A.Jackson De Havilland Aircraft since 1909 (Putnam)
De Havilland D.H.9J
The de Havilland School of Flying began training R.A.F. reservists at Stag Lane on April 1, 1923 using Avro 548s and the Hire Service D.H.9s. These remained in use until 1926, the year in which primary training was transferred to Cirrus Moths. The veteran D.H.9s, including the antique G-EAAC, were then modernised for advanced instruction and given red fuselages with metallic gold flying surfaces. In this form they were known as the D.H.9J, the ultimate variant, with shortened and strengthened front fuselages to carry the heavier 385 h.p. Armstrong Siddeley Jaguar III fourteen cylinder, two row, radial engine, behind which metal inspection doors gave access to the ancillary equipment. The old rigid V strut undercarriage, sprung like the D.H.4 of long ago, by four 6 ft. 9 in. rubber bungees, each wound nine times round the axle, gave place to new D.H. rubber-in-compression units. Aileron circuits were also modified to incorporate the patent D.H. differential gear and Handley Page slots were fitted. An age-old problem which had dogged many First World War aircraft, was at last solved by fitting a gravity tank in the centre section to be switched on during the approach when the air driven pumps were working too slowly to give an adequate fuel supply. The pupil normally occupied the front cockpit, with the instructor in the rear, making it necessary to carry an equivalent weight of ballast when flying solo. In practice it was found that the average pupil with only 10 hours on Cirrus Moths needed but 20 minutes dual before going solo in the larger and heavier D.H.9J.
As the powerful Jaguar engine imparted a somewhat lively performance to the traditionally sedate D.H.9, it was necessary to fit a throttle stop to prevent the use of full power. Many of these engines already had upwards of 4,000 flying hours to their credit, having been purchased secondhand from Imperial Airways Ltd. after their removal from A.W. Argosy 1 passenger aircraft. Three of these engines were collected from Lympne in a seized up condition but they too were successfully overhauled at Stag Lane and gave long years of trouble free service in the D.H.9Js.
The Armstrong Whitworth Reserve School at Whitley also re-equipped with D.H.9Js, two being erected at Stag Lane in 1926 and a further three in 1929, one of which G-AARS, was used temporarily as a flying testbed for the Armstrong Siddeley Serval IV nine cylinder radial engine. When Air Service Training Ltd. was formed in 1931, all three went to Hamble where their black fuselages and silver wings were a familiar sight until 1936. Two other replacement aircraft were also built at Stag Lane for the de Havilland School of Flying Ltd., one in 1927 and the other in 1929. In common with those built for Armstrong Whitworth, they had plywood covered fuselages.
G-EAAC, the veteran D.H.9J which the de Havilland company had preserved so immaculately for so long, acted as a flying workshop for the horde of Moths competing in the 1929 King's Cup Race. Loaded with tools and spares, and piloted by C. A. Pike it landed at Mousehold, Lympne, Hamble, Whitchurch, Blackpool, Renfrew, Cramlington, Sherburn, Castle Bromwich and Heston - ever in the wake of the competitors but seldom needed.
The last D.H.9J was not completed until the autumn of 1931, not long before the type went out of service. This machine, G-ABPG, built as an exercise by senior students of the Aeronautical Technical School, was fitted with an Armstrong Siddeley Jaguar IVC and employed on normal training duties by the Flying School. This had by this time been transferred to Hatfield, and PG was almost certainly the sole D.H.9 of non-military origin.
SPECIFICATION AND DATA
The de Havilland Aircraft Co. Ltd., Stag Lane Aerodrome, Edgware, Middlesex
The de Havilland Aeronautical Technical School, Hatfield, Herts.
One 385 h.p. Armstrong Siddeley Jaguar III
One 500 h.p. Armstrong Siddeley Jaguar IVC
One 340 h.p. Armstrong Siddeley Serval IV
Span 42 ft. 4 5/8 in. Length 28 ft. 9 in.
Height 11 ft. 2 in. Wing area 434 sq. ft.
(G-EAAC) Tare weight 2,452 lb. All-up weight 3,725 lb.
(G-EBGT) Tare weight 2,375 lb. All-up weight 3,900 lb.
Maximum speed 100 m.p.h. Cruising speed 80 m.p.h.
Stalling speed 48 m.p.h. Climb to 10,000 ft. 9 min.
