Development of the S‐76B/PT6B‐36B Engine Acceleration Schedule
Abstract:The effectiveness of the digitally controlled acceleration schedule for the Pratt & Whitney, Canada PT6B‐36B turboshaft engine (as installed in the Sikorsky S‐76B helicopter) has been significantly improved through the use of innovative improvements in flight test methodology. These innovations have allowed the test team to optimize the engine acceleration schedule in order to maximize the response capability of the engine while retaining adequate installed surge margin. These innovations included (1) the replacement of the production engine control microprocessor with a programmable unit which provided the capability for immediate, on‐site adjustment of flight critical sonware, (2) in‐flight adjustment of critical control path gains and schedules in order to facilitate design optimization, and (3) the use of dissimilar engine software in the twin FADEC channels to preserve aircraft safety during test operations. Test results indicated that an optimum balance between engine responsiveness and mandated surge margin had been achieved for all flight and engine operating conditions without resorting to costly engine re‐design.
Document Type: Research Article
Affiliations: Sikorsky Aircraft Corporation, West Palm Beach, Florida
Publication date: 1996-10-01
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