History

World War II

At the start of the Second World War there was the requirement to train large numbers of people in the many individual and team skills involved in the operation of the various military aircraft. Basic pilot instruction was performed in part on Link Trainers both in the United States and Britain.

Developments in aircraft, such as variable pitch propellers, retractable undercarriage and higher speeds made training in cockpit drill essential. The mock-up fuselage was introduced as an aid to training in these procedures. One such device was the Hawarden Trainer, made from the centre section of a Spitfire fuselage, which enabled training in the procedures of a complete operational flight. The Links too, were developed to the stage where the instrument layout and performance of specific aeroplanes were duplicated; the U.S. Army-Navy Trainer, Model 18 (ANT-18), for example, was designed for training in AT-6 and SNJ flying.

In 1939 the British requested Link to design a trainer which could be used to improve the celestial navigation capabilities of their crews who were ferrying "surplus" U.S. aircraft across the Atlantic. Such a trainer could also be used to improve bombing accuracy during night raids over Europe. Ed Link, together with the aerial navigation expert, P. Weems, worked out the design of a massive trainer suitable for use by an entire bomber crew, and housed in a 45 foot high silo-shaped building. This was the Celestial Navigation Trainer. The trainers incorporated a large-size fuselage similar to that of the conventional Link Trainer, but which could accommodate the pilot, navigator, and bomber. The pilot flew the trainer, which included all the facilities and instruments of the smaller conventional Link Trainer, while a bomb aimer's station provided the appropriate sight and targets over which the trainer flew. The navigator was provided with all the radio aids and, in addition, was provided with an elaborate celestial view from which he could take his appropriate astro sights. The stars, of which enough (12) were collimated, were fixed to a dome which was given a movement to correspond with the apparent motion of the stars with time and changes in bomber latitude and longitude.

The first Celestial Navigation Trainer was completed in 1941, and the RAF placed an order for sixty of them. Unfortunately, only a limited number of these trainers were installed in Britain, such as at the Link Trainer School at Elstree, and at a number of special RAF stations. The balance were returned to the U.S. Air Force under Reverse Lease Lend, with the exception of three sets of components which were subsequently used for navigational trainers. However, hundreds of these devices were installed and operated in the United States.

Throughout the war instructors on various RAF stations were contributing their ideas to training and numerous "home-made" devices were constructed due to the long delivery times and low priority given to the manufacture of training aids. An early development was the "instructional fuselage". Such a device would consist of fuselage of the desired type mounted on stands inside a hangar. It could then be used to train air crews in the drills that they have to carry out in the particular aircraft that they are being trained on. Services like, hydraulic, electrical, and pneumatic, and their recording instruments were made to work in a normal manner, so that the various drills carried out by the crew were realistic. Bomb-dropping procedure and abandon aircraft drills by parachute and dinghy were also carried out; the bombs being released into sand trays beneath the aircraft.

Of particular interest are the so-called Silloth Trainers, developed by Wing Commander Iles at RAF Silloth, south of Carlisle. The picture shows one of these trainers for a Halifax bomber. The Silloth Trainer was designed for the training of all members of the crew, and was primarily a type familiarization trainer for learning drills and the handling of malfunctions. As well as the basic flying behaviour, all engine, electric and hydraulic systems were simulated. An instructor's panel, visible in the photo, was provided to enable monitoring of the crew and malfunction insertion. All computation was pneumatic, as in the Link Trainer. Silloth trainers were manufactured for 2 and 4 engined aircraft throughout the war; in mid-1945, 14 of these trainers were in existence or on order. Towards the end of the war a Wellington simulator was developed at RAF St. Athan, using contoured cams to generate the characteristics of the aircraft's flight and engines. This machine, however, did not supplant the Silloth Trainer, as all activity on these ceased at the end of the war.

In 1940 Rediffusion, whose manufacturing division later became Redifon, built a direction finding trainer for ground operators. This simulated the Bellini-Tosi goniometer DF equipment, whereby two such stations could take a fix on an aircraft transmission and pass the resulting information back to the pilot. A similar trainer was designed to train the operators of VHF stations to give fixes to fighter pilots. However, the most important member of this family of Redifon trainers was the C 100 DF and navigational trainer which was first produced in 1941 to train air crews in the skills of navigation using ground beacons.

