Torquemeters Develops Engine Test Rig For Pratt & Whitney Canada

Redevelopment of an existing test facility to extend performance capability and increase flexibility.

PWC had a limited quantity of a new turboshaft variant engine to manufacture; a higher speed version to be installed in new air frame with low visibility on the future sales of that new airframe and consequently of their new turboshaft product. The PWC testing department was tasked to come up with the most cost effective solution to qualify and test the new product without technical compromise.

In order to meet this challenge, the customer elected to try to utilise the existing low speed engine test cell for the new high-speed variant of the engine. The existing driveline of the test cell consisted of a low speed water brake connected to the low speed turboshaft via a coupling, it was capable of 6,500rpm and 1200kW. The high-speed turboshaft variant needed not only a higher speed capability 17,098rpm, identical power 1200kW but a bigger inertia driveline 2.9Kgm².

The first issue encountered in considering the feasibility of modifying the existing test facility was the lack of a commercially available waterbrake capable of testing both variants. Selecting Torquemeters to address this challenge, the current setup was fully reviewed and, after investigation, it was identified that it was possible to move the existing waterbrake furtherback on the baseplate. This created some space between the existing engine cradle and the water brake that could be utilised to fit a new gearbox with a parallel shaft design. The concept was to have a straight through shaft to enable testing of the low speed turboshaft and a vertical offset higher speed shaft for the new turboshaft variant. Torquemeters also integrated its’ phase-shift torquemeter within the gearbox to further accommodate the extremely tight space availability as well as addressing the inertia requirement of the new turboshaft within the design of the high-speed shaft of the gearbox.

With this concept, PWC could reuse the existing water brake geared to deliver the speed and power needed, delivering a high degree of flexibility at relatively low cost. Key features of the installation include;

  • Complete transmission solution
  • One single supplier responsible for the driveline
  • Multipurpose test cell which delivers flexibility
  • Easy install/uninstall low/high speed turboshafts
  • Accurate torque measurement
  • Compact solution: gearbox/flywheel/torque measurement