DB601A-1 = Aa ??

[Shikhov]

Hello peoples!
Really wonder how many famous reseachers are here.
I would like to clear one point re DB601A-1 und DB601Aa performance.
Does the DB601Aa really exist or its data only desinformation for future enimies.
Even many primary sources bacame available now, still serious mentions about two types of DB601A (see Kurfurst comments, but anyway great thanks him for materials):
601A-1 1,3 ata 990 (0)
601Aa 1,35 ata 1045 (0)
This usual look for DB601A began perhabs from W.Green and within 45 years still exist.
It seems Aa is only export marking of usual A-1 and appeared in Swiss and Soviet manuals. What abt another customers ?
Story may be common for Jumo 210Da.
Also this point ageed to 109E V max measured in Germany, UK, Fr, USSR, no one overspeed result.
Mr. Mike Williams in his site mentioned Olivier Lefebre' opinion: Aa = A-1 and
maybe this is final point ?

Igor

[olefebvre]

I never said the Aa was exactly the same as the A-1.
The export customers indeed get the Aa engine but the Russians got a/c with A-1 engines. The Aa documents leaves no doubt it was designed for export since there are absolutly no references to RLM standards within those documents (fuel, oil, doc ref, etc...).
The Aa was based on the A-0 just like the A-1, and used the old kind of supercharger as used on the A-0 but souped up for low alt business. It seems the increased take off rating was of interest for the Luftwaffe afterall since about 25-33% of the produced A/B series engines were of the Aa/Ba kind. Which means that the luft used them as well along with the A-1. Both subtypes being produced over the same period of time.

While there is absolutly no Aa document that i could find with a RLM reference, but i believe it was used most probably on the E-4/B and E-7 variants for which the increased output at take off was most needed.
So far every engine recovered on E-4/B or E-7 crash site seems to have been of the Aa type.

Cheers,
Olivier

[Shikhov]

Dear Olivier,
Thank you for reply and let me exused for misunderstanding. But according to Mr. Mike Williams' site I mean Spitfire Mk.I vs Bf109E ref.106 we can read: "...DB601Aa...not used on LW 109Es ...no german a/c captured were equipped with Aa... " and so on. It was first satisfactory idea abt. A-1/Aa matter I could agreed. But seems I've mistakened. I beg your pardon one more time.
So, could you pleased to indicate a real samples of LW 109Es equipped with Aa engine. Sorry but I don't specially interested in recovered planes before. Please inform if some of them has DB601Aa.
Also you mentioned a Daimler Benz A.G. production figures show 1/4-1/3 Aa share in total 601A quantity. Could you detailed this ?
Acc. to V15A test report seems DB hoped to guarantee 1,35 ata boost and
4700 m full pressure altitude. But finally 601A stayed at 1,30 ata and 1,30 became standard pressure level for next DB engines (601N, E, 605A).
Still thinking if 109E/B equipped by more powered DB601Aa was really made, manual should be appeared, but nothing.

Best regards
Igor

[Kurfürst]

You can read a lot of things on Mike Williams site about Bf 109s, most of it being in very loose contact with the historical reality - to put it mildly, Mike likes to use material in a way to show his own version...

Speaking of the V15a report, he totally misquoutes it, claiming that it was operating above the limit - the original is quite clearly stating the engine was some 40 hp down on power (951ps developed), and they even give corrected curves for the nominal guarateed output but that one is ignored.

You can read the full report here : http://www.kurfurst.bravehost.com/

Same for the comments on 109E/N versions 'towards the end of the battle' - it's just totally untrue, they were there from before the Battle and so on, just one example. Similiarly it's claimed the 1-min ratings were not cleared until mid-1942 for the DB 601, on the basis of a strange logic that a mid-1942 601 manual shows them, and even if manuals from `39 and `40 were that list the 1.40/1.45 ata rating present were shown to both Mike and Neil, they just don't care about it. The 109G and 109K articles are even worser, and damaging as they create and spread new myths and misconceptions instead of clearing them up (for which they have the proper material available).

If I were you, I'd quickly forget everything I read in those three articles. It's quite a good site as far as the primary source collection goes, but otherwise just far too biased and manipulative. Qoutes from Olivier are only interesting for them as long as they help pushing the agenda.

Sorry for the rant, but the sooner you see through it the better.

DB 60x ratings from available material :

601A-1 : 1.30/1.40 ata
601Aa : 1.35/1.45
601 N : 1.35ata (higher was planned but not reached)
601 E : 1.3 ata, then 1.42ata (appears cleared start 1942)
605 A : 1.3ata, then 1.42ata (appears cleared Sept/Oct 1943)
605AM/ASM : 1.7ata, from Q1 1944
605DM : 1.75ata mid-1944

605DB : 1.8 ata from fall 1944
and (convertible engines)
605DC : 1.8ata, then 1.98ata from Feb/March 1945.

[markjsheppard]

Shikov

Oliver knows this but is probably too polite to make reference to the article.

