B.A.T. F.K.26

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Contents

Type Description

• F.K.26
• Four-passenger biplane transport aircraft, of wooden and fabric construction, with the passengers in an enclosed cabin and pilot above and behind in an open cockpit. The fuselage was of rectangular section, very deep near the wings and tapering to a vertical knife-edge at the rear. The front half, from the nose to the end of the passenger cabin, was built up of three-ply, formers and six main ash longerons, mostly of L-section. Five transverse formers divided it into three separate compartments: engine compartment, the fuel tanks and the passenger cabin. These were built up mainly of H-section members reinforced by three-ply, plus diagonal H-section struts between each former, on the fuselage sides. The first and second formers carried the strong ash engine bearers, the third and fourth were placed in line with the front and rear wing spars respectively - the fourth former being in the centre of the passenger's cabin (with no cross members except at the top and bottom), while the fifth served as the end wall of the cabin. Between this and the fourth former was a false former of light construction. The engine and fuel compartments had a single outer covering of three-ply, whilst the cabin portion had a double (inner and outer) covering. Aft of the cabin the fuselage was a box girder of six bays, with four spruce longerons. With the exception of the last one, all the bays were braced with steel cable, the last bay having H-section diagonal struts and a three-ply covering. The pilot was located in the second bay, being supported fairly high up in the fuselage by two channel-section bearers on a three-ply floor. This rear portion of the fuselage was covered with fabric, except for the top, which had a three-ply turtledeck.
  The passenger cabin was exceptionally roomy, measuring roughly, 3 ft. in width, 8 ft. in length, and just over 5 ft. in height, and was furnished with three armchairs and one folding seat, the latter being opposite the door, which was at the rear of the cabin on the port side. Windows, three on the starboard side and two on the port, were fitted with sliding Triplex glass.
  The unswept and unstaggered equal span main planes were made of four interchangeable sections and a centre section to which the upper planes were attached. The centre section was mounted on two pairs of steel struts sloping outwards from formers three and four, each laterally cross-braced by steel wires. The lower planes were attached to a short centre sections, the spars passing through the fuselage and built integral with the respective former. The spars were of laminated I-section, solid where necessary, and the ribs built up of spruce webs and flanges. Tapered ailerons were fitted to both top and bottom planes.The high aspect ratio tailplane featured a curved leading edge and was built in one piece and mounted just above the top longerons, strut braced to the fuselage sides. A triangular fin was mounted above the tailplane with a horn balanced rudder hinged to it and the stern post. One 350 h.p. Rolls-Royce Eagle VII powerplant.

Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
46 ft	34 ft 8 in	11 ft 3 in	580 sq ft	2700 lb	4500 lb	110 mph/ 96 kn	122 mph/ 106 kn	600 mi	8000 ft
14.02 m	10.57 m	3.43 m	53.88 m2	1225 kg	2041 kg	177 km/h	196 km/h	966 km	2438 m

Production Details

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Production Summary

Production References

1. British Civil Aircraft Since 1919, Vol 1, A.J. Jackson (Putnam, 1973)
2. Air Pictorial April 1960
3. Flight 17 Apr 1919
4. British Isles Civil Aircraft Register 1919-2011 (LAAS International)

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