BHP engines

[Kay]

Hi
I've read both the Crowood and the Air Britain books about the DHs but I still didn't manage to understand the difference between what is often referred to as the 200-hp B.H.P. engine and the 230-hp BHP "Puma", maybe because they are sometimes both often referred to as the "B.H.P".
Was the second a completely different engine?Or was it an evolution of the first which was re-named for the occasion?
Of course confusion reaches the top when one reads that *both the Galloway Adriatic and the Siddeley Puma
were often referred to as the BHP Puma, although they were different and not inter-changeable engines.

* : :-/ ???

Thanks in advance.
Kay

Are you confusing B.H.P. with British[or is it Brute?] Horse Power? Having not read the books you mention I may be confused but my reading of your statement leads me to that conclusion ??? But different versions of THE SAME ENGINE can have different power outputs and different countries measure that output in different ways AND use different measurements.Thus BHPand SHP[Shaft HorsePower] will give different numbers for the same engine[that last bit should be in italics!!]In the words of an old TV programme "confused?you will be!!] :-[

[Dan_San_Abbott]

Kay:
The Galloway "Adriatic" 230 hp 6 cylinder-in line engine and the 200 hp Siddeley-Deasy "Puma" were production versions of the 300hp B.H.P. engine that the Air Board put into mass production. The problem arose when Siddeley-Deasy and Galloway made changes in the B.H.P. engine to meet the needs of mass production. This turned out to be a disaster to the D.H.9 program which was to replace the D.H.4 as a 1918 day bomber. To quote Jack Bruce, "The D.H.9 was, in short, a good aeroplane spoiled by a bad engine......"
Blue skies,
Dan-San

[Kay]

Thanks Andy and Dan San,

I read in Windsock Datafile No 72 (Airco DH9) by JM Bruce that:
" the true BHP was produced in relatively small numbers by the Galloway Engineering Co.,its large scale production was in the hands of Siddeley-Deasy (...).Unfortunately in more than one official record these
two different and non-interchangeable engines were quoted as " 230-hp B.H.P." without differentiation.

It would seem therefore that it was just a matter of record keeping, the true output of the Galloway Adriatic and that of the Siddeley Puma being 230 and 200-hp respectively.I still can't understand however why,for example, Ray Sturtivant in *"The DH4/DH9 File" cites some production series powered by the 200-hp BHP (thus the Siddeley Puma) and others by the 230-hp Puma (thus the Galloway Adriatic), has he falled in the same confusion? (I can't believe that).

Thanks in advance

Kay the B in BHP is actually BRAKE.So 230bhp is 230brake horse power,sorry!

[Dan_San_Abbott]

Andy Fox:
The B in BHP does not stand for "Brake". BHP = Beardmore-Halford-Pullinger. These were the designers of the BHP 300hp engine.
Blue skies,
Dan-San

[leo]

True or Not? The BHP's were inspired by German in line engines.

[Aviatik]

I would say true. The early versions followed Austro-Daimler design practices.

[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.....

Dan.I was trying to correct a mistake I made earlier when I said B=brute,this is in lower case as in bhp.I was unaware of BHP engines at the time so wondered if there had been a mistake when writing the thread.Does this make it clear??