J.Bruce British Aeroplanes 1914-1918 (Putnam)

de Havilland 6

  TOWARDS the end of 1916 it was realised that training aeroplanes must be available in substantial numbers if the expansion of the R.F.C. were to continue. The immediate need was for a machine which would have safe flying characteristics, would be quickly and easily produced, and would likewise be quickly and easily repaired. To meet this requirement, Captain de Havilland designed the D.H.6. The aeroplane was a two-seat tractor biplane, and was remarkable for its almost primitive disregard for aerodynamic refinements of any kind. Structural simplicity was achieved almost to an extreme, and popular legend of the day had it that the square-cut wings were “made by the mile and cut off by the yard”. The fin and rudder were originally of typical de Havilland outline, but even these were replaced by rectilineal surfaces in the production machines.
  The fuselage was made in two parts, which were joined by fish-plates just behind the long communal cockpit. The front portion was covered with plywood, and the rear portion was a conventional wooden box-girder with wire cross-bracing. Production D.H.6s had a flat top-decking; on the prototype it was rounded. The tail surfaces were formed of steel tubing, and the undercarriage was a sturdy vee structure with two steel tube spreader bars between which the axle lay; shock absorption was by rubber cord.
  The square-ended wings were entirely conventional in construction, and upper and lower wings were interchangeable. A very heavily cambered aerofoil section was used, and the concavity of the undersurface was pronounced. This feature earned the D.H.6 the nickname of “The Clutching Hand”, and the tall exhaust stacks are usually regarded as responsible for the machine’s other soubriquet of “The Sky Hook”; but the D.H.6’s unhurried progress may also have had something to do with the latter name. The peculiar long undivided cockpit earned the D.H.6 the two lesser-known but picturesquely uncomplimentary nicknames of “The Flying Coffin” and “The Dung-hunter”. The reason for the former is obvious; the latter was bestowed by the Australians because the large cockpit bore an alleged resemblance to a certain type of farm vehicle. In more polite R.F.C. colloquy the type was frequently referred to as “The Sixty”, and occasionally as “The Crab” or “The Clockwork Mouse”.
  The standard engine for the D.H.6 was the 90 h.p. R.A.F. ta, but considerable numbers were also built with the 90 h.p. Curtiss OX-5 engine. The wings of the Curtiss-powered machines were rigged with negative stagger. When supplies of these engines ran short the 80 h.p. Renault was substituted. The first production contract for 700 D.H.6s was placed on January 13 th, 1917, with the Grahame-White Aviation Co., and by the end of the following June, thirty-seven had been delivered.
  The D.H.6 was widely used on training duties at home, in the Middle East, and in Australia. In this work its very indifferent performance mattered little, and its complete lack of vices made it a safe elementary trainer. It was, in fact, almost too safe, for it could be flown with little regard to air speed, had an innocuous stall, and was virtually unspinnable. Towards the end of 1917, the Avro 504K was adopted as the R.F.C.’s standard trainer, and production of the D.H.6 was thereafter tapered off.
  At about this time the depredations of U-boats among Allied merchant ships reached alarming proportions. A remarkable fact was that the number of ships sunk at a distance of less than ten miles from land rose steadily until it represented 60 per cent of the total number of sinkings. At the end of January, 1918, the Commander-in-Chief of the Grand Fleet asked for additional aircraft to patrol coastal waters between the Tyne and the Tees: this area was one of particular danger.
  As a temporary expedient the Air Ministry placed two Flights of D.H.6s and two of F.E.2b’s at the disposal of the Admiralty early in March; both D.H.6 Flights were stationed at Cramlington. So far from being a mere stop-gap, the D.H.6 remained in service as an anti-submarine aircraft until the Armistice, and its use in that capacity was greatly extended in June, 1918. By this time the D.H.6 was being withdrawn from training duties, and some 300 were surplus to requirements. The Air Ministry offered to provide the Admiralty with thirty-two further Flights of D.H.6s, a total of 192 aircraft, for antisubmarine patrol. The Admiralty accepted this offer. Twenty-seven of the Flights were established at various coastal aerodromes, and the remaining five Flights of D.H.6s were operated by the U.S. Naval Air Service for patrols off the Irish coast. (American personnel were available but had no aeroplanes to fly at that time.)
  The anti-submarine D.H.6s operated under appalling conditions, and much hardship was endured by the men who flew and serviced them. Most of the crews were men who were no longer fit for operational duties, but they were always overworked because the Flights were never up to strength. On patrol, the D.H.6 was almost always flown solo, for it was incapable of lifting both an observer and a load of bombs; but about one machine in four was used as a two-seater for convoy work, which necessitated the presence of an observer who could use an Aldis lamp.
  In an attempt to improve performance, after March 14th, 1918, the D.H.6s still in service were rigged with a backward stagger of 10 inches, and the aerofoil section was modified to have much less undercamber. At about this time new elevators and a new rudder, all of reduced chord, were fitted. These modifications added a few miles per hour to the maximum speed, but did nothing to improve the machine’s weight-lifting capabilities. Flotation gear was installed on at least one Curtiss-powered D.H.6, and the aircraft was tested in November, 1918.
  At best, the use of the D.H.6s as anti-submarine aircraft was mere bluff, based on the theory that submarine commanders would not surface nor use their periscopes in areas known to be patrolled by aeroplanes. However, the machines had their moments of action. On May 30th, 1918, a coastal D.H.6 bombed the submarine U.C.49 a few moments after it had torpedoed the S.S. Dungeness; the U-boat crash-dived and escaped.
  After the Armistice a considerable number of D.H.6s came on to the British Civil Register, and others pioneered air transport in the Empire, notably in Australia and South Africa. A D.H.6 was reported to be still in existence at Geelong West, Victoria, as late as 1937.


