Early British Integral propeller - help please

[Hatcracker]

For many years I have owned what I believe to be an early Chauviere design propeller (sporting two Integral Propeller Co Ltd, British Make decals) which is usually mounted along the stairway in my home. However, because of the mounting, I have been unable to read the serial number on the hub until today, when it was removed from the wall due to an impending film shoot at the house. I'm very keen that I might learn something about it's likely history and would be grateful if anyone can help.

I've uploaded some photos, and taken the opportunity to take some exact measurements. It’s a big one at exactly 3 metres (approx 9ft 10 inches). In fact, all measurements are neatly metric, and rather messy in feet and inches (which could be something of a clue?).

Manufacturer: The Integral Propeller Company Limited (British make)
Length from tip to tip: 3 meters
Number stamped above the centre bore (very faded): 713 (I think)
Number stamped below the centre bore: 3
Centre bore diameter: 8cm
Number of bolt holes: 8
Hub diameter: 21cm
Bolt hole diameter: 15cm
Bolt diameter: 1cm
Hub thickness: 16cm (with metal plate)

I hope this information might give to a few clues about which kind of aircraft it might have been used for, but if there's anything else needed, please ask.

Many thanks,

Paul

[Bob Gardner]

Paul,

Your prop looks splendid on the wall of your stairs; about the best positioning of a prop in someone's home that I have seen.

I'll research 3m Integral props.

There will be some lines of data stamped on to the boss which will give diameter, pitch, engine etc. We need this to identify the prop.

With kind regards,

Bob

[Dbahnson]

Also, this is a little less common left hand thread, at least implying a pusher application.

Sadly, most of the original varnish has been removed, as evidenced by the dark halo around the decal. That occurs from someone preserving the decal while still refinishing the rest of the surface, which is now lighter in color.

[Hatcracker]

Bob and Dave,

Thank you so much for your speedy response. I have never noticed any markings on the boss of the propeller, but with the aid of a powerful torch, I can just about make out some characters.

I think Dave might be right about the 'restoration'. My wife acquired the propeller as a present for a significant birthday of mine, and I suspect the 'dealer' did their best to make the item look as 'saleable' as possible - even to the extent of practically eliminating the serial numbers on the boss.

This is what it appears to be - but please allow some interpretive leeway.

C.
00
50
A.D.
03

CHL (These last three characters are almost indecipherable. It's possible there may even be more or less than three characters)

Sadly a photo with a camera phone under artificial light shows absolutely nothing, so I cannot currently upload a pic (Perhaps a studio light and an SLR might prove better)

Many thanks for your continued help

Paul

[Dbahnson]

This speckled appearance to the paint on the hub is distinctly "unusual". I can't recall ever seeing it on any other hubs or blades. I wonder if it was an attempt to embellish it. The way the paint follows the nicks and dents suggests that it was applied late in the prop's existence.






Still, it's an elegantly shaped propeller and is undoubtedly "old".











.

[Hatcracker]

The paint looks far less speckled in real life - much more of a dull 'battleship' grey. The effect is pronounced because there is reflected light from some gold curtains out of shot at the top of the hub, plus I have played with the brightness/contrast settings of the photograph in order to give you the best chance of spotting the serial numbers when online in low res.

Having said that, I think you're right - it's almost inconceivable that its the original paint!

[Bob Gardner]

Paul,

I don't have a 3000mm prop made by the Integral Prop Company listed but I do have 2900mm and 3150mm listed.

The drg nos IPC 2303, 06, 65, 67, 68, and 69 all have diameters of 2900mm, and were for 80hp Renault and Gnome engines, fitted to Maurice Farman aircraft.

IPC 2610 was a four-bladed prop of 3150mm diameter but is one of those props made of two separate two-bladed props, which implies that it was shipped to some overseas location: two such two-bladed props laid side by side occupied much less shipping space than one four-bladed prop. Your prop might be one of these two-bladed jobs!

With kind regards,

Bob

[Bob Gardner]

Paul, a post-script!.

The IPC 2610 prop was used on the 275hp Rolls-Royce engine in the DH4 aircraft.

Bob

[Bob Gardner]

Paul,

Have you just bought a book from me? Part 3 of my series on British prop makers of WW1 describes makers from Farringdon to Lang but includes fifty-one pages devoted to the British Integral Company.

With kind regards,

Bob

[Hatcracker]

Thanks for your speedy research Bob.

I have indeed just bought the relevant volume of your book(s) and look forward to a much greater understanding of the Integral Propeller Company.

