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Old June 30th 04, 07:48 PM
Alan Dicey
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Alan Dicey wrote
The first production fly-by-wire aircraft was the F-16.


Eunometic wrote:

Concord actually. They even wanted to put sidearm controllers on it.


Ron wrote:

F-16 was the first with a DIGITAL FBW. I think Concorde, and

possibly F-111 too had analog systems.

Peter Stickney wrote:

F-111, actually. And, perhaps the A-5 Vigilante, depending on how you
want to define FBW.


A major problem here is that the term fly-by-wire was popularised as a
marketing soundbite by the GD team during the Lightweight Fighter
competition in the early seventies. As such it had no strict
engineering definition. Prompted by the original poster, I was using it
in the way that Harry Hillaker does: -

"'Fly-by-wire' is a totally electronic system that uses
computer-generated electrical impulses, or signals, to transmit the
pilot's commands to the flight control surfaces instead of a combination
of the push rods, bell cranks, linkages, and cables used with more
conventional hydromechanical systems."

(Harry J. Hillaker is retired vice president and deputy program director
for the F-16, General Dynamics Corporation)

- which does come down to a somewhat circular definition (fly-by-wire
is defined as what the F-16 has, so of course it is the first).
However, I think most people understand fly-by-wire to include elements
of electrical signaling and computer control, which leads us back to
Hillakers definition, which makes the defining characteristics:

* electrically signalled
* no manual connection
* pilot flies computer: computer flies plane.

I think this is also the kind of system the original poster was thinking
of, where the aircraft is kept from departing from controlled flight by
the flight control computer overriding the pilot inputs and keeping the
aircraft right on the edge of its flight envelope. My original point
was that the F-15 does not have this kind of fly-by-wire :-)

The F-16 system, manufactured by Lear Seigler, was initially an analog
system, by the way. The first digital-from-scratch FBW aircraft was the
F-18 Hornet.

If you broaden the definition of fly-by-wire to include all
electrically-signalled FCS, there are many aircraft prior to the F-16
that qualify, among them being:

The Avro Vulcan: Tim Laming's The Vulcan Story includes the aircrew
manual which describes the system as electro-hydraulic, and including
artificial feel, autostabilisation and mach trimmers.

The A-5 Vigilante:
http://www.airtoaircombat.com/backgr...p?id=87&bg=305
The aircraft had a primitive fly-by-wire flight control system in which
stick movements of the stick were converted into electrical signals
which fed into actuators that controlled lateral and l longitudinal
movements. The actuators then mechanically positioned the control
valves, the horizontal stabilizer, and the spoiler activators. There was
a mechanical backup system in case this system failed.

Concorde
http://www.concordesst.com/autopilot.html
Concorde has an Automatic Flight Control System (AFCS) installed, that
for the 1970s was state of the art. The system is designed to allow
"hands off" control of the aircraft from climb out to landing. There are
2 mains parts to the system; the Autothrottles and Autopilot, and a
number of associated systems, such as the warning displays and test systems

http://www.concordesst.com/flightsys.html
Although it is described as fly-by-wire, it is not computer-controlled
and there is manual reversion. Shades of meaning, I know.

Autopilot plus autothrottle is not fly-by-wire, by the "F-16"
definitions :-)

I don't know offhand and can't find on the web a good enough description
of the F-111 FCS to tell; but I suspect that it too falls short of the
definition I am using.

Tornado is fly-by-wire, but comes after the F-16. It is also
aerodynamically stable and has a manual reversion mode.

I'm sure there are better qualified people than me on this newsgroup who
can give a more authorative opinion: I only used to work for Marconi
Avionics, so what do I know :-)