Loading Upkeep

quote from a well known owners manual.

Upkeep was released, the wireless operator firing a red very cartridge as the aircraft passed over the dam to signal the release

[ATTACH=CONFIG]216458[/ATTACH]The bomb doors were taken off, flares were used on the raid.

The prototype Upkeep, which was spherical in shape, would not fit underneath the Lancaster. A method was devised to load it from the rear by lifting the Lancaster with crane using an eyebolt attached forward of the rear turret. After the removal of the outer shell, it was no longer necessary to load the cylinder with the tail-lift method as the cylinder on its trolley could fit under the nose of the Lancaster, provided the forward fairing was opened giving sufficient clearance beneath the hydraulic motor.It is likely that this method was used for later test drops and the mission itself.

Without reviewing the sources, from memory, I believe the fairing in front of the bomb suspension did open like that (amongst other reasons, for access to the drive).