THE Marine Aircraft Experimental Establishment based in Helensburgh during the Second World War operated the world's largest indoor water testing tank at Glen Fruin.
Like the operations based at Rhu Hangars, the facility in the glen carried out work which was cloaked in secrecy, says Robin Bird who wrote ‘Top Secret War Bird of World War Two’, which is about MAEE and his father who served there, photographer Bob Bird.
Robin says that the famous Barnes Wallis bouncing or 'skipping' bombs' were tested at what became known as the Admiralty Hydro Ballistic Research Establishment behind security fences in Glen Fruin, and were then used in the celebrated ‘Dambusters’ bombing raids.
Trials on air to sea torpedoes and depth charges were also carried out, and large scale models of land and sea planes were given a 'dunking' in the water tank to study how aircraft were affected by ditching at sea.
MAEE was a secret wing of the Royal Air Force answerable directly to the Ministry of Aircraft Production, and even today the former MAEE buildings in Glen Fruin are well protected as a military outpost for army units based at Garelochhead.
The water tank was constructed in the early part of the war to explore ways of sinking U-Boats from the air. The Ministry posted scientists and technical staff from the research centre at Teddington to serve there.
The 'Tank', as it was affectionally known by those sent to Glen Fruin, was 100 ft long and 10ft wide, with a 100 ft long railway line fitted with a rocket driven carriage to launch projectiles in the water at various speeds and angles.
This was particularly useful for the scientists who had the top priority job of devising ways of how to sink the German submarines. They could study tests through the reinforced glass side on the water tank, or from a gangway above.
Their work took on added urgency as the Battle of the Atlantic threatened to starve Britain into surrender.
At the beginning of the war the only airborne weapon for attacking submarines was the 250lb anti-submarine bomb, or machine gun fire. Aircraft had to spot U-Boats on the surface to attack them, dropping bombs in the same way as they would on a land target.
Usually the submarine would escape such attacks, diving as bombs exploded on impact with the sea, but boffins at Glen Fruin were able to launch torpedoes and depth bombs at various angles and develop delayed impact fuses.
U-Boat crews dreaded depth charges, which the Germans called wasserbomb, or 'water bomb'.
These were a deadly threat when launched from a destroyer, but as a result of the work carried out at Glen Fruin depth charges, rockets and torpedoes were used by aircraft to catch U-Boats on the surface or submerging.
This was a whole new threat, and both coastal and long range aircraft could attack U-Boats hundreds of kilometres out at sea — and radar and Leigh Lights enabled the airborne battles against U-Boats to continue at night.
Says Robin: “There is no doubt, that the Tank at Glen Fruin played an important part in winning the Battle of the Atlantic and putting an end to the U-Boats domination of the seas. By the end of the war half of U-Boat sinkings were by aircraft.”
The Glen boffins also studied aircraft design to lessen the impact of aircraft ditching and to allow the fuselage to float long enough for aircrew to escape the wreckage. This aspect of their work also influenced seaplane design.
Water tank testing was also available outdoors in a field near Rhu, or on the skating pond at the top of Sinclair Street. A large bubble was once towed behind a motor launch so that rockets could be tried out.
MAEE left Helensburgh and Glen Fruin at the end of the war, returning to its former home at Felixstowe, but not before they designed the world's first jet fighter seaplane, the Saunders Roe SRA/1.
With the war against the U-Boats won, the Air Ministry issued in May 1944 the specifications for a jet fighter seaplane to operate in the Pacific and closer to Japan. The MAEE structural design was completed well ahead of the Saunders Roe engine development, so the prototype did not fly until 1947.
Glen Fruin was out on a limb from MAEE Helensburgh, but it was an important arm. Ironically it is all that remains of this establishment in 2009, its 70th anniversary.
Even today the military establishment at Glen Fruin does not encourage visitors. The World War Two water tank facility was even less accessible to anyone other than MAEE boffins and technicians, and there was a 24 hour armed guard.
Robin is always looking for more information about the secret world of MAEE. He visited the burgh three years ago, and he says he was amazed how little local people knew of the establishment.
- The pictures show the entrance to the Glen Fruin establishment, and a ditching model mounted on the railway ready for testing in the MAEE Tank.