Thursday, 31 August 2017

Problems with Early Seafires.


Seafire on H.M.S. Unicorn
 I mentioned in my blog of 12.8.17 (Spitfires to Malta) the improvisation necessary to get the required half flap setting for taking off from HMS Eagle.
This reminded me of another improvisation mentioned in my recent book in response to deck landings with the early Seafires. Capt. George C. Baldwin, who flew Seafires throughout the war, gave the following perspective on problems associated with aircraft-carrier landings with the early conversions: “‘pecking’ was a phenomenon caused by the tail being thrown up as the aircraft caught the arrester-wire and the propeller touching the flight deck and, if it was a wooden propeller, pieces flew off in every direction. Believe it or not, that was cured by just taking a sharp knife and cutting three inches off the end of each blade with no noticeable loss of performance whatever.” [There were also problems with pintles in the undercarriage being easily damaged and with hard contacts of the tail with the flight deck causing the fuselage to bend just in front to the empennage.]

A more chilling scenario may not be noticed in my Appendix One, where FAA pilot Henry Adlam describes a detail of the Salerno operation (September, 1943) with the early Seafire types:
For the Seafire to land on the small deck of an Escort Carrier, even under ideal conditions, calls for considerable skill and experience on the part of the pilot. But at Salerno, the wind conditions were no better than a zephyr breeze and almost a dead calm, conditions entirely to have been expected at that time of the year. Thus the Seafires had to operate with a total wind speed over the deck of only sixteen knots, being the maximum speed of the Escort Carriers, whereas they needed a total wind speed over the deck of at least twenty-eight knots. These were desperately difficult landing conditions for the Seafire pilots; conditions which surely should have been anticipated at the outset when the whole Salerno operation was being planned by Rear Admiral Vian who, despite never having flown an aircraft or having served in an Aircraft Carrier, had been put in charge of this, the first multi Carrier Fleet* of the Royal Navy… After two days the four Escort Carriers had virtually run out of Seafires, no less than forty-eight [my italics] of which had been written off as the pilots attempted to land in windless conditions.

* The fleet in question was composed of the four escort carriers and a support/depot ship, H.M.S. Unicorn, also configured as an aircraft carrier – see illustration below.




[Notwithstanding Adlam’s views, the enigmatic Vian, conclued his 40 year service with promotion to Admiral of the Fleet.

By 1944, the problems with the Seafire had been resolved: Adlam again, with reference to the Seafire XV: ‘An absolute thoroughbred of an aircraft requiring only the most delicate pressures on the controls for it to respond immediately and perfectly… On a runway with plenty of space, the simplest of aircraft to land’.]

Monday, 14 August 2017

R.J. Mitchell: Steam Revisited


Locomotive No.6 at Calshot, 1921 -1945
In my recent book I wrote that Mitchell’s Type 224 design was powered by a Rolls-Royce Goshawk evaporatively cooled engine – using  a new system, whereby the water in the engine was kept under pressure by pumps, allowing it to heat to 150 Celsius and then the superheated water was released to turn to steam in a suitable container, with sides exposed to the airflow – where it would condense, to be returned to the engine. Type 224 first flew in 1934 but it was found that the returning coolant water would often turn into steam again, the pump would cease to operate, and plumes of steam would be seen escaping from wing tip vents.
      This no doubt produced unwelcome memories in Mitchell of his apprenticeship at the locomotive works of  Kerr, Stuart and Co. but at least he must have had other, earlier memories (though possibly not nostalgic ones– see my Chapter One) of his time at the Fenton works during his frequent visits to the naval flying boat base at Calshot:  there, a narrow gauge loco ran between the base and the Eaglehurst camp, built to accommodate the ground staff and aircraft crews who worked at RNAS Calshot. (See photo above). It was not one of at least fifty Wren class engines built at Fenton whilst he was an apprentice there:
Wren class locomotive - Kerr,Stuart and Co.
but was built by Andrew Barclay & Co. Ltd., Kilmarnock to a very similar pattern. The photo below, courtesy of Talyllyn Railway Archives, gives a more close-up view of the Calshot locomotive in its earlier days.

Saturday, 12 August 2017

Spitfires for Malta


HMS Eagle
 
In my recent book I wrote that the reputation of Mitchell’s fighter was further enhanced by the eventual lifting of the siege of Malta. In early 1941, the Luftwaffe had had to take over the action from the Italians and so reinforcements of Spitfires had to be flown in from H.M.S. Eagle (they did not have the range to go directly from Gibraltar). Eventually, sufficient numbers of Spitfires, better organized ground support and the deployment of many experienced pilots, led by the October of 1942 to the lifting of the siege and even to a developing offensive strategy from the island. The Spitfire was once again seen as the significant factor in another British ‘backs-to-the-wall’ campaign.

