G-ADHK Short S-21 Empire Boat

This Empire boat was built by Short Brothers (Rochester & Bedford) Ltd, Rochester

It was built as an experimental aircraft to be operated in conjunction the 'Mercury' the upper component

being a long-range mailplane

It was designed by Arthur Gouge, Chief Designer, Short Bros and

Robert H. Mayo, the Technical General Manager of Imperial Airways, London

The contract based on the Specification 13/33 was placed with Short Brothers - 1935

Estimated cost of approximately UKL 600,000 was to be shared equally between the Treasury and Imperial Airways

Built as an S-21 Class flying boat having 875 / 915 h.p. Bristol Pegasus X engines

The standard fuel capacity was 650 gallons

It had an all-up weight of 38,000 lb, maximum speed of 200 m.p.h. and a range of 850 miles

Entered onto the British Aircraft Register as G-ADHK (CofR 5880) - June 17, 1935

Launched on the Medway River at Rochester - July 27, 1937

First flown without the pylon structure (Captain John L. Parker) - July 27, 1937

The aircraft was fitted with temporary four-bladed wooden propellers and the flight lasted 20 minutes

For the second & third flight the aircraft was fitted with three-bladed viariable pitch metal propellers - August 09, 1937

These flights were for level flight speed tests at 6,000 feet

The Certificate of Airworthiness (CofA 6302) Issued - ?

The aircraft was named 'Maia'

The aircraft were mated to form the 'Short Mayo Composite' - January 01, 1938

An initial taxying trial of 1 hour was undertaken - January 01, 1938

Captain John L. Parker was in 'Maia' and Captain Harold Piper was in 'Mercury'

The second taxying trial of 45 minutes was completed - January 03, 1938

The Composite aircraft successfully rode out a gale at its moorings - January 1938

The third taxying trial of 40 minutes was completed - January 19, 1938

During the taxying trials Bill Hambrook stood atop 'Maia' to observe the release gear

The first flight (20 minutes duration) of the combined 'Mayo Composite' took place - January 20, 1938

First successful 'Mayo Composite' separation near Rochester - February 06, 1938

Further test flying occured in the Felixstowe area of Suffolk ready for trans-Atlantic operations

The first long-haul trial carried out - July 14, 1938

The 'Mercury' was launched from 'Maia' over Southampton and flew 2,040 miles to Foynes and out over the

Atlantic Ocean and returned to Southampton for a flight duration of 12 hours

During this flight 'Mercury' established radio contact with Foynes and Botwood (Newfoundland)

First trans-Atlantic flight from Foynes (Ireland) - Boucherville (Montreal, Canada) - July 21, 1938

As well as the weight of 'Mercury' 'Maia' carried 10 passengers and luggage to Foynes after the successful separation

Flight crew: Captain A. S. Wilcockson (Maia); Captain Don Bennett (Mercury)

The distance from Foynes to Boucherville was 2,930 miles or 4,714 kms

'Mercury' was launched over Foynes at a gross weight of 20,800 lb including 600 lb of payload

comprising of newspapers, press photographs and movie newsreels

On separation 'Maia' would drop down whilst 'Mercury' would assume a climbing attitude

'Mercury' had a range of some 6,000 miles and the flight was completed it 20 hours 21 minutes

This equated to an average ground speed of 144 m.p.h. (232 kts)

On arrival at Monreal 'Mercury' had some 80 gallons of fuel remaining in the tanks

This equated to just 54 gallons burnt per hour which was much lower than anticipated

An attempt to set a new world record for a non-stop distance flown by a seaplane undertaken - October 06, 1938

'Mercury' was launched from 'Maia' to fly from Dundee (Scotland) to Capetown (South Africa)

Severe headwinds and tropical thunderstorms slowed the flight

'Mercury' alighted on the Orange River near Alexander Bay having flown 6,045 miles in just over 42 hours

'Maia' was registered to B.O.A.C. - August 27, 1940

It was destroyed by German bombers whilst moored at Poole Harbour - May 11, 1941