A Request to the RAF Museum’s Archives

The RAF Museum has a very rich and extensive archive base with an endless number of materials diving deep into British aviation history and reflecting most of its sides and time periods. That is why we consider our Archive and Library as a big and essential part of the Museum, equally important as our exhibitions.

Sometimes we are amazed at the unexpected material found in our Archives. For example, in September 2017 our Archives and Library were approached by Gary Morton from Saffron Walden, Essex. Gary had acquired a Gyro Test Table Mk 4, but was unsure how to operate it. He was wondering if we might have some useful information.

The Gyro Test Table was an essential piece of equipment for air technicians as it was used to enable testing of suction and electrical gyroscopes under simulated flight conditions. Gyroscopes were and are the vital parts of aircraft, especially for cockpit instruments. The principle is that a spinning wheel or disc can enable its own orientation regardless of the movement of the holder. No matter in what position you hold the gyroscope it will still maintain its orientation.

Possibly the most interesting use of gyroscopes in aircraft was in unmanned aircraft or drones. Radio-controlled drones were already developed during the First World War. Between the two World Wars a gyroscope was installed in a small biplane called the Queen Bee, which was an unmanned radio-controlled gunnery target. It was needed to stabilise the aircraft in flight.

Nazi Germany developed the first practical cruise missile – the V1, of which thousands were launched against British and Belgian cities. A clever way to ‘destroy this bomb’ was discovered by the American pilot Major R. E. Turner. This involved holding the interceptor’s wingtip close to the wingtips of the V1, which would tip the wing of the drone up, override the gyroscope and send it into an out-of-control dive.

Beside their military use, gyroscopes are still used today to allow civilian aircraft to fly safely due to reliable gyroscopic instruments, such as compasses and artificial horizons.

Regarding Gary’s request about his Gyro Test Table, we happened to have in our collection a beautiful handwritten 1956 Instrument Fitter’s Course notebook by A.W. Robbins who was learning his trade at RAF Melksham.

The notebook is divided in different chapters, each on a different tool or instrument. Our curators have catalogued this notebook in such a way that each of these tools is listed in our Collection Management System. This System is our main tool for cataloguing and accessing our Collection of over one million photographs, books, film, documents and other objects. The public can access a part of our Collection through our online search engine Navigator.

Gary was happy to find out more about his Gyro Test Table and the information enabled him to get it working which you can see in this video:

It shows us what the Gyro Test Table is – a very precise machine which rocks a platform in a very precise manner, simulating flight conditions. The idea is to place a gyroscopic instrument on top of it and ascertain that the readings of the gyroscope are correct.

Gary later acquired a compass to use on his Gyro Table and tested an artificial horizon. These videos show how he was able to test:

The idea is that the gyroscopic instruments correctly display the movements created by the test table. If not, they need to be calibrated or even repaired to make sure they are absolutely accurate. Even the smallest deviation may cause an aircraft to miss its destination by several miles.

In addition to the notebook, our librarian Gordon Leith was able to find an official Air Publication on this Gyro Table. These APs are some of the most important and well sought-after documents in our Collection. They are basically manuals which were and are used by RAF personnel to maintain, repair and operate various equipment used by the RAF, ranging from fast jets to shoe laces.

Gary wrote to us explaining how he chooses to remember and commemorate 100 years of the RAF not only through the operations, the people and the aircraft, but through the equipment and systems that made these aircraft possible:

“I always hated not being able to see them. They are usually hidden away. And when they could be seen, they were lifeless. Lights should be flashing, indicators should be blinking and meters should be spinning. Just like they are in all the movies and documentaries!

Finding the instruments is easy. There must be thousands of these instruments still held in storage warehouses. But now the tricky part, and where the RAF Museum Archives are invaluable. How do you make these things work again?

Thankfully the military have a tradition of actually training their people, not only to fly things and fix things, but also to understand what these things actually do and how they work. The RAF publish these in Air Publications (AP). There is usually an AP for everything referenced against the part number which is usually printed or stamped somewhere on the instrument.

But the numbering system is unfathomable to the lay person. So then you contact the RAF Museum archivists. Give them the name of the instrument and the part number and somehow they will magic you a document that tells you how the instrument works, the circuit diagrams, the working diagrams, the interconnection details and even the definition of the required signals. I am always amazed by what they can find. Even down to hand written notes from the technicians during their training.

I have got about 20 of these instruments working again and mounted in an instrument panel. When I get round to trimming and rerouting the 200 wires on this panel you might see it an air show. Once again these instruments are doing what they were meant to.”