How to Stunt Rudder-Only
May 1964 R/C Modeler

May 1964 R/C Modeler Table of Contents These pages from vintage modeling magazines like Flying Aces, Air Trails, American Modeler, American Aircraft Modeler, Young Men, Flying Models, Model Airplane News, R/C Modeler, captured the era. All copyrights acknowledged.

Not all that long ago, my interpretation of radio-controlled (R/C) rudder-only (RO) flying was that the airplane operated from a single channel controlling the rudder. That is the way it began, I suppose, but as aerobatic competition entered the picture, it expanded to include throttle control on the engine. Some models, I believe might have also had elevators and/or aileron control, but during competition flights, only the engine throttle and rudder were allowed to be manipulated. I have flown many R/C airplanes with just two channels - rudder and elevator - but never with rudder and engine throttle. In fact, the only airplane I have ever flown with only rudder control is an experimental rubber-powered job with an electromagnet coil and a permanent magnet on the rudder. Many magazine articles (like this 1964 R/C Modeler example) - and even books - on RO flight have been published, and I have always intended to try building a rudder-only model set up specifically for RO aerobatics. A notable feature of RO configuration is quite a bit of up-thrust in the engine, which is necessary to initiate climbing and looping maneuvers, as well as to keep the nose from falling in a turn (where normally elevator would take care of it). With rubber-power and engine/motor-powered airplane models with flat bottom airfoils, you need substantial down-thrust to prevent the model from zooming under power, so I imaging using any amount of up-thrust really amplifies the climb.

How to Stunt Rudder-Only

 By Bernard Williams 

The first step along the road to becoming a good Rudder-Only flyer is in selecting the right airplane. A large ship with approximately 66" wingspan is recommended as the larger craft with heavier wing loadings handle better in the wind and are easier for both the pilot and the judges to see. I achieve a heavy wing loading in my modified Live-Wire Cruiser by adding ballast in the form of extra batteries. You will find that a heavy ship does not buffet around in the wind and settles quickly on low engine speeds for faster touch-and-go landings, an important factor with only nine minutes flight time. I also prefer a plane with a long tail moment (the distance from wing to stab), and non-lifting type stabilizers such as utilized on my Cruiser, for it is not only easier to trim for wind conditions, but makes smoother turns and more precise loops.

Another important consideration in contest ships for Class I is their ground-handling features. This is where the right kind of landing gear is important. I personally prefer a two-wheel, wide-spaced, torsion-type gear over the more popular trike gear. The wide-spaced undercarriage, in conjunction with the long tail moment, tends to prevent the plane from ground looping. Along with this, I normally use a rubber tired tailwheel which is permanently locked rather than free-wheeling, in order to prevent unwanted turning tendencies. This assists in keeping the plane from ground looping, as mentioned, but also helps the ship brake to a stop for Proto Taxi. I let the air out of my Veco wheels so that they remain soft, preventing unwanted bounces on landing.

I find, that for Class I, the flat-bottom airfoils are better than the semi-symmetrical type, as the latter tends to hold the inverted position of a loop too long. The flat bottom section allows the nose to drop instantly, making for rounder loops.

Two more important features of contest flying are good wind penetration, and of course, good looping. The former can be achieved by trimming your heavy wing-loaded airplane for a fast "dead-stick" glide. Good looping tendencies can be acquired by using a K&B .35 R/C type engine with approximately 7 degrees upthrust - repeat, upthrust, not downthrust!

Now that your Class I ship has been built and properly trimmed, you are ready for the flight pattern. The first Rudder Only maneuver is the Proto Taxi. Starting from a "braked" position, I slowly open the throttle until my plane is moving slowly along the ground, bringing it to a stop at approximately fifty feet by a combination of retarding the throttle and the braked tail wheel, as previously mentioned. To effect the 180° turn, open your throttle and hold full right rudder until the plane begins to turn. Immediately decrease the throttle to full idle to stop the turn, bringing you into position for takeoff. Slowly advance the throttle until the plane clears the ground, then decrease again to maintain long straight climb. Bring your ship into position for the straight and level flight maneuver. When it reaches a position approximately five hundred feet upwind, you are ready for your Procedure Turn. This is achieved by a smooth even 90° turn to the left, followed immediately by an equally smooth 270° turn to the right. Concentrate on reaching the same point as when you started the procedure turn. Now, on your straight flight back, concentrate on crossing exactly over the top of your transmitter. This brings you into position for the Figure Eight. The most important part of this maneuver is in keeping both halves of the Eight equal in size, while crossing directly over the top of your transmitter, as shown in your AMA manual.

