Bristol Scout propeller

[kwatson]

Amongst the garage full of memorabilia that my father left me, I came across a half propeller. I am clueless on aviation related matters but did a bit of digging around on the internet and became interested in the history.
There's a green motif on the blade that reads "Bristol & Colonial Aeroplane Co Ltd, Bristol, England". The stamp around the hub reads as follows:

B&C 4892
P3019
80HP
CLERGET
SCOUT

There are 8 bolt holes and the central bore measures 4.5" by 2.25". I estimate the total span to be 99".

I wonder whether this was attached to a WW1 Bristol Scout biplane? I can see that not very many of these were manufactured so wonder whether, even as a half prop, I should take separate insurance for it.

Any thoughts advice and especially websites I can go to learn more, would be appreciated.

[Dave]

I think you are likely correct in your assumption. I'll try to look up the number when I get home. Here is a similar one for the Bristol F2b.

As half a propeller, it's not particularly valuable and would be difficult to insure for much additional coverage, IMHO.

[kwatson]

Thanks for the quick review. The F2b example looks excellent. I shall look up a restoration firm to see if I can get it looking like that.
Even though it's a half, I think it's great with the history and all that. I think I might start a collection.
Thanks again Dave.

[Bob Gardner]

Hi Ken,

Sounds like a nice artefact. particularly as it carries the makers data and a decal. The market in early props is only really starting. Before the web there was hardly any way of finding a prop for sale and very little possibility of telling the world that you had one for sale, which kept prices low. Now they are gradually rising to match demand and it is likely that interest in them will increase with the centenary of WW1 beginning in 2014.

But the current gradual rise in prices doesn't seem to extend to part props such as hubs and single blades. Yours might make around £80 gbp (about $160 usd) at auction here in the UK and a dealer like me might sell it for £130 gbp (260 usd).

With regards,

Bob

[Dave]

And not that it needs much confirmation, but the drawing number P3019 is listed solely for the Scout using the 80 HP Clerget.

[Bob Gardner]

There were nine props made for the Bristol Scout of which yours was the preferred prop, laid down as such by the Air Board which was the predecessor of the Air Ministry. Such a prop cost 19 pounds 8 shillings and tuppence.

With regards,

Bob

[kwatson]

Again thank you very much for the feedback. That's about Gbp 1,070 in todays money! It hadn't even occured to me that Clerget was the name of the engine.
Another interesting feaure of the prop is the way it is made. You can see that from looking at the sawn end. They clearly glued together six 1" thick planks of Mahogany and then passed the resulting block through a lathe I suppose to carve out the shape.
The tip is covered in some kind of laminated fabric - why did that do that?

[Bob Gardner]

Ken,

Because of the drag caused by the fixed undercarriage on early aircraft, it (the undercarriage) was constructed as small as possible, thus leaving very little clearance between the prop tip and the ground.

The aircraft took off from grass fields and the draft caused by the prop turning at full power blew up all manner of dust, grass and twigs which caused gradual erosion to the tip. Hence the fabric. It was an early form of ablative shield. It also maintained the integrity of the prop if the tip just touched the ground and the wood began to split.

This compromise between the length of the prop and the undercarriage size, meant that the prop itself was also sacrificial to some extent. The turnover of props was very high by modern standards. I have read of expert flyers having props replaced three times a week. There is also some evidence from the numbers of props made that the ratio of props to aircraft was about ten to one, these props being distributed along the supply chain at the front, at second line depots, at aircraft parks and in depots in England.

The success of the fabric (incidentally it was linen until around 1917 when a strong form of cotton was successfully manufactured in Lancashire) led to the British covering the entire blades. This improved the integrity so that a prop would get a pilot home even with a number of enemy rounds through it.

By mid 1917, a successful and economic way of making brass sheathing was found and in 1918 many British and German aircraft were found with brss tips. Hitherto, this had indicated either a pusher aircraft or a seaplane where stronger protection was required than could be provided by fabric.

With regards,

Bob

[kwatson]

Fascinating - thanks Bob.
My prop has the numbers 13.3.17 engraved to the left of the hub - is that some kind of calibration code? Above an below this number series are what look like initials - these are quite faint and small. One reads "WD" above an arrow, the other reads "AJD" above the letters "18T".
Any ideas what all this means?
Kind regards

[Bob Gardner]

Hi Ken,

WD indicates the War Department of the British Government, which controlled the British Army which included the Royal Flying Corps.

AID indicates the proof mark of the Aeronautical Inspection Department which was the quality assurance dept of all things aeronautical. Its presence cleared the prop as airworthy. 18T indicates a specific inspector.

13 3 17 indicates the 13th of March 1917. Such dates are often thought to be the date the prop was made but is probably the contract date.

Bob

[kwatson]

I am grateful to you for the information.
I'll be keeping my eyes open for more props as I travel around Texas in the future.
Kind regards