[RLWP]

{Here goes, straight from solo into combat}

According to Jane's fighting aircraft of World War 1 (ISBN 1 85170 347 0):

B.H.P Beardmore-Halford-Pullinger

Halford developed a 6cyl watercooled engine in collaboration with Sir W Beardmore and TC Pullen, M.D of Arrol Johnston & Co ltd. At the time this was a 120hp engine.

This was developed to 160hp by Arrol Joston & Co by June 1916 and fitted to a D.H.4.

A new company was set up (Galloway Engineering Co. Ltd) to exploit the new engine. They took the basic design and developed a 12 cylinder Vee, the Atlantic, giving 500hp@1500rpm. This engine seems to have been adopted as a standard and been passed for manufacture to several manufacturers as the Siddeley Pacific (Siddeley-Deasy Motor of Coventry having been producing BHP engines).

That's it for Jane's except... on the next page (p274) is a picture and specification for the 230hp Siddeley "PUMA", a watercooled in-line 6! This seems to be the basis for the Pacific Vee 12.

Incidentally, Jane's refers to engines by horse power H.P. (a British invention by James Watt), and gives output in specifications as Brake Horse Power (B.H.P) at a particular speed. It never refers to shaft horse power.

Jane's is a fascinating, but very confusing book.....