 Since completing this book, I have come across the following anecdote which gives an insight into the sort of desperate measures that wartime emergencies often required and which lay behind the successful lifting of the seige of Malta:

 “Ronnie [Fl Lt Ronnie West DFC & bar] had arrived on Malta after flying off with the first batch of Spitfires, from the carrier HMS Eagle, joining 249 Squadron. He told us that as the Spitfires only had flaps which were either fully up or fully down – no half or partial flaps as with bombers – they had to overcome the problem of really needing partial flap when taking off from a carrier. They achieved this by selecting flaps ‘down’ prior to take-off, then inserting bits of wood which were held in position whilst flaps were selected ‘up’. Thus partial flap was achieved. Once height was made, flaps were selected ‘down’, which released the bits of wood, then ‘up’ again before flying on to Malta.” (From Spitfire Offensive by Wing Commander R.W.F. Sampson, OBE, DFC & bar and N.Franks).

[On 11 Aug, 1942, Eagle was hit by four torpedoes from U-73 while escorting a convoy to Malta; 169 crew were lost; 927 were rescued]     

Tuesday, 28 March 2017

R. J. Mitchell – no Flash in the Pan


The slightest reflection would suggest that the design of the Spitfire had been preceded by considerable experience of high speed flight and the winning of the Schneider Trophy four times. However, a listing of his most significant contributions to aviation reveals promise even as early as the 1920s: 

·      his Commercial Amphibian of 1920 won an enhanced award at the Air Ministry competition for commercial, amphibian, flying-boats. This aircraft was his first independent design and, although it came second to the Vickers Viking, the second prize of £4000 was doubled in recognition of the promise that the aircraft had shown;
·      his modification and up-rating of an earlier company machine, the Sea Lion II, won the Schneider Trophy competition for Britain in 1922;
·      his small fleet of Sea Eagle flying-boats constituted the first British scheduled flying-boat service, operating between Southampton and the Channel Isles between 1923 and 1928;
·      his Swan (1924), a larger scale development of the Commercial Amphibian and which joined the Sea Eagle fleet, was claimed by Supermarine to be the world’s first multi-engined amphibian passenger-carrying machine;
·      the above flying-boat service was incorporated into the newly formed Imperial Airways Ltd. in 1924;
·      his Scarab (also 1924) equipped the Royal Spanish Air Force with an aircraft which, for its time, represented a formidable amphibious bomber gun-ship. This order represented a significant step towards establishing Supermarine as a prosperous aircraft company;
·      in 1925, his Southampton flying-boat, a military development of the Swan, was ordered (unusually)  straight off the drawing-board and became the standard RAF coastal reconnaissance aircraft, replacing the less satisfactory machines of World War I.  Pilots reported that they were trouble free and ‘a joy to fly’ and Jane’s described the design as ‘one of the most notable successes in post-war design’. A total of twenty-four Mk.Is were built and marked real stability and prosperity for Supermarine. Its trend-setting upswept rear hull attracted the comment that it had ‘certainly the most beautiful hull ever built; 
·      in the same year, Mitchell also produced his S.4 Schneider Trophy racer which revolutionized the design of virtually all successive competition entries: he moved, in one bold step, from wire braced biplanes  to a cantilever monoplane. Compared with the top speed of 175 mph claimed for his Sea Lion in 1923, the S.4 gained the World Speed Record for Seaplanes and the outright British Speed Record for all types with 226.75 mph two years later;
·      in 1926 Mitchell appointed one of the first metallurgists to the aircraft industry and his metal-hulled Southampton II led the way towards all-metal aircraft construction. A total of 79 metal-hulled machines were produced as well as numerous hulls for retro-fitting to the wooden-hulled Mark I, even further enhancing the prosperity and status of Supermarine;
·      the increased efficiency of the Mk.II Southampton led the RAF to create a special Far East Flight of four machines which completed a 27,000 mile cruise between October 1927 and February 1928 to Singapore and around Australia (which had only been visited by aircraft on four previous occasions and only circumnavigated by one earlier machine). The 62 time-tabled stages were completed by all the aircraft – as Supermarine publicity said, ‘108,000 machine miles giving no trouble of any consequence’ and as The Daily Mail said: the flight will rank as one of the greatest feats in the history of aviation’;
·      In 1930, Supermarine were awarded a contract (later cancelled for economic reasons by the Government) to build the largest flying-boat in the world – with a greater wingspan than the famous Dornier Do.X and only to be surpassed by the Hughes H-4 Hercules of 1947;
·      by this time, Mitchell had designed his next two Schneider Trophy racers, the S.5 and S.6 which, respectively, won the 1927 and 1929 contests. In the following event of 1931, his uprated S.6B won the trophy outright and later went on the set a new Absolute Air Speed Record of 407.5 mph. This last machine was now of entirely metal, stressed skin, construction.
     Mitchell was now described in Supermarine publicity as ‘one of the leading flying-boat, amphibian and high-speed seaplane designers in the country, had been invited to give a talk on the B.B.C., had been elected a Fellow of the Royal Aeronautical Society and awarded the C.B.E. (aged 36);
·      in 1934, the last of his medium-sized amphibians, the Walrus, was ordered by the Royal Australian Air Force and, in the following year, by the Royal Air Force; eventually a total of 746 were built. It became the standard fleet-spotter  and provided the armed forces with their slowest aircraft  –as well as the fastest which, of course, was the Spitfire;

