I STILL want the data stamped on your British or German Prop

[Bob Gardner]

Hi Everyone,

Sorry for the blunt heading to this post. I wanted to catch your eye.

If you have a British or German aircraft prop from before WW2, I would be grateful if you can tell me the data stamped on it, which will help me construct my research databases.

By data, I mean all the numbers and letters stamped on the hub and the blades. This forum has produced lots of valuable data which has been a great help to a researcher like me.

I have been doing this for some years and am now able to identify and describe patterns in the manufacture of props, including dating props.

With kind regards,

Bob

[maxim08]

Bob,

I see no replies as of yet so perhaps there is a 'two for one' deal about to happen.

Stamp on right blade near hub:



Stamp on left blade near hub:



Hub:



Decal:



So, obviously a Wotan propellor for a 160 Daimler Mercedes motor, but what aircraft type? I would expect to see that stamped below the serial number, but nothing appears to my eye.

What does the P&W stand for below the 'Gepruft'?

The meaning of 'Stand 1290', and what is the rectangular stamp to the left?

The large acronym 'ZUG' on the hub?

Does the '27701215 SP' somehow relate diameter and pitch? It's not the same format as on my D VII Heine so I'm mystified.

Eagerly awaiting knowledgeable replies.

Regards
John

[Bob Gardner]

Thank you John for this excellent info and your photographs. Wotan was the Norse god of war, called Odin in modern English.

Your data translates thus;

Geprüft P & W: is the proof mark of the testing authority of Idflieg which existed from 1915 to 1917. Der Prüfanstalt und Werft der Fliegertruppe; the Test Institute and Hangar (or workshops) of the Flying Troops.

Ausgew: An abbreviation for ausgewogen meaning balanced.

Stand is short for Standdrehzahl, meaning speed of revolution in the context of a test. Here 1290 indicates the speed in rpm to which the prop was tested.

27701215 SP; this reads 277D 215ST for a diameter of 277cm and a pitch of 215cm.

ZUG tr. as drag or pull; in other words a tractor configuration. A pusher would be stamped DRUCK.

The comparatively low serial number with the use of a 160ps Mercedes engine suggests an Albatros D I to DIII. The D V used the 180ps.

PS indicates Pferdestärke, horsepower. German horsepower is slightly different from British horsepower by about 1.5% less.

It is exceptionally rare for a German prop to be marked for an aircraft type. The Germans had aircraft classes, such as C, Cl or D and several aircraft makers would make aircraft for this class, all of which could use the same prop. Equally several prop makers would make props for each class. Identifying German props to aircraft is not easy.

The decal is the best I have seen. Wotan decals were both fragile and faded considerably over the decades. Is there a decal on the other blade? If so is it less defaced? The two birds are Wotan's ravens Huginn and Muninn representing thought and memory. They gathered intelligence for Wotan and were also the means by which Wotan sent information to shamans in trance.

I don't have a Wotan-Albatros prop in my book. May I use yours? If so could you send me hi-res photographs, in exact focus suitable for publication, of the complete prop, of each decal and of the data, with an uncluttered background such as grass or carpet. Send to aeroclocksatbtinternetdotcom, written thus to foil the spam bots.

With kind regards,

Bob

[maxim08]

Hi Bob,

Thank you for the learned reply.

This propeller is in a local museum. Apparently it was dropped off approximately 35 years ago while being carted to the local dump after clearing out an estate! I will ask permission to gain access for better images than the ones my cellphone rendered and use a better camera next time so that you can have something useful to publish.

This is the better of the two decals but I will certainly photo the other. Perhaps a more complete rendering can be generated from the two.

Regarding the '160 PS' reference, recently I have spent considerable time researching the Daimler Mercedes D III, IIIa and variants. In documents published up to November 1918 both the military and common usage usually refer to all of these motors as '160 Mercedes' despite there actual output rating.

As a side note, Daimler documents always refer to F1466, the internal designation for these motors despite the very obvious physical differences between the D III and D IIIa motors.

Regards
John

[Bob Gardner]

Thank you John,

Tell the museum I shall be glad for their help and that I will attribute the prop to them in the text in my book. I've had a quick trial repair of your decal, enclosed. I have left part undone. It will be better at a higher res.

Decals by the way are impossibly difficult to photograph. They are on a curved surface and there is always some reflection. Outside, with diffuse lighting from a cloudy sky, without flash is best.

A point I always try to bear in mind about data on WW1 props is that they are not a precise technological statement, as I tend to regard them. They were often stamped on the prop by the least useful bloke in the workshops. Sometimes I am pretty sure he was illiterate or at least dyslexic. Heine props often have the letter N the wrong way round; Le Rhone baffled some stampers. One has managed Rone, Rohne and Rohn. And I've seen Mercedes engines quoted as having 160ps, 170ps, 180ps and 190ps; and the Benz 150ps as 160ps. So the data often has to be interpreted. Imagine if you were the owner of the prop making business under pressure to make more props for the war effort, whilst your skilled craftsmen were called up, leaving you with old men, young boys and the village idiot. The idiot would sweep out the workshop, make the ersatz coffee and stamp the props. This is of course entirely supposition on my part, to try and account for the vagaries I find stamped on German props!

With kind regards,

Bob