Rolls-Royce last month launched the RR500 turboshaft, a 475-shp derivative of the RR300 that powers the in-development Robinson R66. Certification is scheduled for late 2011, with deliveries pegged to begin in the first quarter of 2012.

“Basically, we took the 300-shp RR300 and increased the airflow,” Ken Roberts, Rolls-Royce president for helicopters, told AIN. Design engineers enlarged the compressor and modified the turbine and other components. The purpose of increasing the airflow was to “keep the operating temperature relatively modest,” he explained. Designers could also have increased power by raising temperatures.

Like the RR300, the RR500 will have an electronic engine monitoring system, and it retains hydropneumatic engine control and will benefit from extended maintenance intervals. While the older Rolls-Royce 250 has TBOs of 1,750 and 3,500 hours for minor and full shop visits, respectively, the RR500 will have 2,000-hour and 4,000-hour intervals.

The new engine is slightly more powerful than the 250 series 2 (which ranges from 420 to 475 shp). “It is targeted at new applications,” Roberts said, but he acknowledged that some existing Model 250 applications might move to the RR500.
Rolls-Royce announced the RR500 turboprop last summer at the EAA AirVenture airshow. The company said it is running the turboprop and turboshaft programs “in a very integrated fashion.”

The RR500 uses the same engine mounts as the Model 250, making it retrofittable to Model 250-powered helicopters. The RR300 is itself certified as derivative on the Model 250’s type certificate.