Bf109E-7 W.Nr3523 of 5./JG5 recovered from Northern Russia in 2004/5 carried a DB601Aa

Text from the article

On 4th April 1942 at 09.05hrs four Bf109’s of 5./JG5 were tasked with flying escort for a Bf110 over the Front. At the same time, four Hawker Hurricanes from 2 GIAP VVS SF with Soviet pilots SLt Pokrovskiy, Mozerov, Orlov and Leshenko were patrolling SU-Quadrant 5880-5882. It was during this patrol that they observed four Bf109's and a Bf110. In the ensuing combat, SLt Pokrovskiy attacked a Bf109E and observed hits to the engine. He recorded the Bf109 as force landing in SU-Qu 4276.

DB601 A
W.Nr11120
Werke 90 Berlin Marienfelde
Top casting 601-102-001b also 3205-4
Date casting on the block of 14.4.39

The is a DB601Aa not a standard A-1 engine, it's part of lot of 1168
DB601Aa/Ba engines running in the 10500-11500 block built from mid 38 to
late 39/early 40.

I also know of one other as well with a DB601Aa

Hope this helps

regards

MS

[olefebvre]

Thanks a lot Mark
i was actually looking for the aeroplane issue, having stored them recently in an unamed box (stupid me !) i had some trouble finding them back. Indeed i did not remember the exact details pertaining to this E-7.

Cheers,
Olivier

[Kutscha]

To be fair, Kurfurst's site is not exactly forcoming with truths either, for he also has an agenda, the 109 was the greastest fighter produced during WW2, and he has a very BIG hate on for Mike Williams and the Spitfire.

Mike can't win with Kurfurst as when he does make changes, Kurfurst still slanders him > Mike is dammed if he doesn't and dammed if he does.

There is much supposition in his 1.98ata K-4 article even leaving out the German notes questioning why 1.98 should be implimented even though the airframes were of such poor quality. He only shows that 1.98 was cleared for use, not that it ever was for the whole 'penny pocket' number of a/c he shows (maybe a handful were) > a mix of K-4s and G a/c, and only 56% operational.

In the 109E flight comparisons, it mentions that the Spits and Hurries flown were 2 pitch props though in fact when the Spit and Hurrie met the 109Es during BoB they were flying CSP props and using 100pn fuel.

Just to balance Kurfurst's rant.

[Kurfürst]

Originally Posted by markjsheppard

The is a DB601Aa not a standard A-1 engine, it's part of lot of 1168
DB601Aa/Ba engines running in the 10500-11500 block built from mid 38 to
late 39/early 40.

I also know of one other as well with a DB601Aa

Hope this helps

regards

MS

Hi Mark,

thanks for sharing the information, it was another piece in the puzzle. But, I am not sure if I got the above right, do you mean the Aa was not produced seperately, but it was made up from modified engines from the DB 601A production blocks? Is this 1168 number the total production or just within the mentioned production block?

[Shikhov]

Thanks a lot especially to Mark & Kurfurst for very interesting info.

But seems too early to make a final conclusion what was the 601Aa.
I'm completely satisfied of 601Aa installation on Bf109E-7 detailed example.
Quite strange plane - used Arado E-1 airframe (3380-3664 block) and equipped with rare enough Aa engine produced 3 years before.
Great example, but may be exist some more?

As far as I understand 1168 is the total Aa/Ba number were produced. Some of them were installed on Swiss and Jugoslavian Emils (153), may be some Do215B were also equipped. Abt. 1000 of rest DB601Aa were on LW hands.
Therefore a figure apeared 1000/4000 E = ~ 1/4 (like Olivier already showed).

Many thanks to Kurfurst for work and new documents - DASA sheets for DB601A-0, A-1, Aa, N. But new question was born - when tables was printed ? It seems in same time no later then mid of 1939.
Please compare with Auszuege aus Fl.datenblatt Bf109E-1, E-3 nach L.Dv.556/3 powercurves (p.22) and Tabelle.
DB601A in Dec.1939 in their final condition was enough different as if for 1937.

From another side as we can see DB601Aa really developed since 1936 and therefore no matter for auslandisch version of A-1 can't be at the time.

Paid attantion for more point:
DB601N offer too little performance growth compare with DB601Aa for
30-min settings:
Aa at 1,27 ata 1050 hp (4100 m) in manuals for foreign cust. 1025 (4200 m)
N at 1,35 ata 1050 hp (4800 - 4900 m)
I can't see difference and any reason for using highly expensive (5 times) and available in small quantity at the time 100 octane C-fuel if LW has on hands so powerfull and reliable engine as DB601Aa.

Seems something wrong in this story.

All the best.

Igor.

[olefebvre]

Originally Posted by Kurfürst

Hi Mark,

thanks for sharing the information, it was another piece in the puzzle. But, I am not sure if I got the above right, do you mean the Aa was not produced seperately, but it was made up from modified engines from the DB 601A production blocks? Is this 1168 number the total production or just within the mentioned production block?

It's a rough estimation of the wknr-range i sent to Mark, in fact the block began below 10500 but contained Versuch engine and possibly some A-0 as well.
There were several other production block.

This discussion reminds me of something i read not too long away