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  4. Helicopter Drive System Facility (HDS)

Helicopter Drive System Facility (HDS)

H-3 Gearbox Freewheel Unit Installed at the HTTF

The Helicopter Drive System Facility (HDS) is the only facility of its kind in the U.S. and allows the entire drive train of the helicopter (both the tail and main transmission) to be tested. The facility provides sufficient flexibility to install and test all of the current and future helicopter propulsion systems. The helicopter transmission, excluding rotors, is installed in the HDS superstructure. Tests simulate flight loads applied by the craft's main rotor. Power for testing is provided by the aircraft’s gas turbine engines and main and tail rotor power is absorbed by waterbrakes.

The heart of the facility is an 8,000 and an 18,000 horsepower stepup (32:1 ratio) gearbox which converts the low speed/high torque main rotor shaft output to high speed/low torque output, allowing the use of waterbrake dynamometers for power absorption over all power ranges up to 18,000 horsepower and 325 RPM main rotor shaft speed. The main rotor shaft can be loaded by multiple (up to 3) waterbrakes which can be configured to match the main transmission power output.

The facility is capable of the test and evaluation of a complete helicopter propulsion system and system components such as engines, main transmission, combining or nose gearboxes, intermediate and tail rotor gearboxes and connecting shafts, disconnect couplings, clutches, rotor brakes, generators, hydraulic pumps, controls, oil coolers and alternate fuels and/or lubricants.

The Central Control Room supports remote operation, control devices, instrumentation, measurement and monitoring of all parameters, real-time data recording and automated data acquisition. Recorded data is tailored to specific test requirements and may include engine input torques/speeds, main rotor and tail rotor output torques/speeds, vibrations and critical system temperatures and pressures.

This facility is used for testing drive system components to their life limit, performance abilities and interfaces between components.  Testing is also conducted to evaluate new components prior to being introduced to the field.  Diagnostic system development is also conducted due to the fact that the entire drive system is installed.