H.King Sopwith Aircraft 1912-1920 (Putnam)
Schneider and Rainbow
Because the Schneider Trophy had been won in 1914 by Great Britain (with a Sopwith Tabloid on floats, as recorded in the 'Tabloid' chapter) the contest of 1919 was to be flown in the British Isles. Here indeed - at Bournemouth, Hants, in September of that year - was an opportunity to show the world how British aircraft-designers and constructors had progressed in the years between, and, in particular, how advantage could be taken of the latest aero-engines (specifically, the water-cooled Napier Lion and the air-cooled Cosmos Jupiter). Though France and Italy were both well represented, it will suffice here to record that the British entries were a short-span Fairey III (Lion), Supermarine Sea Lion I (Lion), Avro 539A (Puma) - and the superb Sopwith creation which now concerns us. For this new floatplane the name Schneider had, understandably, been adopted (or re-adopted, having regard to the earlier chapter headed 'Schneider and Baby') though the name was now commonly used with contextual reference to its Cosmos Jupiter engine.
By way of preface to this present sporting excursion nothing could surpass the following brief excerpts from Peter Lewis' British Racing and Record-Breaking Aircraft:
'Misfortune struck the British team when the Sea Lion, taking-off again after having alighted for safety in the fog, was damaged on striking an obstruction, and the Sopwith Schneider retired as the fog enveloped the course. Subsequently, the contest was annulled because of the confusion caused by the fog ...
‘With a maximum speed of 160 mph Hawker's Sopwith Schneider was the fastest of the 1919 entries, and its Jupiter was faired carefully into the fuselage. The single-bay 24 ft span wings were rigged with slight negative stagger, and the fuselage terminated at the rear to form the lower part of the rudder and to act also as the tail float. The pair of main floats were designed with flat bottoms, and the general design of the Sopwith Schneider was drawn up under the direction of W. G. Carter. R. J. Mitchell was responsible for the Supermarine design ...'
To expatiate on the significance of the names Carter and Mitchell would affront the eyes of any present reader - except, perhaps, in one regard, and that by way of stressing that George Carter (as he was always known to his intimates) was in later years to design Britain's first jet-propelled aircraft, the Gloster E.28/39, and that the Sopwith racer now surveyed was his first really fast aircraft. When Harry Hawker first tried it on 10 September, 1919, however (after its assembly at Hythe near Southampton) the machine had to be beached because the floats were too far aft. The Sopwith Experimental Shop rectified matters in two days. Shades of Monaco and 1914 ...
This dramatic re-entry of the name Sopwith Schneider into the aeronautical vocabulary (the rising, in fact, of a new star in the Sopwith firmament - a metaphor warranted by the form of engine, if by nothing else) drew from technical observers laudations, recollections and prognostications in bewildering profusion, and one in particular that may strike the reader as the acme in pontifical pronouncements, though all may be forgiven when the perpetrator is later identified. This pronouncement which, the purple patch aside, gives a useful appraisal - was as follows:
'The Sopwith Schneider Cup racer shows a number of interesting and more or less typically Sopwith characteristics. The very small span, relatively large chord, and the small gap are very reminiscent of the original Sopwith Schneider Cup machine of 1914. If memory serves one right, the chord and gap, 5 ft. 1 1/2 in, and 4 ft. 6 in, respectively, were the same in the 1914 model as in that of today. The span of the new machine is some 3 ft less, and there is a small backward stagger.
'The floats and chassis are not unlike those of the original, though the section of the front part of the floats, with an outwardly flaring bottom - a sort of "Vee" bottom halved - is new to this firm.
'The main floats have also been extended aft and faired off considerably and a tail float dispensed with. The big 450 h.p. radial engine has naturally called for a big bull-nosed body - even more bull-nosed than the original - and the body has been faired off to a rounded section instead of having been left square. The tail fin and tail plane are likewise faired into the body with large radii, and altogether the machine has been carefully studied with a view to producing the minimum of head resistance.
'With a power loading of slightly under 5 lb per h.p. and with the Sopwith firm's unrivalled experience in the production of small fast machines, this machine should prove to be one of the fastest aeroplanes yet built, and Messrs. Sopwith should stand an excellent chance of winning the Cup for the second time.'
