Designed by Roy Chadwick, the Avro 531 Spider was an unsponsored private-venture single-seat fighter. The Spider used a number of Avro 504 components and had a fabric-covered wooden structure with Warren-girder steel-tube interplane struts.
Originally the Spider was powered by a 110hp Le Rhone 9J nine-cylinder rotary engine and flown for the first time in April 1918. Overall performance was not sufficiently in advance of the Sopwith Camel to warrant quantity production. Armament was one fixed synchronised 7.7mm Vickers machine gun, and a 130hp Clerget 9B rotary was later fitted.
The Spider prototype ended its days in the experimental role.
Engine: 130hp Clerget 9B rotary
Wingspan: 8.68 m / 29 ft 6 in
Length: 6.25 m / 21 ft 6 in
Height: 2.38 m / 8 ft 10 in
Wing area: 17.55 sq.m / 188.91 sq ft
Take-off weight: 688 kg / 1517 lb
Empty weight: 437 kg / 963 lb
Max. speed: 193 km/h / 120 mph at SL
Climb to 5000 ft / 1525 m: 4 min
Service ceiling: 19,000 ft / 5970 m
Range: 250 mi
Armament: 1 x Vickers 0.303 in mg
All Aero 