The Short Mayo Composite Mail Plane.

A unique solution to the problems of long range airmail delivery, proposed by Major Robert H Mayo, Technical General Manager of Imperial Airways, designed and built by the British company Short Brothers before World War II consisted of a 'piggy-back' arrangement of two aircraft.

Mercury annd Maia at Foynes. Photo; National Library of Ireland

The ensemble consisted of a Short S.21 flying boat "Maia" based on the Empire 'C-Class' type already in service carrying, mounted on a trestle, a smaller Short S.20 four engined floatplane "Mercury". With a full payload of 1000 lbs and a maximum fuel load of 1200 imperial gallons Mercury could not get airbourne under her own power but when carried to her operational altitude by Maia, she was capable of crossing the Atlantic unrefueld. Meanwhile Maia was equipped to carry 18 passengers.

Maia's first flight took place on 27th July 1937 and Mercury's on 5th September the same year, on both occasions being flown by Shorts' Chief Test Pilot John Lankester Parker. The first in-flight separation was accomplished on 6th February 1938 with Parker at the controls of Maia and Harold Piper in Mercury near the company's works on the River Medway near Rochester, Kent.

After completing a successful test program the inaugural commercial flight, a transatlantic crossing to Montreal via Foynes in Eire took place on 21st July 1938 with Mercury becoming the first heavier-than-air craft to make a non-stop east to west crossing of the Atlantic. A further record attempt was made in October with a flight from Dundee, Scotland to Alexander Bay in South Africa.

No other examples of the Mayo Composite were built as new types coming into service rendered the concept obsolete and the outbreak of World War Two in September 1939 put an end to its operations. Maia was destroyed in a bombing raid on Poole Harbour and Mercury served for a while with a Free Dutch maritime reconnaissance unit 320 Sqd Royal Air Force before being scrapped to reuse her aluminium for war production.

The video below is a compilation of Movietone News reports on the development and introduction into service of the Mayo Composite.

Saunders-Roe SR.53

The Saunders-Roe SR.53 was an experimental aircraft with a combination of a jet engine and a rocket motor, respectively an Armstrong Siddeley Viper and a De Havilland Spectre. Its purpose was to develop a mixed power fighter to intercept bombers at high altitude - the specification required it to achieve an altitude of 60,000 ft in 2 minutes 30 seconds. Inspired by the Luftwaffe's World War Two  Messerschmit 163 the addition of a turbojet aimed to overcome the major drawback of a pure rocket design, excessive fuel consumption resulting in limited range and the need to make an unpowered recovery to the airfield.

The surviving first prototype SR.53 XD145 at the RAF Museum, Cosford.

Designed by Maurice Brennan two prototypes were built, serial No.s XD145 and XD151, in response to Air Ministry Operational Requirement O.R.337 with XD145 taking to the air for the first time on 16th May 1957 with Squadron Leader John Booth at the controls.

Tragedy struck on 5th June 1958 when the second prototype XD151 was destroyed in an accident taking off from Boscombe Down on its 12th flight, killing John Booth instantly. Testing continued with XD145 with Lt Cdr Peter Lamb as the test pilot and a total of 56 flights were made between the two aircraft.

However, owing to the complexity of the project, the development program had fallen well behind schedule even before flight testing had commenced and the British Government's 1957 Defence White Paper had been published a month in advance of the type's maiden flight, envisioning the demise of manned fighter aircraft and air defence being taken over by guided missiles (a prediction that has since been proved wrong by history). At the same time, developments in radar and jet engine technology had rendered the SR.53 concept obsolescent and the type was cancelled on 29th July 1960. Fortunately the remaining airframe XD145 was preserved and can now be seen at the Royal Air Force Museum, Cosford.

A larger, better equipped development of the design under the designation SR.177 was studied and a mock-up constructed. The Royal Air Force, Royal Navy and Luftwaffe all showed interest in this improved variant, but initial orders for for the RAF were cancelled and the German Air Force controversially went for the Lockheed F-104 Starfighter with subsequent accusations of bribery (See the video below). This left the Royal Navy's small requirement unviable and the project came to nothing.

The video below, from YouTube, with interest interviews with people involved including Eric "Winkle" Brown, has some footage of the SR.53 during its test flights and also covers the SR.177 debacle



Flight magazine's 24th March 1957 edition had an article on the SR.53 which can be downloaded as a PDF by following this link to their archive.