World War II experimental airplane catapult rediscovered

A prototype of a World War II airplane bomber catapult has been excavated by a team from the Museum of London Archaeology (MOLA) in Harwell, Oxfordshire. The site is slated for a new development of the Harwell Science and Innovation Campus, and the existence of the catapult was known from historical records, but as a failed experiment shut down in 1941, it was not documented in detail, so MOLA archaeologists were enlisted to reveal its secrets. This is the first time the catapult has seen the light and been studied in detail since early in the war.

Design work began on the catapult in 1935, the year Germany rearmed in defiance of the Treaty of Versailles. After three years of planning, catapult construction began in 1938, the year Germany invaded Czechoslovakia. It was completed in 1940, the year of the Battle of Britain when 3,000 men of the Royal Air Force kept control of British skies under the brutal onslaught of Hitler’s Luftwaffe.

The advantages to catapulting a bomber plane into the air included saving the fuel expended in takeoff and requiring a much shorter runway than the conventional variety. Even after this project was shut down, the idea of the airplane catapult survived and was deployed with success to launch aircraft from ships.

The circular central pit, 10 feet deep and 100 feet in diameter, contained most of the catapult’s machinery and engines. The catapult was powered by 12 Rolls-Royce Kestrel aero engines which took up all that space in the pit, hence its depth and breadth. Above the mechanics a turntable was mounted into a slot at the top of the pit’s wall. Two concrete runway channels extended 270 feet north and south from the pit.

The way it was supposed to work was that airplanes would drive onto the turntable which would turn towards one of two runway arms extending north and south. On the south arm, the plane would be hooked onto an underground pneumatic ram would be driven down the channel by a blast of compressed air from the 12 Rolls Royce engines. The plane was supported by a trolley on wheels. The ram would drag the plane to top speed at ground level and launch it into the air. The north runway arm has a different design, perhaps for experimental purposes, which archaeologists are still studying to determine how it was meant to be used.

In the end, the Mark III catapult was ever used. Only the prototype was built, and it failed in big ways. Its engines kept wearing out, and most bumblingly, the design did not actually fit the bomber planes that already existed. It never successfully launched a single plane. In 1941, it was filled in and a conventional airstrip built on top.

The construction work at the site will continue and the catapult remains have been dismantled, alas. Before it was removed, the catapult facility was thoroughly photographed and scanned and a 3D digital replica created for future research.

3 thoughts on “World War II experimental airplane catapult rediscovered

  1. The catapult was powered by 12 Rolls-Royce Kestrel aero engines?

    Indeed, the take-off seemingly needs the most energy, but I am not sure, why a catapult necessarily would altogether consume less energy. Contrastingly, the shorter runway than a conventional one seems obvious.

    Is the size roughly the one that would have been used on a ship, and hadn’t similar mechanisms been used on ships already? By accident, I have two dead German grandpas: One had been defusing bombs in 1933/44, while the other one threw a certain amount, i.e. until he ended up in 1945 with shrapnel in head and belly.

    As I recently found out, his tag number was that of a dive bomber unit, and indeed of the one that in 1938 –already with him or maybe not– had obviously been scheduled for a projected German aircraft carrier that never got completed fully, the “Graf Zeppelin”, launched in 1938. Nonetheless, it was never operational.

    To my own surprise, I have documentation on both of them:

    All the bomb technician’s handwritten logs and –as he obviously had messed with his very first one– his court-martial statement. However, of the other one I only knew that he was active in the air force, until I a few years ago, I got hardcopies of two documents.

    One from the early 50ies with e.g. his tag number and how he was killed, and an official war report from a propaganda(!) unit, indicating that in 1941 he had been grounded behind enemy lines, describing in flowery language how it took him 18 hours to make it.

    Who knows? The fact that he was in five years not promoted, might indicate at least a certain distance to the Regime, which –from his own point of view– became irrelevant after March 26th 1945 🤨️

  2. catapults have been used for launching ship board aircraft since late in World War 1 or shortly thereafter. They have been powered by compressed air, steam, or explosive charges. Even the Wright Brothers used a catapult powered by a falling weight to launch their flyer in 1903.

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