SPECIFICATION
  Manufacturers: The Aircraft Manufacturing Co., Ltd., Hendon, London, N.W.
  Other Contractors: The Grahame-White Aviation Co., Ltd., Hendon, London, N.W.; The Gloucestershire Aircraft Co., Ltd., Cheltenham; Harland & Wolff, Ltd., Belfast; The Kingsbury Aviation Co., Kingsbury; Morgan & Co., Leighton Buzzard; Ransome, Sims & Jeffries, Ipswich; Savages, Ltd., Stroud. Power: 90 h.p. R.A.F. ia; 90 h.p. Curtiss OX-5; 80 h.p. Renault.
  Dimensions: Span: 35 ft 11 1/8 in. Length: 27 ft 3 1/2 in. Height: 10 ft 9 1/2 in. Chord: 6 ft 4 in. Gap: 5 ft 8 1/2 in. Stagger: originally nil, later 10 in. backwards. Dihedral: 2°. Incidence: 4°. Span of tail: 12 ft. Wheel track: 5 ft 7 3/16 in. Airscrew diameter: 9 ft 2 in. (with R.A.F. 1a engine).
  Areas: Wings: upper 224-3 sq ft, lower 212 sq ft, total 436-3 sq ft. Ailerons: each 19 sq ft, total 76 sq ft. Tailplane: 36 sq ft. Elevators: 26 sq ft. Fin: 5-5 sq ft. Rudder: 12 sq ft.

  Weights (lb) and Performance:
Engine R.A.F.1a Curtiss Curtiss with flotation gear
No. of Trial Report - N.M.239 N.M.239
Date of Trial Report - November 12th, 1918 November 12th, 1918
Type of airscrew used on trial - A.D.543 A.D.543
Weight empty 1,460 1,539 1,624
Military load Nil Nil Nil
Crew 360 180 180
Fuel and oil 207 207 207
Weight loaded 2,027 1,926 2,011
Maximum speed (m.p.h.) at
2,000 ft - 75 72-5
6,500 ft 66 - -
m. s. m. s. m. s.
Climb to 6,500 ft 29 00 35 00 45 00
Service ceiling (feet) - 6,100 5.400

