Thread: Non-Hydraulic flight controls
09-25-2007, 10:16 AM #1
Non-Hydraulic flight controls
Here's something Ive been wondering for a while and seeing as how I hope to start the interconnected yoke portion of the project soon, I need to get some feedback from you all.
The Learjet 45, believe it or not, is controled by a combination of cables, bellcranks, and pulleys with the exception of spoilers, flaps, and landing gear and some rudder boost.
With that in mind, what is the best way to set up my yokes? To be more detailed, the yokes can be turned full left or right and they will stay there vs. returning to center, just like a Cessna 172, etc.
I have flown several light GA aircraft in real world, and of course those controls dont center themselves up like a Boeing yoke does.
I intend to do heavy modification to two CH yokes and connect them, but I am wondering if I want to just use a very light spring to return the roll moment to center, but not heavily like a 737 would. The same would go for the pitch moment, although admittedly, I want it to have a better self-supporting ability. Maybe a counter-weight would be best for the pitch? Obviously a hydraulic dampner would be way over-done.
09-25-2007, 10:18 AM #2
With the air moving over the control surfaces, you will get a "return to center effect"
Keep that in mind when your building your yoke.
09-25-2007, 10:23 AM #3
THAT was an excellent point, so that is a very important part to remember because although it does look neat to be able to push the column forward and it be tilted to the left or right when you get up to leave the flight deck, if it did center on its own, it's much easier to trim and fly.
Thanks for that point. You'd think that since I have actually flown a good little bit with friends that I would have thought of that point!
09-25-2007, 10:32 AM #4
The higher the airspeed the more the resistance to deflecting the rudder or the elevators.... so the resistance ideally should not be "constant". Some sort of active feedback from the FSUIPC offset for airspeed reflected back to the system and the "resistance" and "re-centering" mechanism would provide more realism...likely at a significant cost of both $ and construction complexity.
It all becomes a question of how far do you go. Pretty you have a $4 Million sim sitting there.
PS: Good reason to go "fly by wire".
09-25-2007, 10:54 AM #5
- Join Date
- Dec 2006
- 20 m N of RWY36R LEMD
I have to agree with Gwyn.
I have never flown an airliner - in fact the last aeroplane I flew was a DH Chipmunk, which I think didn't have an ounce of hydraulics, except perhaps for the brakes.
Controls will "self centre" due to the aerodynamic forces at flying speeds, but this is not a "spring" self centre, more a desire to return to the neutral position. Hence the move of the controls to enter a bank, and the opposite move to leave the bank.
The ERJ 145 has a combination of cables and hydraulics - cables for elevators and hydraulics for ailerons.
The damper in my case adds to the smoothness of the feel - the nearest I can tell you is like moving the steering wheel of a car with no power steering and the front wheels jacked off the ground, to the same effect of a car with power steering - one is "clunk", the other "whirr-clunk".
And for a $100 worth of cylinders, plus a few hours of headscratching.... I can now experience a real"Hydraulic failure ", not to mention those realistic patches of oil under the sim each morning - I just have to talk to Pete Dowson as to how to mimick it. ( Just Joking Pete!)Paul
Project ERJ 145
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