Blackburn Perth

The Blackburn Perth was a British flying boat deployed during the inter-war period. It was essentially an upgraded Blackburn Iris and the largest flying-boat to serve with the Royal Air Force (RAF) at the time (and the largest biplane flying boat ever to serve with the RAF). 

Blackburn Perth
Class Aircraft
Type Reconnaissance
Manufacturer Blackburn Aircraft Limited
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1933
Country Name Operational Year Retirement Year
United Kingdom - UK (Great Britain) 1934 1938 View
ManufacturerName Production From Production To Quantity
Blackburn Aircraft Limited 4 View

The Blackburn R.B.3A Perth was designed as a replacement for the earlier Iris to Air Ministry Specification 20/32. Developed from the Iris Mk. V, the Perth first flew in 1933. It differed from the Iris by replacing the Rolls-Royce Condor engines of the Iris by more powerful Rolls-Royce Buzzards and having an enclosed cockpit for the pilots. Unusually, in addition to its normal armament, the Perth was fitted with a Coventry Ordnance Works C.O.W 37 mm (1.46 in) autocannon in its bows.

Four Perths were ordered for service for the RAF.

The Perth entered service with the RAF in January 1934, when the second aircraft was delivered to No. 209 Squadron RAF at RAF Mount Batten Plymouth.[1] Perths remained in service until 1937, being replaced by the Short Singapore and the Saro London. One aircraft was retained by the Marine Aircraft Experimental Establishment until 1938.

Role Flying boat
Manufacturer Blackburn Aeroplane and Motor Company
Designer John Douglas Rennie
First flight 11 October 1933
Introduction 1934
Retired 1938
Primary user Royal Air Force
Produced 1933-1934
Number built 4
Developed from Blackburn Iris

General characteristics

  • Crew: Five
  • Length: 70 ft 0 in (21.34 m)
  • Wingspan: 97 ft 0 in (29.57m)
  • Height: 26 ft 5.5 in (8.06 m)
  • Wing area: 2,461 ft (233.3 m)
  • Empty weight: 20,927 lb (9,492 kg)
  • Loaded weight: 32,500 lb (14,772 kg)
  • Max takeoff weight: 38,000 lb (17,237 kg)
  • Powerplant: 3 x Rolls-Royce Buzzard II MS 12 cylinder water-cooled inline engine, 825 hp (615 kW) each


  • Maximum speed: 115 knots (132 mph, 213 km/h)
  • Cruise speed: 95 knots (109 mph, 175 km/h)
  • Range: 1,130 nm (1,300 mi, 2,093 km)
  • Service ceiling 11,500 ft (3,500 m)
  • Rate of climb: 800 ft/min (4.1 m/s)
  • Wing loading: 13.2 lb/ft (63.3 kg/m)
  • Power/mass: 0.076 hp/lb (0.12 kW/kg)


  • One C.O.W 37 mm automatic cannon in bow
  • Three .303 in Lewis guns in bow, amidships and tail positions
  • Up to 2,000 lb bombs

End notes