The Small Turbine Engine Test Cell

Four different engine test cycles that simulate typical light helicopter missions can run automatically: executive transport, standard training, autorotation training, and chase/police/news. Additionally, production/overhaul acceptance certification test cycles can run automatically, all the way to 24/7 “continuous life” tests, with stops for only those maintenance items called for in the manuals.

“The goal is to be able to run all the standard test cycles automatically,” says Nathan Heidegger, assistant chief project engineer. “It’s just that much more repeatable, test to test. Plus, when you’re running extended endurance tests, you really don’t want to tie up an engineer and test stand operator to just sit here and watch the engine run all day.” The data collection is real-time, in the cell’s control room. It is also remotely viewable at engineers’ stations.

Still, the engineer on call can get … a call from the system. When the systems spot an anomaly in an operating parameter, any of several events take place: a minor deviation may simply trigger an alert on screen; a larger deviation may command a reduction in power; or a calamitous event may signal immediate shutdown. (The actual parameters are Rolls-Royce proprietary, but you get the idea.)

Three gimbal-mounted, variable focal length (zoomable) cameras record the operations: two are in the dyno room itself, providing a good look at the overall operation and a close look at the power coupling indoors; the third camera keeps an eye on the exhaust stack outside. Any or all camera views are seen and controlled by the test crew.

Test cell throughput enhancements come from several improvements: the cell itself is easily configurable to fit any of the small R-R engines — M250 and RR300 (and, eventually RR500); turboprop or turboshaft; exhaust up or exhaust down. The test operating rpm range extends from 2,000 to 10,000, covering the small-engine line quite well. Different mounts switch quickly, and most hookups are generic. Additional sensors get added when they’re called for.

Throughput is greatly enhanced by the two-cell setup. With their doors literally across the hall from each other, test mechanics can easily move between cells; tools are common and available. Subject engines roll up a ramp (the cells are elevated, remember?) and are fitted with sensor-equipped intakes and exhausts, plus other goodies that may be required for their particular tests. Then, as soon as a cell opens up, the new engine is wheeled in, picked up by a wall-mounted crane, and positioned in its bed, where the fuel lines, controls, and sensors are attached. Then the exhaust duct is lowered into place by an electric hoist. Push the button, and … power!

Paul Bushue says that the existing stands, in service for decades in the main building, still get plenty of work, but that the new stands, with all their improvements in capacity, precision, real-time reporting, datalogging, and automation “have taught me more about how our engines run. This actually helps me better translate information from the older stands.” In other words, learning from one machine makes the other machines’ data more relevant — a free improvement in old equipment!

For more information visit www.atec.com

Tim Kern is an aviation writer, aircraft builder, and private pilot. He is based in Anderson, IN, and can be reached at info@timkern.com.