American sportsmanship which saved Great Britain

The Schneider Trophy

How American sportsmanship saved Great Britain

   The history of the Trophy donated by Jacques Schneider in 1912 is well known and has been detailed in many books and magazine articles.   It was given for an international speed competition to be organized by each nation’s aero clubs for marine aircraft, i.e. for aircraft rising off water.  He believed that the future of aerial transport lay with that type of aircraft and hoped to advance it.

   The Schneider Trophy was raced for 13 times (the 1919 race was voided) and, in accordance with a rule which allowed the winner three times consecutively in five years to retain it in perpetuity, it became the property of the Royal Aero Club in 1931.  This was the culmination of 6 years of British government funded effort to build the competing aircraft, support them with the Royal Air Force and fly them with serving pilots.  What the technology gain through these 6 years led to, in the Supermarine Spitfire fighter and its Rolls-Royce Merlin engine has also been described exhaustively.

   Fig. 1 shows the race speeds and puts them in perspective with the World Record of the date and the speeds of the fastest RAF fighters over the years.  The step change between a biplane with fixed undercarriage and radial air-cooled engine (Gladiator) to monoplanes with retractable undercarriages and liquid-cooled in-line engines (Hurricane and Spitfire) is very evident.

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   What has not been appreciated is that this outcome of world history was made possible by an act of sportsmanship by the United States of America in 1924 when they refused to make an unchallenged fly-over in the scheduled race to gain the Trophy that year.  Had this generous gesture not been made, the race they won in 1925 would have secured them the Trophy in perpetuity, the race series would have ended, the technical advance by the British over 1929 -1931 in particular would not have occurred and the Battle of Britain would not have been won in 1940.  As a consequence, much grief would have come to Great Britain, to Europe and eventually to the United States also.

   This article explains the sequence of events.

The American Curtiss racing seaplanes

   At first, competitors for the Trophy were financed by aircraft builders in hopes of sales resulting from success, although the entries were organized by the national aero clubs.  After World War One, governments became involved, as the aerial fighting had shown the importance of fast aircraft.

   The most effective support of this kind came first in the USA in 1921 when the United States Navy ordered high speed aircraft from Curtiss, also intending to run their own racing team.  The result, after some development and after racing the machines as landplanes, was the Curtiss CR-3 biplane seaplane. This won the Trophy in 1923 at a speed 22% higher than the 1922 winning Supermarine Sea Lion II biplane flying-boat (which had been designed by Reginald Mitchell).  Important contributors to this speed were a new Curtiss aero engine, the D-12 with wet cylinder liners (which later influenced Rolls-Royce in designing the Falcon Experimental, subsequently named Kestrel ) and wing-skin cooling radiators.

   This win meant that the US National Aeronautic Association (NAA) was tasked with arranging the 1924 race in the USA.  The date set was late October in Chesapeake Bay.

   However, France withdrew, Italian aircraft were unsuccessful and Italy also withdrew and a British (Gloster) entry crashed in September.  The USA, whose 1924 Curtiss R2C-2 seaplane had been shown in tests to be 30 MPH faster than the 1923 CR-3, could have made an un-opposed fly-round to claim the race;  there is a maxim in motor racing that “To finish first, first you must finish!”.  This could have been adapted in this case “To finish first, first you must start!”.  The NAA did not take this position.  Instead, they made the sporting gesture of cancelling the race.  It was to be run again in 1925.

   For 1925 the British Air Ministry ordered two high speed aircraft, said to be for research:-   a Supermarine S4 cantilever monoplane designed by Mitchell and a new biplane from Gloster, designed again by Henry Folland, who had been the lead designer for the famous Royal Aircraft Factory SE5 scout (fighter) during the war.  Both were seaplanes, making it obvious that entries for the Trophy were really intended and were made.  The Italian Macchi firm, without government subsidy, entered a cantilever monoplane flying-boat designed by Mario Castoldi.  The American armed services, collaborating for once, bought a team of a new Curtiss seaplane type, the R3C-2 biplane, for the race.  The event was again scheduled for October, over Chesapeake Bay.  Although the S4 crashed there in a trial, probably because of wing flutter (the pilot escaped) , the rest came to the start.  Once again, a Curtiss won.  It was the Army-owned aircraft, piloted by a man who would become much more famous in World War Two, Jimmy Doolittle (see Fig. 2 ).

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   Did the Americans regret their generous action of 1924, thinking that otherwise the Trophy would be theirs for keeps?  They could not foresee the benefit to democracy of their sportsmanship.

