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Daimler Benz vs Rolls-Royce

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Joined: 17 Jan 2015
Posts: 5
Location: Scotland

PostPosted: Sat Apr 09, 2016 12:56    Post subject: Daimler Benz vs Rolls-Royce Reply with quote

Dear all,
I am writing a book on the development of the DB600 series
and the Merlin series (its going to be heavily weighted towards
detail on the German engine - I think the superb RR Heritage books
dont need to be copied and reprinted by myself).

This will include alot of technical information, but also will be
featuring a narrative with some of the personalities and
alot of the technical-intelligence done by both side reverse
engineering the others engines during the war.

I have personal contact with Dr Karl Kollmann from Daimler-Benz
AG (the son of Dr Karl Kollmann, just to make life confusing),
and have a great deal of original documentation on his fathers
work on the Benz supercharger.

To give an idea about this, this includes things like compressor
maps for the DB engines and many test results of their
turbo engines (including compressor maps, images of the turbos etc).

Dr Karl Kollmann finished the war as head of the design office
at Daimler-Benz, second only to Fritz Nallinger.

I would be interested in receiving the following information
from yourselves:

1) "Please answer the question about why......XYZ happened"
2) "Please answer the question about why...."XYZ part is shaped
this way"
3) "Please include a drawing of......."
4) "Please also make sure you cover........subject/person"
5) "Please DONT write about XYZ as -AUTHOR X- already did it"

The provisional title is:

"SUPERCHARGED - the declassified story of the secret wartime horsepower race"

This is a difficult proposition as I`m an engine designer by profession,
not a writer. So its going to take a bit of doing, currently about
140page mark, and I`d expect that to double.

Any comments gratefully received.

Calum Douglas
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Joined: 11 Apr 2016
Posts: 2
Location: Sweden

PostPosted: Tue Apr 12, 2016 15:45    Post subject: Reply with quote

Thank you for sharing this information and inviting us to ask questions.

Some of these questions may be outside the scope if the book but I'll ask anyway.

As far as I know Daimler-Benz was created after a merger in 1926.

* What was the status of the aero engine development at the 1918 armistace at Daimler and Benz respectivly. Any secret projects ?

* Did DB have longtime engineers that had worked on aero engines in both world wars ?

* Why didnt Daimler or Benz continue with small aero engine development after the Versailes peace ? Sure big engines were forbidden for a few years but they choose to exit the market altogheter.

* The bigger question is why DB (after 1926) did not enter the aero engine market when the restrictions were lifted ? Junkers and BMW did, and according to the "BMW aero engines" book by Fred Jakobs BMW made good money selling obsolecant engines like BMW VI until 1937. Some boardroom / director / shareholder discusions about this ?

* Reading about Jumo 210/211 and BMW 116/117 (V12, 20 litre)/(V12, 36 litre) there is mention of a "reichluftfarts-ministerium" or "transport goverment board" (I have seen different names and years) that about 1928 or 1930 asked BMW and Junkers to develop a "20 litre class" and a "30 litre class" inverted V12. I think they payed for the developmenmt as well.

What authority issued this program and at what date ? What was the specifications and the reasoning about them ? How much of the development cost did the government pay? Were the engines allowed to be sold to the civialian market or were they military secrets? What were the details of this deal ? Original documents with translations would be awesome.

Was the DB600 part of the same program? DB600 is mentioned under the prototype name F4 and F4B. Did DB ever work on an engine in the "20 litre class" ? Possibly "F3" ? What was F1 and F2 ?

* From what I have been able to guess, DB got back inte the aero-engine business for the profitable military market. Did they consider the civilian market at some point ?

Some questions about specific engines:
* 603 Why go for a master/slave connecting rod ? Was it the right choice ? Was it reliable ? Was the con rod a source of problems ?
* 604 Did it work reliably? Could it be made to work ?
* 608 Enlarged 601 (154mm*164mm) More info would be nice.
* 609 A V16 project. I have seen the bore spec as both 162 and 165 mm. What was it? Did they have a running engine that proved the crank shaft would work. Did they have good reasons to think they could make it work ? What were the specs ? Did they have a special fireing order that limited crankshaft torison problems ?
* The infamous double engines. Ive read they started burning but more in deph information would be nice.

