O.Tapper Armstrong Whitworth Aircraft since 1913 (Putnam)
At the time of Green's and Lloyd's move to Coventry, the factory was occupied with large-scale production of the R.E.8, one of the aircraft which Lloyd had worked on while still at Farnborough: it was appropriate, therefore, that this was the aeroplane that formed the basis for the design that was the first to carry the Siddeley Deasy name. Known as the R.T.1, this aeroplane was an attempt to improve on the R.E.8 which, in the RFC, had earned a reputation, not altogether justified, for shedding its overhanging top wing in a dive; it was also reputed to have a dangerous tendency to spin. It was probably more in an endeavour to eliminate these characteristics, rather than to improve the performance, that was the purpose behind the R.T.1 design.
The fuselage of the R.T.1 was essentially the same as that of the R.E.8, but the wings were of entirely new design, being of equal span with two-bay bracing and with the top wing having a greater chord than that of the bottom. Modifications to the fuselage consisted only of raising the observer's gun-ring by a few inches and providing a deeper fuselage top fairing to match. The horizontal tailplane was similar to that of the R.E.8, but the fin and rudder were both of greater area and with a more rounded shape. The small ventral fin of the R.E.8 was retained.
Only three R.T.1s were built, each one growing from a fuselage taken from a batch of 150 R.E.8s then on the Siddeley Deasy production line. The first R.T.1 was powered by a 200 hp Hispano-Suiza engine and fitted with a nose radiator similar in appearance to that of the S.E.5; it bore the serial number B6625. The second aeroplane, B6626, had the same engine as the R.E.8, an RAF 4A, developing 150 hp, in a standard R.E.8 mounting, whilst the third aircraft, the final version, reverted to the 200 hp Hispano-Suiza engine, this time enclosed in a neatly rounded cowling with an underslung radiator. In this version, as with the RAF-powered aircraft, the engine exhaust gases were discharged over the top wing by means of twin stacks. The third aircraft also had modified wingtips and horn-balanced ailerons with rounded tips.
The first flight of the R.T.1 was made from Radford aerodrome by J. H. James, later to become well known for his exploits with the Gloster 'Bamel' racer. He had with him as passenger the designer John Lloyd, who vividly recalls that a prolonged spin made this first flight more memorable than most. The date of the first flight is uncertain, but it is known that the second aircraft, the one with the RAF engine, was undergoing official tests by December 1917.
As compared with the R.E.8, the wing area of the R.T.1 was increased by some 12 per cent, with a wing loading of 6 lb/sq ft, as against nearly 7 lb/sq ft in the case of the R.E.8. In spite of this, the R.T.1 with the same engine was as fast as the R.E.8, clocking 101 mph at 6,500 ft, but, as might be expected, the climb performance was better, the R.T.1 reaching an altitude of 10,000 ft in 19.2 min, while the service ceiling was 16,000 ft, some 2,500 ft higher than that of the R.E.8. The view forward and downward from the pilot's seat of the R.T.1 had been criticized and to improve it a gap was cut in the lower wing root; this had the effect of reducing the speed by about 2 mph at 15,000 ft and increasing the time taken to reach 10,000 ft by about 3 1/2 min. The R.T.1 with the 200 hp Hispano-Suiza engine, and in its final form with the rounded nose, was tested in March 1919 and proved to be some 10 mph faster than the earlier version and to have a service ceiling higher by some 2,000 ft. The aircraft was reported to handle well and one of them underwent Service trials on the Western Front, whilst the other two went to training units; however, it must have been fairly clear from the start that there was little prospect of the R.T.1 going into production, and it seems probable that the design was undertaken more as an exercise for the newly established Siddeley Deasy design team than as a serious attempt to find a replacement for the R.E.8.
Dimensions: Span 41 ft 9 in (12.73 m); length 27 ft 8 in (8.43 m); height 11 ft 7 in (3.53 m); wing area 433 sq ft (40. 23 sq m).
150 hp RAF 4A 100 hp Hispano-Suiza
Max weight: 2,590 lb (1,175 kg) 2.707 lb (1,228 kg)
Empty weight: 1,773 lb (804kg) 1,803 lb (818kg)
6,500 ft(1,981 m): 101 mph (163 km/hr}
10,000 ft (3.048 m): 98 mph (158 km/hr) 108 mph (174 km/hr)
15.000 ft (4.572 m): 91 mph (147 km/hr) 100 mph (161 km/hr}
to 6.500 ft (1,981 m): 10.5min 10.6min
to 10.000 ft(3.048 m): 19.2min 18.5 min
to 15,000 ft(4,572m}: 41.5min 36.4 min
Service ceiling: 16.000ft(4.877m} 18.000ft(5,486 m)
J.Bruce British Aeroplanes 1914-1918 (Putnam)
ARISING out of Parliamentary criticisms of the administration of the Royal Flying Corps and the work of the Royal Aircraft Factory, a committee was set up under the chairmanship of Sir Richard Burbidge to inquire into the affairs of the Factory.
The committee was set up on May 12th, 1916, and issued its report in the following year. One of its chief recommendations was to the effect that the Factory should not engage in aircraft production, even of an experimental nature. The report was officially accepted: the acceptance ultimately resulted in a substantial reduction in the staff of the Factory and the release to industry of several of its most experienced members.
Among those who left was Major F. M. Green, who had been Chief Engineer at the Royal Aircraft Factory. In January 1917, he, with S. D. Heron and J. Lloyd, joined the Siddeley-Deasy Car Co., who were contractors for several types of aircraft. One of those types was the R.E.8, in the design of which Lloyd had had a considerable share.
