I have just moved up to a 4 channel plane and i am wondering now what the point of the rudder is now. I used the alerions now and I find the rudder just messes things up now. What should I use the rudder for now?

stevo,

Rudder is useful for lots of application. Coordination of turns, aerobatics, correcting for crosswind landings.......

Moving up to a 4-channel means you now have to learn a new control, and the rudder is probably the most powerful single control on the plane. I regularly demonstrate this to my students by flying a short flight - take-off, figure 8, pattern and landing using only the rudder, not touching the ailerons.

When your shooting a landing approach and the plane is not aligned with the runway, you can make heading corrections with the rudder. This is especially important in crosswind landings where the ailerons are used to hold the up-wind wing low and the rudder is used to fly the plane straight down the runway.

Aerobatics require proper use of the rudder. When you pull on a vertical up line, many planes will require a small amount of rudder to keep the line straight. In a loop, some planes require right rudder to make sure the plane is tracking properly through the loop. Stall turns and spins are more applications that require the rudder.

So you can see, the rudder is not just an ornament adorning the hind end of the plane, but one crucial control surface, and one that should be learned and mastered if you want to progress to more advanced level of flying.

Hogflyer

I find that making turns with rudder and some up elevator (plane rolls and dives a little with rudder) I can make turns without losing altitude. To make tighter turns using lots of aileron causes a loss of vertical lift, and therefore loss of altitude.

You use the rudder to keep from destroying the airplane on takeoff. You use it to keep from stalling it on final approach.

Steering the airplane on the ground on the takeoff roll is impossible. So it's obvious you steer it on the ground with the rudder. Well, when the wheels lift away, the airplane is very often at it's most vulnerable to stall. The wing is just beginning to fly and can often be very close to a stall. If it's bumped by gusts, that pushes one wing even closer to the stall. The engine and prop are pushing with torque and p-effect and the wing is at it's weakest to fight back. Heck, it just got pushed by the gust, right.

Try to straighten out the airplane at liftoff with the ailerons and you're adding to the airplanes problems. The downgoing aileron has just added AOA to the wing that's already close to the stall AOA. And stalls are caused by excessive AOA.

Use the rudder to steer the airplane until it's safely clear of the runway on takeoffs. You'll have airplanes that live longer.

Same things are true on landings. When the airplane is close to the runway and at it's slowest, you really do not want to be trying to steer it with the ailerons.

And after all, why would you want to roll with ailerons when the wing is barely clear of a runway?

hogflyer covered how useful it is in flight. I'd like to add to that just one thing. Have you ever seen a modeler fly pattern maneuvers? Or seen video of the guys who fly at meets like the Tournament of Champions? You don't have to be that good to use the rudder, but you won't be good at all doing lots of maneuvers unless you learn to use the rudder to correct the airplane's path in maneuvers.

One of the first maneuvers most developing pilots learn is the cuban-8. One of the flying fields around here has an "expert" who claims the rudder is worthless. Some days his cuban-8s look like he's only been flying for a week. He's been flying for years and years and years. And thinks it would have been a waste of time to learn to use the rudder.

BTW, people usually don't watch that guy fly to see his maneuvers. They do however watch every one of his takeoffs. He regularly blasts an airplane on takeoff. It seems he is "very unlucky" with wind gusts. Seems his engine torque is greater than others too. Because he almost regularly has one of his models snap on takeoff, and it's gotta be either the wind or torque, right?

I agree with hogflyer. The rudder is a very important (some would say the most important) control surface. Although it is not often taught early in one's RC training you should eventually learn how to use it properly.

The best book I have found on this subject is Stick and Rudder: An Explanation of the Art of Flying by Wolfgang Langewiesche. You can find it for less than $10 here:
[link=http://www.amazon.com/Stick-Rudder-Explanation-Art-Flying/dp/0070362408]Amazon[/link]

The Knife Edge maneuver and the Immelman maneuver make use of the rudder. If you can circle the field in Knife Edge it could be that you have "arrived". I chuckle every time I use the rudder when I'm flying my Flying Lawnmower and make a turn. It does not have a rudder! My rudder usage seems to be on auto pilot. On at least three occasions I have had a plane in the air when a failure occurred with the ailerons. Two were with student planes. I was able to safely land the planes using the rudder for turns.

I can assure you the rudder is a very important control surface. One of the problems is in the responses a model airplane is capable of rendering a misconception of its usefulness. I find myself using aileron more, banking the plane, and using the elevator to turn with. But, that is not the usual practice for a passenger containing Cessna 172 with a family out for an afternoon flight.