The measurement of my propeller is exactly 2,998mm from furthest tip to furthest tip through the middle of the centre bore. (Given the metric neatness of all other measurements, I'm guessing the 2mm is shrinkage or the dreaded 'restoration')

Is it possible that some Integral propellers were built and stamped without being recorded - or if the records are not entirely complete? Do the indistinct characters on the boss, or the hub/bolt diameters give any greater clue?

A nagging doubt has now surfaced in my mind. Perhaps the Integral decals may not be legit (although as Dave points out, it looks like they were on the propeller before any 'restoration' took place.

In any event, thank you for your detective work. It really is most interesting.

Kind regards,

Paul

[Hatcracker]

Integral Propeller serial number layout

Further characters are emerging along the top half of boss when a strong light is shined at a very acute angle across it. However, with probably a hundred years worth of bumps and scratches (coupled with the 'restoration') it is very difficult to determine what is a character and what is a scratch.

It would help enormously if I knew what I was looking for. If you have a typical layout of the markings on an early IPC propeller and what they mean, I can hunt for the relevant characters.

For example: I can see an I. and a C. at the leading edge of the boss about 10cm apart. With the extra light held at an acute angle, I can just make out a faint P. in the middle of them. It appears the first line of characters might have originally read I.P.C. (presumable for Integral Propeller Company)

If anyone has the layout of markings (or a photo) from an early example, I'd be very grateful to see it, especially as the film crew are scheduled to re-mount my propeller on the stairs on Friday (after which, this level of close examination will be quite tricky)

Thanks for all your help

Best regards

Paul

[Hatcracker]

Having looked through some of the many photos on this site, I found this: http://www.woodenpropeller.com/images/DH1h3.jpg which is an early Integral propeller with serial numbers clearly visible.

Armed with the knowledge of where the characters should be, and using with my high intensity light shined at an acute angle, I have been staring at the hub trying to see characters, where there were none before.

And I think it's worked.... or perhaps i'm hallucinating.

Attached is a drawing of what I think may be buried under the paint and the restorative effort. Please allow some leeway for me misinterpreting a character for a scuff mark, or even seeing something that doesn't exist at all. Some of these marking are incredibly faint.

Please feel free to suggest what I might actually be seeing, and of course if any of this helps identify why this propeller was ever built.

Many thanks once again

Paul

[Dbahnson]

For one thing, a hundred years later after a propeller has been put into use the exact dimension of length may not apply. It was not uncommon to remove some of one tip to balance the prop out after the other tip had been damaged by ground or debris contact. In that case the diameter will typically be lower than the design diameter.

I'll have to look through any data that I have, but frankly if Bob doesn't have it I likely don't either. Speculating on missing letters or digits can be exasperating, but it may be worth a try.


Finally, it can be very frustrating to try to determine propeller usage on early propellers. All of us (particularly Bob) can spend hours trying to figure them out and still come up empty. That's just the way it is.

[Bob Gardner]

Paul,

Congratulations on your deciphering. When I bought and sold WW1 propellers a decade or so ago, I slowly developed the knack of a particular squint, through half closed eyes, to read the data on an ancient prop!

The data you have discovered is excellent.

Firstly it is in the style of an early Integral prop dating from before WW1. You will see a similar layout which is more readable on page 95 of my book, Figure 125, showing a DH5 prop (stamped in the manner of the time as DE H 5).

On your prop HP 120 AD refers to the 120hp Austro-Daimler engine which was one of the first successful in-line, water-cooled aero engines developed in Europe. The design was used by combatant nations on opposing sides during World War I.

In 1912, the Austro Daimler Company allowed Arrol-Johnstone Ltd of Dumfries, Scotland, an automobile maker associated with William Beardmore & Co. of Glasgow to produce their 120 horsepower, six-cylinder engine under licence. On the outbreak of war in 1914 these engines in Britain were renamed as Beardmore engines.

Beardmore later developed the engine by fitting larger cylinders to produce 160 horsepower.

In both guises the engine was used on the:
Martinsyde G100, with a prop diameter of 2900mm, drg no. LP920.
RE8 with T28017, D 9ft 2 ins.
FE2B with T5638, D 2810mm.
and the Vickers FB14 with V2600, D2900mm which is D9ft 7ins.

Thus, 9ft 7ins is the closest to ten feet, 98mm or 5ins short.

Please try a bit more squinting with an angled bright light to see if you can read the diameter and pitch, written as D 2 40 and P 2 80 (sic) for example. My experience of such squinting is that the data will suddenly appear readable. In my mind this occurence is much like a crossword clue which is suddenly obvious.

With kind regards.

Bob

[Bob Gardner]

Pierre-Michel,

Bonjour mon ami!

Could you look at the French databases for Integrale to see if Lucien Chauvière made a 3000mm two bladed prop. As you will have seen above, Paul's 3000mm Integral is not in the British list.

Avec le respect,

Bob