The first product of the new Siddeley design team was a modification of the R.E.8, known as the Siddeley R.T.1. The R.T.1 embodied a number of R.E.8 components, and affords an interesting comparison with the Royal Aircraft Factory’s own R.E.9. The R.T.1s were, in fact, taken straight off the Siddeley production line, for they were the last airframes of the batch of R.E.8s originally ordered as B.6481-B.6630.
The first R.T.1 was B.6625, which had a 200 h.p. Hispano-Suiza engine cowled in a manner which closely resembled the installation in the S.E.5a; long horizontal exhaust pipes were fitted.
The fuselage was basically that of the R.E.8, but a deeper top-decking was fitted; this raised the observer’s gun-ring by some inches. The fin and rudder were larger than those of the R.E.8; the rudder was horn-balanced, and bore a strong resemblance to that of the R.E. 9.
But the greatest difference between the R.E.8 and the R.T.1 lay in the mainplanes. The wings of the R.T.1 were of equal span, with the upper of considerably greater chord than the lower; the new wing arrangement was adopted specifically to provide a stronger structure. There were two bays of interplane struts. Ailerons were fitted to upper and lower wings; the upper ailerons were attached to false spars fitted some way behind the rear main spar.
The second R.T.1, B.6626, bore the strongest resemblance to the R.E.8, because it was fitted with the 150 h.p. R.A.F. 4a engine in the standard R.E.8 installation. This version was tested in December, 1917. It was first flown without any gaps in the lower wing-roots, but these were later provided in order to improve the pilot’s downward vision.
Although the wing-span of the Siddeley R.T.1 was a foot less than that of the R.E.8, it yet looked like a larger aeroplane. It was intended to be a replacement for the R.E.8, for an official description states: “The type R.T.1 machine is the R.E.8 re-designed. Modifications have been made with the object of improving the machine generally, rather than bettering the performance.” The R.T.1’s armament was peculiar: the pilot had a Lewis gun mounted above the centre-section, firing forwards and upwards to clear the airscrew.
A third version of the design had a 200 h.p. Hispano-Suiza engine in a different form of cowling. The radiator was underslung, and the engine-cowling had a rounded nose rather like that of the D.H.9. Exhaust stacks like those of the R.E.8 were fitted, but were splayed outwards. This third machine had horn-balanced ailerons. An R.T.1 with a Hispano-Suiza engine was officially tested in March, 1919.
One of the R.T.1s was sent to France for Service trials in 1918. The type was not adopted, however, possibly because of the prospect of Bristol Fighters equipping the Corps Reconnaissance squadrons.
Manufacturers: The Siddeley-Deasy Motor Car Co., Park Side, Coventry.
Power: 150 h.p. R.A.F. 4a; 200 h.p. Hispano-Suiza.
Dimensions: Span: 41 ft 9 in. Length: 27 ft 8 in. Height: 11 ft 7 in. Chord: upper 6 ft 6 in., lower 4 ft 9 in. Gap: 4 ft 8 1/2 in. Stagger: 2 ft 5 1/2 in. Dihedral: 3 30'. Incidence: 4 30'. Span of tail: 13 ft 1 in. Tyres: 700 X 100 mm.
Areas: Wings: 420 sq ft. Ailerons: total 68 sq ft. Tailplane: 24 sq ft. Elevators: 12 sq ft. Fin: 7 sq ft. Rudder: 11 sq ft.
Tankage: Petrol: 37 1/2 gallons. Oil: 51/2 gallons.
Armament: One fixed Lewis machine-gun mounted above the centre-section to starboard of centre, firing forwards and slightly upwards above the airscrew; one free Lewis gun on Scarff ring-mounting on rear cockpit.
Service Use: The R.T.1 numbered B.6625 was at Wyton, the aerodrome of No. 31 Training Squadron, in March, 1918.
Weights (lb) and Performance:
Version R.A.F. 4a engine without gap in lower wings R.A.F. 4a with gap 200 h.p.Hispano-Suiza engine
No. of Trial Report M.162 M.162 M.253
Date of Trial Report December, 1917 December, 1917 March, 1919
Type of airscrew used on trial T.6296 T.6296 T.28152
Weight empty 1,773 1,773 1,803
Military load 185 185 185
Crew 360 360 360
Fuel and oil 272 272 359
Weight loaded 2,590 2,590 2,707
Maximum speed (m.p.h.) at
6,500 ft 101 - -
10,000 ft 98-5 97-5 108
13,000 ft 94-5 93-5 -
15,000 ft 90-5 88-5 100
m. s. m. s. m. s.
1,000 ft 1 20 1 35 - -
2,000 ft 2 50 3 15 - -
5,000 ft 7 45 9 00 - -
6,500 ft - - - - 10 35
8,000 ft 13 55 16 20
10,000 ft 19 10 22 30 18 30
12,000 ft 25 50 30 30 - -
15,000 ft 41 30 50 00 36 25
16,000 ft 50 10 - - - -
Service ceiling (feet) 16,000 15,000 18,000
Production and Allocation: Three R.T.1s were delivered to the R.F.C. One went to the B.E.F. in France in 1918: two went to training units, one in 1917 and the other in 1918.
Serial Numbers: B.6625-B.6630, ordered under Contract No. A.S.7903.
H.King Armament of British Aircraft (Putnam)
R.T.1. This two-seat reconnaissance machine of 1917 had one Lewis gun on a Scarff ring-mounting, the level of which was raised during development by building up the coaming of the fuselage. There was a second Lewis gun for the pilot, over the centre-section to starboard, firing above the airscrew at a slight upward angle.