·    The prototype Spitfire of 1936 marked a dramatic increase of over 100 mph over the most recent RAF fighter in service and Supermarine received an even more dramatic initial order of 310, three months later. Mitchell died, aged 42, without seeing the fighter go into squadron service and without knowing that nearly 23,000 examples were built and in a multitude of main variants.

* * * * *

For details of the aircraft mentioned, see my other blogposts.

For reference sources, see my Blogpost: “Source Material and References" – an extended bibliography is included in my R.J.Mitchell at Supermarine; Schneider Trophy to Spitfire (details below) which also provides material for wider reading, grouped according to specific areas of interest. 










Monday, 27 March 2017

R .J. Mitchell’s Early Modifications (1919 to 1921).

 


Whilst Mitchell was busy with his first medium-sized, slow-flying designs (the Commercial Amphibian and, later, the Seal/Seagull II development), his firm was still interested in the possibility of selling the concept of a small naval “scout” to the Navy and Mitchell was involved with the various modifications to this fast seaplane type.

    The company’s interest in the fast interceptor had begun with an Air Ministry requirement, N.1B, for a fast manœuvrable single-seat seaplane or flying-boat fighter with a speed of 95 kt at 10,000 ft and a ceiling of at least 20,000 feet. The resultant Baby had been designed by F. J. Hargreaves, who was in charge of the drawing and technical offices at Pemberton Billing and who continued for a little while after the company became “Supermarine”. Hargreaves’ close liaison with the Admiralty Air Department produced an aircraft with what appeared to be a dangerously small fin and rudder, typical of aircraft drawn up by this design team but the Baby was, in other respects, a more ‘in house’ response to the ambitious N.1B specification.
N.1B

However, this machine did not go into production because of the ending of World War I but, as Mitchell had joined the firm in 1916 and had then been involved at least with the Nighthawk (see my Blogpost: 'What was R.J. Mitchell's First Design?'), it is entirely likely that he had had some design input in the three N.IB airframes that were built: by the time of the Armistice, N59 (see photo above) had been completed and was being evaluated by the Navy and N60 was largely complete. The third, N61, was under construction and was most probably (in view of its extensive departures from the N59 design) the one bought back from the Air Ministry for entry in the 1919 Schneider Trophy competition, in the hope thereby to gain some very useful publicity.  The modifications were such that it was re-named the Sea Lion I.


Sea Lion I.

Sea Lion I

The particular configuration of this aircraft suggests that the modifications to the Baby design were largely Hargreaves’. The fin and rudder were enlarged in a shaping not followed later by Mitchell (see fin sketches below); likewise, the base of the latter was used as a water rudder, the interplane struts were splayed outwards, and the wings had balanced ailerons on the top wing only and had an inverse taper. Also, the hull was decked to keep down spray and so the front of the fuselage was far less sleek than Mitchell’s later Sea Lion II and Sea King II:
Sea King I (see later)                   Sea Lion I                                   Sea Lion II
                   

In appearance, the aircraft suggested that the man with overall responsibility for this aircraft seemed to have favoured rugged seaworthiness rather than speed through the air; as such, it was the Royal Aero Club’s choice over the slightly faster Avro 539A, for the third entry to the 1919 Schneider Cup competition – possibly hedging their bets because of the already proven sea-going qualities of Supermarine machines. But, by the time of the Schneider contest, Hargreaves had left the company and it was Mitchell who would have assumed last-minute responsibility for this aircraft.

