Rudder Control

[Milt]

Was it the Wright Bros who caused us pilots to have to learn to operate aircraft rudders in reverse? Did it come about because of the difficulty in crossing over the rudder control wires?

What other machine or vehicle turns/yaws the opposite way to the control input?

Now that we have all overcome our natural instincts for rudder control there is no going back.

Those of you who were riding a motor cycle when you learned to fly will appreciate the difficulty in conversion.

[FlapsOne]

Left Pedal = Left Yaw.

Am I missing something here, or is this a Southern Hemisphere thing?

[forget]

Early aircraft, up to World War 1 vintage, had the rudders in the ‘reverse’ sense. Probably came from horses and four wheeled carts, left end of bar moves forward and you go right. Makes sense when you think it through – but this meant crossing over the cables on their way to the rudder. After a series of accidents caused by mis-rigging the whole thing was simplified by running the left cable down the side of aircraft to the left side of the rudder and vice versa. Its obviously the norm now – but it is ‘unnatural’.

[Genghis the Engineer]

Actually in most modern rudder mechanisms the cables do cross in the back of the aircraft. Some aircraft can be mis-rigged, it's one of the reasons for the "controls full and free - and in the correct sense" check.

There's a (now obscure) American ultralight called a JC24b Weedhopper, which has a stick that operates in the "push-right / roll right" sense, and the pedals (actually nosewheel steering, there's no independent rudder) which is "push-right / turn-left". On the ground it's the most confusing flying machine I've ever flown and totally unnatural, and I speak as somebody comfortable with flexwings.

So, in my opinion everything working in the same sense push-left = roll-left = yaw-left, or push-right = roll-left = yaw-left is natural. Just don't cross them.

But you can get used to anything with time !

G

[forget]

Milt, Now that the appropriately named NotSoFantastic has spoken, and we’ve all been put in our place, you’ll no doubt desist from asking aviation questions on an Aviation Questions Forum. Don’t you have anything better to do?

[Mark139]

I can remember as a lad of about 12 convincing this bloke to let me fly his radio controlled plane as I knew all about it. It took me about 20 seconds to wreck the thing as he'd reversed the elevator control.

I made my excuses and left him with his pile of balsa.

[Flyin'Dutch']

Although I can sympathise with the originator of this thread I must say that converting the use of rudder after being a proficient cyclist for many years was not half as difficult as trying to cycle with your hands crossed over the handlebars on your bike.

Ever tried that one?

Did it hurt?

FD

[Shaggy Sheep Driver]

....And a bicycle with steering geared so handlebars turned left gives front wheel turned right and vice versa is unridable.

Bicycles are actually turned by 'counter steering'. To turn left, you move the bars to the right. The bicycle intially steers right, then drops over into a banked turn to the left. Cylists (including me) are genrally not aware of this, and don't really know how they turn - they just 'do it'.

Motorcyclists are very aware of it, because with the much heavier and faster-turning wheel of a motorcycle this gyroscopic effect is very obvious, to the extent that to make a motorcycle deliberatley 'turn in' quickly, the rider deliberately counter-steers; pull on the left handlebar or push on the right handlebar, and the bike immediately drops into a controlled right turn.

This effect obviously doesn't happen at very slow speeds where the gyroscopic effects of the spinning wheel are too weak. I call this sort of turn 'yaw mode'. It is used when wheeling the bike in and out of the garage, or when riding at very low speeds, such as 'U' turns in the width of the road etc.

SSD

[Flyin'Dutch']

SSD you write:

Motorcyclists are very aware of it, because with the much heavier and faster-turning wheel of a motorcycle this gyroscopic effect is very obvious,

But this is already evident on a (push)bike and explains why cycling home after a booze up on the whole is more succesful than a walk.

Cycling is inherently stable due to the gyroscopic effects of the spinning wheels whereas walking is in itself an unstable activity requiring much more coordination of the (intoxicated) cerebellum.

I have, of course, no experience myself but have noted this many times when drunken friends tried to walk home without succes but after negotiating the mounting phase of the bike-ride managed to get home safely.



FD

[Tralfamadore]

I will never forget watching the first test flight of a Puchaz (glass fibre two seat glider) after a rebuild following a crash when the fuselage had broken in two aft of the cockpit. The guy flying it was on the radio and was struggling to stay behind the tug using all his energy to push the stick forward. It transpired that the elevator trim cable crossed over on its way to the back and had been rebuilt straight. The chap flying it got away with it - I do remember the tug flying alongside him and over the radio to a load of instructors on the ground saying "Your trim tab is fully down" and not one of us instructors realising that it should have been UP (with the trimmer fully forward). We worked it out after he'd landed!

[Flyin'Dutch']

What happened to the good old positive checks, one wonders.

FD

[Tralfamadore]

Flyin' - it was the trim tab not the elevator itself so you can't do a positive control check.

[Gertrude the Wombat]

What other machine or vehicle turns/yaws the opposite way to the control input?

Boats. If you find a tiller natural after years of messing around in a dingy you have great difficulty steering a bigger posher boat with a wheel!

[Flyin'Dutch']

Flyin' - it was the trim tab not the elevator itself so you can't do a positive control check

Why not?

I do before I fly, be it a glider or something spammy.

FD

[Lowtimer]

....And a bicycle with steering geared so handlebars turned left gives front wheel turned right and vice versa is unridable.

At last, a thread where I have an apparently extraordinary skill to brag about! Some years ago I was sent off on one of those corporate team building days where you had various hearty outdoorsy tasks to perform e.g. cross the river with a hairpin, a tree trunk and a reel of cotton. The best bit was some special pushbikes which were rigged up not only with back-to-front steering, but also with pedals that worked the wrong way round to drive the thing! I was the only person who could ride it.... how? I just sat on it and tuned my mind in... "Think Chipmunk... Think Chipmunk..." Worked a charm. Mind you, that doesn't explain why I was also able to pedal in reverse with such facility, maybe I just have a weird brain.

[englishal]

"Boats"

Old ships, like the Titanic, had a wheel that you turned to the right and the boat swung to port, so I suppose you can get used to anything.

Seems to make sense though, pushing right rudder and the nose yaws to the right and vice versa

EA

[Tralfamadore]

FD Point taken - no reason why you can't do a positive check on the tab - I guess my answer came from the fact that I'd never heard of someone doing it on the tab as well as the elevator. We do it (or rather I did it some years ago ) on the elevator because they can be misconnected. But given that the tab is fixed you would assume that if the elevator responds to a positive check then the tab is OK too.

Then again, if you had just rebuilt the fuselage.......

[Gertrude the Wombat]

I guess my answer came from the fact that I'd never heard of someone doing it on the tab as well as the elevator

I was taught to do it. Now I get told "don't wind the bl**dy thing right through its travel, if it gets that four times a day the wires will stretch".

[Tralfamadore]

I was taught (and in turn taught others) to exercise the trimmer fully forward and back but not to do a positive control check = i.e. have someone walk round the back and hang on to it while you move the trim control. And I have never heard of anyone doing it - I was an instructor for 16 years (although perhaps not the most observant person in the world! )

[Mike Cross]

Positive control checks are usually only essential after re-rigging, however you can get caught out.

I went to collect a Beagle Pup 150 after an undercarriage repair some years ago. The maintenance organisation insisted that tehy had not disturbed the flying controls but the fact was that the trim tab was badly misrigged. A quick circuit with a lot of forward stick pressure got me back on the ground.

Why should exercising the trim tab throughout its travel do any more harm than the "full and free" check that you do on the rest of the controls?

Mike