FBW

[avio@superherc]

The "J" got everything digital, but no Fly By wire. Why is it still depending on pulleys and cables?

[BobWoods]

The "J" got everything digital, but no Fly By wire. Why is it still depending on pulleys and cables?

Reliability in a combat environment?

[Steve1300]

Lightning strikes, computer malfunctions, maintainability in a combat environment. Probably the same reason that many of us get frustrated now when our cars act wierd and we can no longer do anything to fix it ourselves without expensive test equipment. It is better, when the chips are down, that we know that our hands are controlling things and not some programmer's actions five thousand miles away and ten years ago.

[SEFEGeorge]

Guess that's one of the reasons I disliked the J model. Too damn much digital crap for a combat area aircraft who spends much of it's time "in the weeds." Fighters, strat airlifters, etc., one thing, but tactical airlifters are another.

[GVS]

SEFEGeorge is right.Sometimes we're just smart enough to sct stupid.

[mooseherc]

Why not go fly by wire with a cable and pulley back up like the C-17?

[Steve1300]

Complications. If you don't need the extra junk, keep it maintainable. The Herk has enough to cause a big workload without doubling up with systems that don't do more than the original. It used to be good just to have autopilot and AC. If we were a non-tactical aircraft where a huge rear area maintenance base can sit in a high-per diem area, OK, but many times the Herks are down in the dust being flown around the clock. We really gain nothing by complicating systems that have worked well for over fifty years.

[US Herk]

The "J" got everything digital, but no Fly By wire. Why is it still depending on pulleys and cables?

My guess would be certification issues. Its one thing to put a FADEC on a powerplant, it's another thing entirely to make the plane fly by electrons and get that through certification. With the existing flight control systems already certified by the FAA and accepted by the USAF (and RAF, the lead customer), it would get acceptance quicker, be maintained with the same maintenance, minimal manual revisions, minimal training differences, minimal logistics changes, etc. It's cheaper and efficient. Besides, it works well...especially for a combat aircraft.

[SEFEGeorge]

I've never experienced, that god, but in case of a hydraulic failure you can still man-handle the controls. It might take the effort of both pilots and maybe more, to overcome a hydraulic lock, but it can be done, or so I have been told.

Flying the old recips was, to me, a lot more "pilot actuated." The fly by wire then was cables and tension regulators, pulleys and bellcranks. Changed many pulleys and bellcranks for bad bearings in RVN. Not always easy but it sure was easier than changing out actuators, dealing with hydraulic lines and leaks, etc.

[Spectre623]

Lockheed probably kept the cables and pulleys because they remember the airbus that flew itself into the trees as the pilot was screaming" soc' leblu" or whatever, and trying to pull up. Bill :)

[SEFEGeorge]

I think it means "g** damn it."

[tinyclark]

The autopilot is fly by wire.

[bischoffm]

Engine controls are fly by wire:cool: