04/30/2019. Remarks by Johan Visschedijk: "Deriving its extraordinary appellation from a characteristic arrangement of cabane struts - a name that was initially unofficial, but came to be accepted as a result of common usage - the 1½-Strutter was both the first British aircraft to be built with a synchronized gun as standard equipment and the first true two-seat fighter to see RFC service.

Designed and built for the Admiralty, the unarmed prototype was completed in December 1915, and series deliveries to the RNAS followed from February 1916.

A single-bay biplane of wooden construction with fabric skinning, the 1½-Strutter featured air brakes in the lower wing and an adjustable incidence tail plane. At an early production stage, armament was standardized on a synchronized 0.303 in (7.7 mm) gun with a second weapon of similar caliber on a Scarff ring mounting in the rear cockpit.

1½ Strutter in RFC markings (Van Swindelle Collection)

The 1½-Strutter was used by the RNAS in both escort and (without observer) bombing roles, and 77 of the first 150 aircraft ordered by the Admiralty were transferred to the RFC owing to the exigencies of the times. A single-seat bomber version of the 1½-Strutter was built in parallel, some examples of this variant being converted as two-seat fighters. Initial production aircraft were powered by the 110 hp Clerget 9Z nine-cylinder rotary engine, but, in the autumn of 1916, this gave place to a 130 hp Clerget 9B.

1½ Strutter built by Ruston Proctor (Bryan Gibbins Collection)

At least 1,513 1½-Strutters were built in the UK (by the parent company, Egerton, Fairey, Hooper, Mann, Ruston Proctor, Vickers, Wells and Westland). The 1½-Strutter was license-built in France as a single- and two-seat bomber (Sop 1B1 and Sop 1B2) and two-seat reconnaissance aircraft (Sop 1A2), primarily with the 110 hp and 135 hp Le Rhóne 9J and 9Jby nine-cylinder rotaries, 4,500 allegedly being produced by Amiot, Bessoneau, Darracq, Esnault-Pelterie, Hanriot, Liorè et Olivier, and Sarazin.

1½ Strutter supplied to Belgium (Bryan Gibbins Collection)

The US government procured 514 from France, and others were supplied to Belgium and Russia."