Beacons; Finding Home When Alone Over The Ocean (Long Patrol)

An introduction to the beacon systems that gave Fleet Air Arm aircraft a way to find a carrier after dark or far out at sea.

The early Type 72X appears on a carrier in 1936 and becomes the starting point for the wartime beacon family.

A one-revolution-per-minute beam and a synchronized watch give an aircraft a reciprocal bearing on its carrier from roughly fifty miles away.

The beacon evolved as more carriers operated together and radar demanded the highest position on the mast.

The Type 72X and 72DM assumed a trained observer or telegraphist air gunner could interpret the signal, an arrangement poorly suited to a busy single-seat fighter pilot.

Early-war views of HMS Ark Royal and HMS Illustrious make the beacon's move from the masthead to a lower position immediately visible.

The principal engineering paper explains the mature Type 72DP first and treats earlier systems in relation to it, forcing historians to reconstruct the development sequence carefully.

A modest transmitter, rotating reflector, precision timing controls, and a lightweight masthead hut made the Type 72X function as a radio lighthouse.

The Type 72DM could synchronize its sweep through north at the minute, making the bearing easier to turn into a course home.

The Type 72DP modulated its carrier wave with information characteristic of each true bearing and stabilized the rotating aerial against changes in the ship's course.

The later DP system shifted more work to the ship so a pilot, especially in a single-seat aircraft, could receive a simpler homing indication.

A visual course display could make beacon guidance continuously available, while the broadcast system could guide many aircraft from different directions at once.

The January 1947 paper, revised in June, mixes wartime Type 72DP evidence with YE material and discussion of systems still ahead.

Precision Fleet Air Arm watches were an essential, easily overlooked part of the earlier beacon method.

American beacon equipment entered Royal Navy service in the Pacific and was later succeeded by the allied TACAN system.