I have seen a long list of "projects" DB600 al the way to DB632. How much work was actually done on these projects ? I suspect some of them were little more than a formalized idea list.

How many engineers did DB have working on aero engines during 1930s ? During the war ?

How was the co-operation between engine makers in peace and during the war? Did RLM demand cooperation/sharing of secrets ? In what way ?

Did the competiton within germany cause changes in DB corporate priorities ? Maybe the succes of Jumo 213 caused DB to invest more in the 603 for example ?

How many engineers would work on a prioritized piston engine project ?
How many craftsmen would be needed to make parts for the prototypes of a prioritized piston project ?
- During the study/planning phase ?
- During the make blueprints for first prototype phase ?
- During debugging phase ?
- During incremental improvements phase ?

Did DB ever consider aircooled engeins ? If so in what configuration ?

How much freedom did DB have to puersue their own ideas vs micromanagement from RLM or Goering himself ? How was this freedom in 1930s compared to wartime ?

Was there different turf-wars inside DB about the direction of aero-engine development ?

What were the background and life of different engine projects ?
600/601/605 How did it get started ? Blessed by RLM.
603 Nallingers skunkwork project ? Never prioritized by RLM ?
604 Bomber B engine. Canceled. Any idionatal data would be awesome. What firing order did they come up with to balance it ?
609 Initiated by DB or RLM ? A very unique and intresting engine, any information would be awesome.

Anecdotes about the RLM proving helpful or incompetent beuractras will add a new intresting dimension to the book.

Did DB get annoyed when Goering/RLM gave Bramo to BMW ? Did DB get something else to keep them happy ?

Well thats a list of things I have wondered about. Some questions might have been answered in german books but it would be valuable for the field with english sources as well.
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Joined: 13 Jul 2003
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Location: Huntsville, Alabama USA

PostPosted: Tue Apr 12, 2016 18:48    Post subject: Reply with quote

That is quite a nice list, dpersson.

One thing I would like to see is discussion of available fuels and how these affected engine design decisions.
Kimble D. McCutcheon
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Joined: 11 Apr 2016
Posts: 2
Location: Sweden

PostPosted: Wed Apr 13, 2016 02:51    Post subject: Reply with quote

Comparing engine to engine is wonderful and a complementary
view would be to compare the technical philosophy of the two
companies. DB strikes me as being more conservative than
RR. RR had projects with sleeve valves, vapor-colong and
two strokes.

I have not seen any such DB projects. Did they experiment
with or consider unconventional valves, two strokes,
barrel engines or diesels ? Maybe they were more conservative
or maybe there were more important things to do after
the war then documenting obscure engine projects ?

RR seem to have been more willing to explore new ideas to the
point of actually trying to build them, with the many X24
variants etc. But without "betting the farm", always
keeping a traditional backup like Kestrel/Merlin/Griffin.

To what degree were these perceived differences true ?
If true, were they part of a long institutional tradition
and/or the result of the current head of engineering
at the companies ? Maybe it was just a matter of the
size of the funding from the government?

I'm also interested in how DB viewed Jumo/BMW/RR products
and their technical culture.

As an example of head of engineering having big influence
I am reminded of having read somewhere about Karl Maybach.
When air-cooling was discussed he said he came out of his
mothers womb water cooled, and that was then end of the

Some specific engine questions
DB-609: Having a 45 degree V16 probably meant the intake
plumbing would take all space inside the narrow V and leave
no room for an engine gun through the prop hub ?

DB-609: Did it keep the master/slave conrods from the 603 ?

DB-609: Did DB expect it to be competitive on the specific weight ?

DB-603: I have read figures about TBOs of 10 to 30 hours.
Was it that horrible ?

DB-604: Considering articulated conrods giving slightly
different piston movements in each bank. Did that cause
every bank to have its unique camshaft profile to match
the particular piston movement? Different ignition timing
because of this ? Maybe they were different but mainly for
'balance reasons instead ?

DB-604: I have read hints about a bigger version of the
135*135 bore/stroke 604 being planned ? Any more data
about this enlarged X24 engine ?

For all engines as much data as possible would be value.
In addition to the normal specs, whats about the length of the
con rods, both main and articulated ? Supercharger diameter
and speed. Bearing types. TBO for different versions ?

