Graheme White propellor identification

[Andy Craven]

I have a wooden propeller with the following markings stamped into the top of the boss:

I.P.C
D. 2 45
P. 1 50
HP 60 CN
B 17196


Does anyone have any idea what this might be?

[Dbahnson]

Are the numbers clear and complete? "IPC" typically is the "Imperial Propeller Co." but I can't find anything resembling those stampings on the list I have of their propellers. The "60 HP CN" is unfamiliar and 60 horsepower is unusual for WW1 era and later propellers. It's possible that the "CN" refers to "Canton Unne" but that purely speculative, and I don't even know if they made a 60 HP engine, although their 260 HP engine was used on the Salmson A2A. (But if the stamps are clear that wouldn't be relevant.)

If the "C" looks like it could be a "G" then it's possible it refers to "Gnome", often abbreviated as "Gn", usually with the "n" in lower case.

How was it determined to be a Grahem White?

It would help if you could post some photos and confirm that the length from tip to tip 245 cm, or just over 8 feet, and whether it is a left hand or right hand rotation. (See the last paragraph under "A Propeller is an Airscrew" on this page.)

Lots of possibilities with lots of uncertainties at this point, and more information would be needed.

[Andy Craven]

Grahame-White propellor identification

Thanks. A couple of photos are attached. You'll see the 'C' could be a 'G' as the lower half has been rubbed off. It measures just over 8' and I think it is LH rotation. The Grahame-White link is merely from the decals.

[Dbahnson]

Can you remove the barometer and look at the dimensions of the hub, also checking to see if the hub has been cut out to accommodate it? I suspect that it is a very early prop using an early Gnome engine. If so the hub dimensions should match the Gnome on this chart.

If it's a match then it may be a very early Graheme White airplane using one of the low horsepower Gnome engines. See this page for possibilities and look for a pusher aircraft on that list using a Gnome engine that's close to 60 HP. (It was not unusual for the stamped HP to be different than what's listed on modern references.)

Perhaps Bob Gardner will check in at some point and offer his valuable opinion. If the hub is intact behind the barometer I would consider that a highly collectible prop.

[Bob Gardner]

Greetings Andy,

Welcome to our forum and thank you for your excellent photographs.

It is unusual to see an IPC propeller without a drawing number.

Your data translates as;
IPC Integrale Propeller Co if made in Britain or France and Imperial Propeller Co if made in Germany (Your prop is British)
D2.45 the diameter in metres
P1.50 the pitch in metres
HP 60 the horse power of the engine
B17196 where I believe B indicates made in Britain (Pierre-Michel: is this correct?)

The dimensions of the prop suggest it was made for a low powered engine. The letters GN are common and usually indicate Gnome, but not in this case.

I have an Integrale prop listed in my data base with identical data and the serial number 17361. It too has no drg number after the letters IPC. It is listed for the Green 60hp engine, which was manufactured in Britain in 1909 and 1910.

The Green Engine Co was a British engine company founded by Gustavus Green in Bexhill to sell engines of his design. He flourished, especially as a designer of aeroplane engines, during the first two decades of the 20th century. The engines were manufactured by the Aster Engineering Company.

The firm produced a range of water-cooled, mostly inline engines up to about 1915. Green engines powered many pioneering British aircraft, including those of A. V. Roe, Blackburn, Handley Page, Grahame White, Samuel Cody, and the Short Brothers. They had several advanced features in common; cast steel single-piece cylinders and cylinder heads, two valves per cylinder driven by an overhead camshaft, white metal crankshaft bearings and copper and rubber-sealed water jackets.

In 1909, the C.4 had been the only motor to complete the tests for the Patrick Alexander Competition but was not awarded the £1,000 prize, because the rules called for a 35 hp engine while the C.4 only averaged 31.5 hp. The competition was re-run the following year for more powerful engines and this time, Green gained the prize with the D.4 which produced 60hp.

Up to 1912 Green was the only source of all-British aircraft engines capable of producing 60 hp and so the only choice when prizes were offered for all-British aircraft competitions. The best known case is John Moore-Brabazon winning the £1,000 Daily Mail prize for a circular 1 mile flight by a British pilot in an in his D.4-powered Short Biplane No. 2 in 1910.

Your propeller is therefore from the dawn of European aviation. It is exceptionally rare for an early prop to survive. In thirty years of research I have not seen another example. It is irreplaceable. It might be the only surviving example of Green's D.4 propeller.