  Tankage: Petrol: 25 gallons. Oil: 4 gallons.
  Armament: When used for anti-submarine patrol, one 100-lb bomb or a roughly equivalent weight of smaller bombs was carried.
  Service Use: Widely used at training aerodromes in the United Kingdom, e.g. No. 1 Training Depot Squadron, Stamford; No. 39 Training Squadron, Narborough; No. 42 Training Squadron, Hounslow; No. 44 Training Squadron, Waddington. Home Defence: No. 77 Squadron. Middle East: 20th Training Wing, Abu Qir. Australia: Central Flying School, Point Cook, Werribee, Victoria. For anti-submarine patrols: Tyne, two Flights at Cramlington; Humber to Tees, five Flights; Tees to St Abbs Head, four Flights (e.g. at Tynemouth, Sea Houses and Elford); Portsmouth Group, four Flights; South Western area, eight Flights (including No. 250 Squadron at Padstow); Irish Sea, six Flights; Ireland, five Flights operated by U.S. Naval Air Service.

  Serial Numbers:
Serial Nos. Contractor Contract No. |
A.5175-A.5176 Aircraft Manufacturing Co. -
A.9563-A.9762 Grahame-White Aviation Co. 87/A/1359
B.2601-B.3100 Aircraft Manufacturing Co. 87/A/1844
B.9031-B.9130 Aircraft Manufacturing Co. A.s.17567
C.1951-C.2150 Grahame-White Aviation Co. 87/A/1359
C.5126-C.5275 Kingsbury Aviation Co. A.S.22909
C.5451-C.5750 Harland & Wolff A.S.19062
C.6501-C.6700 Morgan & Co. A.S.20465
C.6801-C.6900 Savages A.S. 19896
C.7201-C.7600 Ransome, Sims & Jeffries A.S. 18918
C.7601-C.7900 Grahame-White Aviation Co; 87/A/1359
C.9336-C.9485 Gloucestershire Aircraft Co. A.S.32956
D.951-D.1000 Grahame-White Aviation Co. A.S.32667
D.8581-D.8780 Aircraft Manufacturing Co. -

  Production and Allocation: Contracts were placed for a total of 2,850 D.H.6s. A total of 2,282 were completed, and 1,754 of those were distributed to R.F.C. and R.A.F. units. Training units received 1,531; Home Defence units received seventy-one in 1918; and 152 went to the Middle East. The R.A.F. had 1,050 D.H.6s on charge on October 31st, 1918. Of these, sixty-nine were in Egypt and forty were en route to the Middle East; thirty-three were at schools in the U.K. and a similar number with Home Defence units; eight were in Ireland; 594 were at various aerodromes; five were at Aeroplane Repair Depots, two with contractors, and the remaining 266 were in store.
  Costs:
   Airframe without engine and instruments,
   (i) for R.A.F. 1a £841 10s.
   (ii) for Curtiss £885 10s.
   Engines: R.A.F. la £522 10s.
   Curtiss OX-5 £693 10s.

A.Jackson British Civil Aircraft since 1919 vol.1 (Putnam)