The trainers were installed in five separate cubicles which housed the trainee pilot, navigator and radio operators, and enabled these crews under the control of an instructor, to carry out navigational exercises, plotting their track from the bearings set up by the instructor. This trainer was similar in principle to the other two Redifon trainers. Suitable decoupling was provided so that up to five receivers and goniometers could be operated from one set of transmitting goniometers enabling the instructor, at the cost of limited flexibility, to teach five crews simultaneously. The transmitting goniometers were mounted on a chart at the position of the beacon stations so that the designated north/south stator coils were aligned with the meridian passing through the particular beacon. The DF receivers were standard RAF airborne units and it was thus possible to tune them in and operate them as would be done in real life. The complete receiving goniometer stators could be physically oriented by the "pilot" of each aircraft to correspond to the aircraft heading during the flight.

The equipment had provision for the superimposition of interference such as enemy jamming. Some installations were equipped with sound effects and epidiascopes so that pictures of target areas and other landmarks of importance could be projected in front of the trainer. These installations were known as Crew Procedures Trainers. Well over 100 of the C 100 navigational trainers were built and installed on RAF Bomber Command operational training units and navigational training stations throughout the country and in Canada at the Empire Air Training Stations until the end of the war, plus the small number of trainers installed on USAF stations in this country.

In late 1942 Rediffusion were instructed to install this equipment on the first of the American 8th Air Force's stations at Bovingdon, which was known as a crew replacement centre. The American authorities quickly appreciated the benefits of this trainer and requested that it be made to operate with American equipment as installed in the B17 Flying Fortress. In 1943 Rediffusion developed for the American Air Force a Dead Reckoning Navigational Trainer to train up to ten navigators flying in formation. The production model of this trainer, the C500, utilised the C100 and provided hyperbolic Gee fixes with an existing static Gee trainer.

One of the best technological successes of the war was the part played by the Trainer Group at the Telecommunications Research Establishment (TRE) in the design of synthetic radar trainers. This group, under G.W.A. Dummer, developed trainers for all of the new radars developed during the war years. In addition to devices attached to Link Trainers, a novel flight simulator for training in AI (Aircraft Interception) was invented. This trainer, the Type 19, was a complete crew, fixed base, trainer for AI combat, which consists of four stages: following an interception course provided by a ground operator, guided by on-board radar, visual contact and the moment of firing. The type 19 provided training in the complete sequence by provision of positions for the pilot and AI operator, and instructors unit, computers for simulation of the attacking aircraft and the relative position of the "enemy", a visual projection unit and a course recorder. The flight simulation computer (known as the Type 8, Part II) was used in a number of TRE trainers, including mobile units whose function was to tour operational squadrons to train in the use of the latest versions of airborne radar. The visual projection system, designed by A.M. Uttley, was used in the larger AI training installations at RAF Operational Training Units. The image, displayed on a hemispherical cyclorama mounted in front of the pilot, consisted of a night sky and ground of controllable brightness with a tail silhouette of a bomber which moved correctly in bank, range, azimuth and elevation in response to relative movements of fighter and bomber. The first AI crew trainers went into service in 1941, while the first complete Type 19 trainer was installed in 1943. It has been estimated that the use of the TRE synthetic radar trainers saved £50,000,000 worth of aviation fuel alone.

In addition to the trainers mentioned, above many others were developed by adding extra features to the basic Link Trainer for such tasks as gunnery instruction. In Britain, the JVW Corporation Limited, formed to market and service Link Trainers, successfully produced a torpedo attack trainer for the Royal Navy, a tank trainer for the Army, and a night vision tester and glider station keeping device for the RAF. The epidiascope visual system for the Torpedo Attack Teacher was produced by Strand Electric, better known for stage lighting. Another simulator with a strong visual element was the Royal Aircraft Establishment's Fixed-Gun Trainer for fighter pilots, developed towards the end of the war, the needs for training in more specialised skills were met by the adoption of a multitude of purpose-built devices.