The original "Upkeep" bomb was externally spherical as desired by Barnes Wallis ,the cylindrical steel cylinder being faired by wood into a sphere. Examples were dropped three times between April 16th and 22nd 1943 by ED 365 off Reculver. Each time the fairing disintegrated on contact with water. It was then dispensed with and a successful drop with the steel "core" achieved on April 29th. The extended development history of the smaller , Mosquito borne, spherical " Highball " ended shortly after the end of the war .