I am planning on making a pair of rudder pedals from scratch. I don't know whether they should be hinged, or slide forwards and backwards.
On real aircraft, how do they work? Does it vary from plane to plane?
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asked Mar 1 '14 at 23:40
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$\begingroup$ I think the OP should clarify: Is the question relating to how the pedals adjust to different pilots (e.g., Diamond DA-42, where a lever releases the pedal mounting to slide forward and back - in this case the seat is non-adjustable, or how the pedals move (pivot or slide) when used in flight. $\endgroup$ – Skip Miller Dec 10 '14 at 18:33
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$\begingroup$ Interesting that most answers here seem to contradict the answer here. $\endgroup$ – fooot♦ Dec 10 '14 at 18:38
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I've never seen "sliding" rudder pedals in a light GA plane - though there may be such designs in transport aircraft, especially fly-by-wire planes.
If you're looking for simplicity for a homebuilt aircraft or simulator I'd go with hinged pedals pivoting at the floor similar to what you'll find on a Piper Cub (which can be made by welding tubes together into an I shape), or any number of similar floor-mounted designs:
(As shown in the first picture, toe brakes can be easily retrofitted onto such a design, and as shown in the second you can mount square pedals on them if you want to, though the round bar has some advantages.)
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$\begingroup$ "I've never seen "sliding" rudder pedals in a light GA plane - though there may be such designs in transport aircraft, especially fly-by-wire planes." What GA planes do you base your statement on (just curious)? $\endgroup$ – flyingfisch Mar 2 '14 at 4:02
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1$\begingroup$ @flyingfisch Mostly Pipers & Cessnas, a few LSAs that I've had occasion to climb into as well. They've all had some kind of pivot mechanism (either a simple pivot like above or torque tubes) rather than a track that the pedal slides in. I could certainly see designing a sliding rudder pedal though - it would be simple enough to make it work with cables, and even easier with an encoder for fly-by-wire aircraft. $\endgroup$ – voretaq7 Mar 2 '14 at 7:24
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$\begingroup$ yeah, I guess it would be easier to build sliding pedals than pivoting ones... $\endgroup$ – flyingfisch Mar 2 '14 at 16:26
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$\begingroup$ I know some Extras have "electrically adjustable rudder pedals", but I don't know how they operate. $\endgroup$ – Dan Pichelman Mar 2 '14 at 18:34
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$\begingroup$ @DanPichelman I'm not sure about the Extras but the Pipistrel Virus has a pretty awesome setup for (manually) adjustable pedal distance: youtube.com/watch?v=NfgllFkauZY $\endgroup$ – voretaq7 Mar 3 '14 at 2:20
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Sliding pedals are very unusual - I do not know of a single aircraft which uses them. It is also mechanically more complex and fragile - you would need to keep all those sliding lines clean, at a section of the aircraft where dirt is most common.
But there are three different ways to hinge the pedals. The most common one is at the bottom, but they could also be mounted on a crossbar. By using two crossbars, you get a parallelogram wich helps to keep the pedals at the same angle.
This picture shows the "cockpit" of the schooling glider SG-38, simply because it doesn't hide anything. As you can see, the pedals sit at the ends of the parallelogram, and you could add another hinge at their base easily for activating brakes (which the SG-38 did not have). Now you would have two degrees of freedom which make controlling two separate functions easy.
The third way is to hinge the pedals from the top. This again helps to add a second degree of freedom, especially when the top hinged mechanism uses two parallel rods to again ensure a constant angle of the pedals, independent of their position relative to the hinge point.
answered Dec 10 '14 at 18:24
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On the Cessna's I've flown they both slide and pivot- sliding directs the rudder, pivoting engages the respective wheel's brakes.
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$\begingroup$ OK, maybe it varies from manufacturer to manufacturer then. $\endgroup$ – flyingfisch Mar 2 '14 at 4:04
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$\begingroup$ @CoderTao All the Cessnas I've been in have had rudder attached to torque tubes (built something like this) - I consider that a pivot (around the mounts on the floor) rather than a slide (in a track). Is this what you're describing, or have you seen something different? (Incidentally side-by-side Pipers have similar rudder pedal designs, but with the torque tube above the pedals instead of below them - you can sometimes find full rudder pedal assemblies for both Piper & Cessna on eBay) $\endgroup$ – voretaq7 Mar 2 '14 at 7:20
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$\begingroup$ I can't comment on the actual construction / physical implementation- I never looked that close at them (best I can say is they're similar to what's seen here: farm3.staticflickr.com/2724/4337838025_18c852a8f2_o.jpg ); only that there were two actuating motions, one which seemed to be a linear slide, and the other a pivot. $\endgroup$ – CoderTao Mar 2 '14 at 11:26
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The gliders I've flown (Blanik L-23 and Grob 103) have hinged pedals with regards to controlling the rudder, and they slide closer or farther in tandem to adjust for different pilots' heights.