Now to identify the perpetrator of the seemingly immemorial 'if memory serves one right, the chord and gap were 5 ft. 1 1/2 in, and 4 ft. 6 in, respectively' (and not forgetting that 1/2 in); for here one must admit that, of all men, this particular one was so positioned and equipped as to throw off with sincerity this classic of minutiae. He was, in fact, W. H. Sayers, who was eminent in the Experimental Construction Department of the RNAS, designer of (for instance) the Grain Kitten light ship's fighter, and technical editor of The Aeroplane not only in 1914, but from 1919 to 1928 as well. Thus, of all men, Sayers should have an intimate knowledge of Sopwith seaplanes old and new.
Yet, in common with other observers, even Sayers failed to stress the most significant fact of all - that here was an aeroplane which (whatever resemblance it may have borne to Pixton's tiny 100-hp Monaco mount of 1914) was designed to use a brand-new British radial engine more than four times as powerful (450 hp nominal), the successors to which were to establish the name ‘Bristol Jupiter' in almost every country of the world – to set the pace indeed even for Wright and Pratt & Whitney in the USA.
Very clearly - even if certain dimensions did recall old practice - the new Schneider racer represented not only a substantial aerodynamic advance (for example, in the smooth, hollow portion of the rudder displacing the earlier tail float) but a major step also in the stresswork that was implicit in the adoption of a new and very powerful engine. The installation of that engine, moreover, presented problems of its own; and the manner in which that newly risen 'star' (or newly blossomed 'sunflower') the Cosmos Jupiter radial, with its relatively large diameter of about 52 in (1,320 mm) by reason of its nine big air-cooled cylinders, was blended with the airframe is attested by superbly detailed photographs.
That the world-renowned name 'Jupiter' was in 1919 still prefixed by the company name 'Cosmos' and not by the 'Bristol' of later years (though indisputably the names of the engine's designers were Roy Fedden and L. F. G. Butler) is explained by the fact that the Cosmos Engineering Company did not go into liquidation until February 1920. Technically, it is important to note that the Jupiter's cubic capacity was roughly 25 per cent greater than that of the A.B.C Dragonfly, though behind each projecting cylinder was a cone-shaped fairing. The petrol tanks, four in number, were in the top and side fairings of the fuselage, and the circular cross-section occasioned by the engine and the tanks was carried gradually into the flat sides of the rear fuselage by stringers. Though of the usual wooden cross-braced construction, the fuselage was covered at the front with aluminium and at the rear with fabric.
Bracing of the stubby single-bay wings was by streamline wires, and there were ailerons on all four panels, following standard Sopwith practice; so in respect of airframe design interest was centred on the unusual tail assembly. Still italicising 'aileron' and ‘fuselage' (though 1919 was already in its autumn) Flight had this to say: 'The extreme front portion of the fin is built integral with the fuselage. The rest of the fin, although curving gradually into the top of the body, is a separate structure, bolted on after the tail plane is in place. The rudder is unusual, inasmuch as its lower portion is very thick, forming a continuation of the fuselage. The latter does not come to a sharp edge at the rear, but is some 6 to 8 ins. wide at the stern post. The leading edge of the rudder is made of the same width, and is covered with plywood. There is thus no external rudder crank lever, while the single pair of levers for the elevators is housed inside the fin. The hollow lower portion of the rudder serves as a tail float.’
In this new aeroplane, beyond a doubt, Sopwith had produced a high-speed aeroplane that was worthy of their name - a name, however, that was now inscribed (as distinct from the fuselage 'hoarding' of Pixton's machine) only on the fin. Registered G-EAKI, the seaplane was otherwise bedizened as the pictures show (for the era of Civil Registration was now upon us).
At this point there is brought to the reader's attention the Sopwith Rainbow, a re-engined, renamed and reduced landplane version of G-EAKI - 'reduced' connoting here that the span was shorter by 3 ft (0.9 m). The word had a double significance, however, by reason of the re-engining, for in place of the Jupiter (which was itself in the teething phase) was one of the dreaded Dragonflies - adopted, it has sometimes been said, because the Jupiter was no longer available, though all the facts may not be known. That the Rainbow was sometimes called the Sopwith A.B.C is sure.
