Originally Posted by
IFMU
That is awesome.
The latest press really doesn't answer any questions. As a former FBW guy I'd like to know.
I know nothing about the CH-148, but have climbed in and over the S-92 FBW development aircraft, and looking at the top deck it retained the standard hydraulic actuators, SAS and mixing unit as I recall. The only bit missing was the control rods from the actual cockpit controls. I think the fundamental difference from FBW Fixed wing, that typically use Electo Hydrostatic Actuators or Electo-Mechanical Actuators, is that in an aeroplane you can gain significant weight and complexity savings by reducing/removing the hydraulic distribution system. Whereas, the hydraulic pumps in a helicopter are almost co-located with the control actuators (for the Main Rotor) so this benefit cannot be obtained. That said, I am interested to know why helicopters cannot also use EMAs as I'm sure the control loads and input frequency for an F35's flying controls must be comparable to that of a helicopter MR, and this would take away the need for the primary hydraulic pumps and the TR Servo hydraulic lines (with their attendant vulnerability).