"Mary Shafer" wrote in message
...
On Thu, 25 Mar 2004 05:41:52 -0500, "R Haskin"
wrote:


"Michael Kelly" wrote in message
m...

John Mullen wrote:

The Su has a pull-through fuction on the fbw ISTR. Might be a
factor?

Probably not since the the F-15C isn't FBW and only has an overload
warning function. You can over G a F-15C.

Michael Kelly, Bone Maintainer

Actually fly-by-wire aircraft can be over-Gd -- it happens to F-16s all
the
time.

The F-15, while not "fully" fly-by-wire, has a primary flight control
system
that is FBW (called the CAS, or Control Augmentation System) and a
hydromechanical backup system.

All modern FCSs are electronic, not mechanical or hydraulic, but we
don't consider them to be FBW. We just consider them to be analog or
digital FCSs. However, it's possible to have hydraulic or mechanical
FCSs.

The part that makes the system FBW is a distinction between cable tripped
valves, or electric valves. (current, or hydraulic)

The point is that FBW is strictly between the pilot and the control
surfaces. That's it. Nothing to do with the feedback control in the
flight control system. After all, the SR-71 was summing electric
inputs from the FCS with the push-rod and cable inputs from the pilot
back in the '60s.

The 747-200 and the DC-10 are termed "hybrid FBW" for having cable driven
hydraulic valves controlled electrically.

You can have FBW without having a feedback control FCS, not that
anyone does, and you can have an FCS without having FBW, which the
F-15 does and the SR-71 did. Or you can have both, which the F-16 and
F-18 do.

An the Boeing 717.