The Secret of Langham Dome Trainer

About 24 km northwest of the city of Norwich, in north Norfolk, England, lies the abandoned remains of RAF Langham, a former Royal Air Force base. Established in 1940 as an emergency landing ground, it soon became a satellite station for the larger RAF Bircham Newton and later, a station in its own right. Being located close to the North Sea, it became home to one of the RAF’s Coastal Command Strike Wings, tasked with striking German ships. Now encroached upon by a grass field, a few broken buildings, a concrete airstrip and a mysterious black concrete dome are all that remains of RAF Langham.

Until a few years ago, nobody knew what the dome was used for. Some thought it was used for night navigation training by projecting stars on the dome. Others thought it was used as a torpedo-attack trainer. Some even suggested that it was built by Bernard Matthew’s poultry farm to rear turkeys.

langham-dome-trainer-1

Photo credit: Gioconda Beekman/Flickr

The dome was indeed a secret training facility, but not for torpedo attack or night-time navigation, but to train anti-aircraft gunners to shoot down enemy planes. It was one of 43 Dome Trainers built around the country. But the one at RAF Langham is only one of six that survive today, and the only one that is accessible to the public.

The Langham Dome Trainer stands 25 feet tall and 40 feet wide. Projection equipment inside the dome played film of aircraft and dive bombers making mock attacks that was projected on the interior walls of the dome. The image was moved around the dome using a complicated system of cameras and mirrors, with full sound creating a realistic experience for the trainees who sat in the middle of the dome with an anti-aircraft gun replica.

On firing at the image of the attacking aircraft, the replica gun projected flashes of yellow light onto the wall of the dome, which allowed the instructor to measure the accuracy of the shooter. These flashes can only be seen by the instructor and not by the trainee because they were made to observe through a yellow filter. For its time, it was a very sophisticated training simulator.

The Dome Trainer was designed by naval officer Henry Stephens. Stephens was sitting at a newsreel theatre and watching a film of ground-based gunners firing at aircraft, when he began to wonder how the gunners were trained and how they could be made to be more effective. Eventually, the idea of the Dome Trainer came to him.

Working with Kodak and Technicolour, Henry Stephens designed the Dome Trainer and built a state-of-the-art ‘Cinematographic Apparatus’ which projected the stop-frame films onto the interior walls of the dome, to simulate the action of being dived-bombed during an enemy attack.

langham-dome-trainer-11

Photo credit: langhamdome.org

langham-dome-trainer-12

How the projection and gun system worked, based on a sketch by Frank Phillipson. Photo credit: langhamdome.org

The first Dome Trainer was installed at the Royal Naval Gunnery School, Whale Island, Portsmouth, and it became a huge success. Eventually, 43 such trainers were built across the UK including one at Langham which survives today.

Henry Stephen’s invention came at a time when the allied forces were suffering great loses at sea because of the lack of proper anti-aircraft gunnery training. In these early days of the war, untrained anti-aircraft gunners would shut their eyes and pull the trigger, or even run away. Even those who had experienced attacks from the air in the First World War, twenty years earlier, realized that they were now facing something far more dangerous. Aircraft were faster, more maneuverable, more heavily armed and much more difficult to defend against.

The invention of the Dome Trainer gave the military the opportunity to teach trainee anti-aircraft gunners to overcome their fears and their instinctive reactions, to remain calm and to concentrate in what was a very life-like, battle situation. Gunners were first given theoretical lessons in how to aim at a fast-moving target and then practiced in the Dome. Once gunners became proficient, they were trained with live ammunition firing onto real targets towed by aircraft elsewhere on the North Norfolk coast.

The Langham Dome Trainer was listed as a Scheduled Ancient Monument in 1986. Last year, the concrete structure was restored, painted over white and a museum was installed inside.

langham-dome-trainer-2