No. 618 Squadron RAF

No. 618 Squadron RAF
Mosquito B Mark IV development aircraft, DK290/G of the Aeroplane and Armament Experimental Establishment based at Boscombe Down, Wiltshire, in flight following modification to its deepened bomb bay to accommodate two "Highball" weapons for trials, March 1943
Active	1 April 1943 – 14 July 1945
Country	United Kingdom
Branch	Royal Air Force
Insignia
Squadron Badge heraldry	No badge authorised
Squadron Codes	No markings known to be carried
Aircraft flown
Attack	Bristol Beaufighter Twin-engined fighter
Bomber	De Havilland Mosquito Twin-engined light bomber Fairey Barracuda Single-engined torpedo bomber/dive bomber

No. 618 Squadron RAF was a squadron of the Royal Air Force during the Second World War, intended to carry of a variation of the Barnes Wallis designed Bouncing bomb code-named "Highball". Due to various circumstances the "Highball" weapon was never used and the squadron disbanded at the end of the war.

No. 618 Squadron was first formed at RAF Skitten on 1 April 1943, as part of No. 18 Group of Coastal Command, from crews of No. 105 Squadron RAF and No. 139 Squadron RAF. The unit was initially equipped with Beaufighter Mk.II fighter-bombers, but quickly changed to converted Mosquito Mk.IVs.

The "Highball" device was intended to bounce across the sea until it hit an enemy ship, sank and exploded. Unlike the cylindrical Upkeep weapon used by No. 617 Squadron RAF in Operation Chastise, the "Highball" was more spherical. The Mosquito selected for the conversion work to carry "Highball" was the Mk.IV series II: the work entailed removing the bomb bay doors and equipping the aircraft with specialised carriers enabling them to carry two "Highballs", each weighing 1,280 lb (580 kg), in tandem. The bombs were designed to skip across water and to provide weapon stability and accuracy. Before release they were spun backwards at 700 to 900 rpm by a ram air turbine mounted in the bomb bay's midsection, fed by an extendable air scoop. The bombs were to be dropped from a maximum altitude of 60 ft (20 m) at a speed of 360 mph (600 km/h).

In the event, through lack of weapons, training and aircraft, No. 618 Squadron was kept frustratingly inactive and never attacked the Tirpitz. Instead the unit was selected for carrier-borne operations in the Pacific.