4 bolthole propeller

[ACowell]

Hi,
Last week we were given a wooden propeller in Belgium.
As my husband is a retired aircraft engineer who used to work with Seaking (helicopters), Fairchild, Fokker and Avro, we are very much interested in the aircraft of this propeller.

4 boldholes which do not go trough the hub
Length: 2,60m (8 foot 6 ?, see pictures for inches)
Hub inside: 6,55 cm (2”58 ?)
It’s difficult to identify the numbers around the hub.
Wood looks like mahogany

The husband secretly hopes it’s a fokker.
Thanks a lot on your assistance.

[Dbahnson]

It might be for a Fokker but there's no way to be sure and there are lots of other possibilities.

[ACowell]

What could be the other possibilities?
Is there anyway for us to find out to which A/C this propeller belonged and how to time stamp it?
Sorry this part of aviation is quite new to us, so any help is really appreciated.

[Mtskull]

The four holes indicate that the propeller was fixed with a Rupp fastener, a device which enabled propellers to be replaced more quickly than using many bolts.
This suggests that the propeller is of German origin and dates from the late WW1 era.

Apart from the obvious (direction of rotation and the dimensions), your best chance of finding out more about your propeller lies in carefully deciphering all of the numbers and letters stamped on it. There is still no guarantee that it can be identified but you never know...

[Dbahnson]

Unfortunately, Bob Gardner has not been active on this forum for several months. (I hope he is OK.) He was able to identify or narrow down many of these German props by diameter and pitch plus any markings. Some are listed in his four volumes of German manufacturers with lots of illustrations, but knowing the manufacturer is a key component of that research.

The metal sheathing and the pointed tips suggest a little later application around WW1, or possibly a seaplane use. I agree on the Rupp fastener.

The likelihood of any wooden propeller being linked to a specific aircraft is nearly zero. Even linking to a specific make and model is a challenge, particularly with German manufactured props. The folklore that often goes with a particular propeller is almost always inaccurate, sometimes unintentionally and sometimes claimed by an owner to get a higher price on a sale.

[ACowell]

Thanks for the info.
If it is late WWI I’d need to move my post to “early wooden propellers” ?

[Dbahnson]

Thanks for the info.
If it is late WWI I’d need to move my post to “early wooden propellers” ?

I moved it to the early category, mostly on the basis of the Rupp fastener. I don't actually know how long its use persisted, but the ability to rapidly exchange propellers was a WW1 innovation.

Can you post a good photo of the entire propeller from tip to tip and centered with the camera "looking" directly down the center of the center bore?

And sometimes the critical numbers can be derived with magnification and various light angles. You can often gently rub a little turpentine over the stamps to highlight their edges. I have all of Bob Gardner's books and he might have some clues included in those.

[ACowell]

I moved it to the early category, mostly on the basis of the Rupp fastener. I don't actually know how long its use persisted, but the ability to rapidly exchange propellers was a WW1 innovation.

Can you post a good photo of the entire propeller from tip to tip and centered with the camera "looking" directly down the center of the center bore?

And sometimes the critical numbers can be derived with magnification and various light angles. You can often gently rub a little turpentine over the stamps to highlight their edges. I have all of Bob Gardner's books and he might have some clues included in those.

I’ve added the photos, I hope they are ok, as the prop is quite large, it is difficult to get it on in one shot and capturing the details.

Spend half of the afternoon deciphering the numbers, seeing something different on each turn, not sure if it supposed to be like this but figures at 12 and 3 seem to face the inner side while the figures at 6 and 9 seem to be read from the outside,even though not sure about the ones at 6
Seems to be:
@12: 2085, underneath: 52 2005
@3: 718 followed by something36
@6: 185-1 but looking from the other side 7-937
@9: 2005

[pmdec]

Hi,

There was Rupp fastner hubs, or like systems, later than WW2. So, this type of fitting could be from any date between 192x and 194x.

Regards,
PM

[Dbahnson]

The overall design including the thin metal sheathing are more typical of post WW1 props, and nothing about this suggests it was for a WW1 Fokker.

[Mtskull]

The overall design including the thin metal sheathing are more typical of post WW1 props, and nothing about this suggests it was for a WW1 Fokker.

Being able to see the entire propeller makes such a difference. Certainly looks much later than WW1.

Having now spent many a happy hour trawling the internet for photos of Rupp fasteners, I find that it is hard to find a photo of a wooden propeller on a German aircraft of the inter-war period, that isn’t fitted with one.
Its use seems to have been almost universal, so unlikely to be of much help in narrowing down the possibilities for this propeller.

[ACowell]

Thanks for having a look at it. As we do not have a clue where the propeller originates from. Is was hanging in a garage.
But what seems a bit odd to me is that normally the bold holes are centred meaning at 3,6,9 and 12 o’clock, while they are off centre on this prop.

[pmdec]

Hi,

T.../...
But what seems a bit odd to me is that normally the bold holes are centred meaning at 3,6,9 and 12 o’clock, while they are off centre on this prop.

The "bolt" holes seems perfectly "centered" to me, that is they are, as always, on a circle which has the same center taht the central hole (see your pic with circle and lines added).
Regards,
PM

[ACowell]

Hi,
Is there anybody who is able to shed some light on the propeller?

[JR44]

I think there has been quite a lot of light shone on a prop with no maker and hard to read markings.