Control surface mechanic questoin.

[Guest DNelson]

Just to clarify, hydraulic boost is not the same as fly-by-wire. As I recall, not even 757/767 is truly fly-by-wire. In the 757/67, moving the yoke or rudder pedals a certain distance will move the corresponding control surface a proportional distance, whether you're parked at the gate or going Mach .8 at FL 350. With fly-by-wire, which first appeared in the 777 for Boeing, the flight control computer decides how much to move the control surface, based on the current flight regime.

[michal 44]

>Just to clarify, hydraulic boost is not the same as>fly-by-wire. Well, I would be really astonished if anyone visting these forums would put equivalence between these two.Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[Guest DreamFleet]

When we were researching the ATR 72, that we built for Flight One, we visited the factory in Toulouse, France, and toured an aircraft that was being assembled in the very same facility that the first Caravelle jet was built decades before.The cabin was still "bare bones", and I'll never forget seeing those control cables going back from the cockpit, turning around pulleys, and going out to the wings.Also happy to see mention of the 707. Rudder boost was all it had, everything else was manual.I flew a 707 sim at Lufthansa 4 years ago. It was a pleasure to hand fly, even on an ILS to minimums. :-)Regards,http://www.dreamfleet2000.com/gfx/images/F...R_FORUM_LOU.jpg

[michal 44]

>Rudder boost was all it>had, everything else was manual.Even ATR? Who would think of it? Good to know Lou.Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[mgh 89]

Even when the controls are hydraulically powered there will still be mechanical (cable or rod) connections from the pilot's controls in the cockpit to to the hydraulic jacks which are generally located close to the control surfaces.

[Guest BOPrey]

Power assisted controls? That sounds much better. I can imagine that rod (cable) running the full length of the entire ATR72 body. BTW, I bought the F1 ATR72, excellent plane and every thing works.

[Guest CRJ700FO]

>Even when the controls are hydraulically powered there will>still be mechanical (cable or rod) connections from the>pilot's controls in the cockpit to to the hydraulic jacks>which are generally located close to the control surfaces.thats what it is in the canadair regional jet.the yokes are independently controlled (ie the right yoke controls the right elevator and right aileron and vice versa). two torque tubes interconnect the yokes so they move in tandem on both axis.cables run from the yoke to the elevators and airlerons (run through fancy systems of anti-jam mechanisms, etc). from there they connect to a hydraulic PCU (primary control unit if memory serves me correct). it is this PCU that moves the flight control surface.in addition the ailerons are assisted by flight spoilers (a set, x2, on each wing plus 2 ground spoilers for a total of 8 spoilers).each control surface is affected by 3 PCU's, each tied to its appropriate hydraulic system (1 routed through the #1 engine, 2 routed through the #2 engine, 3 is an independent system used primarily for the landing gear). this way each control surface has triple redundancy for any failures (engine loss, hydraulic leak, PCU runaway, etc).typically on a hydraulic flight control system there are no trim "tabs". trimming simply moves the entire control surface. usually the elevator is not moved, but rather the entire stabilator (hence the term stab trim) is moved. in the crj the aileron "trim" simply moves the yoke in the desired direction (ie it "resets" the yoke neutral position).hope this helps.