This aircraft served with 617 squadron No. 5 group, Woodhall Spa, Lincoln (Spring 1945).
- B I Special
- 32 Aircraft were adapted to take first the super-heavy "Tallboy" and then "Grand Slam" bombs. Upgraded engines with paddle-bladed propellers gave more power, and the removal of gun turrets reduced weight and gave smoother lines. For the Tallboy, the bomb-bay doors were bulged; for the Grand Slam, they were removed completely and the area faired over. For some Tallboy raids, the mid upper turret was removed. This modification was retained for the Grand Slam aircraft, and in addition the nose turret was later removed. Two airframes (HK541 and SW244) were modified to carry a dorsal "saddle tank" with 1,200 gal (5,455 L) mounted aft of a modified canopy for increasing range. No. 1577 SD Flight tested the aircraft in India and Australia in 1945 for possible use in the Pacific, but the tank adversely affected handling characteristics when full and an early type of flight refuelling designed in the late 1930s for commercial flying boats was later used instead.
The Grand Slam was a 22,000 lb (10,000 kg) earthquake bomb used by RAF Bomber Command against strategic targets during the Second World War.
Known officially as the Bomb, Medium Capacity, 22,000 lb, it was a scaled up version of the Tallboy bomb and closer to the original size that the bombs' inventor, Barnes Wallis, had envisioned when he first developed his earthquake bomb idea.