   The “British government went mad!”(as W. Cox, an ex-Supermarine designer said in a 1963 lecture) after the 1925 race.  They decided to go the whole hog towards winning, ordering three new seaplane types (Supermarine, Gloster and Bristol), an improved Napier Lion engine for the first two and a new Bristol air-cooled radial engine for the latter.  This began the programme which would ultimately bear fruit in the aircraft and engine which in the hands of the RAF, the FAA and many pilots from other nations, saved Great Britain in 1940.

   The British team was to be managed by the RAF and flown with service pilots.  However, it soon became clear that this new equipment could not be ready for 1926 and the British asked for a postponement until 1927.  This was refused;  the US services believed they could win and so retain the trophy, and the US were ready to see it finished to concentrate on more commercial activities.  It was hoped by the British that, as there seemed to be no-one else who would challenge, the NAA would repeat their altruistic action of 1924.  This hope was dashed when Italy, at the express command of the Italian dictator Benito Mussolini, entered a team of Macchi-Castoldi M39 wire-braced monoplane seaplanes.  Whether the race for the Trophy would be terminated on the 25th October 1925 now rested with this effort.  As it happened, the Italians were not ready by that date, asked for a fortnight’s delay, were granted it and then beat the Curtiss racers, which had been repowered with new engines.  This time there is little doubt that the Americans did regret their generosity.

  With the end of official US participation and with occasional French efforts which never reached the starting line, the Trophy competition would continue as a needle match between Italy and Great Britain.  

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Trophy racing 1927 -1931

   It is not necessary here to describe the 1927, 1929 (a bi-annual race series was agreed after 1927) or 1931 races, only to note that:-

1.   Mitchell’s Supermarine seaplanes, S5, S6 and S6B with RAF pilots, won all three;
2. The monoplane aircraft reverted to wire-braced wings after the S4 crash (see Fig. 3);

3. After the naturally-aspirated Napier improved Lion powered the S5 to the 1927 win, the momentous decision was taken by the RAF Supply and Research chief, Sir John Higgins, to force a reluctant Rolls-Royce Managing Director to supply a racing engine for 1929 (the engineers were very willing).
4.   Henry Royce decided to up-rate an existing supercharged V12 type (becoming the “R”) rather than build a specialised V16.  This V12 was then improved for 1931, despite starting a defence of the Trophy “too late” because of official doubts of the value of the effort and a poor national financial position (the latter resolved by Lady Houston’s guarantee of £100,000 (worth nearly £7 million in today’s depreciated money, although it is not known if this was taken up).

The lessons learned during the 1927 -1931 Schneider Trophy series:

by Reginald Mitchell and his team at Supermarine

• About the airflow around thin (under 10% thickness/chord ratio), elliptical plan-form wings.
• About control at high speeds, with attention to eliminating flutter.
• About cooling of water and oil (the surface cooling of the Schneider aircraft was too vulnerable for military service).
• About Al-alloy metal construction.

by the Design, Development and Experimental Manufacture teams at Rolls-Royce over 1929 – 1931

• About the advantage up to 400 MPH of the liquid-cooled engine – provided that the installation was got right by close co-operation between engine and aircraft builders (which led to the creation of the Flight Test Establishment at Hucknall aerodrome in 1934).
• About the sound mechanical foundations needed for all later high-power piston engines;

Particular examples:-  RR50 casting Al-Si-Cu alloy;

                                    Internally-cooled exhaust valves.

Generally, carrying to much higher stresses and temperatures the knowledge of how to avoid the local anomalies which can quickly reduce any machine to ruin:-

Stress concentrations;

Resonances;

Fatigue;

Hot spots;

Differential expansions.

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• About the confirmation of Henry Royce’s philosophy for advancing the State-of-the-Art of aero-engines:-

Careful design using all available knowledge;

RUTHLESS testing by all possible means (rigs and complete engines);

Exhaustive analysis of all failures;

Repetition of the “Design-Make-Test” cycle until successful qualification for service;

 And, most importantly, BEING ORGANIZED TO DO ALL THIS ON SHORT TIME SCALES.

[This philosophy, which may seem obvious but needs a lot of courage to be applied when time and the budget are short, is still relevant today.  There is an American saying “Why is there never time to make it right in the first place, but often there has to be time to make it over?”]  

For both Supermarine and Rolls-Royce the most valuable result of the 1927 -1931 campaigns was the knowledge of these things implanted or reinforced in the minds of well-established teams of people who carried on the work of their firms when the pioneers died.  The names of these team leaders are famous in industrial history:-  in 1936 Ernest Hives became the main moving force in Rolls-Royce;  Joe Smith carried on at Supermarine when Reginald Mitchell died in 1937.