De Havilland D.H.6

   Over 2,000 D.H.6 primary trainers were built by the Aircraft Manufacturing Co. Ltd. and seven main sub-contractors during 1917-18. For a brief period it was the standard trainer of the R.F.C., and for ease of maintenance and repair was built with an eye to structural simplicity rather than beauty of line. It was a rugged two-bay biplane of primitive aspect, seating instructor and pupil in tandem in a single cockpit. Although of orthodox wire-braced wooden construction with fabric covering, the sides of the front fuselage were plywood covered and the 90-h.p. R.A.F. 1A V-eight air-cooled motor was bolted to the top longerons without any pretence at cowlings. A small number were fitted with Curtiss OX-5 water-cooled engines with a radiator which somewhat improved the frontal appearance.
   When civil flying began after the war, over 50 D.H.6s or ‘Clutching Hands’ - a soubriquet deriving from their heavily cambered wings - were sold for civil purposes. The first of these was notable for being the first aeroplane in the United Kingdom, and probably in the entire world, to receive civil markings. As K-100, first of the temporary British series, it was flown a great deal at the Hendon race meetings by Capt. Gathergood and others during the summer of 1919. It was a unique aircraft fitted with one of the horn-balanced rudders of typical D.H. shape taken from one of the prototypes, instead of the standard straight-sided production type. In March 1920 the Marconi Wireless Telegraph Co. Ltd. bought it for experimental R/T work, after which it became well known at Croydon. There, as G-EAAB, it was flown continuously by Mr. G. Shaw until written off in a crash in November 1921. The strength, the ample spares backing and the unbelievably safe flying characteristics of the D.H.6 made it an obvious choice for instruction. G-EALS and ’LT were operated by the Cambridge School of Flying at Hardwicke Aerodrome during the summer of 1919 and two others, G-EAGE and ’GF, were in use during the same period at Hendon with the Grahame-White Aviation Co. Ltd. It was more widely used, however, for joy flights, the firms concerned being the Bournemouth Aviation Co. Ltd., Ensbury Park, with G-EAFT; the Golden Eagle Aviation Co. Ltd., Blackpool, with G-EAHD, ’HE, ’PG, ’PH and ’RJ-’RM; the Warwick Aviation Co., Birmingham, with G-EAHH; the Nelson Aviation Co. Ltd., with G-EAJM; Stallard Airways, Herne Bay, with G-EANJ; By Air Ltd., Baginton, with G-EAQB and ’QC; Leatherhead Motor Services Ltd., Croydon, with G-EANU; the International Aviation Co. Ltd., Hooton, with G-EARA-’RD; Blackpool Flying Services Ltd., with G-EAUS and ’UT and the Manchester Aviation Co. Ltd., with G-EAHI, ’TI and the ex Grahame-White G-EAGE.
   Lancashire was thus the main hunting ground of the itinerant D.H.6, while the beaches of the neighbouring North Wales coast also served as landing-grounds for the Manchester Aviation Company’s aircraft. The career of International’s D.H.6 G-EARB was typical of many. This was a former R.F.C. trainer B 5533 built by Harland and Wolff, first flown as a civil machine on 15 March 1920. At the beginning of the season L. J. Rimmer flew it to Bidston, Cheshire, where it carried out 10 hours’ pleasure flying. Later it made a two-hour flight to the Isle of Man, where a further 12 hours’ flying was completed at Douglas by the end of June. It then rounded off the year’s activities by being blown over in a gale. Although they initially earned a very considerable amount of easy money, the postwar slump of 1920 forced many of these companies out of business and most of the D.H.6s were short-lived. A few were acquired, however, by a select band of pioneer private owners. Grahame-White’s G-EAGF was sold to the Hon. Elsie Mackay in October 1921, Leatherhead’s OX-5-powered G-EANU was acquired by J. V. Yates at Croydon in May 1922, A. B. Ford operated G-EAOT in 1920-21, the late Dr. E. D. Whitehead-Reid was active at Bekesbourne, Canterbury, with G-EAPW in 1920, P. A. A. Boss had G-EAQQ.and H. B. Elwell of Blackpool successively owned G-EAQY, ’RL and ’VR during the period 1922-25. One example was dismantled at Sherburn-in-Elmet and rebuilt as G-EAWG, a monoplane with a 150-h.p. Bentley B.R.1 rotary and an Alula parasol wing as detailed in Appendix A. Another, G-EAWD, had wings of lesser camber and was the private mount of Capt. G. de Havilland, who, in the cold and wet, bravely completed the course to finish last in the Croydon Handicap Race on 17 September 1921.
   From the ruins of early ambition there emerged a new and more lasting phase in the history of the civil D.H.6. After the Director of Research, Air Ministry, had finally approved their modification as three-seaters, they were permitted to carry a second fare-paying passenger at an all-up weight of 2,380 lb. In Lancashire, S. N. Giroux acquired the hangars at Hesketh Park, Southport, and used the beach as his aerodrome, at the same time buying up the aircraft of the International and Golden Eagle concerns. He began operations in 1921 as the Giro Aviation Co. with G-EARC, ’RJ, ’RK, ’RM and ’VG, and in 1959 still offers pleasure flights with vintage Fox Moths from the same pitch. In 1925 a new D.H.6 G-EBEB was built at Hesketh, probably by cannibalization of earlier machines, and was joined in May 1929 by G-EBWG bought from R. J. Bunning, an itinerant joy-rider. These were named ‘Maysbus’ and "Silver Wings’ respectively, and became famous on Southport Sands, giving thousands of holidaymakers their baptism of the air until replaced by Avros 548s in 1933. The Giro premises were used for Anson overhaul during the war, with the result that the stored remains of faithful EB and ’WG, and those of several more elderly examples, were burnt.
   The critical 1921-22 seasons found the Martin Aviation Co. Ltd., another new D.H. 6 operator, doing good business with the three-seaters G-EAWT, ’WU and ’WV in the Isle of Wight. These machines, which were fitted with 80-h.p. Renault motors, became a familiar sight in all parts of the island and were well patronized, although ’WU was written off in a minor landing accident on 31 March 1922. Giro and Martin were virtually the last users ol the D.H.6 as a commercial aircraft, although F. J. V. Holmes of Berkshire Aviation Tours converted G-EBPN and ’VS at Witney in 1926. He toured the Midlands with them for a couple of years until they were sold in April 1928 to British Flying and Motor Services Ltd. at Maylands Aerodrome, Romford. By 1930, when only Giro’s ’EB and ’WG remained in service, V. N. Dickenson produced a final example G-AARN, flying it from a field near St. Albans until he pensioned it off in 1933.