However, the “non-event” of the 1919 Schneider Trophy contest was of no help to Supermarine’s hopes for this type but the company persisted with their fighter flying-boat concept with their next two fast flying-boats, the Sea Kings.


Sea King I.
As Mitchell’s design inputs began in 1916, it is more than likely that he had also been involved with the Sea King modifications to the original N.1B Baby design; however, little is known about his involvement in the N60 version, also bought back from the Air Ministry, and which, it seems likely, became the Sea King I.
This aircraft appeared, largely unmodified, at the 1920 Olympia Aero Show, after Mitchell’s  appointment as Chief Designer, but how long it had been in existence in this guise before this date is unknown; certainly the direct repetition of the earlier, apparently inadequate tail configuration looks backwards rather than to the future:
 N.1B Baby and Sea King I          Sea Lion I            Sea King II  (see below)
      

One speculates that, at this time, the profitable modifications to the A. D. Boats had so pre-occupied Supermarine that a relatively unmodified N60 Baby was sent to the Olympia Aero Show essentially as a marker for the company’s continuing interest in the naval fighter scout concept. There is no record of the aircraft having flown, thus adding to the speculation surrounding the Sea King I. The following publicity for this aircraft, apparently re-engined, would seem to imply that control might not be quite adequate; it also reveals that the company was hoping to sell to the many private flyers that World War I had produced, if military orders could not be achieved:
The ‘Sea King’ is a small fast single-seater which for general purposes follows the structural methods of the ‘Channel Type’ boat. With its 160 h.p. Beardmore engine it puts up a speed of 96 knots, so that it is either a thoroughly sporting little vehicle for the single or unhappily married man, or is a useful small fast patrol machine for Naval work along troublesome coasts. Its chief difference in design from the ‘Channel Type’ lies in the fact that it only has a monoplane tail of the depressing kind and so takes rather more flying on the part of the pilot than does the bigger machine.
Had there been any sales, perhaps Mitchell might have wished to modify the tail surfaces but, unfortunately, neither the military nor the ‘single or unhappily married man’ came along to buy one and it had to await the Mark II development by Mitchell two years later. 


 Sea King II.
In response to the continued Air Ministry interest in a fighter design for shipboard use, Mitchell now produced an amphibian modification of the Baby/Sea King I machine: ‘designed as a high performance fighting scout, specially adapted for getting off gun-turret platforms of capital ships, or getting off and landing on the decks of aircraft carriers. The strength and design of the hull are such that it can operate on and from the water under any weather conditions in which it would be possible to operate any other sea craft [boat] of equal size’ (Supermarine publicity). It was produced in 1921 and so its modifications can be attributed entirely to Mitchell and, indeed, it bore distinct evidence of his taking over the design department at Supermarine.
The most obvious revision of the earlier design was the more generous fin and rudder area (see sketches above) – and it would appear from the Supermarine publicity quoted below that this had a noticeably beneficial effect). As with his Seal (see my Blogpost: 'Precursors of R.J. Mitchell’s Walrus'), the tailplane was now placed almost midway on the fin and the retracting gear of the Seal was again utilized. At the same time, Mitchell also devised a very simple method for the removal of the undercarriage system and a Seal type combined tailskid and sea rudder was also employed.
   The wing-tip floats were the same full depth type as employed on the Baby, Sea Lion I and Sea King I and the tailplane outline was similar to that of the Sea Lion I or the Seal II but with the lower position of the latter – whose reversed camber (“of the depressing kind” continued the Baby tradition.  The aerodynamically balanced ailerons and rudder of the Sea King I were again abandoned in favour of the Baby configuration; the more streamlined Baby/Sea King I hull was retained.

