11/30/2007. Remarks by Johan Visschedijk
: "The T.B. (Twin Blackburn, the company’s first multi-engined aircraft) was ordered as a long-range anti-Zeppelin floatplane. As armament 72 Ranken steel darts were carried, each weighing one lb (0.45 kg), to be trown from above at the Zeppelin. However, its two 100 hp Gnome Monosoupape rotary engines supplied insufficient power to climb above 8,000 ft (2,438 m). The first of 9 aircraft flew in August 1915, they saw limited service and all were broken up in 1917."