Using cast aluminium alloy cylinder blocks and heads with die-cast aluminium alloy pistons, the Arab had a bore of 4.72 in (120 mm) and stroke of 5.12 in (130 mm) for a capacity of 717.76 cu in (11.762 L), developing 208–212 hp (155–158 kW) at 2,000 rpm.

[1] First bench-run in 1916, the Arab was obviously inspired by the Hispano-Suiza V-8 engines but with very little in common when examined in detail.

The order formed part of the strategy of Sir William Weir to bypass the skilled engineering workforce needed to build Rolls-Royce Eagle and Falcon engines, through the use of cast aluminium cylinder blocks that minimised the need for machining.

[2] However, the Arab was ordered before flight testing, and when the engine went into the air, chronic vibration problems emerged which were never cured.

[3] Despite this massive manufacturing effort, the Arab proved largely useless, and nearly half of the production run of the Bristol Fighter, Britain’s best two-seat fighter of the First World War, went into storage because plans to power the aircraft with the Arab were abandoned due to the engine’s failings.