The Supermarine description of this version of the single-seat flying boat fighter type also draws attention to its flying qualities as well as to the many practical features now incorporated by the designer (a theme that would become familiar in the Mitchell story):
The manœuvrability of the ‘Sea King’ Mark II is one of its most important features. It can be looped, rolled, spun, and stunted in every possible way. Longitudinally, the machine is neutral, and flying at any speed throughout its entire range either with engine on, gliding, or climbing, no load is felt on the control stick. This balance has been obtained entirely on the stabilising surfaces, and no mechanical adjustment by the pilot is required. . .The engine, a 300 h.p. Hispano Suiza, is mounted in a streamlined nacelle, which contains oil tank, radiator and shutters, piping, controls, etc. The whole unit is very accessible and the engine can be replaced very easily.Interchangeability and ease of upkeep and repair have been carefully studied. The complete wing structure, including power unit, can be removed from the hull by withdrawing eight bolts. The wing structure consists of top and bottom centre sections, and top and bottom planes of equal span. One set of struts are [is] carried on either side of the centre section. The top planes have a dihedral angle of 1° and the bottom planes one of 3°. The engine unit is carried on two sets of inwardly inclined N struts, and can be removed and replaced without interfering with any wing structure member . . .The amphibian undercarriage, which can be removed by the undoing of ten bolts in all, folds up under the wings, and when folded is well clear of the water. It is raised and lowered by a worm and bevel gear.

The Sea King II was designed and built in six months and made its first flight at the end of 1921 but, once more, no orders were received; however, there was some further development in 1922 and 1923 – see my Blogpost concerning Sea Lions II and III.


For reference sources, see my Blogpost: “Source Material and References" – an extended bibliography is included in my R.J.Mitchell at Supermarine; Schneider Trophy to Spitfire (details below) which also provides material for wider reading, grouped according to specific areas of interest. 


* * * * *

More information, photographs, and a three-view drawing of the Sea King II, as well as a full account of all Mitchell's completed designs and of the man behind them, will be available in a few weeks' time:

What Was R. J. Mitchell’s First Design?



Early evidence of Mitchell’s design work is his contribution to the P.B.31E Nighthawk of 1916.  He was, no doubt, also involved with Chief Designer Hargreaves’ Sea Lion I and, after the latter left in 1919, was involved in various conversions of the Admiralty designed aircraft, A. D.  Boats, which Supermarine bought back from the RAF to be converted for passenger and photographic survey work. However, the first overall design which might be attributed to R. J. was the so-called Commercial Amphibian of 1920.

The first aircraft involved in commercial flying after the end of World War I were conversions of military machines – like the Channels - the name given to Supermarine’s conversions of the A. D. Boat. As they were by no means well suited to their new roles, the newly formed Department of Civil Aviation at the Air Ministry announced, in March 1920, two competitions for commercial designs ‘of British Empire origin’ to promote ‘Safety, Comfort and Security’ in air travel. With a view to developing international travel, and bearing in mind that there were few airfields available, one of these competitions was specifically for amphibian seaplanes with a first prize of £10,000 and a second one of £4,000.
    It was not surprising that Mitchell was asked by Supermarine to design an entry for the seaplane competition, which was to commence on 1 September of that year. By later standards, entry requirements were extremely modest: in the amphibian category, these included seating accommodation for a minimum of two passengers; a range of 350 nautical miles at 1,000 feet at a speed of not less than 70 kt; and a load of 500 lb to include passengers and life belts but not including crew. There was also a requirement of a flight of three minutes at 5,000 ft. to check if the machine would fly itself at this height and with enough height to recover if necessary. Based at  the experimental station at Felixstowe, the amphibian competitors should take off from water and fly to the land-based experimental station at Martlesham Heath.

Commercial Amphibian at Martlesham
 As the Commercial Amphibian can be claimed to be the first comprehensive design by Mitchell,  it is surely very understandable that the end-product would be a conservative one. Also, there were only about twenty weeks separating the announcement date of the competition and that of the trials, leaving little time for innovative thinking. Not surprisingly therefore, Supermarine described the new design as ‘practically a "Channel" type boat, with a wheeled undercarriage hinged on each side’ although the comparable side views show considerable changes in the Mitchell design:
Channel II             Commercial Amphibian

As regards the Channel precedent, the Commercial Amphibian had a biplane layout in which similar dimensions of height, and length were adopted and the sea rudder was similarly placed to that of the Channel – vertically below the leading edge of the tailplane – but now converted to act also as a skid for taxiing over land. The wing-tip floats were also of the Channel sort and the oval hull and the general arrangement of its built-on planing surfaces continued the Linton Hope/Channel principle of hull construction [see my Blogpost: 'Mitchell's Wooden Hulls'].
   On the other hand, Mitchell increased the area of the lower wing; he also incorporated features of a much smaller aircraft, Hargreaves' Sea Lion I: the fin and rudder outlines were similar although a proportional increase in surface area above the tailplane allowed our designer to provide a more symmetrical appearance to the fin. And the Sea Lion's outwardly raked inter-plane struts were repeated in the new, and larger, machine.
    Between the Amphibian’s struts there were canvas stabilising screens, full length between the inner pairs and quarter length between the middle ones. These screens were relatively uncommon by the end of the 1914-18 War but survived on several later Supermarine designs as well as on the Channel and Sea Lion, perhaps (in the case of the inner ones, at least) mainly to protect the engine and propeller from spray on take-off or landing. It was the present machine which was most extensively fitted with them and, in this respect, it did not look particularly like an advanced design. As many of the features from the Channel and the Sea Lion I were thereafter abandoned by Mitchell, the present design can be regarded as something of a ‘time capsule’, a summing-up of earlier practices rather than a statement of the way forward.