SPECIFICATION
Manufacturers: The Aircraft Manufacturing Co. Ltd., Hendon, London, N.W.g; and other contractors.
Power Plants:
   One 90-h.p. R.A.F. iA.
   One 90-h.p. Curtiss OX-5.
   One 80-h.p. Renault.
Dimensions: Span, 35 ft. 11 in. Length, 27 ft. 3 1/2 in. Height, 10 ft. 9 1/2 in. Wing area, 436-3 sq. ft.
R.A.F.1A 2-seater R.A.F.1A 3-seater Curtiss OX-5 2-seater Renault 3-seater
Tare weight 1,460 lb. 1,670 lb. 1,539 lb. 1,360 lb.
All-up weight 2,000 lb. 2,380 lb. 1,926 lb. 1,900 lb.
Maximum speed. 66 m.p.h. - 75 m.p.h. -
Initial climb 225 ft./min. - 185 ft./min. -
Ceiling - - 6,100 ft. -
Duration 2 3/4 hours 2 3/4 hours 2 3/4 hours 3 1/2 hours


ALULA D.H.6

   D.H.6 fuselage and tail unit fitted with a 200-h.p. Bentley B.R.2 rotary and the Alula high lift wing. Conversion by the Blackburn Aeroplane and Motor Co. Ltd. at Sherburn-in-Elmet 1920 to the designs of A. A. Hoile of the Commercial Aeroplane Wing Syndicate Ltd. One aircraft only: G-EAWG, first flown 2.1.21 by Capt. Clinch, later modified with dihedral from the centre line and braced with a rigid structure below the wing. Flown by F. T. Courtney 4.21, dismantled and despatched to St. Cyr, near Paris for further tests.

O.Thetford Aircraft of the Royal Air Force since 1918 (Putnam)

de Havilland DH 6 (Airco)

   In April 1918 the RAF inherited from the RNAS the DH 6 anti-submarine role, which had been established the previous month. At the end of 1918, the RAF still had 1,060 DH 6s on charge, serving for the most part with thirty-four Flights, deployed around Britain’s coastline and which eventually became Nos 236, 244, 250, 251, 252, 253, 254, 255, 256, 258 and 272 Squadrons of the RAF. Basically trainers, they had been adapted as light bomb-carrying anti-submarine patrol aircraft. Their introduction to this role had been one of several expedients forced on the Admiralty by the growing menace of German submarines around Britain’s coasts. Powerplant: One 90hp RAF la, Curtiss OX-5 or 80hp Renault engine. Span, 35ft 11in; length, 27ft 3in. Loaded weight, 2,027lb. Max speed, 75mph at 2,000ft; service ceiling, 6,000ft.

