H.King Sopwith Aircraft 1912-1920 (Putnam)
In several respects the Gnu was the most interesting and promising of the three civilian offerings that were introduced by Sopwith to the public around mid-1919 (the other two being the Dove and the 'Transport' the last-named type or class being represented by the Atlantic and the Wallaby). As early as 29 May, 1919, the first Gnu (K-101) was flown by Harry Hawker now safely back from his transatlantic venture from Brooklands to Hendon, the occasion being the subsequent reception accorded to the US Navy-Curtiss flying-boat crewmen (notably their leader, Lieut Cdr A. C. Read) who had just completed the first Atlantic crossing by air, by way of the Azores and Lisbon. This first Gnu was, in fact, the second British-registered civil aeroplane, the first having been K-100, a D.H.6 owned by Airco though still bearing RAF markings.
Sopwith's re-entry into the civil passenger-carrying business was marked with due ceremony and a sense of public relations, no less than sixty guineas being paid by Miss Daisy King of Leeds, not so much (it may be supposed) for the privilege of trying the new aeroplane as being flown by the heroic Hawker, though Harry had brought his wife with him in the Gnu from Brooklands. Among those present at the reception for the Americans was T. O. M. Sopwith, and the ticket for the flight in the Gnu was auctioned by his old rival Claude Grahame-White. It was just like old times; for not only had "G-W" competed with 'Tom' in early sporting events but was an aircraft constructor in his own right, having built his first machine in 1910. Moreover, just as he had championed the aeroplane for war, so, now, was he seeking to promote it as a public-transport vehicle. (All this, of course, quite apart from the fact that for so many people Grahame-White was 'Hendon' - in its best - known and best-loved sense).
As for the Sopwith Gnu that was central to these postwar civil promotions, this can best be introduced by turning back the pages of history - as represented by those of this present book - to reconsider the Three-seater of 1913, and to reiterate a view thus expressed:'... the present writer would go so far as to proclaim the early-1913 Sopwith "land tractor" (as it was sometimes called) as the true begetter of a line of British transport biplanes built with particular success to a particular formula: that is, with the passengers seated in a forward, fenestrated, compartment, with the pilot behind them, and having no more engine power than was strictly necessary to perform (jointly with generous wing area) a rigorous operation with exemplary economy.' In this regard one explained that the line of aeroplanes one had in mind came to its full fruition 'in the well-nigh incomparable de Havilland series of the inter-war years, culminating in the little Fox Moth.’
Yet instantly, now, there seems to be a basic contradiction to this view, for a prominent design-feature of the Sopwith Gnu was the seating of the pilot not behind his passengers but ahead of them. This seeming contradiction, however, is quickly explained - first by remarking that de Havilland, in some of their civil designs, adopted this same (Gnu) formula; second by observing that the seating arrangement was of psychological, rather than technical, importance, prime considerations being the pilot's view of where he was flying and (in those times) the passengers' view of the pilot. In any case, the Gnu's passengers numbered two only, as in the 1913 tractor already mentioned.
As for economy, expressed in terms of engine power, Gnu K-101 was accompanied to Hendon by another specimen, K-136, the second of twelve that were built in all, and having a 110 hp Le Rhone engine, whereas K-101 had a 200 hp Bentley B.R.2. (In this last regard, it may be noted, the quoted figure of 200 hp instead of the familiar military rating, or nominal output, of 230 hp, may have signified a civil rating, though Sopwith sometimes gave even the Snipe '200 hp').
That many modifications were made to Gnus is clear, though the Australian installation of a Wright Whirlwind engine is touched on only at the very end of this chapter. Another Australian 'mod' was the fitting of an 18-gal (82 litre) petrol tank under the centre section, and thus above the pilot's seat. With a Gnu so fitted, from a little clearing on a bend of the River Murray, F. S. Briggs essayed a take-off in this 'heavily loaded machine of small horse-power' (as he described it). Briggs climbed as steeply as he dared, but one cylinder of the 110 hp Le Rhone cut out and a 60-ft fall into a gum tree Briggs considered ‘fortunate’. Even so, as the Gnu stalled, he put his right hand over the side to switch off the engine - only to get his hand trapped, and a finger fractured, by the three-ply side of the fuselage. Into the bargain, he got an involuntary bath in 18 gallons of petrol. No fire, thank Heaven; but the petrol stung 'like Hades'.
