4 when deliveries permit -
23. III. / JG 77 Bf 109 G-10 K-4 when deliveries permit -
24. III. / JG 300 Bf 109 G-10/R6 via K-4 to Me 262 planned, deadline
25. IV. / JG 300 Bf 109 G-10/R6 via K-4 to Me 262 -
26. I. / KG(J) 6  Bf 109 G-10/R6 K-4/R6 when deliveries permit -
27. II. / KG(J) 6  Bf 109 K-4 K-4/R6 when deliveries permit -
30. I. / KG(J) 27 Bf 109 G-10/R6 K-4/R6 when deliveries permit -
31. I. / KG(J) 55 Bf 109 G-10/R6 - -
32. II. / KG(J) 55 Bf 109 K-4 - to industrial defense
33. Ist Italian FG Bf 109 G-10 K-4 when deliveries permit -
34. IInd Italian FG Bf 109 G-10 K-4 when deliveries permit -
35. IIIrd Italian FG Bf 109 G-10 K-4 when deliveries permit -

FROM
Fritz X. Kober - Jakob Maria Mathmann : The Messerschmitt Bf 109 Vol.2. Schiffer Publishing, 1996.  English edition.

This order notes in relation of I./JG 27, III./JG 27, III./JG 53, IV./JG 53 to increase the maximum boost pressures to 1,98 ata manifold pressure. It is not known if and how many units had converted to 1,98ata before that order came, but it should be noted these units, in particular III./JG 27, III./JG 53 and IV./JG 53 were the major users of the Bf 109 K-4 in the Lufwaffe.

It is also known these were the Bf 109 units in 1945 that stayed in the West and continued to perform actions against the Western Allies, as opposed to the most of the Jagdwaffe that tied to slow the down the Red advance in the east.

The four Wings/Gruppes tasked to increase boost pressure to 1.98ata could still muster considerable strenght - and basically they were the only units remaining on the Western front in the last months.



Overview of unit strenghts for the units that used 1,98ata. As per 9th April 1945.
Source : Alfred Price : The Last year of the Luftwaffe

Unit - On hand - Servicable

I./JG 27 - 29 - 13
III./JG 27 -  19 - 15
III./JG 53 - 40 - 24
IV./JG 53 - 54 - 27
---------------------
Total : 142 on hand, out of which 79 is servicable at the given date


Picture of Bf 109K Werknummer 334 210, taken in 1945 :

 


Thus ends the sermon

[Squire]

It seems like many other a/c types that the 109K-4 and 109G-10 had several varients (for lack of a better term), used during the war. That some flew at 1.98 ata I dont think is in question, but rather what type would best be representative in the game of a typical version.

Like most ac modelled in AH, its not going to get 3 different varients of one type each representing a specific fuel and engine type that saw service. Its unlikely we will ever see that.

Personally I dont think that 150hp would make much of a difference either way, in any case, for all the debate about it .

I think the 109K-4 running at 1.98 ata is equivelant in game terms to a Spitfire XIV at 25 lbs boost. They both represent the "absolute best possible" wartime varients of each type.

As it is I think we will probably see a 1.8 ata 109K-4 and a +21 lb boost Spitfire XIV in AH.

...Plus a 100 octane Tempest, as opposed to a 150 octane version.

[MiloMorai]

What unit is the 109 from, in the photo?

The four Wings/Gruppes tasked to increase boost pressure to 1.98ata could still muster considerable strenght - and basically they were the only units remaining on the Western front in the last months.

You mean 109 units, right?

56% sevicability of the under strength Gruppen is considerable strength? If you say so.

[Crumpp]

It seems like many other a/c types that the 109K-4 and 109G-10 had several varients (for lack of a better term), used during the war. That some flew at 1.98 ata I dont think is in question, but rather what type would best be representative in the game of a typical version.

Totally agree Squire.

To add to that:

If you are going to include things like boost pressures that were cleared only in the last few weeks of the war then it must be done across the board for game balance.  I am speaking about all aircraft, not just the 109, Spitfire, or whatever.  Otherwise you will have 1944 aircraft flying against 1945 variants.

Additionally all aircraft have a rather wide range of performance in reality.  Production aircraft vary based on percentage which the manufacturer guarentees.  

Where we get into trouble is trying to nail this performance down to an "exact" value.  Airplanes simply do not work that way.  Especially when the extreme's of these percentages are modeled and then mismatched.  To put it another way, it is not representative to take the high value from one aircraft and match it against the low value for it's opponent.

IMHO, this does not need to be a bad thing.  It gives gamemakers a rather large swath of "realistic" performance and the ability to model a balanced game enviroment.

All the best,

Crumpp

[Guppy35]

If that's what the 109s topped out at, so be it, but then you better not complain about Spit LFIX/XVIs with +25 boost either

[parin]

What if we were to have a fuel option when selecting our aircraft and Perk the higher octane!!

[Kurfürst]

Originally posted by Squire
I think the 109K-4 running at 1.98 ata is equivelant in game terms to a Spitfire XIV at 25 lbs boost. They both represent the "absolute best possible" wartime varients of each type.