Harry Hawker's racing number in the 1920 Aerial Derby - for which the Rainbow, with its simple V landing gear and neatly cowled Dragonfly, had been prepared - was 13; and early in its race-report Flight declared:… another machine approached the aerodrome, and we recognised Hawker's Sopwith. To everyone's surprise, instead of making the required half-circuit of the aerodrome, Hawker flew straight in [sir] to the aerodrome past No. 1 pylon, but not across the line. It was obvious by his time of arrival that he would have found a place in the handicap, so there was much disappointment at his not finishing correctly. On landing he said he thought the finish was the same as last year's, hence the mistake. Well, Hawker, do not have No.13 next time!'
One bright, if minor, sidelight on this 1920 race was the presence on the Committee of Management of Grp Capt C. R. Samson, CMG. DSO - and what this one-and-only 'Sammy' didn't know about Sopwiths old and new could hardly have tilled a page of his log-book.
To Flight's 'hard luck' story just recounted may be appended that journal's comments on the Rainbow itself (the usual figure of 320 hp being quoted as the Dragonfly's output). Thus: ‘Owing to the impossibility of obtaining a Bristol "Jupiter", which was the power plant originally installed in the Sopwith "Schneider" machine entered for that race at Bournemouth last year, a smaller engine had to be used. The one which could be fitted with least trouble was the A.B.C. "Dragonfly", and consequently this was chosen. The lighter weight of this engine permitted of reducing the area while retaining the same landing speed, and consequently slightly smaller wings were fitted. The result was that the speed was still quite good-somewhere in the neighbourhood of 150 m.p.h. (241 km/h).' In fact, the speed was considerably higher than Flight's approximation.
The Rainbow, Flight went on to declare, had 'vertical wings (no stagger)', whereas it may be recalled that Sayers, in The Aeroplane's description of the Jupiter-engined Schneider seaplane, had correctly noted that this earlier version had 'a small backward stagger’. However, that at one stage at least, the Rainbow itself had backward stagger, seems certain though the point is a fine one indeed, for the amount of back-stagger quoted by Sopwith for the Schneider had been a mere 2 1/2 in (65 mm).
Such trivial considerations, in any case, seemed all the more so because they were completely overshadowed by the Sopwith company's liquidation on 11 September, 1920, and by the withdrawal of the Rainbow (which had been entered as having a Jupiter engine) from the 1920 Gordon Bennett Aviation Cup race in France. (Late in September 1920, after a lapse of seven years, the contest named had been revived. The proposed British entries - apart from those by France and the USA, the latter including the astonishing Dayton-Wright cantilever monoplane with retractable landing gear, variable-camber wing etc. etc - were the Martinsyde Semiquaver (pilot, Raynham), the Nieuport Goshawk (Tait-Cox) and the Sopwith Hawker Rainbow (H. G. Hawker). The Goshawk and Rainbow having withdrawn, only Raynham was left for Britain and even he was compelled to retire in the first lap, leaving Sadi Lecointe to win the cup outright, for France had gained it in three successive races).
How were the (prospective) mighty fallen in this Gordon Bennett affair of September 1920! - though this was not the end of the Rainbow, even if no crock of gold awaited it. With a Jupiter installed once again, with the airframe refurbished and the legend 'Sopwith Hawker' painted on the fin so as to follow its elegant contour, G-EAKI not only appeared at Croydon for the 1923 Aerial Derby (the last of the series) held on August Bank Holiday, but finished second - to Larry Carter in the Gloster I. The pilot was Walter Longton, and his speed was 164.02 mph (264 km h). Although it had been planned to refit floats and to try once again for the Schneider Trophy (the race was at Cowes, Isle of Wight, in late September 1923, and was won by Lieut D. Rittenhouse, US Navy) the spinner of the Rainbow came adrift while Longton was making a final test of the aircraft as a landplane, and the forced-landing near Brooklands was such that Longlon was lucky to emerge unharmed through the side of the fuselage.
