Model Variants (Including Prototypes)
"Sopwith Gunbus" - Base Series Name
"Greek Seaplane" / "Pusher Seaplane" - Original name used on early Greek Navy order for two-seat training seaplanes; powered by Anzani radial piston engine of 100 horsepower.
S.P.Gn ("Sopwith Pusher, Gun") - Two-seat armed fighting biplane seaplanes for Greek Navy; armed through 1 x 7.7mm machine gun at the bow (flexible mounting); powered by Gnome Monosoupape rotary piston engine.
Admiralty Type 806 - Royal Navy Air Service designation for revised design; fitted with Sunbeam V8 water-cooled engine of 110 horsepower; 1 x 7.7mm machine gun armament; two modified as landplanes from five-strong fleet.
"Gunbus" - Definitive form with Sunbeam engine of 150 horsepower output; pilot position switched to front of fuselage with gunner at rear; bomb panel added to fuselage floor; bomb carriers added under lower wing assembly; 30 aircraft ordered with 17 completed and 13 withheld for spares; official wartime operation from February 1915 until very early 1916.