As many Power/Height diagrams as possible. I just love
data tables and diagrams. But I think they can serve an
important role for the war gaming community. Important to
make realistic flight simulators etc.

The piston aircraft community is pretty small, but I hope
that computer games can bring in new blood and maybe grow the
size of people doing research and buying books.

I have seen a growth of similar interest in the tank game
community where tank specs are discussed by people who probably
not gotten into it otherwise. Also references to Speilbergers
tank books are made, spreading the technical interest in

Why have needle bearrings in the DB engines ? Did the use
of lower quality "ersatz" lubricants play a role in this ?

Did DB work directly with Rheinmetal or other gun-makers to
solve reliability problems with engine guns in V engines ?

Did RLM instruct DB to focus on engine power and saving on
strategic material even if TBO had to be sacrificed ? How
low could TBO go and still be acceptable to luftwaffe ?
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PostPosted: Wed Apr 27, 2016 10:38    Post subject: feedback Reply with quote

Thankyou to everyone who replied, it was all useful info.

I`ll not attempt to respond to all those suggestions as it will
get unreadable and its not my intention to type the books contents
into this forum ! Smile

However I`d say 50% of whats suggested here I`d already planned
to cover, I can add in another 20% - but due to scope/time limitations
some of the requests here I cannot cover.

Some questions will sadly remain forever un-answered as due to the
time passed, we`re dealing with at best - family members recollections.

Kind Regards
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Joined: 17 Jan 2015
Posts: 5
Location: Scotland

PostPosted: Sat Sep 10, 2016 16:25    Post subject: progress update Reply with quote

Hi Everyone,
The book is coming along quite well, I have about 85,000 words - and
at least one publisher seriously interested. So not bad.

I have started a "blog" type thing about the research I`m finding on
my facebook page (sorry I know thats not everyones cup of tea -
but I dont have time to do anything more universal), but there is
some info on my own website too.



I have been overly sucessful in some areas everyone has asked for - and uncovered almost nothing at all in many others.

Areas I think I`ll be able to make a genuinely totally new historical contribution to:

1) German synthetic fuel types, combustion and detonation testing and the work of the DVL, IG-Farben and similar on fuels. I cant spoil the book too much but I have found several German fuels that I`d never heard of and also got Oppau / DVL Supercharge method performance curves for them.

I think this can significantly help to explain the German fuels problems, and I think Kimble will not be disappointed in the material uncovered.

2) I have a very significant amount of material on the RLM - and how their engine project management systems differed from that used in Britain. I dont think the conclusions will surprise anyone; but should solidify certain rumors.

3) I have obtained a large number of interrogation transcripts of German scientists, engineers and pilots as to "what went wrong and why". Which are all very interesting.

4) The final area which I think I have genuinely new information is on details of many of DB`s mysterious other engines - which were tested and I have obtained power curves for most of them. I have in particular tried to find (and suceeded in finding out alot about the ultimate German projects - the 213J and 603N, including power curves for both.

Unfortunately I have uncovered very little on engines before 1928 - certainly not enough to make a useful new contribution.

I`m also discovering what I`m sure many researchers on this topic
have discovered, which is that in many archives - during moves and so on, "conveniently" the things that go "missing" are always the real lynchpins -
so a few of my wishlist items have gone frustratingly unsolved.

I have also some very useful figures on typical DB time between rebuilds, acceptance test hours / testplans / schedules and also how many engineers they had in each department at Unterturkheim.

I have found some papers on the DB master/slave rod, but ran out
of time to copy them - so that will have to wait until my next trip to the

I`ll hope to maybe meet some of you at the AEHS conference later this month in Ohio.

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Joined: 16 Sep 2003
Posts: 55
Location: Victoria, AUSTRALIA

PostPosted: Mon Oct 17, 2016 22:59    Post subject: DB 609 Reply with quote

Re the detail of this engine, in the book, "Power To Fly" there are TS and LS drawings of the DB 609 which clearly show:

1/ It was a 60 deg Vee, not 45.
2/ It had a cannon tunnel is the Vee.
3/ It had a one-piece crankcase/cylinder block construction
4/ It had side-by-side con rods with plain bearings for the big-ends
5/ It had large diameter, narrow roller bearings for the mains

The drawings are on p152 and 154 of the Setright book.
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