Well, I think we all agree that the VC10 isn't listed as FBW plane. At least not where I'm looking.

 

But knowing that vololiberista is a huge VC10 nut, it's interesting reading about the details of that plane. I knew that she incorporated some fancy stuff, like a wing relief system (may not be the actual name) but FBW? :mellow: I don't know, not by definition I guess, as some of you knowledgeable folks are pointing out.

Short of copying 28 pages of AP electrical diagrams etc which I don't think is necessary.

 

Agreed. It shouldn't need 28 pages to make your point.

 

 

The first link you posted states:

 

PFCU is an individual small hydraulic system with an electrical pump and small reservoir to feed the control jack.

 

The latest one refers to PCUs. Is PCU the same as PFCU and, if not, what is it?

Well, I think we all agree that the VC10 isn't listed as FBW plane. At least not where I'm looking.

 

But knowing that vololiberista is a huge VC10 nut, it's interesting reading about the details of that plane. I knew that she incorporated some fancy stuff, like a wing relief system (may not be the actual name) but FBW? :mellow: I don't know, not by definition I guess, as some of you knowledgeable folks are pointing out.

 

The "wing relief system" is actually called "Aileron Upset" and deflects both ailerons up by 7deg. reducing as the altitude increases. However, it's normally turned off during the "after take-off" check unless the a/c is very heavy in which case it stays on until the climb check.

PFCU "Powered Flight Control Unit" PCU "Powered Control Unit"

The Control column is "not" an integral part of the hydraulic system. ie. Moving the control column has no effect on the hydraulic system as does say your car brake pedal or clutch pedal.

The control column therefore has no direct link to the control surfaces and has to have a "feel" system incorporated. Therefore it's a fly by wire system. Analogue instead of digital. Concorde was the same.

The picture below illustrates what the pilots see. In the yellow box the two top red lights are the "Feel Fail" lights. The one below is the "Power Controls" fail light. To the right are the A and B aileron upset switches with their associated MI's

 

The control column therefore has no direct link to the control surfaces and has to have a "feel" system incorporated. Therefore it's a fly by wire system.

If only that feel system would define it, the 737, 757, 767 and even the 747 are FBW too. That artificial feel setup is used among those. Fun fact, this often gets forgotten by certain folks. Not you, don't worry. ^_^

 

For example, if the #2 and #3 hydraulics fail on the 747, the artificial feel system also fails and your only feedback remains the one coming from some, now 'fixed', mechanical springs.

 

I think Rónán pointed out that even the VC10 setup really looks like a mechanically controlled, hydraulic assisted aeroplane. Perhaps check the 737's schematics. http://www.smartcock...ING/B737NG.html We may agree that this is not a FBW plane. But the setup shows character traits like on your VC10 example. For instance, the rudder pedals connect to the PCU. Not the rudder itself.

 

Maybe it helps to keep in mind that the FBW stuff processes the pilot's inputs to some extend. You can augment normal controls too, the MD-11 does this, but it's not that like the Airbus stick where for example the stick deflection for the pilots stays the same (normal law) and the computer translates that to a proper control surface deflection throughout the speed range of the plane.

 

Since you've mentioned Concorde to be the same as the VC10. It kinda was, but only in the mechanical backup mode. When running the two electrical circuits, which was the standard on that plane, it translated the control column movements to electrical signals. Copper cables then made sure that they reach the servo units. Concorde also provided for e.g. automatic stabilization and protection against too high angles of attack.

 

Those copper cables are the 'wires' we are talking about when using the general term FBW. Not talking about how an autopilot feeds the system.

 

My very first test of the force controlled Stick in the homebuild cockpit

It's a modded Thrustmaster Cougar, very very close to the real deal.

Nice setup and impressive work on the cockpit. Next thing is the big screen, huh?

The control column therefore has no direct link to the control surfaces and has to have a "feel" system incorporated. Therefore it's a fly by wire system.

 

That's a non-sequiter.

 

In hydraulically powered flying controls feel was often incroporated mechanically either by a bob-weight (to give a force proportional to "g"), by a simple spring, or by a spring whose stiffness varied with dynamic pressure, or a combination of them. None required wires or electricity.