But, nevertheless, Mitchell showed an early instance of boldness and originality by abandoning the biplane tailplane and twin rudders of the Channels (still evident in the Handley Page H.P.42 of the 1930s) in favour of a single fin and tailplane. It is worth noting that the competition rival Vickers Viking III went through three more variants before the Mark VII, the Vanellus, appeared five years later with a more modern-looking single tailplane and rudder. And Mitchell’s rudder was also a departure from the minimalist approach of previous Admiralty inspired rudders – perhaps his work alongside Hargreaves on the Sea Lion I had had some influence in this respect. Additionally, Mitchell remodelling of the nose with a prominent boat-like entry to counter spray was to prove successful in his future Sea Eagle, Scarab and Seagull designs.
   A further feature was Mitchell’s design for a retracting undercarriage, necessary because the Air Ministry competition was for an amphibian aircraft. At this time, an American landplane, the Dayton-Wright R. B. Racer, had a fully retracting landing gear designed specially for the Gordon Bennett race of 1920; on the other hand, the Air Ministry commercial competition was satisfied with devices which merely lifted the wheels out of the water, in order to facilitate take-off and alighting.  Supermarine’s concern for ‘boats which fly’ offered no previous experience of retractable undercarriages for Mitchell to call upon and so it is noteworthy that, for his specially designed mechanism, he chose a geometry which displaced the wheels outwards rather than forwards – thus avoiding any change of trim when the wheels were moved up or down.
    One other particular feature of the Commercial Amphibian must also be mentioned: the enclosed passenger cabin [see the opened cabin roof top in the photo above]. The competition’s intention of ascertaining ‘the best type of Float Seaplanes or Boat Seaplanes which will be safe, comfortable and economical’ might have seemed to make an enclosure for passengers inevitable but it should be noted that the other two amphibian entries had open cockpits for the passengers, one seated next to the pilot and the other two side-by-side behind. Open cockpits at this time were the norm and they saved weight, but they were far from ideal for operation over water and in northern climates – Cozens, a contemporary observer, described how previous Channel passengers ‘had an uncomfortable ride on many occasions’ and, although ‘wearing flying coats and helmets they looked wet and miserable as they got into a boat that was rowed out to meet them’.

No adjustments or replacements to the Mitchell aircraft were required, despite its one-off design and the short notice of the competition, and the Supermarine entry was the only one which completed all the tests that were stipulated and whose landing gear did not give trouble at any time. The judges also noticed with approval an effective tiller arrangement for steering whilst taxiing on water, the equipment for sea use, and the way in which the shape of the forward part of the hull kept spray off the passengers’ compartment. On the other hand,  the novel undercarriage gave rise to criticism for being none too clean, from the mechanical and the maintenance points of view. The lateral control of the Commercial Amphibian was also considered not immediately responsive enough.
   Unfortunately, the fitting of a Rolls-Royce Eagle engine in order to lift the considerable more loaded Channel design led to a  loss of  competition points, resulting in its coming second to the Vickers Viking.   However, the Air Ministry report on 11 October stated that ‘the results achieved for amphibians show that considerable advance has been attained … and the competing firms deserve congratulations on their enterprises.’ They also recommended a doubling of the second prize money to £8,000 as ‘the proportion of the monetary awards does not adequately represent the relative merits of the first two machines’.

A modest beginning to be sure but, as we shall see later, its general design and its overall performance gave rise to a call from the Air Ministry for a development of this machine which led to the Sea Eagle and the Seagulls between 1923 and 1926.


* * * * *

For reference sources, see my Blogpost: “Source Material and References" – an extended bibliography is included in my R.J.Mitchell at Supermarine; Schneider Trophy to Spitfire (details below) which also provides material for wider reading, grouped according to specific areas of interest. 

More information, photographs and a three-view drawing of the Commercial Amphibian, well as a full account of all Mitchell's completed designs and of the man behind them, will be available in a few weeks' time: