wooden propeller identification

[renzo]

dear all, I have a wooden propeller WW1, with the following markings:
n°31678
200PS
BENZ
D295
S180
EDUL

Does any one know of which German aircraft this propeller belongs too? I have added a file with pictures. I think it could belong to a Friedrichshafen GII Bomber.

[Dbahnson]

Beautiful item and nice to have the hub with it, which is rare. I'm hoping that Bob Gardner or pmdec will see this and try to identify it. Be patient.

[pmdec]

Hi,

Sorry, but no idea from me... Very strange metallic hub with 8 bolts on one side and, it seems, 16 on the other???

Hope Bob will know the brand and will have some date from the prop number.

Regards,
PM

[Bob Gardner]

Good Morning Renzo,

Thank you for this data which I have added to my database.

I can't give you an exact answer. The Benz engine was widely used, particularly so by the Imperial Navy.

The serial number 31678 is very likely to be a Heine serial number. Alb CV II, LVG CV, DFW CV, and Alb JI aircraft all used the 200ps Benz engine with Heine props that had fractionally different dimensions from yours.

The Friedrichshafen GII used both the 200 and 225ps Benz. I have one Friedrichshafen G II recorded with a diameter of 2900mm, but not made by Heine.

So, my tentative answer is that your prop came from an Alb, LVG, or DFW CV aircraft.

With kind regards,

Bob

[renzo]

dear bob,


thank you for your reply. I tell you a bit about the history of this prop.

My father, who used to be a doctor/surgeon, wa sin his spare time a pilot. He used to fly a Piaggio P149D (ex luftwaffe), an italian plane. He is so found of it that this plane actually is put on display in his own yard.
His colleague was found of motorcycles. He had an old propeller, which, according to him, was 'saved' by his grandfather during the first world war. My father had an old motorcycle so they swapped.


The grandfather lived near Roeselare, in a little town called Rekkem. There used to be two German airfields around Rekkem, and one of those airfield, the Friedrichshafen GII was stationed.

so now about the prop:

it's has a logo, which I couldn't find anything on the web (see annex), so I don't think it's a Heine prop. Does anyone has an idea what the logo is from?




Also it states EDUL, counterclockwise turning prop as seen from in front of the aircraft (German wisdom). What I found out is that most props have EDULZUG, tractor prop. So I think it's a pusher prop, hence the Friedrichshafen G II.

renzo

[Dbahnson]

Renzo, I think your prop was used in tractor, not a pusher, configuration. It is a right hand rotation (that's the design, based on a screw, which comes in both right and left hand threads), so mounted on the normal Benz engine it would only work in tractor configuration. (That can't be changed by putting it on backwards. It's a consequence of its construction.)

See this prop just as an example of a right hand threaded prop stamped with "Edulzug".

[renzo]

you might be right, still the logo is strange, any idea's?

[Dbahnson]

I'm inclined to believe the stamp you see is an inspector's stamp rather than a logo, possibly with the inspector's initials.

[Bob Gardner]

Renzo,

Only Heine had serial numbers in the 31,000 range. They started making props before anyone else in Germany c1910 and also made more props than anyone else.

For those who don't follow the minutiae of WW1 German aviation abbreviations, EDUL is the abbreviation of Entgegen Dem Uhrzeiger Lauf which translates as against-the-direction-in-which-the-clock-runs. Anticlockwise in English. EDUL almost always is accompanied by the word ZUG indicating pull or tractor; thus EDULZUG. A pusher prop would replace zug With DRUCK (sometimes DRUK) meaning push. But such props are extremely rare In German WW1 aviation.

With kind regards,

Bob

[Dbahnson]

Renzo,

Only Heine had serial numbers in the 31,000 range. They started making props before anyone else in Germany c1910 and also made more props than anyone else.

Bob, don't you also think that it's rare to see a Heine prop with canvas clad tips?

It's a gorgeous prop. I hope it can be further identified.

[Bob Gardner]

Dave,

Yes! Thank you for concentrating my mind. I was astonished when I first saw the photograph but I forgot to go back and look at it carefully.

Fabric was not used on German props.

The fabric in this photograph is pure British. The olive-green colour and the length of the fabric on the blade follows exactly the instructions laid down in The Handbook on Propeller Construction issued by the Department of Aircraft Production at the Ministry of Munitions. Even the way the end of the fabric on the blade is folded back conforms to British practice.

I have recorded a number of German propellers made for British engines and aircraft and similarly a few British props made for German engines and aircraft. In both cases this was to get forced down enemy aircraft back into the air for testing.

I'm about to search my databases to see if I can find a CV aircraft captured intact by the British.

With kind regards,

Bob

[Bob Gardner]

I have checked my records. There were fourteen German CV aircraft with the 200ps Benz motor brought down by the British during 1917 and 18, mostly DFW and LVG aircraft.

I have one photograph of a DFW CV with British markings. It was the DFW CV with leading edge radiators. And I have three photographs of LVG CV aircraft in British markings. The use of British markings on captured enemy aircraft indicated that they were returned to airworthiness.

It is therefore possible (perhaps even likely) that some were fitted with bespoke British made propellers to replace their damaged original prop.

This line of evidence above, coupled with the British style linen on the prop blades, makes it possible that Renzo's prop is a British made replacement for a downed CV aircraft. It is an astonishing discovery.

With kind regards,

Bob

[renzo]

Dear All,

now i'm even more confused. Bob, if it is in fact a British made prop, why do they put German markings on it? 200PS (HP), Benz, EDUL? Or could it be, worst case, that the prop is a fake one?
renzo

[Bob Gardner]

Renzo,

I don't think it could be a fake. I agree it has German style data and British style fabric. I cannot provide a clear answer as to why.

It is well documented that, where possible, German aircraft forced down by the British were returned to airworthiness so that the flying characteristics could be explored and demonstrated to RFC pilots.

The existence of photographs of four German C V aircraft with British roundels suggests that these at least were returned to flight.

A possible solution is that the German prop of such an aircraft was damaged and was repaired by the British to British standards; which here includes adding fabric (which is Irish Linen) to the blades.

I know the front line in Flanders moved back and fore. Was the airfield at Rekkem ever occupied by the RFC or RAF during WW1, as well as the Deutsche Luftstreitkräfte?

With kind regards,

Bob

[Bob Gardner]

The conclusion that I have reached above now explains the peculiar stamp. The letters AM are those of the British Air Ministry, which was formed on 2 January 1918.

With kind regards,

Bob