Undeterred by the O-1230/H-2470's failure, Lycoming turned to an even larger design, the 36-cylinder XR-7755, the largest aviation piston engine ever built. This design also experienced problems, and was only ready for use at the very end of World War II, when the aviation world was turning to turbojets and turboprop engines to power future large aircraft. There was apparently some interest in using it on the Convair B-36 Peacemaker bomber, but the 28-cylinder Pratt & Whitney R-4360 "Wasp Major" four-bank radial was used instead.