Piper Cub Vs F-15

In article , Alan
Dicey wrote:

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.

The first two are what a fly-by-wire system is.
The third is one particular implementation of fly-by-wire.
And it doesn't matter whether it's analog or digital,
or whether the a/c is inherently unstable and the FBW
system keeps it in the air. Those are also just implementations of
fly-by-wire .
Claiming you're the first because of your particular implementation
is disingenuous.

--
Harry Andreas
Engineering raconteur

Harry Andreas wrote:
In article , Alan
Dicey wrote:

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


The first two are what a fly-by-wire system is.
The third is one particular implementation of fly-by-wire.
And it doesn't matter whether it's analog or digital,
or whether the a/c is inherently unstable and the FBW
system keeps it in the air. Those are also just implementations of
fly-by-wire .

If I understand you correctly, you hold to the view that any
electrically signalled flight control system is fly-by-wire? I think
that makes the Vulcan a pioneer, along with the Vigilante.

The point I was trying to make was that the term has only gained
currency recently, starting with the F-16. It has since been applied
retroactively to aircraft that lack the intermediate computer (be it
digital or analog), some of which have electromechanical equivalents
(mixer boxes) and/or control augmentation systems, autopilots or terrain
following systems. I don't think the term fly-by-wire was applied to
these aircraft when they were being designed or in service, but I would
be happy to be proved wrong, in the interests of illumination.

Claiming you're the first because of your particular implementation
is disingenuous.


Thats a bit harsh. I stated up front that circular reasoning was
involved in the definition I was using and also indicated that the line
wasn't clearcut. No dishonesty or insincerity involved.

And its not my claim, nor ever has been: it was GD's claim, and only in
the sense that they made a selling point out of it.

To me, fly-by-wire will always mean a system where the pilots inputs are
moderated by the flight control computers. As we have just
demonstrated, it has no clearly-agreed technical meaning, a fact which I
ascribe to its birth in the mind of a marketeer.

In article , Alan
Dicey wrote:

Harry Andreas wrote:
In article , Alan
Dicey wrote:

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


The first two are what a fly-by-wire system is.
The third is one particular implementation of fly-by-wire.
And it doesn't matter whether it's analog or digital,
or whether the a/c is inherently unstable and the FBW
system keeps it in the air. Those are also just implementations of
fly-by-wire .

If I understand you correctly, you hold to the view that any
electrically signalled flight control system is fly-by-wire? I think
that makes the Vulcan a pioneer, along with the Vigilante.

As long as we're talking about the primary flight controls.
I'm not familiar enough with the Vulcan to say.


The point I was trying to make was that the term has only gained
currency recently, starting with the F-16. It has since been applied
retroactively to aircraft that lack the intermediate computer (be it
digital or analog), some of which have electromechanical equivalents
(mixer boxes) and/or control augmentation systems, autopilots or terrain
following systems. I don't think the term fly-by-wire was applied to
these aircraft when they were being designed or in service, but I would
be happy to be proved wrong, in the interests of illumination.

Lots of things fall under a later definition, say, supercruise...


Claiming you're the first because of your particular implementation
is disingenuous.


Thats a bit harsh. I stated up front that circular reasoning was
involved in the definition I was using and also indicated that the line
wasn't clearcut. No dishonesty or insincerity involved.

I wasn't criticizing you....


And its not my claim, nor ever has been: it was GD's claim, and only in
the sense that they made a selling point out of it.

....I was commenting on GD's re-definition of the term. Sorry if that
wasn't clear.


To me, fly-by-wire will always mean a system where the pilots inputs are
moderated by the flight control computers. As we have just
demonstrated, it has no clearly-agreed technical meaning, a fact which I
ascribe to its birth in the mind of a marketeer.

Can't argue with that.
ciao.

--
Harry Andreas
Engineering raconteur

Harry Andreas wrote:
In article , Alan
Dicey wrote:
If I understand you correctly, you hold to the view that any
electrically signalled flight control system is fly-by-wire? I think
that makes the Vulcan a pioneer, along with the Vigilante.


As long as we're talking about the primary flight controls.
I'm not familiar enough with the Vulcan to say.


One reference below, look about 3/4 down the article for a paragraph
entitled Vulcan: A Revolutionary Forebear.

http://www.defensedaily.com/cgi/av/s...e=1001a380.htm

Anybody know if the B-52 was electrically signalled?

How about Victor or Valiant?