Freestyle Aerobatics

Model Airplane News, Jun 2004 by Somenzini, Quique

Rolling loops & circles

Rolling loops and circles are among the most difficult acrobatic maneuvers to perform. And just like other freestyle maneuvers, they have certain control-setup requirements. One is to adjust the control rates for this specific maneuver. Just using dual rates will allow you to do these maneuvers-with lots of practice. But if you want to execute them at world-championship caliber, setting up a separate flight mode will greatly help you. Let's have a look at this spectacular maneuver.

Rolling loops and circles are basically the same maneuver but they're executed on different planes: rolling loops on a vertical plane and rolling circles on a horizontal plane. During both maneuvers, the airplane will have to turn or climb 360 degrees while it's rolling. The roll rate as well as the radius (or diameter) of the circle or loop also needs to remain constant. If you're adventurous, you can do other maneuvers such as rolling Cuban-8s, rolling reverse Cuban-8s and rolling humpty bumps. If you've seen a recent giant-scale aerobatic event, I'm sure that you've noticed that rolling maneuvers are very popular in freestyle aerobatics.

HOW TO DO IT

I learned to do rolling loops in 1980 and first introduced them at the Holland F3A World Championships closing airshow in 1985. The key to this maneuver is to make the airplane turn, or climb, while it's rolling. To accomplish this, you need to use the rudder and elevator to steer the airplane. Let's imagine that you will roll to the right and do a loop entering from an upright position. This is known as an inside rolling loop. To start, don't worry about the number of rolls; you can add or subtract rolls later. First, start rolling to the right; it is better to do the roll slowly, as it makes it easier to time control inputs.

As soon as the airplane starts to roll, apply a few degrees of left rudder to yaw the tail down and move the nose of the airplane up. As the airplane rolls, the amount of rudder input will increase until it reaches the nose-up position. Now, ease off the rudder and start to apply some down-elevator to keep the airplane looping at the same radius. Just like rudder input, the amount of down-elevator applied will increase until the airplane is upright. At this point, a half-roll has been completed.

Continue rolling right while keeping the roll rate constant. From upright to nose-down, the rudder will slowly move from left to right and be neutral when the airplane is halfway in between. When pointed down, the rudder will stay to the right to keep the nose of the airplane yawing into the loop. The right rudder will progressively increase and reach its peak a few degrees before reaching nosedown. By now, ¾ roll will have been completed. At the nose-down position, start to add up-elevator to keep the airplane yawing (tail out and nose in). Between ¾ and a full roll, move the rudder from right to left, ending back in the starting position. As you practice the maneuver, you'll see that timing the rudder and elevator inputs is critical to keep the airplane's nose yawing and the radius of the circle constant.

ROLLING CIRCLES

Rolling circles are done basically the same way, only you're turning instead of climbing. To make the radius of the circle round, you'll need to use less rudder input when at knife-edge and less elevator input when the airplane is inverted. By changing and combining both controls in the same manner as you did with rolling loops, you'll be able to make the airplane roll and circle at the same time. Now that you have an idea of how to execute the maneuver, let's take a look at the radio setup.

SETUP TIPS

For rolling loops and circles, you need to use more rudder throw than what's needed for general flying. Also, when the number of rolls decreases in the maneuver, rudder throw has to increase still more; a single roll per loop or circle demands the most from the rudder. The elevator rate stays the same as during general flying and should work fine. Reducing aileron throw will help make controlling the roll rate easier and constant. The most common mistake pilots make is to use too much aileron; this can produce an inconsistent roll rate during the maneuver.

I like to fly my airplanes with a lot of rudder, as I feel this works better for the mode I fly (mode 1). With both elevator and rudder on my left thumb, I try to have the airplane feel balanced with about the same control authority. Stick movement will then be more or less symmetrical-moving about the same for left/right and up/down. Other pilots use very little rudder for general flying and adjust their airplane so it will fly at knife-edge with the throttle at full bore. The airplane should climb at full throttle in a knife-edge. Either method will work; it's just a different way to feel the airplane. If you are in this last group of pilots, you'll probably find it better to set up a flight mode or to use dual rates on the rudder. Dual rates will work, but a flight mode will allow you to adjust the airplane to perfection!