The Hawker company was to build no more out-and-out racers, though on 7 September, 1953 (almost exactly thirty years after the Rainbow's end) a special Hunter set up a new World's Absolute Speed Record of 727.6 mph (1,171 km/h).
Schneider (Cosmos Jupiter)
Span 24 ft (7.3 m); length 21 ft 6 in (6.5 m): wing area 222 sq It (20.6sq m). Empty weight 1,600 lb (726 kg): maximum weight 2.200 lb (998 kg). Maximum speed 160 mph (257 km/h).
Rainbow (A.B.C. Dragonfly)
Span 21 ft (6.4 m): length 18 ft (5.5 m). Maximum speed 160+ mph (257+ km h).
Flight, August 28, 1919.
THE SOPWITH "SCHNEIDER CUP" MACHINE
As the firm who won the Jacques Schneider Cup at Monaco in 1914, special interest attaches to the machine entered by the Sopwith firm for this year's Schneider race, which is to be held at Bournemouth on September 10. It will be remembered that the race of 1914 was won by Mr. Howard Pixton, who was flying a small Sopwith tractor seaplane of the twin-float type. The machine, in a general way, was not unlike the little land tractor "Tabloid," except that, of course, she was fitted with floats in place of the wheels. Later on the "Sopwith Schneiders" were called upon for work of a much more serious character, and during the earlier part of the War these machines did a tremendous amount of good work in the R.N.AS. The race of 1914 was over a distance of about 150 miles, and was covered by Mr. Pixton on the Sopwith in 2 hours 13 2/5 secs. The next best time was made by Burri on an F.B.A. flying boat, which completed the course in 3 hours 24 mins. 12 secs. As already announced, this year's race will be held over a distance of about 200 miles, the course being from Bournemouth to Swanage, thence to Christchurch, and from there back to Bournemouth. The length of the course is approximately 20 miles, so that competitors will be called upon to cover the course ten times. This should give the spectators a very good view of the machines, not only as they pass the turning points, but from the cliffs at Bournemouth the machines should be well in view the whole time. There can be little doubt that as regards speed the machines entered this year will be greatly superior to those of 1914, and, although the distance is longer, the times should be considerably shorter than the two hours taken by Pixton in 1914.
The machine entered by the Sopwith firm for this year's Schneider race is a small tractor biplane of the twin-float type. It is fitted with a Cosmos "Jupiter" radial engine of about 450 h.p. Judging from estimated figures of performance, and from data of wing loading and load/h.p., which figures we are not, unfortunately, permitted to publish this week, the Sopwith should show an astonishing turn of speed. The machine, as already mentioned, is a small single-seater, with only one pair of struts on each side. The planes are given a slight backward stagger, although this is so slight as to be almost unnoticeable.
As regards its construction, the Sopwith machine follows usual Sopwith practice. Its fuselage is the usual wood girder, wire-braced structure, but a superstructure of light stringers has been added so as to give the fuselage a good streamline form. The machine, it will be seen from the accompanying photograph, has very clean lines, and everything has been done to reduce head resistance. Thus as regards the tail planes, the vertical fin grows out of the body, so to speak, although it does not form an integral part of the fuselage, and the rudder continues the streamline of the body, being very thick as regards its lower portion. No external crank levers are fitted to the rudder, and the elevator crank lever is placed centrally, where it is covered by the detachable vertical fin. A notable feature of the machine is that no tail float is fitted. This in spite of the fact that the two main floats are not extraordinarily long.
The accompanying photograph, taken while the machine was being erected at the Sopwith works at Kingston, does not show the floats in place, but it gives a very good idea of the simplicity of the undercarriage structure, which consists of four streamline steel tube struts, cross-braced with Raf-wire The two floats are simply bolted to the transverse struts joining the chassis struts.
With regard to the floats themselves, these are of the plain non-stepped type. That is to say, there is no actual step, in the ordinary sense of the word, but from a point slightly aft of the centre of the floats the bottom is perfectly flat and slopes upward towards the heel. The nose of the floats is cut off at a slight angle to the transverse axis of the machine. In general it may be said that the Sopwith Schneider 'bus has a very strong family resemblance to previous Sopwith machines, and it is certainly not a "freak" machine in any way. This is not meant to indicate that she will not be fast, however, for being quite a small light machine, and having a light engine of 450 h.p., she cannot very well help being fast, but that as regards her general design and construction she is quite an orthodox seaplane of the small type. Sopwiths were the first to show the world that a biplane can be made fast, and their present machine may be expected to uphold the reputation, especially as it will be piloted by Mr. Hawker.
