[1] Conceived to replace the Crusader/Zulu on the production lines, Louis Coatalen designed a companion engine for the V-12 Cossack, giving it the name Afridi.
The twin overhead camshafts were driven by gears, directly operating two inlet and two exhaust valves per cylinder.
Those that were built found favour as motor-boat power-plants and only one flew trials in a Short 184 seaplane.
The difficulty is that this gives a slightly different piston stroke and journal rotation centres for each bank, which can lead to unbalance and possible vibration problems.
[1] After initial use by Coatalen, the car was sold to Sir Malcolm Campbell for an attempt at the world land speed record.
The V-12 Tartar was of radically different construction in that individual cylinders formed each bank as opposed to groups of three in integral blocks.
From its 15.4 L (939.8 cu in) displacement the Tartar developed 300 hp (224 kW) but failed to gain any orders; however it may have provided inspiration for the large Sunbeam Sikh airship engine which also had individual cylinders.