Ynyslas, Welsh for ‘the green island’, is a small coastal village north of Aberystwyth. It can be found wedged between the stretch of beach along Cardigan Bay and the shores of the Dyfi estuary. This spot is a part of the Ynyslas Sand Dunes, themselves a part of the Dyfi National Nature Reserve. As such the area is one of outstanding natural beauty. Here you can see all manner of flora and fauna while exploring the wilderness of Wales which has been teeming with life since ancient times.
Despite such a tranquil backdrop to a sunny afternoon stroll, Ynyslas hides an explosive secret. During the latter years of the Second World War, Ynyslas was home to a top-secret weapons testing range.
The Base
The sand dunes of Ynyslas were commandeered by the military and added to the numerous firing ranges along Cardigan Bay. The range came to be known as Ministry of Supply Experimental establishment Anti-Aircraft (MOS EE AA) Ynyslas and was home to at least nine commissioned officers and over two hundred ordinaries all under the purview of a Superintendent of Experiments.
With the threat of invasion long over, the coastal defences which had been erected in 1941; such as pillboxes and barbed wire transformed into a perimeter for keeping unwanted attention away from the site. Behind this curtain, the Ynyslas range was first used for testing unrotated projectile rockets from a short-range rocket-firing anti-aircraft gun that had been developed for the Royal Navy and created by military scientists led by Sir Alwyn Crow CBE. However, at the same time Germany was developing the V1 and V2 rockets which had built in guidance systems and could be used to hit long-range targets. These very weapons had devastating effects on London in the final year of the war. As a result, the attention of British military scientists shifted to the development and testing of rockets propelled by fuel cells. Once again, this ‘Guided Projectile Project’ was headed up by Sir Alwyn and took place on the dunes of Ynyslas.
The Camera Observation Post
On each of the military’s ranges and rocket firing test tracks you would find a blast-proof observation building that was designed by the British Concrete Federation (BCF). Ynyslas was no different and its own post can still be seen today. The specification for this building is quoted in a document for the erection of a similar structure at the Walton-on-the-Naze military camp and describes a brick-built building with a solid concrete roof with enough square footage to allow up to twenty people to observe the rocket’s flight. The Ynyslas Camera Observation Post was an important part of the testing process as it allowed scientists to record and organise the initial results taken from a projectile experiment.
The Carpenter’s Workshop
The Ministry of Supply Experimental Establishment Anti-Aircraft Ynyslas was not only home to military personnel but employed local tradesmen too. These civilian workers kept the military camp in tip-top shape and this building house the woodworkers. The work that took place here, in what is now a private garage, ranged from the upkeep of furniture on the base to designing and creating housings for measuring equipment.
Research Buildings
A few of the research buildings that form the centre of operations at Ynyslas Military Camp survive. At one stage MOS EE AA Ynyslas had five research huts; three for Radar Research Defence Establishment (RRDE) as labs and warehouses, one for Signals Research and Development (SRDE) to house its telemetry equipment and one for the Army Group Royal Engineers (AGRE) for working on the motors. There was also an additional lab building designed as a dark room for developing kine-theodolite films, radar tracking records and telemetry plates.
Observation Instrument Bases
Dotted across the site we can see what appears to be concrete platforms in the ground with a rusted bolt in the centre. These were in fact mounting bases for a kinetheodolite. A kinetheodolite was a theodolite (a small tripod-mounted telescope surveying instrument for measuring horizontal and vertical angles) containing a cine camera instead of the classic telescope that could take a continuous film of a moving target, in this case a rocket, whilst simultaneously recording its altitude and azimuth. What is even more interesting about these is that the instruments at Ynyslas were operated by members of the women’s Auxiliary Territorial Service (ATS).
Rocket Test Firing Track and Bases
Close to the foreshore car park at Ynyslas National Nature Reserve, concrete bases that supported the missile fire track can be seen running along the dune and up toward the Sea Rivers Caravan Park. On these tracks the missiles could be launched up the estuary onto the mud and sand flats. Several fragments of these rockets have been found at Ynyslas and continue to be found beneath the sands. At the outbreak of war, most military scientists had their minds set on projectiles that could carry high explosives or penetrate armour plating. These came in the form of the RP-2 and RP-3 rockets. The RP-3 was made up of a 4ft long tube made of steel, with four fins at the rear and filled with cordite explosive. These rockets could hit speeds of 1520ft per second at 1000ft altitude and a phenomenal 1740ft per second at a height of 3000ft. The very first prototype of these unrotated rockets were fired on 25 October 1941 and entered factory production in 1942. Many of the fragments recovered at Ynyslas reflect those very tests that were conducted on the RP-2 and RP-3.
HMS Camroux III
The small Merchant Navy coaster, Camroux III, was requisitioned during the Second World War and was a part of several rocket firing experiments at Ynyslas. Whilst assisting with operations at Ynyslas the Camroux was moored at Aberdyfi and could be sailed into the estuary when required. In addition to the Merchant Navy sailors, army personnel were also quartered aboard the ship, approximately twelve to fifteen officers who would oversee the top-secret exercises.
The mixture of sand and mud on the Dyfi estuary flats provided an excellent testing ground for firing rockets mounted on the deck of the HMS Camroux III. The officers aboard had divided up the foreshore into a grid, each section with a unique code. As each salvo of rockets were fired, their impact point could be noted down and compared to other results to ascertain the efficiency of particular projectile designs.
The Women’s Auxiliary Territorial Service
Most importantly the success of MOS EE AA Ynyslas was not solely due to the arduous work of the male members of the research groups. The women of the ATS played a huge part in maintaining and operating the site. Many of the women served as Experimental Assistants and were responsible for recording results in any of the several Observation Posts. From here they would draft reports based on their findings and report back to the Superintendent of Experiments. In a letter written in June 1946 by the Chair of the Guided Projectile Working Committee, Major L W Jubb, he recalled how much the Superintendent of Experiments, Lt Col T L G Todd longed for the invaluable sills of the ATS ladies after they had been demobilised and replaced with male Regulars.
The End for MOS EE AA Ynyslas
A rare document that makes reference to the Ynyslas range is in fact the transfer order for the removal of personnel and equipment to nearby Aberporth. By 17 March 1946 all those who had been working on the rocket projects at Ynyslas were rolled into the teams based at Aberporth. It was from this site that the idea of the rocket as something other than a weapon could begin to be realised. Peacetime meant more time to research and develop fuel cell rockets and the possibility of space travel became one step closer.
In conclusion, this stunning stretch of Nature Reserve contains, amidst its beauty, some stark reminders of the world’s last major conflict and the stories of the men and women who worked tirelessly to stem the tide of fascism and the advance of Adolf Hitler’s forces in Europe and afar. It is only right that we remember them and try to bring their once secret existence to light.
Written by C. James McPherson MA MSc.