AS-365 Decrease in Fuel Flow with Increase in speed
Just cleaning up some old documents, and came across some technical information from Eurocopter on the AS-365 family. Fuel flow in cruise shows a distinct notch for all weights at about 240-280 kg/hr. For example, at maximum weight, at sea level, ISA, the curve increases normally until it reaches a point of 128KTAS, with a fuel flow of 278kg / hr, then as the speed increases a mere 2 knots, it suddenly drops to 270Kg/hr. This change is at a consistent fuel flow of 278kg, that then drops back to 270 kg/hr for all weights (obviously different airspeeds) with a 2 knot increase in airspeed.
At 5,000 ft, the change occurs at 240kg/hr, when it drops back to 233 kg/hr for all weights with a 2 knot increase in airspeed. Much the same sort of thing happens at 10,000' when the fuel flow goes from 206kg/hr to 199kg/hr
This appears to fly in the face of common sense and previous experience.
Is there a change in rotor RPM somewhere here? Or something else????