Hopefully, the Gnu 'limousine' (as it was sometimes styled) was originally launched much along the lines set out in the following contemporary description, based on one prepared by Sopwith themselves:
'The "Gnu" has been designed to meet the requirements of a light, high-speed machine for passengers or cargo. It can be equipped either with the 200 Bentley rotary or with the 110 h.p. Le Rhone both engines having proved extremely reliable upon active service. Accommodation is provided for two passengers, or the equivalent in cargo, who are totally enclosed in a roofed and windowed cabin. The pilot is placed well forward in front of the cabin, and has very good visibility, being well protected from the "slip stream", enabling him to fly long distances without suffering discomfort. The "Gnu" possesses a speed variation of 100 percent. [Sic - presumably meaning that the speed range was about 2 to 1] pulling up when landing and taking off [curious, though comprehensible, phrasing] - owing to its light weight - very quickly. With the 200 h.p. Bentley rotary, fuel is provided for a range of 250 miles, whilst in the case of the Le Rhone engined machine, this distance becomes 300 miles. The engine unit is extremely accessible, and in the event of necessity can be changed by two mechanics in five hours. An adjustable tail plane is fitted, enabling the pilot to trim the machine to suit the particular load that is being carried at the moment. The construction is on perfectly normal lines.'
To this account it may be added that the two passengers were seated side by side under a glazed roof which hinged outwards from the centre in two sections, though from K-140 onwards most of the Gnus dispensed with this elaboration, and the passenger compartment was open. That the hinged roof was in any case a concession to postwar 'refinement' rather than actual demand may have been implicit in The Aeroplane's remark that the Gnu should appeal to those who desired 'to travel by air in comfort, relative silence, and the absence of wind' quite as strongly as would the Dove to those 'who rather prefer to experience even the minor discomforts of flying rather than forgo any of its sensations.’ As in the case of the Dove, incidentally, a factor of safety of 6 was quoted - so, the span and length corresponding roughly with the dimensions of the Hippo fighter - many of the Gnu's passengers may actively have sought the 'sensations' of flying. Certainly, the 'joyriders' of those times (who constituted a large proportion of the people carried by air) could have been impressed - according to temperament - either by cribbed, cabined confinement, or by the breezy environment wherein, perhaps, their friends or relations had lately fought in Sopwith aeroplanes. In this connection it may be recorded that, after its Hendon debut, K-101 was flown by C. D. Barnard to give pleasure flights at Southport, Lanes, where it was quickly crashed - on 10 June, 1919. (Barnard had served with the RFC, was a Sopwith test pilot during 1919, was shortly thereafter with de Havilland, became famous for long-distance flights, operated an air circus, and was eventually engaged in experimental flying with Flight Refuelling Ltd. In associating his name with the Sopwith Gnu and what has just been said concerning it, one may further emphasise the closeness of the links remaining after 1918 between Service and civilian flying by noting that in 1921 a former RNAS/RAF pilot, Hubert Broad, joined de Havilland to serve with Barnard and others arriving in his own Sopwith Camel G-EAWN!).
As for the remaining Gnus, the outline of their story was as follows: K-136 (Hawker's escort to Hendon in May 1919) became G-EADB, was later variously owned, and crashed in March 1926; K-140 became G-EAEP, remained unsold, and was dismantled at Brooklands in July 1920; K-156 (G-EAFR) unsold, withdrawn from use October 1920; K-163 (G-EAGP) various owners, notably pioneer Lieut Col Sir Francis McClean - whose magnanimity had permitted the early start of British Naval aviation - crashed May 1926; K-164 (G-EAGQ) unsold, dismantled August 1920; K-169 (G-EAHQ) to Larkin-Sopwith Aviation Co, Melbourne, as G-AUBX, registration cancelled (after use by Fulham Air Transport, Melbourne) March 1922; G-EAIL to Larkin-Sopwith as G-AUBY, privately used, destroyed in freak storm April 1946; G-EAIM to Larkin-Sopwith (believed as spares); G-EAME, ‘MF, 'MG and ‘MH unsold, registrations cancelled September 1921.
