Providing a coupling for Bloodhound's fuel pump

JBJ Techniques has been involved in the design of the fuel pump test rig on the Bloodhound SSC. The brief was to produce a suitable drive coupling with a maximum diameter of 160mm which was capable of transmitting 550Nm at 10,000rpm; it needed to be as short as possible while being able to accept misalignment within the drive-train.

The high torque capacity of the Sier Bath coupling - proposed by JBJ - meant that it fitted within the existing adaptor arrangement and the crown tooth gear form on the coupling allowed for relatively high misalignment without transferring loads between the shafts.

The fuel pump is the pump for the rocket, it is an end suction centrifugal pump driven by a Jaguar 'F' type V8 engine. It pumps the oxidising agent (hydrogen peroxide) into the rocket engine which contains the solid rubber fuel.

The end-suction centrifugal pump is an impeller mounted within a volute housing; the impeller is mounted on a shaft supported on two bearings. One is mounted close behind the impeller with a pressurised double mechanical seal to prevent leakage. A bearing housing accommodates the length of the shaft and ensures a suitable gap between the bearings sufficient to support the rotating parts.

JBJ's proposed solution required a special drive shaft, which when connected to the output flange of an automotive gearbox enabled easy assembly of the Sier Bath Unit. 3D models were supplied and approved by the Bloodhound team and after manufacture the complete assembly was dynamically balanced to ensure that the coupling operated without generating any additional forces.