Skip to content

World War Two experimental catapult unearthed by archaeologists

MOLA Bird's eye view of excavated Harwell catapultMOLA
The prototype catapult was unearthed at the site of a Harwell Science and Innovation Campus development

An experimental catapult designed to launch World War Two bomber planes into the sky has been excavated.

The prototype Royal Aircraft Establishment Mark III Catapult was unearthed at the site of a development at the Harwell Science and Innovation Campus in Oxfordshire.

It was made to enable take-offs using shorter runways and so the planes could be loaded with more fuel.

The contraption was built between 1938 and 1940 when the site was RAF Harwell.

MOLA Outer walls of the Harwell catapultMOLA
The structure was filled in and by 1941 a normal runway was built across part of it
MOLA Archaeologists excavating one of the catapult's armsMOLA
Archaeologists have been excavating the catapult's arms

However, the project was abandoned without ever launching an aircraft, because the engines would wear out and the design did not properly fit the bomber planes.

The mechanism was taken out and a normal runway built over the top.

The technology was a precursor to Catapult Armed Merchant (CAM) ships, which launched Hawker Hurricanes at sea via rocket-propelled catapults.

Presentational grey line

How was the catapult meant to work?

MOLA Reconstruction showing plane on catapult trackMOLA
A turntable directed the planes to one of two short runways
  • A large rotating turntable directed aircraft towards one of two concrete track runways only 82m (269ft) long
  • The aircraft was attached to an underground pneumatic ram using a towing hook
  • Underneath the turntable Rolls-Royce Kestrel aero engines compressed air to 2,000 psi to drive the ram
  • High-pressured air was forced into the pneumatic ram, which rapidly expanded to the length of the guided track
  • The bomber would then be catapulted into the sky

Source: MOLA

MOLA Reconstruction of Harwell catapultMOLA
The project was abandoned without ever launching an aircraft
Presentational grey line

Archaeologists at the Museum of London Archaeology (MOLA) have now recreated a 3D digital replica of the remains.

Project officer Susan Porter said: "This fascinating structure reminds us of the rapid experimentation and innovation of the interwar years and World War Two.

"Crucially, recording the location and appearance of every inch means that the catapult is preserved by record for future generations."

MOLA Harwell catapult with surrounding landscapeMOLA
The catapult has now been dismantled to allow construction works in the area to continue

The catapult has now been dismantled to allow construction works in the area to continue, though the remains are being archived.

Excavations also uncovered large lights from another nearby runway, and a light anti-aircraft gun emplacement used to defend it from attack.

Presentational grey line

Follow BBC South on Facebook, X, or Instagram. Send your story ideas to [email protected].