Perhaps the best-known of the Gnus was G-EAGP, for apart from being owned by the pioneer already named (McClean, who was also Chairman of the Royal Aero Club) it won the first race for the Grosvenor Challenge Cup - competed for annually, under Royal Aero Club conditions - on 23 June, 1923. The pilot was Fit Lieut W. H. Longton, the engine a 110 hp Le Rhone (the rules admitting only British aircraft, with engines not exceeding 150 hp), and by flying the 404-mile (650 km) course at an average speed of 87.6 mph (141 km/h) Longton showed what these early British transports could accomplish on low power.
Too low, perhaps, the power. Too late, assuredly, the date.
Gnu (200 hp Bentley B.R.2 or 110 hp Le Rhone)
Span 38 ft 1 in (11.6 m); length 25 ft 10 in (7.8 m); wing area 354 sq ft (32.9 sq m). Maximum weight 2,400/2,500 lb (1,090/1,134 kg). Maximum speed (Bentley) 110 mph (177 km/h); maximum speed (Le Rhone) 93 mph (150 km/h); landing speed 40 mph (64 km/h); climb to 5,000 ft (1.525 m) (Bentley) 5.5 min, (Le Rhone) 7.75 min; range (Bentley) 250 miles (402 km), (Le Rhone) 300 miles (483 km).
N.B. Although a maximum weight of 3,350 lb (1,520 kg) has sometimes been ascribed, this is greatly at variance with the figures quoted above, and is certainly suspect, except as a special case - even when allowance is made for the fact that in 1919 a 'normal load’ of 845 lb (383 kg) was quoted jointly with a 'maximum safe load' of 1,202 lb (544 kg). Nor, apparently, can the higher weight of 3,350 lb be linked with the fitting of a Wright Whirlwind J-5 radial engine to G-AUBY in Australia - even if the equally suspect power of 300 hp is credited to that particular J-5, as it sometimes is. (A more typical output for an engine of this series would be 220 hp, while the engine weight, at about 500 lb (227 kg), would likewise approximate to that of a standard 230 hp Bentley B.R.2).
Flight, December 25, 1919.
SOME POST-WAR SOPWITH MACHINES
THE Sopwith Aviation and Engineering Co. is by no means disposed to rest upon its laurels, and testimony to this effect is furnished by the origination of the three new peace types: the "Dove," the "Gnu" and the "Transport." Further, the company's design and experimental department is being maintained at its full strength and is as busy as ever. Some interesting developments are likely to be heard of in the near future. With the single exception of lighter-than-air craft their experience as that of pioneer designer-constructors covers all types of aircraft, flying boats, sea planes and "land" machines. Furthermore they have built, and had standardised, everything from bombers and torpedo-carriers to high-speed scouts, and in every type they have attained eminence. No better proof of this could be asked than the way in which their type names have become household words.
The "Gnu" is a light high-performance three-seater passenger or goods machine of the single-engined tractor type, having an enclosed cabin for the passengers or goods at the rear of the main planes. There are two models of the "Gnu," but these differ only as regards the engine fitted, and, consequently, in the performance. In one model a 110 h.p. Le Rhone is fitted, and in the other a 200-h.p. Bentley rotary, the latter giving an extra 17 m.p.h. in the speed and a slight increase in range and climb. The general construction conforms with usual practice and the factor of safety is 6. The following characteristics apply to both models. Span, 38 ft.; chord, 5 ft.; gap, 5 ft.; stagger, 11 ins.; dihedral, 2 1/2°; overall length, 25 ft. 6 ins.; height, 10 ft.; area of main planes, 350 sq. ft.; weight fully loaded, 2,160 lbs. (Le Rhone), 2,400 lbs. (Bentley); maximum safe load 1,202 lbs. (Le Rhone), 820 lbs. (Bentley); loading per sq. ft. 6.1 lbs. (Le Rhone), 6.85 lbs. (Bentley); speed range, 53-93 m.p.h. (Le Rhone), 65-110 m.p.h. (Bentley); climb, 5,000 ft. in 7 3/4 mius. (Le Rhone), 5,000 ft. in 5 1/2 mins. (Bentley); range, 220-300 miles (Le Rhone), 200-250 miles (Bentley).