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Springcot 3
11-16-2009, 07:07 AM
I have a propeller which I am keen to date accurately.Stamped on the hub is :-

EBORA (star of dots) PROPELLER Co.Ld.

TYPE (DOT)95A(star of dots) No 796 (dot) E2 FR.B.

PAT:A P:6210/17 (dot)

150(dot)H(dot)P(dot) HISPANO(dot)

SPAD(dot)S(dot)7(dot)

DRg 108A DIA 8ft(dot) 8Pn. P. VAR(dot)

In the above I have used the word "dot" where it is situated in the middle of the line, and the lower case where the letter is in fact a small capital situated at the top of the line.

The crankshaft mounting hole is 2 3/4" in diameter. Near the hub on one side is a large "1" with a small square with "A10" and "1 0" inside it. This is repeated on the other blade with a large "2" instead of "1".

Any info. would be gratefully appreciated

Bob Gardner
11-16-2009, 11:25 AM
Good Afternoon Springcot,

Welcome to the forum.

Your prop dates from late 1916 to mid 1917.

This data is very different from most on British props. It describes an Ebora type 95 prop. Ebora was an English prop making firm in Kingston on Thames owned by a Dutchman Jan Schiere who was educated in France and first worked for Handley-Page.

The term DRG NO 108A does not relate to a British drawing number and might possibly refer to the French serie numero 108. British props on French-built aircraft used by the British were often copies of the original French prop and Éclair made a series of props for the 150hp Hispano beginning with serie 100 for a 150hp Hispano all of which had a diameter from 7ft 8ins to 8ft 0ins, the same as this prop.

P var indicates Pitch variable but this does not mean that it is a variable-pitch prop in the modern sense, merely that there were several different pitches for a prop of this design. The reference to a patent application might indicate that it was a new design, as perhaps does ‘Pitch variable’.

French prop designs were adopted by the Army Board and given an AB drawing number, although I have no records of any for the earliest SPADS with 150hp engines. But the dimensions and shape of this prop suggest that it is AB761.

The serial no of the prop is 796. I have seen another example with the serial number 1012.

With kind regards,

Bob

Bob Gardner
11-16-2009, 11:39 AM
Afternote;

The British used about 185 SPADs. A few, perhaps 30, were French built. The remainder were built by Mann Egerton and the English Bleriot and SPAD Co Ltd.

Bob

Springcot 3
11-17-2009, 01:27 PM
Hi Bob,

Thank you so much for the info. I mentioned that near the hub on one side is a large "1" with a small square with "A10" and "1 0" inside it. Could you explain this please.

I acquired the prop in the '70's, and from what I read on the web site, did the right thing by not touching it in any way restoration - wise.

I was tempted to re-glue the fabric at the very tips where it had slightly come away from the surface, but even managed to resist that!!

Thanks again for your help,

Kind regards,

Ian

Bob Gardner
11-17-2009, 02:30 PM
Good Evening Ian,

You have done well in looking after your prop. The crucial thing to remember is that it can always be restored at some time in the future but doesn't have to be done immediately.

The letters to which you refer are AID for the Aeronautical Inspection Department. These are in effect the air worthiness stamps. Each inspector had his own number, here AID 10.

If any other forumites have an Ebora prop that might be for sale could you let me know as I am gathering one or two for the descendents of the original maker.

With kind regards,

Bob