P.Lewis British Bomber since 1914 (Putnam)

Geoffrey de Havilland’s outstanding versatility as a designer was fully demonstrated in the course of the 1914-18 War as - in turn - he evolved fighters, bombers and trainers. It was as a trainer that the extraordinarily angular D.H.6 was designed and served mainly. Alternatively powered by the 90 h.p. R.A.F.1A, 90 h.p. Curtiss OX-5 or the 80 h.p. Renault, according to availability of supplies, the two-seat, two-bay biplane was never to be considered as endowed with enough power. Consequently, when the D.H.6 was adapted early in 1918 for anti-submarine patrol around the coast of the British Isles, it was at a disadvantage from the start and was perforce flown solo to enable it to carry a single 100 lb. bomb or the same load of smaller missiles. Despite modifications carried out from March, 1918, with the object of improving the performance of the D.H.6 to make it more effective against U-boats, all that was achieved was a slight increase in top speed, but the machine was unable to improve its bomb-carrying ability.

O.Thetford British Naval Aircraft since 1912 (Putnam)

de Havilland 6

   The stark, utilitarian lines of the D.H.6 can be ascribed to the fact that it was designed for rapid and simple production in 1916 at a time when the RFC was expanding and needed many more training aircraft in a hurry. Captain (later Sir Geoffrey) de Havilland achieved this purpose admirably, and over 2,200 D.H.6s were built by the parent company and seven sub-contracting firms.
   Few aeroplanes can have had so many nicknames, for the D.H.6 was variously known as 'The Sky Hook', 'The Crab', 'The Clutching Hand', 'The Flying Coffin', 'The Dung-hunter' and 'The Sixty'. As a trainer, the D.H.6 saw widespread service at home and overseas during 1917, but was gradually withdrawn with the subsequent standardisation of the Avro 504K.
   By a curious turn of events, the D.H.6's decline as a trainer witnessed its introduction in a first-line operational role as an anti-submarine hunter with the RNAS. Early in 1918 the Admiralty asked for additional aircraft to patrol off the coast between the Tyne and the Tees, an area where U-boats were doing great damage, and the first two Flights of D.H.6s formed at Cramlington in March. In June 1918 a further 192 D.H.6s were made available for antisubmarine work, and 32 more Flights were established at coastal air stations, five of them operated by the US Navy.
   Little success was achieved by the D. H .6s, nor could it be expected with a performance so inferior that, in order to lift a mere 100 lb of bombs, the observer had to be discarded. Modifications such as the introduction of back-stagger and a new aerofoil section on the D.H.6A did little to improve the lack of speed, and D.H.6s fitted with the far from reliable Curtiss OX-5 engine suffered frequent descents in the sea. Fortunately, the type floated for long periods and thus improved the chance of rescue.
   On only one occasion did a D.H.6 come near to destroying a U-boat. This was on 30 May 1918, when UC-49 was attacked, but it crash-dived and made its escape.

UNITS ALLOCATED
   Thirty-four Flights allocated as follows: two Flights (Cramlington): five Flights (Humber to Tees); four Flights (Tees to St Abbs Head); four Flights (Portsmouth Group): eight Flights (South Western Group); six Flights (Irish Sea). After April 1918, organised as Nos.236, 241, 242, 244, 250, 251, 252, 253, 254, 255, 256, 258, 260 and 272 Squadrons.

