Saunders-Roe SR A/1
Following discussions between Hugh Francis of the Marine Aircraft Experimental Establishment (MAEE) and Henry Knowler, chief designer of Saunders Roe, the idea of a flying boat fighter was generated. It was then schemed and serious work was started at the beginning of 1944 in Beaumaris, Anglesey, where Saunders Roe had their Design Office. The official specification was E.6/44 and the aircraft's designation SR A/1 followed the then new nomenclature of the SBAC for the drawing system for each company, A/1 signifying the first aircraft of Saunders Roe under that system.
The new aircraft was designed around two Metropolitan-Vickers F2/4 Beryl turbojets designed under the direction of Dr D. M. Smith, chief engineer of that company's Gas Turbine Department. These engines, the first British axial-flow engines, delivered 3,3001b thrust initially, raised later to 3,8501b following successful type tests. They were small in diameter by comparison with the centrifugal type compressors favoured at that time by other engine makers. Two could therefore be installed side by side without making the hull's beam unduly great. The intake was provided with an extendable lip which was intended to overcome water ingestion troubles, should they occur. In the event, they did not and, although the lip was used on test, it was not normally needed, as the SR A/1 was intended for operation from sheltered or inland waters. Both engines shared the oval shaped intake. The hull shape was of faired vee form, entirely of metal construction, made up of strong keel members, closely spaced frames, light upper longitudinals and carefully filled skin rivetting. The engine exhausts were toed out five degrees each side of the centre line. The pilot's cockpit was pres-surised and air-conditioned by air tapped from both power unit compressors. Provision was also made for a "G" suit.
Another "first" was the Martin Baker ejector seat, which was the first to be delivered to an aircraft manufacturer from the works. The pilot had four 20mm Hispano cannon mounted immediately ahead of him in the nose, each gun having 240 rounds. In addition, two 1,000 lb bombs or eight rockets could be carried.
The wing was a single spar structure, fitted with dive brakes and dive recovery flaps, as well as ailerons and landing flaps. The tail unit was of similar construction to the wing. The aircraft had a Mach Number of 0.81. The uniqueness of the controls lay in the, combined use of geared and spring tabs, allowing a simple and neat type of manual control without fine balance or trailing edge troubles.
Control on the water was by means of a small rudder integral with the rear step. It could be locked centrally when in flight or, when on the water, linked to the rudder pedals. Lateral support was by means of hydraulically retractable floats which were rotated mechanically as they retracted inwards so as to lie inverted in the under surface of the wing, thus creating minimum drag. The four main wing fuel tanks together with two overload drop tanks gave an endurance of around 212 hours.
When it was agreed that construc-tion of the SR A/1 should proceed, three prototypes were authorised. These were allocated the serials TG263, TG267 and TG271. The design was completed at the Beaumaris Works and the components were made there. They were transported to Cowes for assembly and test flying.
Geoffrey Tyson undertook the flight testing of the new flying boat. He first taxied TG263 on July 16, 1947 and, finding everything in order, took it off.
The SRA/1 was improved later by the fitting of an “acorn” at the intersection of the fin and tailplane to cure a slight buffet. The first take-off had taken only twelve seconds and the rate of climb was exceptional. Apart from this, the only other visible alteration was the fitting of a metal cockpit canopy following the loss of a transparent hood in the course of a test flight. This was one of the earliest sliding hoods to be pressurised as high as 6.75 lb/sq ft.
So well did the flight testing go that Tyson was able to demonstrate the prototype at the SBAC Show at Farnborough two months after its first flight. Testing continued steadily through 1948 and the prototype was joined by TG267 and TG271. The second flew on 30 April 1948 with 1587kg Beryls and the third followed on 17 August 1948 with fully rated Beryls of 1746kg. The second to be built, TG267, was lost with its pilot at the Marine Aircraft Experimental Establishment at Felixstowe on 17 September 1949. He had been practising for a local air display in conditions of poor visibility and crashed into the sea. Squadron Leader 'Pete' Major took TG267 up that morning to prepare for the aerobatic routine he planned to perform for the public that afternoon. During a slow roll, he let the nose slip down while inverted, then instinctively pulled on the stick rather than pushing out from his upside-down position. The aircraft broke up on impact, and no trace of Major was found; much of the aircraft was salvaged over the next ten days.
Engine development continued on the other two with simulated failures (and one or two genuine ones), re-lighting sometimes being a problem. On one occasion Tyson suffered a double flame-out at about 20,000ft and was unable to relight either engine. He had been some 20 miles South of the Isle of Wight and managed to glide home.
Chief Naval Test Pilot Lt Cmdr Eric "Winkle" Brown flew the third SR A/1, TG271, for the first and only time on 12 Aug 1949 at the behest of Saunders-Roe. He wrung out the tubby little 'boat, reaching Mach .82, pretty much the top speed of the SR A/1, in a dive. approaching to land at Cowes and, at the very last moment when he was committed to the touch down, he saw a half submerged baulk of timber. The log tore a 4-5ft gash in the starboard front hull and ripped off the starboard stabilizing float. Despite his best efforts, Brown could not keep the starboard wing from digging in and cartwheeling TG271 onto its back. Struggling free underwater, Brown almost succumbed, but was held up by Geoffrey Tyson, the Saro test pilot responsible for the majority of the SR A/1 testing, who had leapt off the supporting launch when he saw Brown in trouble. Despite extensive searching, the sunken third SR A/1 prototype was never located, such are the peculiarities of the Solent tides.
Although the design of the SR A/1 was begun before the end of World War 2, its construction was authorised after hostilities ended. Export orders were hoped for. It became clear that exports were unlikely and this, together with the loss of the two aircraft brought the development programme to a halt.
Tests were resumed for a short period beginning in November, 1950, after a brief revival of interest during the Korean War.
The last public appearance of a SR A/1 was in June, 1951, when Geoffrey Tyson took the remaining prototype to London for display at the Festival of Britain. He landed on the Thames in Woolwich Reach and was towed to a mooring opposite where the Royal Festival Hall now stands. The aircraft, TG263, then bearing the registration G-12-1, remained for three days and was then towed back to Woolwich Reach.
The last remaining SR A/1 came to the end of its working life in June 1951 and it was presented to the College of Aeronautics at Cranfield. Its engines were removed and given elsewhere for a speed record attempt. Some time later, it passed to the Skyfame Museum at Staverton, near Cheltenham, and into the care of Mr Peter Thomas, its founder.
The completely restored first prototype, TG263, resides today at the Southampton Hall of Aviation, along with an example of its ejection seat (the first delivered by Martin-Baker to an aircraft manufacturer) and a MetroVick Beryl powerplant, both exhibited outside the airframe.
Engines: 2 x Metropolitan-Vickers F2/4 Beryl turbojets, 1474-1746kg
Wingspan: 14.02 m / 46 ft 0 in
Length: 15.24 m / 50 ft 0 in
Height: 5.11 m / 17 ft 9 in
Wing area: 38.60 sq.m / 415.49 sq ft
Max take-off weight: 8633 kg / 19033 lb
Empty weight: 5108 kg / 11261 lb
Max. speed: 824 km/h / 512 mph