   This is not to say the lessons listed above brought instant results – Mitchell produced an awful fighter (F224) to Ministry specification F7/30 in 1934, before creating the Spitfire in 1936;  and Rolls-Royce’s first attempt at a new 27 litre V12 engine in 1933 (the PV12) contained many feature which had to be discarded before the Merlin II appeared in 1936 to power production Spitfires and 4-month younger Hawker Hurricanes.  It is hard to know why these false starts were made, except that Royce (after enduring a colostomy for 20 years) was very near his end when the first Kestrel-Replacement studies were made in mid-1932.  On his part, Mitchell had never previously designed a fighter and perhaps paid too much attention to an un-imaginative Ministry specification.  Certainly, their F10/35 specification was then written round the completely new fighter which Mitchell wanted to do next:-   a cantilever monoplane with thin wings,  a retractable undercarriage and closed cockpit (see Fig. 4.)

   At any rate, when Mitchell and Rolls-Royce got their joint minds fully into gear, the rest is history.  An important part of that history was made by the RAF fight in 1940 with the Messerschmitt Bf109.  That fighter is therefore reviewed here briefly.

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The Messerschmitt Bf109

   While Reginald Mitchell and Sydney Camm and their teams at Supermarine and Hawker were working on the designs which became the Spitfire and Hurricane, Willy Messerschmitt at Bayerische Flugzeugwerke in Germany was preparing his entry into a fighter competition, the Bf109.  Of course, he had no experience of flight over 300 MPH, unlike Mitchell but like Camm (it can be assumed that they both had absorbed what the British official report R&M1300 published in January 1931 had told the world about the 1927 Schneider seaplanes).  Messerschmitt obtained his speed by ignoring an official instruction to keep wing loading under 100 Kg/Sq. Metre (20.5 Lb/Sq. ft), choosing to use 33 Lb/Sq. ft (E3 model, see below and Fig. 5).  To then reduce the stalling speed he fitted automatic leading-edge slots (never used on any other fighter) plus large trailing-edge flaps.  The metal construction was also particularly light (Al-alloy and some Mg-alloy).

   The Bf109 went through several models before 1940 and the rivals in the Battle of Britain are compared below:-

	Hurricane 1	Spitfire 1	Bf109E-3
1st delivery	December 1937	August 1938	Late 1939
Wing Plan	Plain tapered	Elliptical	Plain tapered
Wing Loading Lb/Sq.ft	26	25	33
Wing average thickness/chord	15%	9.5%	12.6%
Maximum Speed MPH @ 20k ft	11% less than Spitfire	360* **	Very similar to Spitfire*
Armament	8 x 0.303″ mg	8 x 0.303″ mg	2 or 3 x20mm, 2 x 7.92mm mg

*The author wishes to avoid a contentious subject, which can be read up exhaustively on the internet.  A particularly valuable source is:- www.spitfire performance.com. The Hurricane vs Spitfire difference is given in a June 1940 official report by A. Collar.

**Using normal throttle limits.  With 100 Octane fuel, fully available in service in early 1940, it had been found in 1939 tests that super-rich mixture enabled boost pressure to be raised in the Merlin II to give +30% power below 10k ft (fuel Grade 100/130).  This was officially limited to 5 minutes and was obtained by pushing through a frangible throttle restricter.  Low-level speed was increased by 9%, with a shorter time to climb to fighting altitude.

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   As dog-fighting machines it was found that the lower wing loading of the British aircraft enabled them to turn well inside the Bf109.  On the other hand, the direct fuel injection system of the Bf109 Daimler-Benz DB601 engine permitted it to escape by a sudden dive which the carburetted Merlin with a petrol float could not follow instantly unless full bank and then bottom rudder was applied.  Some RAF pilots complained of this Merlin characteristic. Others did not.

The Battle of Britain

   The objective of the Germans from August 1940 was to secure aerial supremacy over the Channel.  This the Kriegsmarine had demanded as a prerequisite to attempting to convoy the army in an invasion, knowing their low strength and aware that a large force of destroyers had been assembled by the RN at ports from Portsmouth to Harwich.  The Norwegian campaign, Dunkirk and in the Channel/Narrow Seas generally had shown that dive-bombing could sink ships.    This aerial objective meant defeating Fighter Command, by shooting down enough of its pilots and/or making. their airfields unusable.

   The Spitfire and the Bf109 first clashed over Dunkirk and the Luftwaffe pilots then found that they had met their equal, where previously in the Battle of France they thought that they could generally defeat the Hurricane (see Fig. 6).