The rudder is used to maintain a "coordinated turn". This means the tail follows the nose. Its also used to make the plane "dirty" to increase drag and alter the flight configuration relative to the ground path. Think of a slip-to-landing where you use a forward slip in lieu of flaps to decend at a grater than normal rate. Remember, flaps came later. Besides, when the flaps cease to work it can come in very handy.

Or, when you wish to cross-control to side slip - cross wind landings or rapid decent from higher altitude. Or to keep flames off the wing or smoke out of the cockpit, etc.

Since we're not inside and can play around doing all sorts of manuevers from the safety of the ground its easy to forget how useful it can be. Another thing, if you have access to a flight simulator you can experiment with different aircraft to gain some perspective on how various airframes react to the different controls. This is not to say its exactly like the real thing, but my G4 selection clearly demonstrates an effort on the part of the programmers to provide realistic reactions for various models that highlight the different characteristics each possess.

Try doing a knifeedge with a P51 Mustang or a slip to landing with a Yak54. The rudder on the P51 is very effective along the roll axis but on the Yak54 its fairly well confined to the yaw axis.

Use the rudder if only supplying simultaneous left input along with left aileron just to assist in coordinating a turn (minimize skid). Or, just do some knifedges without a rudder.

If you will consider the wing a two-part surface (ie. left wing...right wing), a spin is when one wing is flying and the other isn't. As you approach a full stall you can kick in hard rudder to one side inducing a stall to one wing (side) while the other continues to fly. The plane "spins".

As a plane slows you may find aileron ineffective but the rudder will still be flying. Its nice to have directional control from something!

Anyway, don't lose respect for the controls you have. You may need them.

Kindest regards,

Clay

For that matter, any maneuver that requires a straight line approach requires good rudder control. You cannot enter, say a good Half Reverse Cuban Eight without entering it straight and level. The level is aileron, the straight is rudder. Then, pulling straight back on the elevator stick to the required 45 degree angle, then straight, at that angle, followed by the inverted flight (again elevator followed by rudder to keep it ( straight being the nose pointing in the right direction) then the pull under to finish up the maneuver, requires some rudder to keep the nose pointed in the right direction.

For pattern folks, they are graded, scored, on how the maneuver looks, if it is straight, and if it has the right components. Minor corrections are allowed because control is what it is all about, and doing the maneuver as close to perfect is an absolute. Even in wind, which is always there, so it takes rudder control to do this and mastering it is a goal.

CGr

Hey...I came in here to say this. Stealing my thunder, rwright? )

when I do a snap roll on top of a loop, I need to use the rudder to help it snap.
Sometimes it'll go off track on it's way down, I just apply rudder to striaghten her out.
I think it's call an avalanch.

To do a humty dum, I apply rudder as needed on her way up after completing
the half roll..it usually starts going off track after that. Then i do a half loop
then a half roll again. To make it look purdier or keep it on track i apply rudder as needed.

I usually have the rudder peg, then slide the airleron slowly to make her go flat when trying
to do a flat spin. Sometimes i have to apply opposite rudder when the groud starts getting close.lol
It depends on the model..some i can just release the sticks and it'll recover

A good manuver to pratice with a trainer for a newbie is the slow roll. You bascailly have to use all the control surfaces
to keep the model tracking decent. If you get better, then extend it to a 4 piont roll.
But mostly it will good like a wicked 6 1/2 piont roll when you first start doing it.
If you can master a slow roll..a kinfe edge, inverted flight is not going to be that be of a deal.

A stall trun as a turn around manuver instead of doing split S or immelman all of the time will help
wake up the left hand again.

As you get more flight time in , you will start noticing that you can apply slight rudder/yaw to keep you model
on track.

I learned to fly on a 3 channel glider. Throttle(electric motor), elevator, and rudder. Since I was teaching myself and had no help I put the rudder on the rudder channel. Didn't want to have to re-learn the control when I got a four channel plane. I have not yet met anyone who learned to fly this way. Have met several who learned on 2 or 3 channel gliders, but in those cases the rudder was always on the aileron channel. I too have saved more than one plane being able to fly with rudder alone.
I only have 2 planes without rudder, an Aerocat(foamie propjet), and a duct-fan A-4 Skyhawk. I find it very irritating to try to give a touch of rudder to line up an approach or make a turn and have no response. Using rudder is just ingrained too deeply into my flying.

Think the sooner you can start using it the better, I just used ailerons for ages with the exception of slow rolls / knife edge but now I'm doing more and more 3D whilst I don't have to think about the sticking for ailerons I have to really concentrate with rudder input which you'll probably eventually want to use for inverted flight and turning in Harriers etc.
I'm sure in a while the rudder will just become second nature to me as well and I'm making myself use it for all turns now but if I'd started using it a year ago I'd probably be that much more advanced now !!!!!