Flight, September 4, 1919.
THE JACQUES SCHNEIDER CUP RACE
The Sopwith Seaplane
In our last issue we were able to publish a brief description and an illustration of the Sopwith machine, but we were not at liberty to give any particulars of dimensions, etc. This week, however, we are publishing complete scale drawings and photographs, from which can be formed an idea of the small size and general arrangement of the Sopwith Schneider Cup racer. The machine, which is fitted with a 450 h.p. Cosmos "Jupiter" engine, has been very carefully streamlined in order to cut down resistance. Thus, although constructionally not of the monocoque type, the body has the rounded shape which one usually associates with that form of construction. The fuselage is the usual wood girder-braced structure, but the circular shape of the engine cowl is carried gradually into the flat sides of the rear portion of the fuselage by the addition of longitudinal stringers. The front portion of the fuselage is covered with aluminium, the rear part with fabric.
The 450 h.p. "Jupiter" engine is bolted to the flat nose of the fuselage, and is faired off with an aluminium cowl, through which the cylinder heads project. A "spinner" is fitted over the propeller-boss, and it will be noticed that each cylinder is faired off by additions to the engine cowl, taking the shape of a slice of a cone. The pilot's head is also faired off, and altogether everything has been done to cut down resistance to a minimum. The fuel tanks are carried inside the top and side fairings of the body.
The planes, which have a very slight backward stagger, are of short span, and have one pair of struts on each side, in addition to the usual centre section struts. Wing bracing is by streamline wires, and is of standard type. Ailerons are fitted to both upper and lower planes.
The tail planes are of the usual type, and do not call for any special comment; with the exception, perhaps, of the fin, which is somewhat unusual. The extreme front portion of the fin is built integral with the fuselage. The rest of the fin, although curving gradually into the top of the body, is a separate structure, bolted on after the tail plane is in place. The rudder is unusual, inasmuch as its lower portion is very thick, forming a continuation of the fuselage. The latter does not come to a sharp edge at the rear, but is some 6 or 8 ins. wide at the stern post. The leading edge of the rudder is made of the same width, and is covered with plywood. There is thus no external rudder crank lever, while the single pair of levers for the elevators is housed inside the fin. The whole gives a very neat impression, offering a minimum of resistance. The hollow lower portion of the rudder serves as a tail float.
The two floats are of the flat-bottomed type. That is to say, there is no Vee bottom, and no step in the ordinary sense of the word. It will be noticed, however, that the rear part of the float bottoms slopes upward in a straight line, and does not continue the curve of the front part. The latter is placed at a slight dihedral angle, as shown in the front elevation. The consequence is that the nose of the floats forms an angle with the transverse axis of the machine.
There can be no doubt that as regards speed, the Sopwith Schneider machine will be difficult to beat, fitted as it is with an engine of 450 h.p., and being very small. The weight, all on, is about 2,200 lbs., so that the wing loading will work out at something like 10 lbs./sq. ft. This will mean that the landing-speed will be fairly high, and if the day of the race should prove windy, with a rough sea, alighting might prove a matter of some difficulty. The loading is slightly less than 5 lbs./h.p., probably one of the lightest engine loadings ever attained in an aeroplane. A few years ago this was a fair average weight of the engine itself, and the Sopwith should be practically able to "helicopter."
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 "Schneider Cup" seaplane was described in FLIGHT for September 4 last, so that a further description is unnecessary here, and the following brief characteristics should suffice. Span, 24 ft.; chord, 5 ft. 1 1/2 ins.; gap, 4 ft. 6 ins.; stagger (back), 2 1/2 ins.; overall length, 22 ft.; weight, 2,200 lbs.; speed (as land machine), 170-175 m.p.h. The engine is a 450 h.p. Cosmos "Mercury."