   In the ensuing battles over England, where possible Spitfires fought the German fighter escorts while the 58% more numerous Hurricanes attacked the bombers.  Their defeat was, of course, the object of the defence.  By shooting down the multi-place bombers, along with their own tally of Bf109s, the Hawker fighter pilots inflicted about 60% of the crew losses suffered by the Luftwaffe during the battles.    Although the collapse of Belgium and France had allowed the Luftwaffe to rebase itself 200 miles nearer England, fortunately the small fuel capacity of the Bf109 meant it had little time for combat over targets well inland.  Drop tanks were not  available until after the battles.  This, the Radio-Location and Observer Corps networks and the well-organized command systems, were essential aids to the fights in the air.

   Whether Fighter Command was in crisis by late August 1940 is a contentious subject, but there is no doubt that Hitler’s order to attack London in early September, in retaliation for a pin-prick raid by Bomber Command on Berlin, gave relief to the Command airfields.  Losses then inflicted on the Germans, after they had assumed that they were winning, led to Hitler’s conclusion in mid-September that the fight for supremacy had failed and the invasion operation must be postponed. 

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After a further postponement to 1941 in October, it was cancelled altogether in December.  The Battle had been won.

 “What if” the 1927 – 1931 Schneider Trophy races had not been run?

   As described, if the US sporting authorities had claimed the 1924 race by a fly-round, they would then have won the Trophy in perpetuity by their win in 1925.  The races series would have finished.  The British government would not have begun the R & D high-speed programme in late 1925.  The design and development teams of Supermarine over 1927 -1931 and Rolls-Royce over 1929 – 1931 would not have learned the lessons listed above about high-speed aircraft and high power-to-weight engines which they did.  Mitchell’s fighter to F7/30 could not have been better than the F224 of 1934 and he would not have known how to improve it.  The next Rolls-Royce engine would not have been much of an advance in Power/Weight ratio on the supercharged “F” of 1928, i.e. 520 HP@ 13,000 ft for 900 lb, 0.58 HP/lb.  The Merlin II of 1936, produced with the new knowledge, gave 1,030 HP @ 16,250 ft for 1,335 lb, 0.77 HP/lb, 1/3^rd higher.  Not only would the Spitfire never been produced to accompany the Hurricane into battle, but the Hurricane would have had a less powerful engine and lower performance. 

   It is not too much to say that the Battle of Britain would have been lost in a very short time.

   The above has to be speculation, but there is an actual known example of the lack of progress without the stimulus of Schneider Trophy competition.  After their great successes with the Trophy racers, Curtiss did not compete after 1925.  They amalgamated with Wright in 1929 and discontinued liquid in-line engine development in favour of air-cooled radial engines.  When they built a new fighter at a date which allowed its export version to compete in some numbers with the French Armée de l’Air in 1940, this was the P-36 (see Fig. 7).

  It was fitted with a Pratt & Whitney air-cooled radial engine and it could only achieve 313 MPH at 8,500 ft. with the light armament of 4 x 7.5 mm mgs.  The history of its performance against the Bf109E-3 in the 1940 44-day Battle of France is uncertain (like so much of the performance of that service) but it cannot have been very effective.  The Luftwaffe did what it pleased in that campaign and were, of course, a major factor in the French defeat.

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   Had the Battle of Britain been lost in August 1940, Hitler would have continued to attempt the invasion of the British Isles.  It has been contended that the Royal Navy, even without the umbrella of the Royal Air Force, could have defeated that invasion and there is no doubt that they would have sacrificed themselves towards that end.  However, in the 4 months before August 1940 while still learning anti-shipping tactics, the Luftwaffe sank 19 British and French destroyers, most of which were within air cover.  What would have happened to our anti-invasion fleet without that cover cannot be known.  It might not have succeeded in thwarting the invasion or the defensive mining of a secure channel for re-supply which the Germans intended to create.  Once ashore, the Wehrmacht would have found a very weak British army.

   All that can be said is that, if Great Britain had lost the aerial Battle of Britain, it would certainly have suffered much more grief than it did.  The United States might have faced a wholly hostile shore across the Atlantic.  That it did not do so stemmed from their own sporting gesture 16 years earlier.

Derek S. Taulbut.

28 July 2018

Major works consulted

• The Schneider Trophy Races.  R. Barker.  Chatto and Windus.  1971.
• The Aerodynamics of the Spitfire.  Journal of Aeronautical History.  2016/03.  J. Ackroyd.  This includes the Aeronautical Research Committee report by A. Collar in June 1940 which analysed the 40 MPH speed difference between Spitfire and Hurricane.

• Various specialised web sites.