Help needed on propeller identification

[Karl]

Hello
This is my first post on the forum, the reason being I have just bought myself my first wooden propeller. The markings on it are: 561 No59 9720 P3000 80HP GNOME SCOUT, D2500 P2200, G561 No59 9720. I know some of the Bristol Scouts had 80HP Gnome engines so could that be what this is off? As I said I am new to this, and I appreciate the wealth of knowledge on this forum, so any help with interpreting these markings would be very much appreciated.
Thanks

[Bob Gardner]

Karl,

Your data translates as;

9720; prop maker's serial number
P3000; The drawing number of the prop, designed by the British & Colonial Aeroplane Co. Ltd
80HP GNOME SCOUT; The French rotary engine
D2500; Diameter in mm
P2200; Pitch in mm
G561 No59; Propeller no 59 in batch 561

The prop was the standard prop authorised for the Bristol Scout C and the Sopwith Pup. Most were made of walnut, which cost the government £12-5s-0d. Some were mahogany £12-15s-0d.

Both aircraft were made initially for the Royal Navy. But if your prop has small squares about 7mm x 7mm containing the letters AID, it was made for the RFC. If instead there is a small circle of about 10mm diameter containing the letters ADP, it was made for the RNAS.

The batch number 561 was very probably made by The British & Colonial Co. and dates from around Spring 1918.

With kind regards,

Bob

[Bob Gardner]

Karl,

Postscript; my book, Part 2 in my series on British WW1 aircraft props, has fifty pages describing the props of the British & Colonial Co, should you wish to read further.

With kind regards,

Bob

[Karl]

Bob
Thank you for that great information, and I am so pleased to confirm it is WW1. It has three of the square AID marks as well as a A and arrow, which is I assume the aviation equivalent of the WD arrow army mark? If this prop was made by the British & Colonial Co would it have been made for the Bristol Scout or could it just have been likely fitted on a Sopwith Pup? Would the manufacture date indicate what type it would have been used on? 1918 is late for the Bristol scout, but maybe they were still in use at that date for training? Also by 1918 I think the Sopwith Pups had changed to a more powerful engine. By 1918 were they making these as spares for existing aircraft? I don't know how often a propeller needed changing, was it part of a regular maintenance service, like changing tyres on a car?
Thanks again for the information, I wanted a WW1 propeller and bought this speculatively as I thought it looked early, so I am so pleased the markings confirm it.
Regards
Karl

[Bob Gardner]

Karl,

As there are AID stamps on your prop it was made for the Army, for the Royal Flying Corps. AID incidentally indicates the Aeronautical Inspection Department and the presence of their stamps shows that your prop was passed as airworthy and hence might have flown. This would be confirmed by witness marks where the hub plates pressed on the hub and by a slight ovality in the bolt holes.

As your prop was made for the RFC it is most probably from a Sopwith Pup, which reached its zenith in the summer and autumn* of 1917 so many would still be around nine months later in early 1918. I think that the 100hp Pup was a minority, used only in the Home Defence Squadrons.

I think it unlikely that your prop was made by Bristol. This Bristol design was selected by the Air Board in late 1917 as the best available for the Pup and Scout and was made by several makers. Perhaps you could post here photographs of the data from which I might be able to identify who made it. And please let me know the AID numbers; I know some of the numbers used at the Bristol prop shop.

*Lamberton & Cheesman

With kind regards,

Bob

[Karl]

Thanks Bob
I've tried taking some photos this evening but not very good in artificial light so I will try again tomorrow evening, outside, weather permitting. The markings don't show that well, I'm afraid the prop has been knocked about a bit during it's life. The person I bought it off said it had been hung up in a pub for many years. I'll be back in touch tomorrow.
Kind regards
Karl

[Karl]

Bob
I've attached 3 photos, one showing the central boss with the writing around it, another of the AID marks, there are four in total, the two on the right are barely visible though. The number on the lower left one is either E63 or E68 I think, and the third photo is of the whole prop. There is no gun setting line on the central boss which I have seen on other propellers. Was the line used for setting up the sychronisation of the gun firing? Would the absence of such a line indicate that the plane this was meant for didn't have a gun which fired through the propeller?
Kind regards
Karl

[Bob Gardner]

Karl,

Thank you for the photographs which are a great help. The layout of the data is in the style of B & C, although their usual stamped B & C is missing.

The AID inspector 63 is recorded on Bristol Props, although not with the suffix E.

I have been researching the records of Bristol's prop shop to find a definitive answer for you. Below are the batch nos, the G nos, from late 1917 to mid 1918. Each line records the batch no., the drg no. where recorded and the aircraft type, and date where recorded in the ledger. The Sopwith Pup was officially known as the Sopwith Scout and is so described in the B & C ledger, so I use this term here.

You will see that your G no., G561, was in the last batch of props made by B & C during the war, the batch running from G554 to G562. All were Sopwith Scouts. It would appear that all were made to drg no. P3012, except for G562 where P3000 was used.

Note that almost all Sopwith Scout props made by B & C from late 1917 onwards used drg no P3012, except for G561 which used P3000.

The ledger description of your batch no. is undated but G843 is dated 30 July 1918 and G995 is dated June 1926.

• G Nos
  129-130; P3012 Bristol Sc, Sop Sc
  264; P3012 Sop Sc
  302-306; P43 Bristol Sc, Bristol F2B, Jan 18
  337-338; P43 Bristol Sc, Mar 18
  397; P3012 Sop Sc
  404-5; Sop Sc, Bristol Sc
  430-434; Bristol Sc, Mid Feb to mid Mar 18
  451-52; Bristol F2B
  554-562; Sop Sc, P3012 and P3000
  
  With kind regards,
  
  Bob
  

[Bob Gardner]

Postscript; the condition of your prop is excellent. Most are in a far poorer condition than yours. It's best left as it is except that cleaning gently with warm water and a little washing-up liquid (as a degreaser), leaving it to dry for some days, and then polishing it carefully with pure bees wax, will transform it. You can buy tins of bees wax from B & Q in Britain.

Bob

[Karl]

Thanks Bob
I really appreciate your efforts on this, I didn't ever expected to get such a detailed response. I wanted to display a picture of the appropriate plane next to the prop so it is good to get it narrowed down to a single type, and a Sopwith Pup, I couldn't be happier. As you can see from the photos the prop has had a rough life, but I'm happy with it, faults and all. I hope I still look as good when I'm 96! I really can't thank you enough for looking out this information for me, you certainly know your stuff!
Kind regards
Karl

[Karl]

Bob
I sent my last reply before I read your postscript. Yes, I will do minimum to the prop, I understand the importance of keeping it as original as possible. Interestingly, when I got it, the tips were covered in black sticky backed plastic. It looked as though it had been done years ago, probably to improve the look, and the plastic covering itself had worn through in places, I assume due to years of bad handling. As the plastic was split and cracked in places I decided to remove it. It peeled off quite easily to reveal a good amount of the original fabric covering underneath which I was pleased about. Unfortunately one of the propeller blade edges has broken off some time in the past over a length of about 18 inches, but there's nothing I can do about that. The way I look at it is it is lucky to have survived at all, most of these must have been cut up, thrown out etc over the years, and I will give it a good home from now on! Thanks again for all your help.
Kind regards
Karl