Ceiling 25,000 ft. Range 390 miles
Constructor's No. C. of A.
and Registration as 9J Remarks
H9277* G-EAAC 8.7.26 Formerly D.H.9B K-109; scrapped 1933
66 G-EBEZ 17.12.26 Fitted with Lion in 1923; scrapped 1933
76 G-EBFQ 11.12.26 Built as Puma trainer; scrapped 1933
82 G-EBGT 19.8.26 Crashed at Hatfield 16.10.32
H5844* G-EBHV 29.9.27 Built as Puma trainer; scrapped 10.28
181 G-EBLH 25.8.26 Crashed at White Waltham 12.5.27
282 G-EBOQ 17.8.26 A.W. Reserve School; scrapped 10.29
283 G-EBOR 15.9.26 A.W. Reserve School; scrapped 1.29
326 G-EBTN 14.9.27 D.H. Reserve School; scrapped 1933
397 G-AARR 4.10.29 Air Service Training Ltd.; scrapped 1936
398 G-AARS 17.10.29 Air Service Training Ltd.; crashed 10.34
399 G-AART 5.11.29 Air Service Training Ltd.; scrapped 1936
704 G-AASC 20.12.29 D.H. Reserve School; scrapped 1931
1990 G-ABPG 14.10.31 D.H. Reserve School; scrapped 1933
* R.A.F. serial of military original.
A.Jackson British Civil Aircraft since 1919 vol.1 (Putnam)
De Havilland D.H.9J
Just after the First World War four civilian flying schools were given contracts for the annual training of R.A.F. Reservists. The de Havilland School of Flying began this training at Stag Lane on 1 April 1923, using Avro 548s, Hire Service D.H.9s and pilots who included A. J. Cobham, W. L. Hope, H. S. Broad, V. N. Dickenson and others. By the end of 1924 the D.H.9Cs had all been pensioned off and replaced by standard Puma-engined D.H.9s equipped as tandem two-seaters for advanced training. The de Havilland Company had already declared its intention of retaining the ancient G-EAAC in order to find out just how long an aeroplane would last under normal flying conditions. Thus it had not been converted to a 9C, and now joined the School fleet as a trainer and was repainted in battleship grey with red struts and silver surfaces.
The school flourished until 1926, in which year the Avro 548 primary trainers gave place to Cirrus Moths and the veteran D.H.9s, including G-EAAC, were modernized and redesignated D.H.9J, the ultimate variant. The lengthy nose was cut right back to accommodate the heavier 350-h.p. Armstrong Siddeley Jaguar 14-cylinder two-row radial engine. The V-strut undercarriages with their bungee shock-absorbers were replaced by the new D.H. rubber in compression unit, and the original aileron circuit was modified to incorporate the patent D.H. differential aileron system. The school colours were also revised, and the D.H.9Js were among the smartest aeroplanes of their day, with red fuselages and struts with gold flying surfaces. The powerful Jaguar engines imparted a rather lively performance to the traditionally sedate D.H.9, even though the use of full power was prevented by a throttle stop. The engines themselves had previously been fitted in A.W. Argosy Is and had been purchased secondhand from Imperial Airways Ltd. Many of them had upwards of 4,000 hours’ flying to their credit, and others were in a seized-up condition but after overhaul gave sterling service in the D.H.9Js.
Two D.H.9Js G-EBOQ and ’OR were newly converted for the Armstrong Whitworth Reserve School in 1926, but were replaced by three new specimens in 1929. These were G-AARR - ’RT, one of which, ’RS, was also used as a flying testbed for the Armstrong Siddeley Serval IV engine. When Air Service Training Ltd. was formed in 1931, they moved south to Hamble, where ’RS crashed in 1934, and the others continued in daily use until 1936. Later specimens included G-EBTN, built at Stag-Lane in 1927 as a replacement for G-EBLH, which crashed at White Waltham on 12 May 1927. A further example, G-AASG, flew in 1929 after the elderly G-EBHV retired. The last D.H.9J, however, did not appear until the autumn of 1931, not long before the type was withdrawn from service. This machine, G-ABPG, powered by a Jaguar IVC, was built as an exercise by the students of the de Havilland Technical School. It went into normal Flying School use and was probably the only purely civil D.H.9 airframe of non-military origin ever constructed and in common with all D.H.9J aircraft converted after 1925, had a plywood-covered front fuselage.
Manufacturers: The de Havilland Aircraft Co. Ltd., Stag Lane Aerodrome, Edgware, Middlesex.
Power Plant: One 385-h.p. Armstrong Siddeley Jaguar III.
Dimensions: Span, 42 ft. 4 5/8 in. Length, 28 ft. 9 in. Height, 11 ft. 2 in. Wing area, 434 sq. ft.
Weights: Tare weight, 2,375 lb. All-up weight, 3,900 lb.