The end of a perfect flight - Bernie Williams brings the Cruiser in for a dead stick landing.

Now for the Touch-And-Go landing. Whether or not you attempt this step should be decided in advance and predicated on prevailing wind conditions. At best, it is risky, for failing the Touch-and-Go cancels your flight entirely, and you must decide whether the few extra points are worth the added risk. If you decide to attempt it anyway, put your plane on the correct heading and decrease the throttle, judging your descent so that the plane will land as near the center of the circle as possible. When the wheels are about to touch down, decrease engine to full idle, allowing the ship to touch and roll. After achieving this, increase your throttle slowly to attain a smooth takeoff again.

You are now ready for your stunt maneuvers. It is important to maintain an easy viewing position to aid the judges in their scoring. The first maneuver, the Wing Over, is achieved by decreasing throttle to full idle, As soon as the nose begins to drop, increase the throttle to full bore until the plane is climbing steeply. When the ship reaches the top of the climb, or stall point, hit full right rudder, turning 180°, followed immediately by decreasing the throttle to idle, allowing the plane to recover on its own.

The next five maneuvers are: (l) Three Horizontal Rolls (2) Immelmann Turn (3) Three Inside Loops ( 4) Cuban Eight (5) Rolling Eight, All five are done on high speed engine. To start these maneuvers, hold full rudder until the plane spins down, building up the proper speed, then letting the rudder neutralize. You will find that with the proper amount of upthrust in your engine, your ship will do all of these looping type maneuvers with complete ease.

A special note is in order for the three horizontal rolls. If the day is quite windy, I always do my rolls upwind. The reason for this is to save time, as it takes too long to work your plane the necessary upwind distance for doing all three rolls, and you will find that by doing your three rolls into the wind, you will be in a good position for the next maneuver.

After the Rolling Eight, the next maneuver is the Tail Slide. This is accomplished by heading the plane into the wind at medium throttle. Make one right turn to dive and let, the plane recover on a down wind heading. If you have the right engine speed, the plane will climb steeply, as in the wingover. When it reaches the top of the climb, reduce the throttle to low - if you had enough climb, and you steered your plane straight, it should slide. This is not a "luck" maneuver as most fliers will try to tell you. Once you learn the proper engine speed and technique, you will find that you can perform the Tail Slide quite consistently.

The next maneuver is the Traffic Pattern Approach. This one is passed off too lightly by most flyers, and consequently, they do it poorly, getting fewer points. To rack up the maximum points for this maneuver, it is very important to know your glide angle on low speed engine. After you have determined this, get your plane to the proper altitude so that when you are on the landing approach, the craft will land in the 100 foot circle. Make sure that you maintain your starting altitude through all your turns, keeping these turns as smooth as possible. After the turn to the approach, keep the descent smooth and free from corrections in your attempt to hit the circle. If you see you are going to miss it, let it go, for it is far more important to make a perfect landing and not hit the spot, as so many fliers fail to do in making that last minute turn. Don't forget - if you hit the prop, you are finished as far as the taxi return is concerned, as with today's rules the taxi return is worth just as many points as three loops or any other maneuver. If you have a plane with a long tail moment like the Cruiser, and with the tail wheel locked as previously mentioned, the taxi, or Proto Return should he quite easy and a good "point-maker." To taxi your plane, try to keep the ground speed as low as you can to aid you in keeping the plane under full control. I always speed the engine upwind just a little if I need to turn the plane, but as soon as you have your heading to the spot, slow the motor down once again.

This concludes the maneuvers. You probably noticed that I omitted the three spins. My reason for this is lack of time in the maneuvers, combined with the fact that my plane with its long tail moment and trimmed to fly a smooth pattern, will not spin anyway! In closing, let me remind you that articles, diagrams, and words of advice are only the beginning, and that conscientious practice is, after all, the flyers greatest asset.