TECHNICAL DATA (D.H.6)
   Description: Two-seat elementary trainer, later used for anti-submarine patrol. Wooden structure, fabric covered.
   Manufacturers: Aircraft Manufacturing Co Ltd, Hendon. Sub-contracted by Grahame-White Aviation Co, Gloucestershire Aircraft Co; Harland & Wolff; Kingsbury Aviation Co; Morgan & Co; Ransome, Sims & Jeffries; and Savages pd.
   Power Plant: One 90 hp RAF Ia, 90 hp Curtiss OX-5 or 80 hp Renault.
   Dimensions: Span, 35 ft 11 in. Length, 27 ft 3 1/2 in. Height, 10 ft 9 1/2 in. Wing area, 436 sq ft.
   Weights: Empty, 1,460 lb. Loaded, 2,027 lb.
   Performance: Maximum speed, 75 mph at 2,000 ft. Climb, 35 min to 6,500 ft. Service ceiling, 6,100 ft.
   Armament: Up to 100 lb of bombs below wings.

H.King Armament of British Aircraft (Putnam)

D.H.6. The analogy of the D.H.5 and Whirlwind is less remarkable than that adducible between the D.H.6 and Tiger Moth, the trainers of two wars which rendered arduous, if thankless, service on anti-submarine patrol. For this assignment the first-war 'Clutching Hand' carried a single 100-lb bomb or equivalent load and was generally manned by the pilot alone. The effectiveness of the type was not confined to keeping periscopes submerged, for on 30 May, 1918, an attack was made on UC-17, unhappily too late to prevent the torpedoing of SS Dungeness.

K.Molson, H.Taylor Canadian Aircraft since 1909 (Putnam)

de Havilland D.H.6(Canadian)

   While the Curtiss JN-4(Can) had been decided on as the standard trainer of the RFC(Canada), it was felt that an alternative machine should be available. The D.H.6 was selected for this purpose and, as soon as the JN-4(Can) production permitted, the engineering department and experimental shop of Canadian Aeroplanes Ltd started work on it, probably in the spring of 1917.
   The D.H.6 was a British trainer then in favour in some quarters of the RFC. It had been designed with ease of production in mind, resulting in a somewhat inelegant angular appearance, and had some reprehensible features which earned it nicknames such as ‘Clutching Hand’ and ‘Sky Hook’. The 90 hp RAF, 90 hp Curtiss OX-2, 80 hp Renault, and 140 hp Hispano Suiza engines were all used to power the British versions.
   The version selected for Canada was an early one with wide-chord unstaggered wings, and it was proposed that a Curtiss OX engine be fitted. Canadian Aeroplanes changed all fittings to those used in the JN-4(Can). They extended the longerons forward to engage a JN-4(Can) spider fitting which supported the radiator and the forward ends of the engine bearers, and the fuselage plywood covering was extended forward to the radiator. Anti-drag wires were added from the front of the longerons to the wings in a similar manner to the JN-4(Can). What appears to have been an oil drain line extended from the port side of the nose and down to the undercarriage spreader bar to lead any drips clear of the machine.
   The undercarriage was redesigned to take JN-4(Can) fittings and axle. The JN-4(Can) flight-control system was installed but the cross shaft behind the rear seat protruded through the fuselage fabric and was fitted with an external elevator-operating lever on each side.
   The D.H.6 project in Canada seems to have been instigated by Lt-Col C. G. Hoare (later Brig-Gen), commanding officer of the RFC (Canada), who is reported to have followed its progress closely. The machine was completed in July 1917 and taken to Leaside Aerodrome on the northwest outskirts of Toronto where he test flew it.
   The prototype was unnumbered and unmarked, with roundels and rudder stripes added later. It was retained at Leaside Aerodrome and used as a ‘hack’ aircraft to enable administrative officers to keep their hands in, and Capt W. A. Bishop, vc, visiting Canada on leave, flew it at Leaside on 27 October, 1917. Its fate is not known; if it survived the war it quite possibly would have been purchased by F. G. Ericson and associates along with the Curtiss JN-4(Can)s, but it did not appear on the 1920 Canadian civil aircraft register.
   The sole aircraft produced was the first British type to be licence-built in Canada.

