 The supporting research for the acquisition of such patents had been typically performed by HDL, who conducted extensive experiments and built full-scale test beds as part of their activities.On 29 May 1959, the completed SR.N1 performed its first engine run.This engine run was aborted when telemetry from onboard accelerometers had indicated high stress levels which threatened the craft's structural stability in the long term; these stresses had been generated as the result of an integral shroud that had been placed around the plane of the fan to increase aerodynamic efficiency, and was quickly resolved by its removal, providing greater clearance for the tips of the fan blades.