I found the aircraft to be a bit tight on the controls during a standard hover, and Barnes recommended using the force trim release buttons to loosen it up. That helped a lot — although it then seemed to be a bit too sensitive. But like pilots, every helicopter has its idiosyncrasies. A pilot simply gets used to each aircraft's, and it didn't take long to figure out how to handle this one.
The aircraft has force trim on both the cyclic and collective, so the pilot can adapt either or both controls to his own “pilot technique” feel for flying the aircraft. All hovering can, however, be done by simply “beeping” it where you want it to be by engaging the autopilot's velocity hold (VHLD). There is also a beeper trim button to move the aircraft up or down.
Placing a green circle at a point on the map display of the runway with zero airspeed dialed in puts the aircraft in a stable, hands-off hover. Repositioning the green circle repositions the aircraft. Changing the heading while maintaining zero airspeed turns the nose of the aircraft without changing its position. To change position, the pilot simply dials in where he wants to go. If it's a stable hover and the wind blows it off its hold point, it will recalculate and return to the original position.
Takeoffs, both normal and max performance, were without drama. Climb-out for a normal takeoff was at 75 kt., 750 fpm at 59/60% torque. The aircraft can monitor OAT and aircraft weight to determine best rate of climb, for both normal and OEI climb-outs, and indicate that rate by a little white triangle on the airspeed indicator.
Vibration level was moderate — acceptable but not great — although Barnes pointed out that the test aircraft only had one vibration suppression unit, whereas standard S-76Ds would likely have three or four, reducing vibration levels much further.
We climbed to 2,000 ft. holding 100 kt. in the climb, then accelerated to 130 kt. and engaged VNAV and RNAV (airspeed and area) to hold us on a steady course and altitude.
An assortment of charts is available to the pilot on the digital map (DMAP) display, to include Jeppesen approach charts and Thales multifunction moving maps. Barnes pulled up a vector chart to demonstrate the aircraft's flight path control. He simulated a large storm cell directly between our points A and B, then used the cursor control to mark a point to the right of the storm cell. The aircraft automatically turned toward that mark. He then remarked the original Point B, noting that when the aircraft reached the new point in space, it would automatically track to Point B, avoiding the storm. This was all done using the trackball and pushing a single button.
Sikorsky initially installed the Honeywell Primus 440 weather radar on its S-76s but discovered customers were replacing that with the 660 system. So, the Primus 660 is now the standard weather radar for the S-76D. The Thales system also offers XM Weather for on-screen satellite weather service as an option. Also available as an option is ADS-B and GPS precision approach capabilities.
To test basic flight characteristics, we took the aircraft up to its 155 kt. Vne, pulling only 50%. Barnes noted that while Vne is 155 kt., because of the efficiency of the Pratt & Whitney engines, maximum cruise speed for best range is 154 kt. He also noted that Sikorsky already has the data to expand the 155 kt. Vne limit “down the road.”
For steep turns, Barnes “beeped” the aircraft over into a 30-deg. angle of bank and put it on automatic hold. The aircraft held steady at 110 kt., pulling only 40% torque. The 30-deg. angle of bank is the maximum for automatic hold. That can be manually overridden to allow up to a 60-deg. bank — with a warning voice letting you know when you are reaching power limits.