As it is I think we will probably see a 1.8 ata 109K-4 and a +21 lb boost Spitfire XIV in AH.

Not really, the 1.98ata 109K-4 is equaivalent of the +21 lbs boost Spit XIV, for simply +25 was never cleared for the Spit XIV`s engine. From what I`ve seen, the first mentioning of +21 lbs XIVs facing enemy fighters is from March 1945, that`s the earliest documented date, but maybe two months before in January. Coincidently, a 109K wing was also using 1.98ata for operational trials in January ('Gruppe 2/11', I suppose II/JG11, didn`t check).

A +25 lbs XIV`s equivalent would be the 2.3ata 109K at around 2300 PS, as both were strongly wanted but did not make it until the wars end.

Besides.... the 1.8ata version should be with the G-10 or G-14/AS imho, for their performance is very similiar.


Guppy, nobody says no to +25lbs IXs... they saw service, in fact far more service than XIVs, low or high boosted. Add to that the +25lbs IX is a perfect match for the G-14 in both timeframe and performance.

[Squire]

Spit XIV (and other fighters, some USAAF) were using 150 octane to chase V-1s from July 44 (that was the original use for the fuel), and 2nd TAF was cleared for 150 octane in general use from @November 1944.

150 Octane XIVs ran at 25 lbs boost, as did the LF IXs.

"Late Mark Spitfire Aces" Alfred Price page 67: "For these operations some Spit XIVs had thier engines modified to run on 150 octane". - Reffering to the anti V-1 missions.

http://www.spitfireperformance.com/spit14speedns.jpg

...however, the inclusion of 150 octane "versions" is unlikely to represent "typical varients".

That was my point.

As for the 1.98 ata 109K-4 you quote various sources, some of which are contradictory. I really have no idea when 1.98 was the "norm" for 109K-4s. I will leave that to those who have more data than myself.

[MiloMorai]

Originally posted by Kurfürst
Coincidently, a 109K wing was also using 1.98ata for operational trials in January ('Gruppe 2/11', I suppose II/JG11, didn`t check).

Nice spin you put on to try to make like there was a large number of K-4s when even in your own article you say only 11 K-4s + 38 G-14s in JG11. Eleven a/c is only a staffel not a Gruppen(wing). A attempt at twisting data.  

Didn't check. How forgetful you are when it is convient for you. You participated in theads that discissed whether it was II. or 2.

Also, nice spin you put for C3 fuel. So how much C3 did the Italians receive after that initial delivery in Dec. 44 when the fuel shortage was not as critical? And, what use did the Italians have for J-2???

[Kev367th]

Originally posted by MiloMorai
Nice spin you put on to try to make like there was a large number of K-4s when even in your own article you say only 11 K-4s + 38 G-14s in JG11. Eleven a/c is only a staffel not a Gruppen(wing). A attempt at twisting data.  

Didn't check. How forgetful you are when it is convient for you. You participated in theads that discissed whether it was II. or 2.

Also, nice spin you put for C3 fuel. So how much C3 did the Italians receive after that initial delivery in Dec. 44 when the fuel shortage was not as critical? And, what use did the Italians have for J-2???

Actually I think he means the 109-G10s being used for operational testing.

Trying at the moment to get a document enlarged and cleared up that is dated 1 day before OKL, Lw.-Führüngstab, Nr. 937/45 gKdos.(op) 20.03.45 thats shows LW units and the fuel they are using.
All 4 K4 untis are listed as using B4 which incidently should finally clear up the "it is not known how many or if K4 units changed prior to the order". Obvioulsy they DIDN'T.

Nothing new in his original post, same old rehash of suppositions, and assumptions.

Actaully how many of the directives from
OKL, Lw.-Führüngstab, Nr. 937/45 gKdos.(op) 20.03.45
actually were carried out?

Plus why not mention that Butch who says February clearance for ata1.98 also mentions C3 fuel shortage in the same paragraph? Nice how you pick and choose from the same source.

[Squire]

And just to clarify when I compared the Spit XIV at 25lbs and the 109K-4 at 1.98 ata I was not making a direct comparison regarding the engine hp output. I was simply saying that both those a/c represent an improvement over the initial types that were issued, and that "at some later point..." they got the extra hp, through better fuel, and that the onus is on us to illustrate why either should be modelled as the "standard" in the game.

[Karnak]

Can you show some documentation about the +25lbs in the Spit XIV?  All I have ever seen for that is a calculated sea level speed of 390mph.  So far as I know the Spit XIV never exceeded +21lbs boost, at least not during the war.

[Kev367th]

It didn't exceed 21lbs during the war, but it was tested up to 25lbs boost (2400+ HP!!!).

[Squire]

Well if the +21 lbs was achieved on 100/130, I cant see them putting 150 into in to run at the same boost.

My book could be wrong, but it states a speed of 400 mph at 2000 feet for XIVs modded to run on 150 gas for anti V-1 missions.

Unless the 150 stuff was only given to the IXs and P-51s. You guys tell me.

EDIT: I realised im in danger of hijacking the topic here, so lets drop this and start another thread on that if you have any more info, the thread was re 109K-4s at 1.98 ata.