Integral Propellor company prop

[johnpic]

I have recently acquired a four bladed wooden propellor, made it is believed with Honduras mahogany, by the above company. It was given by Tommy Sopwith of the Sopwith Aircraft company to an engineer employed by the company on his retirement in 1919 0r 1920. The hub is stamped IPC (presumably Integral Propellor Company) B17044 and D5.9''P6 RH - presumably for right handed rotation. It only has two fixing holes on the hub and am not sure if it was ever fixed to a plane. It is in excellent order and is a superb piece of workmanship. Any ideas as to further identification or information - and any idea of its value - would be appreciated.

[dbahnvt]

I don't have the number in any of my listings. It's an unusual length (5'6") for a prop of that era.

[johnpic]

Integral Propeller prop

The length is 5.9'' not 5.6''. Would this make it more usual for the period referred to in my enquiry?

[Bob Gardner]

John,

Thank you for your phone call and e-mail, sent privately to my website, and for your question to this forum.

I am afraid that it is difficult to reconcile your information although I have spent several hours trying to do so.

IPC does stand for the Integral Propeller Company. They made few four bladed props and these were for the BE2C (2) and various AIRCO aircraft designed by de Havilland (7) plus one or two others. I have no record of a four bladed prop being made for Sopwith by IPC. They did make a few two bladed props for the Sopwith Pup. Sopwith hardly made any aircraft with a four bladed prop; possibly one Sopwith Baby, the prototype and only Snail and the post war Atlantic.

IPC drg nos generally consist of 3 or 4 digits following the letters IPC. I haven't seen one begin with the letter B.

The diameter is tiny. I have no record of any World War One aircraft with a diameter less than six feet six and then only one. The smallest diameter on military WW1 props begin around 2300mm, about seven feet six inches.

The square nature of the diameter and pitch, they are very close to each other, suggest a light fast aircraft of small dimensions.

Your prop is certainly something unusual. If you could attach a photo of the complete prop and of the data stamped on it we might be able to help further.

With regards,

Bob

[MWP_Lamar]

John,

Is your prop 5.9 inches or 5 feet 9 inches? There seems to be a discrepancy here.

Lamar

[johnpic]

Length of propeller

Lamar

Sorry for the confusion. The length is 5 foot 9 inches.

John

[Bob Gardner]

Many thanks for the photographs which you sent by e-mail.

Sadly I am still not able to identify the prop. The Integral Decal is an
early type probably from around 1913. The slender shape of the blades
confirms this.

I have now checked all the French Integrale drg nos as well as the English
ones. The number 1704 is a possibility, at least in the sense that it fits
in with the run, but it does not make the lists of commonly used French
props.

I can find no Sopwith at that time that had a four bladed prop except the
Sopwith Gunbus, of which only a handful were made. It was a two seater so a
prop as small as this is very unlikely. Can you confirm that the prop
against your brick wall stands about four feet high, when sitting on its two
tips (as in Pythagoras).

Other 'outside-the-box' thoughts are that it is a very large auxiliary prop
used on an airship to generate electricity. These exist up to three feet in
diameter but would not have such a flimsy two bolt mounting. A ceiling fan
would and there is sometimes a similarity between very early airscrews and
the first ceiling fans. I don't think it was made as a fan but the mounting
might suggest that Sopwith used it as such. I don't give either of these
ideas much credence.

The final thought is that Sopwith made a radio controlled guided missile
(Yes! In 1917). This small aircraft, called the AT was powered by an ABC
Gnat 35hp engine which might possibly have had a four bladed prop, although
not likely. Its Mk II version called the Sparrow, had a two bladed prop as
one would expect.

So the short answer is I don't know. Might I use your photograph in the
next update of my prop book? I am now exhausted and am going to lie down
with a bottle of good ordinary claret.

With regards,

Bob

[johnpic]

Integral Propellor company prop

Hi Bob

Many thanks for your further comments, very interesting - sorry to give you such a headache, but hope th claret helped a bit!
In answer to the points you raise, yes, the prop stands at 4 feet two inches, when sitting on its two tips.
Unfortunately there is no further data on the back of the prop or on the edges of the hub.
You may certainly use my photgraphs in your next update of your book.
If you do come up with any further thoughts I would be pleased to receive them.
Not that I am thinking of selling it, because it was a gift to me, but have you any idea what it might be worth - I'm thinking perhaps for insurance purposes?
Best Wishes and good hunting!
John

[Bob Gardner]

John,

I do wish you would ask me a question that I can answer.

I regret that there is very little published data on WW1 props. Dave Bahnson started this forum to provide a focal point for information. But the problem is that many, possibly the majority of props cannot be identified. English ones are easiest; then French. German ones almost always can only be identified to an engine type, very rarely to an aircraft type. Early American ones seem to be even more arcane in their markings.

The market in props is comparatively new and only exists really through the Internet. It is rare for props to appear anywhere else, apart from the occasional specialist auction. One consequence is that prices can be variable. Two ardent enthusiasts at an auction can bid a prop to preposterous heights. Conversely, good examples sometimes sell for low sums.

So, I don't know.

But I guess that at a British auction it would sell in the bracket £600 to £1000. If you have some written or photographic provenance of Tommy Sopwith presenting it, or if you know to whom he presented it, this might increase its value. Armed with a photograph of it with Sopwith, at a specialist auction, where you have guided the hand of the cataloguer, it might make £2000

Quad erat demonstrandum. I don't know.

With regards,

Bob