Garuda propeller

[pmdec]

Hi Gino,

If late Mercedes 100 HP also used a six bolts hub, it is not a way to give a date for your prop
I am conviced it is a very early one from two facts:
- the markings are complete but also very neat: on one GEPRUFT, there is the umlaut impressed (two dashes inside the upper part of the U),
- from the pitch (140 [centimeters] and the engine speed [1200rpm, 1270 max], the "geometrical" aircraft speed is only ~100km/h, that is about a 90 km/h (56 mph), a very low one.

But perhaps Bob could tell something about that from the prop number? Could it be a prewar prop with a second airworthy marking later (and perhaps a refitting with a new decal at this date)?

Anyway, a very rare and interesting prop!

Regards,
PM

EDIT: http://www.aeroconservancy.com/barographpaper.htm
Il you magnify the page (Ctrl + +), the prop (and the metallic hub!) look very like yours on a LVG.

[Bob Gardner]

I have several hub photos of German prop hubs and this one looks much the same as the others. Six bolt-holes existed on German aero-engines in 1914 and probably early 1915. Some German hub plates do have lightening discs cut in a way that reveals part of the hub aperture. So I believe this hub plate is original to the prop and beyond doubt it is of German design.

Garuda serial numbers that I have recorded, run from the 1200's to the 23,000's. These date from 1911 to 1919. So my guess is that 3222 dates from c1914 to mid 1915.

There is a trap that I fall into every now and then. I find a propeller dating from 1918 with six bolt-holes which I initially think must be wrong in some way. But a 1915 Alb B II with a 100ps engine might well be flying only three years later in 1918 as a training machine or squadron hack etc. and be in need of a replacement prop.

PM. Cerise sur le gâteau The cherry on the cake. I understand the idiom but what does this Canadian Institute regard as the cherry on its cake?

I met bees wax when I was a dealer in clocks, particularly long-case clocks (commonly called grand-father clocks). Furniture dealers brought bees wax to my notice. It is very widely used on both new and old finishes throughout the antique trade in Britain and has been in use for centuries. So, I think it is safe to use. But care must be used because it might react with something the previous owner used on the prop. Hence my advice to always try a small portion on some small insignificant part of the prop; and not to use a modern aerosol version which has added silicates which often react with old finishes.

With kind regards,

Bob

[gino]

Hi
The previous owner of the propeller was a gunner(ground) during WW2.
He found this propeller at his base close to Monchen Gladbach during
that periode and brought it home as a souvenir the way it is right now,
including the metal hub. This is also the reason why I think that
it is still the original one.
I decided not to remove the plates and leave it the way it is. Looks nice
with the metal hub anyway.
I also think not to touch the propeller at the moment because it looks
fantastic and think waxing is not required at the moment.
If I decide to treat the propeller later, I will use the bees wax as recommended
by Bob. Soon or later, wood has to be treated one day and there seems
to be not many options were bees wax should be probably the best choice.
Thank you all for your inputs on this one,



Best regards
Gino

[pmdec]

.../...
PM. Cerise sur le gâteau The cherry on the cake. I understand the idiom but what does this Canadian Institute regard as the cherry on its cake?
.../...
With kind regards,

Bob

Hi Bob, the cherry is just that the entire site is in English and French. The site gives, IMHO, very appropriate advices about relative humidity and temperature considerations for the best conservation for different kind of artifacts, with statistics, not only general considerations. This is not very easy to find such advice outside "antiquarian world" (which have too often only an appearance goal).

Regards,
PM

[Bob Gardner]

Oh Yes. I see. I misunderstood.

Bob

[maxim08]

Dave,

A quick comment regarding the radius on the centre mounting hole. Most German propellers that I have seen for Daimler-Mercedes motors of this era have this radius half exposed through the first row of lightening holes. Not sure why, but it does seem consistent.

I agree, the hub looks original. Bolts should be 12mm and about 180mm long.

Regards
John