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Old 12th May 2019, 20:56
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Re: Published Accounts of the Fw 200 C-3 – A Critique on Water-Methanol Injection

Part 3 of 5 Explorations, Level Two, A second Finding

Returning briefly to the baseline text, Green's 'Warplanes of the Third Reich', on page 513 in the section on the Ju 352 are the intriguing words on operating with the Bramo 323 R-2 “an auxiliary fuel system was used to supply C3 fuel (96 octane) instead of the normal B4 (87 octane), resulting in 1,200 h.p. for take-off and emergency use.”

In fact, this feature was not unique to the Bramo 323 R-2 installation in the Ju 352 but would seem to have been generic to all 323 R-2 installations.
In the fuel system for the Bramo-engined Fw 200 C-3 (and so all subsequent sub-types and variants), each wing contained two small fuel tanks outboard of two larger fuel tanks in the inner wing. Each of the smaller tanks had a standard capacity of 260 litres. In the Bedienvorschrift-Fl for the Fw200 C3 these smaller, outer tanks are described as Startbehälter. (The larger inner wing tanks are each 380 litres and are described as Reisebehälter.)
The Bedienvorschrift-Fl for the Fw200 C-3 clearly mandates that all tanks be filled with Fliegerbenzin A2, Oktanzahl 87. However, the equivalent document for the Fw200 C-3/U4, the initial VLR Fernaufklärer variant of the Fw 200 C that was built in an unbroken sequence of 25 examples from W.Nr. 0070 to 0094, includes these additional words in the engine section “Startleistung mit Krafstoff Oktan 100 4 X 1100 PS = 4400 PS.” Also included in the text is this statement “Für den Start wird aus den Startbehältern Kraftstoff mit 100 Oktan und für den Reiseflug A 2 Treibstoff mit 87 Oktan verwendet.” ("For the take-off, 100 octane fuel is used from the start tanks and 87 octane A 2 fuel is used for cruising.")
[I am much indebted to the public sharing of this document at http://www.deutscheluftwaffe.com/arc.../Dokumente.htm]
From this we can conclude that as combat loads increased, and as C3 fuel became more widely available (which was not the case when Fw 200 C-3 was introduced to service in late-1940) this nominally 100 octane fuel was used in the wing starter tanks to boost take-off power.
This may have only begun with the Fw200 C-3/U4 variant, indeed this facility may have been limited only to use with the Fw200 C-3/U4, since Ladeplan 8-200 000-7043 b of 15-Jul-42 (reproduced on p.99 of Nowarra) specified B4 fuel for ALL tanks of the following Fw 200 C-4 sub-type.
The use of C3 fuel from the Startbehälter increased the take-off power of each 323 R-2 engine from 1,000 PS to 1,100 PS. (Note, however, this is still only half the increase to 1,200 hp that was quoted by Green above.)

So the water-methanol fabrication does have a second and larger grain of truth in that the Bramo 323 R-2 installation specified by the RLM had always included provision for the possible use of a higher grade fuel for take-off.

Taking a step back for a moment, this is a remarkable coda to the story of the Bramo 323 in Luftwaffe service. By lineage, the Bramo 323 was a very old engine design indeed, having its origins in the Bristol Jupiter of the 1920s. When it came to the choice of what engines should be used to power the last generation of Do 17s in 1936/7 the Bramo 323 was selected for the bomber Do 17 Z versions. However, the 323 was simply too thirsty to meet the range requirements of the recce version and instead the BMW 132 was chosen for the Do 17 P. (In parallel the earlier versions of the Fw 200 also used a version of the BMW 132, the BMW 132 H-1 “Schnellwechseltreibwerk”, a 132 sub-type that was available for civil commercial export.)
So perhaps the most remarkable aspect of this tale is that an engine design with too poor a specific fuel consumption to be fitted to a strategic recce aircraft in 1936/40 was transformed by the addition of a Kommandogerät into the supremely useful and economical engine of a maritime patrol bomber and recce aircraft that routinely flew sorties in excess of twelve hours.

There are several loose-ends here that would be interesting to cooperatively explore further:

What other citations from the Green interpretation can be traced in German and English sources published before 1970? (Just now my copies of Green's 'Famous Bombers of the Second World War' and the Kens+Nowarra 'Die deutschen Flugzeuge 1933-1945' volume from the 1960's are in boxes somewhere and I know not which.)

Might it be possible to trace the source that Green used as evidence for his water-methanol statements? (What happened to Green's papers after his death?)

Could a poisoned source have been involved? At least one confirmed 'poisoned' source has been traced. This is for the He 219: an undated, unreferenced typed document packed with fantastical details. (See the four-page 'Entwicklung der He 219 Baureihen' reproduced in full across pages 42 & 43 in Nowarra: "UHU" - He 219, Band 73, Podzun-Pallas 1982.) The account of the He 115 also shows traces of a poisoned source having been used: too many specious details that do not stack up with what has subsequently come to light.

Are there some broader lessons-learnt here? A few fairly obvious points suggest themselves:
If the statement is about technology and the known use of this technology dates to a much later period, then the statement needs to be double-checked. [Was this usage only in engine bench testing or restricted to trials aircraft or documented as a very limited initial release? What hard contemporary evidence is there for actual unit service use at the earlier date? Literally thousands of people were involved in building the BMW 323R-2 at BMW Zühlsdorf, or maintaining and flying the aircraft fitted with these engines in Luftwaffe and French post-war service. Someone would have been able to offer something relevant.]

If the statement covers something that can be checked in the Jane's AWA 1945-46 edition and there is no evidence in AWA to support it then it would be prudent to check further.

If the statement is general to a type or sub-type and the aircraft handbook and/or operating manual does not support the statement, then the probability is it is most likely wrong, possibly even completely incorrect.
Contemporary aircraft and engine handbooks and/or operating manuals are generally ultra-reliable guides. Some contain a very few errors but these are usually no more than minor differences in dimensions.

At the general level, perhaps also this: not all evidence is of equal weight. Indeed some of it may have been deliberately falsified by individuals whose motivations are now unfathomable. (I have my own hypothesis about this might have come to pass in immediate post-war Germany.)

And there may be some other points worth learning from this tale that have just slipped by me.

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