With kind regards,

Bob

[Andy Craven]

Thanks and fascinating. By way of further detail, attached are a couple of photos from the hub. Without a caliper, I think the dimensions are:

Hub thickness 4"
Centre bolt 2 1/2"
Bolt size 1/2"
Bolt circle 6 5/8"

Is this at all consistent with your earlier thoughts.

[Bob Gardner]

'Afternoon Andy,

Hub measurements from early props were recorded by the Germans and the Americans but I have never come across any British listings.

Bob

[pmdec]

Hi,

@Bob: Sorry, I don't know why there is a B before what seems the prop [why so high?] number.

@Andy Craven: Could you post a pic of the other decal, with the all the blade width visible on the pic?

Regards,
PM

[Dbahnson]

Thanks and fascinating. By way of further detail, attached are a couple of photos from the hub. Without a caliper, I think the dimensions are:

Hub thickness 4"
Centre bolt 2 1/2"
Bolt size 1/2"
Bolt circle 6 5/8"

Is this at all consistent with your earlier thoughts.

That bolt circle diameter eliminates the Gnome as a possibility, but Bob has already found the more likely engine.

As we frequently see, the hub has been cut out to accommodate the barometer, which is all too common and always a terrible shame with one of these very old artifacts.

[pmdec]

Hi,

Waiting for a pic of the the decal on the right wing (right relativly to last pic of the post #3), I will become the "Devil's advocate":

- on the decal pic (post #3), which seems to be the left one from the darker laminations, it will be extraordinary if the varnish was 100 years old,
- both decals seem to have the same orientation (that is, both directly readable on the #3 whole prop pic) whereas one is expected to be upside down,
- from the hub pics of the #6 post, the brown varnish was passed after the installation of the barometer, but the decals are above the varnish.


How can this be if the decals are original?

[Bob Gardner]

Well spotted Pierre-Michel. I had not noticed this.

You seem to be suspicious of the prop? I'm not. I have two props of similar dimensions listed in my database, both recorded in an early British official document. I also own an early Chauvière prop with the same decal, but I must have a look at it to see how the decals are placed on the blades.

We are all aware of peculiar mistakes in the data stamped on propellers; the German props most of all. I began to wonder if some German stampers were illiterate. British WW1 props also have errors in the stamped data. But I can't recall any French errors?

With kind regards,

Bob

[pmdec]

Hi,

You seem to be suspicious of the prop? I'm not. I have two props of similar dimensions listed in my database, both recorded in an early British official document. I also own an early Chauvière prop with the same decal, but I must have a look at it to see how the decals are placed on the blades.
.../...

I have to admit that I am somewhat paranoïac... And I can be more: from this picture: https://bit.ly/2OiUfQb the Green 60 HP engine was right handed (the chain is not crossed, the plane is a pusher and then the prop left handed).
The prop of this post is also left handed, then, if it was for a 60 HP Green it was a pusher. And in this case, not only one of the decal is upside down, but both are on the wrong side!

And even more paranoïd, it seems also that under the barometer:
- there is no dust at all,
- the wood looks like it was recently cut,
- the wood has a very pink color like new cut mahogany (from Asia countries?)...
- And what are these two cruciform screws for?

But I will refrain to said it is a fake because I am very impressed by the "font" of the markings which looks exactly as it has to...

Perhaps a "deco thing" made a long time ago with a true prop?



PM

[Bob Gardner]

Greetings Pierre-Michel,

Several of the aircraft which used Green Engines were pushers.

When the latest trans-oceanic storm has finished with us and moved on to La Belle France, I'll venture to my storeroom and photograph my similar prop, for comparison.

With kind regards,

Bob

[pmdec]

Hi Bob,

.../... I'll venture to my storeroom and photograph my similar prop, for comparison.../...

Is it the one of the page 33 of your third book? It seems very large and the pitch high: do you know them?

I forgot to answer about stamping errors on French prop: there are none because French are the best at this work*

Regards,
PM

*Oups! Not sure it is true!...

[Bob Gardner]

Pierre-Michel,

It isn't in any of my books. I only bought it a short time ago and that book is seven years old, but the decal on mine is similar to the one on the preceding page. I'll photograph it when the sun next shines.

I agree that the French are superb; your wine and cheeses are magnificent.
And you are excellent at losing, which you did wonderfully at Waterloo, and in 1870 against the Prussians. And you were losing wonderfully in 1914 until we came to help you.

Avec le respect,

Bob