Hi guys...


I have come to ask a question which is puzzeling me, as soon as my precedent hi-boy is 3 channel and has no alirons how do you steer the aircraft in the air, as it it can't roll. Is it diffecult? or is it easy? Thanks again

It shouldn't be a problem, my quess is that plane is a slow flyer. I have flown several planes with the use of only the rudder. It takes a little more time to turn but once the rudder is applied the wing usually will dip slightly causing the plane to turn. Have fun flying mate!

You will note that the rudder only (no ailerons) plane has a lot of dihedral. This is what causes the plane to bank when you apply rudder acting simular to what would happen if you had ailerons.

You will be using roll-due-to-yaw steering with the rudder causing the plane to roll. The important thing is that you plug the rudder servo into the aileron channel. You want your normal roll stick to still perform the roll function, despite the fact that it is moving the rudder servo.

Dihedral, a high wing location and sweep back will cause roll in the direction of the rudder.

Anhedral, a low wing location and forward sweep will cause roll opposite to the rudder.

First you have to understand the difference between a coordinated and uncoordinated turn. The first involves the use of both rudder and ailerons while the second is the use of only the rudder. Here is a brief, but not complete explanation:

http://www.grc.nasa.gov/WWW/K-12/airplane/turns.html

Notice when using the ailerons, the nose of the aircraft has to be lifted up to compensate for loss in vertical lift. The best way to understand what is really going on is to break down the components of lift using vector analysis. In any case, a rudder only turn is simply skidding the aircraft around the turn.

Three-channel models fly just fine but aren't as responsive as those with ailerons. Also dihedral is a stabilizing force that makes turns somewhat more difficult for rudder only models.

Ciao,

Eagle Al

Quote from eagleal "Three-channel models fly just fine but aren't as responsive as those with ailerons. Also dihedral is a stabilizing force that makes turns somewhat more difficult for rudder only models. "
Sorry Al, dihedral may be stabilizing force but it definately does NOT make turns more difficult with rudder only models. Just the opposite, it makes it possible to do turns with a rudder only model. If you do not believe that, try flying a 3 channel with a flat wing and rudder and elevator (no ailerons). You will find it next to impossible to make a decent turn if you can at all.

Three channel flying is every bit as easy four. You simply add in a little elevator to keep the nose up during a turn. What causes the airplane to bank during a rudder only turn is that as you apply rudder, the outside wing begins to skid around the inside wing, therefore generating more lift on the outside. As soon as you enter a turn, give it elevator, and the turn will be as coorinated as with four channel. Jim

Rodney first you might learn how to spell "definitely". Rudder only turns aren't decent turn. You are making the model turn by a series of skids in the air. Remember the rudder controls the yaw axis. Next dihedral is a stabilizing influence primarily used on trainers. The purpose of dihedral is to keep the wings level. If a wing drops in a turn, its lift increases due to a better angle of attack. Here is some reading to help you out of your confusion:

http://www.mindspring.com/~cramskill/dihedral.htm

In regard to rudder only turns, you might try to understand the following:

http://avstop.com/AC/FlightTraingHandbook/Rudder.html

The aircraft will turn using only the rudder, but the nose will drop unless up elevator is used. Essentially using the rudder to turn is a series of skids.

The primary purpose of the rudder is to make a coordinated turn using both it and the ailerons. With an aileron turn, the lift vector is tilted. The lift vector is resolved into its two components: the vertical and horizontal parts. The latter is what turns the aircraft while the former supports the aircraft in the air or overcomes the force of gravity. Notice that the vertical component is decreased compared to when the aircraft was flying straight and level. To increase the vertical component, the nose of the aircraft has to be slightly raised in the turn.

And what role does the rudder play in this? The ailerons create adverse yaw or drag that prevents the nose of the aircraft from perfectly tracking the path of the turn. The rudder counteracts this yaw and keeps the turn smooth or coordinated.

When you're flying a rudder only model with or without dihedral, you must use the rudder and elevators. The rudder to yaw the aircraft, and then the elevators to correct the slipping nose. Otherwise, the plane will spiral out of control.

Ciao,

Eagle Al

A rudder only plane can turn and roll just as well as an aileron plane (depending on design). I have been told otherwise but have quieted many skeptics after flying my Seniorita and Lazy Bee. Seeing is believing.

I had a little Kadet Jr. and it could do rolling circles !!! It would blow people away. But the fact is, they were easy. Hard over, then up down, up down, up down....... Three channels are a great way to get started. In my case, they were a step up from the 2 channel planes I had flown the first couple of years. The Kadet Jr., the Colt, the Eaglet and a bunch of other models made wonderful three channel planes. I'm surprised I don't see more of them . Folks nowadays tend to jump right into a four channel plane, what we used to call full house. But you don't need to. Three channel planes tend to instill confidence and just simplify things. I think it is a path that is overlooked far to often in the rush to be a pilot. I think 4 channel planes tend to overwhelm newbies and make them nervous. A good 3 channel will have them smiling and enjoying themselves much sooner. Many folks will tell you they are unnecessary. Well, I guess that is more true than not. But the idea is to have fun and provide a positive reinforcement as soon as possible. Success early will motivate the trainee to come and fly their brains out every chance they get. And that establishes the proficiency that allows them to progress rapidly and independently. Teach a man to fish........that is what a 3 channel does.

Thanks Guys you have really boosted my confidence here to continue building my precedent hi-boy, i am going to be buying my fuel tank and so on later today so i am ready to build. Thanks!!!