Sopwith Triplane Typhoon

Armstrong Whitworth F.K.2 and F.K.3

For a description of the format and data included in Production Tables, see here.

Type Description and Production Data

F.K.2 F.K.3
Production Summary
F.K.2
Two-seat, two-bay, equal-span tractor general-purpose biplane, designed as an improvement over the B.E.2c, with a simplified structure that was easier to build. It differed from the B.E.2 in eliminating welded joints and complex metal components in the structure, and having greater dihedral on the upper wing. It retained the seating layout of the B.E.2, with separate cockpits for the pilot and observer, with the latter in front. Compared to the un-numbered, two-seater of 1915 (see note 1), it featured a larger, comma shaped rudder and revised wingtips. The fabric covered staggered mainplanes featured ailerons on all four wings. The undercarriage main legs were attached to vertical oleo shock-absorbing members; it had a single central skid ahead at the wheels as an anti-overturn provision. One 70 h.p. Renault or 90 h.p. RAF 1a powerplant.
Production Details
Serial Range C/n Batch
Qty
Conv. Canc'd Notes
 1 aircraft built by Armstrong Whitworth, Gosforth.
 none    1      See note 1
 7 aircraft ordered from Armstrong Whitworth, Gosforth, to Contract 94/A/103 dated September 1915.
 5328 - 5334    7      
 1 aircraft of unknown provenance - see note 2.
 A1967    1      
Total Production 9

F.K.3
Production version of the F.K.2, with a new fin and rudder and both crew placed in a single, extended cockpit with the pilot forward, allowing the observer a more effective field of fire with his single, pillar mounted Lewis gun. One 90 h.p. RAF.1a powerplant. Many were re-engined with the 140 h.p. RAF.4a and twelve aircraft were fitted with longer and heavier 120 hp Beardmore. To carry the extra weight, span was increased by 2 ft, but though the extra power enhanced the climb rate, top speed was little changed and these machines were converted back to RAF engines when they became available. From to the letters "A.W." embossed on the metal engine cowling, the F.K.3 gained the nickname "Ack-W"; with the aarival of the F.K.8, this got changed to "Little Ack", the larger F.K.8 being "Big Ack".

F.K.3 (RAF.1a) Specification
Span Length Height Wing Area Empty Wt Max AUW Cruise Speed Maximum Speed Endurance Service Ceiling
40 ft 1 in 29 ft 11 ft 11 in 442 sq ft 1386 lb 2056 lb 87 mph/ 76 kn 3 hr 12000 ft
12.22 m 8.84 m 3.63 m 41.06 m2 629 kg 933 kg 140 km/h 3658 m

Production Details
Serial Range C/n Batch
Qty
Conv. Canc'd Notes
 1 aircraft built by Armstrong Whitworth, Gosforth.
 none    1      See note 1
 7 aircraft ordered from Armstrong Whitworth, Gosforth, to Contract 94/A/103 dated September 1915.
 5328 - 5334    7      
 1 aircraft of unknown provenance - see note 2.
 A1967    1      
Total Production 9
Known F.K.3 Rebuilds
Serial Range Notes
 A9972  
 B8827  Built from spares and salvage by 7th Wing ARS
 B9968  
 F4219  Built from spares and salvage by 26 TS
Total Rebuilds  (4)
Civil Registered F.K.3
C/n Initial
Registration
Military Serial Notes
 4 aircraft converted as indicated in 1919.
   G-EABY  B9629  To E.D.C. Herne, Porthcawl. Marked 'Porthcawl' on fuselage side.
   G-EABZ  B9518  To E.D.C. Herne, Porthcawl. Marked 'Rhondda' on fuselage side.
   G-EAEU  B9612  To Kingsbury Aviation Co.
   G-EALK  B9603  To L.G. Lowe.
Total Production  4

Production Summary

All Aircraft By Type and Constructor
Constructor F.K.2 F.K.3
Built Canc'd Built Canc'd
 Armstrong Whitworth 9 0 143
 Hewlett and Blondeau 200 150
9 0 343 150

Notes

  1. One un-numbered, two-seater was produced in 1915. It is assumed that this was effectively the prototype of what was to become the F.K.2 [3]
  2. A1967 allocated July 1916; reported to have 70-hp Renault. The exact origin and status of A1967 are not clearly known [3].

Production References

  1. Armstrong Whitworth Aircraft Since 1913, Oliver Tapper (Putnam, 1973)
  2. The Aeroplanes of the Royal Flying Corps, J.M. Bruce (Putnam, 1982)
  3. Windsock Mini Datafile 13, The AW FK.3, J.M. Bruce (Albatross Productions, 1998)
  4. British Military Aircraft Serials, 1878 - 1987, Bruce Robertson (Midland Counties Publishing, 1987)
  5. Contract ledger in AIR 20/761 via http://www.airhistory.org.uk/rfc/aircraft.html

Page Revision History

Revised at Version 2.0.0
  • Added Type Description and Specification details.
  • Added Requisition Numbers.
  • Added Contract Table.
  • Corrected note 1.
  • Added missing note 2.
Revised at Version 1.4.0
  • Moved A1967 from Rebuild to FK.2.
  • Added civil registered FK.3.