Galloway Adriatic

The Galloway Adriatic was a WW1 era inline-six aircraft engine. In British military service the engine was known as the 230 hp BHP, a designation it shared with a version of the same engine built by Siddeley-Deasy. Although the Galloway and Siddeley-Deasy versions followed a similar design, they had different dimensions and few interchangeable parts. Siddeley-Deasy developed their version of the 230 hp BHP as the Siddeley Puma.

Design and development
Beardmore-Halford-Pullinger (BHP) were initially tasked with developing an aero-engine to compete with the latest German inline six-cylinder models. Although BHP's design was projected to produce 300 hp the engine's output came in below expectations. The original name given to engine was the 200 hp BHP. The engine's name was later changed to the 230 hp BHP to better reflect its actual output. Finally, the engine's name was changed to the Galloway Adriatic.

The Adriatic's cylinders were constructed in groups of three with each block being made from a single aluminum casting. The relatively large and intricate aluminum casting was challenging to produce which led to significant production delays.

Three steel cylinder liners were screwed into a single iron casting which formed the head. A single steel stamping formed the cooling water jacket for groups of three cylinders. It is notable that the Siddeley Puma's cylinder heads and water jackets are made of aluminum.

Each cylinder contained one large inlet valve and two smaller exhaust valves. This unusual three valve per cylinder design was common to both the Adriatic and Puma engines.

The crankshaft was a hollow forging made of chrome-nickel steel supported by eight bearings. Seven were plain bearings made of babbitt alloy encased in steel shells. The other bearing was a double thrust rolling-element bearing which took all the axial load from the propeller. The camshaft was fitted in an aluminum housing running the entire length of the engine.

Ignition system had 100% redundancy with two spark plugs per cylinder and two magnetos. Cylinder firing order was 1,5,3,6,2,4.

Some Adriatic engines were fitted with experimental superchargers designed by Harry Ricardo.

Production
The Adriatic was produced at Galloway’s Kirkcudbright facility near Dumfries in Scotland. Galloway Engineering were a subsidiary of William Beardmore and Company specifically setup to produce Beardmore Halford Pullinger (BHP) engines. Some parts for the engines were produced by Arrol-Johnston (another Beardmore subsidiary) in the town of Dumfries.

The Adriatic was one of a series of upright water-cooled inline aircraft engines produced by Beardmore and its subsidiary companies. Production of these engines had started in 1913 when Beardmore acquired the rights for licensed production of the Austro-Daimler 6. During the time the Adriatic was in production, Arrol-Johnson was producing the Beardmore 160 hp. Both the Galloway Adriatic and the Beardmore 160 hp were partly designed by Frank Halford.

In addition to the 94 Adriatic engines produced by Galloway, the firm also supplied components to Siddeley-Deasy. At the end of WW1, the RAF had 89 Adriatic engines in service versus 3,255 built by Siddeley-Deasy. All of the Adriatic engines were fitted to aircraft based in the United Kingdom.

Applications

 * Airco DH4
 * Airco DH9
 * Avro 529
 * Beardmore W.B.1
 * Bristol F.2 Fighter
 * Airco DH.10
 * Sopwith Rhino