BAT Bantam

The BAT F.K.23 Bantam was a British single-seat fighter biplane produced by British Aerial Transport Company Limited of London during World War I.

BAT Bantam
Class Aircraft
Type Fighter
Manufacturer British Aerial Transport
Origin United Kingdom - UK (Great Britain)
Country Name Origin Year
United Kingdom - UK (Great Britain) 1918
Country Name Operational Year Retirement Year
France View
Netherlands View
United Kingdom - UK (Great Britain) 1921 View
United States of America View
ManufacturerName Production From Production To Quantity
British Aerial Transport 15 View

Frederick Koolhoven's first design for the British Aerial Transport Company (BAT) was the F.K.22 single-seat fighter. It was a two-bay biplane of wooden construction. It was planned to have a 120hp (90 kW) A.B.C Mosquito radial engine but the failure of this engine led to the installation of the 170hp (127kW) A.B.C.Wasp I in the first and third aircraft. The second machine was fitted with a 100hp (75kW) Gnome Monosoupape rotary engine and was the first to fly at Martlesham Heath in January 1918. The original contract called for six development aircraft but three aircraft were built as the F.K.23 Bantam I, the second prototype then being renamed the Bantam II. The Bantam I was the same wooden structure but was slightly smaller. Two further prototypes of the larger design were also built followed by at least 9 development aircraft. One aircraft was delivered to the Royal Aircraft Establishment on 26 July 1918, one was delivered to the French at Villacoublay and a further aircraft to the United States Army Air Corps at Wright Field in 1922.

The production Bantam had to be modified due to unsatisfactory spin characteristics of the prototypes. Continuous engine problems and downsizing of the Royal Air Force were factors in no more orders for the Bantam. Koolhoven returned to Netherlands with one aircraft where it was re-engined with a 200hp (149kW) Armstrong Siddeley Lynx radial engine. Several examples were operated as civil racing aircraft.


  • F.K.22 Bantam I : Prototypes and evaluation version, 2 built.
  • F.K.23 Bantam II : Production aircraft, 3 prototypes + 9 aircraft were built.

Role Single-seat Fighter
Manufacturer British Aerial Transport Company Limited
Designer Frederick Koolhoven
First flight 1918
Introduction 1921
Primary user Royal Air Force
Number built 15

General characteristics

  • Crew: 1
  • Capacity: 378 lb (171.46 kg) disposable load
  • Length: 18 ft 5 in (5.61 m)
  • Wingspan: 25 ft (7.6 m)
  • Height: 8 ft 2 in (2.49 m)
  • Wing area: 185 sq ft (17.2 m2)
  • Empty weight: 830 lb (376 kg)
  • Gross weight: 1,333 lb (605 kg)
  • Fuel capacity: 22 imp gal (100.01 l; 26.42 US gal)
  • Powerplant: 1 × ABC Wasp II 7-cyl. air-cooled radial piston engine, 200 hp (150 kW)
  • Propellers: 2-bladed BAT tractor 5 ft 4 in (1.63 m) pitch, 7 ft 10.5 in (2.400 m) diameter


  • Maximum speed: 138 mph (222 km/h; 120 kn) at sea level
    134 mph (216 km/h; 116 kn) at 10,000 ft (3,048.00 m)
    127 mph (204 km/h; 110 kn) at 15,000 ft (4,572.00 m)
    121 mph (195 km/h; 105 kn) at 20,000 ft (6,096.00 m)
  • Landingspeed: 50 mph (80 km/h; 43 kn)
  • Endurance: 3 hours 30 minutes
  • Service ceiling: 20,000 ft (6,096 m)
  • Rate of climb: 1,579 ft/min (8.02 m/s)
  • Time to altitude: 5,000 ft (1,524.00 m) in 3 minutes 10 seconds
    10,000 ft (3,048.00 m) in 7 minutes 12 seconds
    15,000 ft (4,572.00 m) in 21 minutes 29 seconds
  • Wing loading: 7.2 lb/sq ft (35 kg/m2)
  • Power/mass: 0.1274 hp/lb (0.21 kW/kg)


  • Guns: 2× forward firing, synchronised 0.303 in (7.7 mm) Vickers machine guns

End notes