A practice 10.000 lbs 'Upkeep' weapon attached to the bomb bay of Wing Commander Guy Gibson's Avro Type 464 (Provisioning) Lancaster, ED932/G 'AJ-G', at Manston, Kent, while conducting dropping trials off Reculver.

The first air drop trials of 'Upkeep' were at Chesil Beach in December 1942; these used a spinning 4ft 6in sphere dropped from a modified Vickers Wellington. The same aircraft was used until April 1943 when the first modified Lancasters became available. The tests continued at Chesil Beach and Reculver, often unsuccessfully, using revised designs of the mine and variations of speed and height.

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Avro Chief Designer Roy Chadwick adapted the Lancaster to carry the mine. To reduce weight, much of the internal armour was removed, as was the mid-upper gun turret. The dimensions of the mine and its unusual shape meant that the bomb-bay doors had to be removed and the mine hung partly below the fuselage. It was mounted on two crutches and before dropping it was spun up to speed by an auxiliary motor. Chadwick also worked out the design and installation of controls and gear for the carriage and release of the mine in conjunction with Barnes Wallis

A replica ‘Upkeep’ bouncing bomb at Yorkshire Air Museum, Elvington