Propeller identification

[Vasek]

Hello,

I have a propeller, actually it is the hub and one blade. I have owned it for years. I am trying to find out some information on it. It is made of wood. It has a decal on the one blade “The Integral Propeller Co. Limited” On the front hub ring it has “I. P. C. 1708. DG. 6296. 100. H. P. R. A. F. B. F. Iz. On the back of hub it has the #3. Also on the front of the propeller next to the hub it is marked “ALD 32”.
Any help would greatly be appreciated.
Thank you for your time,

Vasek

[Dbahnson]

I can't find that drawing number.

Can you post photos of the prop and of the stamped info? Bob or pmdec may have information but it's easier with photos, and also the length of the prop.

[Vasek]

Here is the photo.

[Dbahnson]

It's left hand thread, probably indicating a pusher configuration, and although the photo is small it looks to me as if the hub represents a 4 blade propeller that's missing three of them.

UPDATE:

The closest thing I can find to a match is "T6296" designed for use on a BE12/12A or an RE8/8A using an RAF4A engine. That's an RAF drawing number, so it's very possible that it was built under license from RAF to Integral, which could explain the odd combination of "IPC 1708 with "DG 6296". In other words, Integral may have simply cross referenced the RAF drawing number with their own identifier, which could explain why it's not listed in the IPC list of drawing numbers.

Further support for that is that although dimensions are not given, the RAF model IS a 4 bladed left hand tractor. That implies that it wasn't a pusher as suggested earlier but rather fitted to an engine that rotated counterclockwise by design or by reduction gearing, as did the RAF4 engine.

So this photo may show what the propeller originally looked like.

[Bob Gardner]

Excellent process of deduction Dave ! A pleasure to read.

With kind regards,

Bob

[Dbahnson]

Thanks, Bob, but I'm not sure my assumption is completely correct. If we ignore those goofy periods that we've seen in other stamped sequences, I think the logical cluster in this one is, "IPC 1708, DG 6296, 100 HP RAF, BE 12" (assuming that " B. F. Iz" might have been hard to read). We know that horsepower numbers were often inaccurate, but usually not by a margin of 50% as this would have been.

Any thoughts? Maybe the OP can get a good photo of the stamped information for us to decipher.

[Bob Gardner]

Dave,

Only that the data refer to 100 hp whereas T6296 refers to the RAF 4A engine of 140 and 150hp. An afterthought; this must be what you mean by 50% error?

Vasek (is that a Polish name?)

Could you please measure the prop from the tip to where the centre of the hub would have been. Multiplied by two will give us the prop diameter, which will help considerably.

Dave

I expect that we won't unravel this puzzle. The usual thoughts cross my mind;

The stamper was illiterate or disabled or distracted in some way.

It was an experiment using different stamps from normal, so the letters stamped were atypical and irrelevant or in the usual font but made with a different type of metal from normal.

With kind regards,

Bob

[Dbahnson]

Dave,

Only that the data refer to 100 hp whereas T6296 refers to the RAF 4A engine of 140 and 150hp. An afterthought; this must be what you mean by 50% error?

Bob

Yes, that's what I meant by 50% error. We commonly see HP numbers vary by 10 or 15 units, some of it probably related to improved methods of determining horsepower over the years.

But there was an earlier RAF engine, the RAF 1, of 90 HP used on the B.E. 2c which preceded the B.E. 12. So recognizing the frequency of stamps being mis-interpreted due to subsequent wear on the prop, or as you have often suggested, simply mis-stamped by careless or unqualified employees of the manufacturer, then one has to at least speculate that this prop could possibly have been used on the earlier B.E. 2c (although I think that's less likely). That's why I've asked Vasek if he could get photos of the actual stampings, particularly as "B.E. 1z" is the description of the stamping, and the fact that the stamp doesn't say "RAF 4". (While you might expect a modified version of something to indicate that with a suffix, e.g. "4", you wouldn't be as likely to see the first design be identified with a suffix of "1".)

This just comes from Wikipedia in the description of the B.E. 12:

The B.E.12 was essentially a B.E.2c with the front (observer's) cockpit replaced by a large fuel tank, and the 90 hp RAF 1 engine of the standard B.E.2c replaced by the new 150 hp RAF 4.

The Wikipedia article on the B.E. 2 is interesting . . .

[Bob Gardner]

Mmm!

Intriguing.

We need the measurement Vasek!

With kind regards,

Bob

[Vasek]

I made a couple of photos. I found out that the forum significantly reduces size of the uploaded photos, so I uploaded them here:

http://leteckaposta.cz/266426802

It was a four blade propeller.

I am in the Czech Republic, Central Europe.

Your knowledge is amazing!