   One 90 hp Curtiss OX-2. Span 35 ft 11 1/8 in (10-95 m); length 27 ft 11in (8-51 m) approx; height 10ft 9 1/2 in (3-29m); wing area 436-3sqft (40-53sqm). Empty weight 1,530lb (695kg)*; loaded weight 1,926lb (874kg)*. Maximum speed 75 mph (120-7km/h)*; climb 6,500ft (1,981 m) in 35min*; service ceiling 6,100ft (1,859m)*.

*Figures for D.H.6(Can) are not available but they should be very similar to these official figures for a British OX-powered D.H.6.

Jane's All The World Aircraft 1919

The De H.6 was produced as an elementary training machine for pilots, and, to meet requirements, fundamentally different from those which are desirable in machines for war use.
   High performance was not desired, was in fact rather to be avoided. Cheapness and simplicity and strength of construction, together with ease to repair and a low landing speed, were of primary importance.
   As a result of these considerations, the De H.6, vulgarly known alternatively as the "Clutching Hand" or the "Sky Hook" vhas very few of those rather expensive refinements of form which characterise most modern machines.
   It has, in fact, rather the appearance of having been built by the mile and cut off to order, which is, of course, a testimony to the thoroughness with which the desired simplicity has been reached in the design.
  
  
  
Specification.
Type of machine Biplane "Tractor"
Name or type No. of machine De H.6.
Span 35 ft 11 in.
Gap, maximum and minimum 5 ft. 8 1/2 in.
Overall length 27 ft. 3 1/2 in.
Maximum height 10 ft 9 1/2 in.
Chord 6 ft. 4 in.
Total surface of wings, including
   centre plane and aileron 436.3 sq. ft.
Span of tail 12 ft.
Total area of tail (empennage) 81.0 sq. ft.
Area of elevators 13.0 sq. ft. each
Area of rudder 12.0 sq. ft.
Area of fin 5.5 sq. ft.
Area of each aileron 19.0 sq. ft.
Engine type and h.p. 100 h.p. R.A.F. 1A.
Airscrew, diam., pitch and revs. 9.085 diam., 10.0 pitch, 1,800 r.p.m.
Weight of machine empty 1,460 lbs.
Weight of machine full load 2,027 lbs.
Load per sq. ft. 4.64 lbs.
Weight per h.p. full load 20.27 lbs.
Tank capacity in gallons 26 gallons.
Performance.
   Speed low down 66 m.p.h.
   Landing speed 39 m.p.h.
   Climb.
   To 6,500 feet 29 minutes.
Disposable load apart from fuel 360 lbs.
Total weight of machine loaded 2,027 lbs.

Журнал Flight

Flight, January 9, 1919.

"MILESTONES"

THE DE HAVILLAND, OR "AIRCO," MACHINES

The D.H. 6

Towards the end of 1917 the question of training pilots became pressing, and the need for a machine designed especially for school work became apparent. To meet this demand the D.H. 6 was designed. The objects kept in view in designing her were: Simplicity, and therefore ease of manufacture, maintenance and repair, interchangeability of parts, low landing and stalling speeds. Hence the straight tips and control surfaces. The flat, and nearly vertical, nose of the fuselage might be thought to offer unnecessary resistance. It should be remembered, however, that this is a school machine, and we believe we are correct in saying that this detrimental surface was intended to assist in safeguarding the machine against being dived at too high a speed by inexperienced pupils. For the same reason plain cables are used in the wing bracing. An ingenious quick-release dual system of control is fitted, by means of which the instructor can cut out the pupil completely by the movement of a single lever, and it should be particularly noted that this quick-release includes not only aileron and elevator, but also rudder control. A remarkable feature of the D.H. 6 is the low speed at which it can be flown. The standard machine has a maximum speed of 75 m.p.h., and lands at about 30 m.p.h., while it may be actually flown at speeds below 30 m.p.h. The standard model is intentionally made slightly unstable for purposes of teaching, but a few slight modifications will turn it into a stable machine. Furthermore, by fitting streamline wires instead of the wing bracing cables, and by cowling-in the engine the maximum speed can be increased to 90 m.p.h. In this form the machine should be very well suited to pleasure flying, especially as it was primarily designed for cheapness of manufacture.