Every competition pilot who is involved in this aspect of the hobby understands the satisfaction that comes from flying the perfect sequence, no matter what the weather conditions. This is something that takes time to accomplish.
If a person is competitive, he or she will rarely be satisfied, even when the perfect routine is executed, because he or she will wish to replicate it time and time again. To make this possible, the pilot must fully understand his or her flying skills and limits, the aircraft, and what control inputs are needed throughout every part of the flight.
When precise figures must be flown, one quickly realizes the importance of the rudder. Although a newcomer may think that the rudder surface is used only to taxi the aircraft on the runway, that is wrong!
An experienced pilot will use the rudder as much as any other control surface. It can correct the attitude of the aircraft with respect to various yaw inputs. If a pilot is to perform an aerobatic schedule of 10 back-to-back maneuvers, timing with respect to the rudder is essential.
Throughout the years, I have seen many pilots struggle with proper rudder usage. In fact, incorrect rudder can be fatal for an airframe. I have seen Giant Scale aerobatic airplanes crash while performing torque rolls close to the ground, simply because the pilot became disoriented and didn’t know what direction of rudder to use.
Throughout the course of this column, not only will a few basic flight practices and mental strategies be revealed, but I’ll share a few tips for using the rudder in the wind.
Mental Preparation: Proper Rudder Usage
One of the most challenging aspects of various International Miniature Aerobatic Club (IMAC) routines is the fact that aerobatic maneuvers are flown one after another with a brief line segment, unless there is a specified break in the sequence. A pilot must master the aircraft and know exactly how to position the model for the best possible presentation throughout the sequence.
With the exception of cross-box maneuvers, the airplane should travel along the X axis on a track parallel to the flightline. When trying to maintain this distance, a pilot will quickly realize the need for rudder input.
When I first began aerobatic competition, fellow competitors told newcomers that it was important to practice straight-and-level flight. In fact, they said that a pilot should be able to perform one pass parallel to the runway, perform a half-reverse Cuban 8, and perform another pass at the same height and distance as the first, but traveling in the opposite direction.
This method may seem mundane, but it serves as a foundation. Rudder corrections become necessary to keep the aircraft at the same distance from the pilot at all times.
These passes also teach the importance of keeping the wings level. If this is not the case, as soon as the pilot begins the turnaround maneuver, the aircraft will wander off course and multiple rudder and aileron corrections will be needed to get it back on track. In addition to upright level flight, a pilot should become familiar with using the rudder while the airplane is inverted. Depending on the class being flown, much of an IMAC sequence can be inverted.
In IMAC competition, the general downgrade is 1/2 point per 5°, so if the airplane is off by 10° in yaw, as the pilot pulls to establish a 45° up-line (for example), that maneuver will be downgraded by one point. This downgrade basically occurs before the maneuver begins.
Whenever the aircraft is traveling vertical and the top of the airplane is visible, the rudder direction needed to correct the flight path is straightforward. If the airplane drifts to the left, right rudder is needed to correct the flight path. Similarly, if the airplane begins to drift to the right, left rudder is needed.
I have often seen pilots add incorrect rudder input when the aircraft is either vertical with the bottom facing the pilot or while performing a 45° climb while inverted. To overcome this weakness, I recommend that a pilot continue to practice the straight and level passes, but instead of performing a half-reverse Cuban 8 as the turnaround maneuver between passes, he or she should perform a stall turn with a half-roll up and down. Pull to a vertical up-line, and rudder directions will be simple.
After the half-roll up is performed, rudder direction may seem unclear. When looking at the bottom of the airplane while it is in a vertical attitude, rudder should be added to the direction that the airplane is drifting from the perspective of the pilot.
If I am the pilot and I am observing my aircraft drifting toward my right shoulder while it is traveling vertical, with the bottom facing me, I need to add right rudder input to correct the heading of the aircraft. Only enough rudder input to correct the orientation of the airplane should be given.
The Wind’s Impact
By now, it should be clear that the flight path of the aircraft is judged, so the 1/2-point-per-5° rule is still applicable!
If the airplane was considered a dot at the CG, this dot should always move parallel to the runway or perpendicular to the ground. However, when wind is present, it is necessary to lean the airplane’s heading in a manner that is into the wind so that the flight path, or the dot that is located at the CG, is still parallel to the runway and perpendicular to the ground (or perpendicular to the runway if flying a cross-box maneuver).
During a crosswind, constant use of the rudder is needed to keep a correct flight path. This will differ depending on the direction and severity of the wind, as well as the weight and design of the aircraft.
Because of these factors, pilots must practice in all weather conditions to understand their aircraft and how to plan a flight accordingly. No rule exists for how much rudder will be needed on a particular airframe when flying in wind. Instead, a pilot must practice and develop a feel for the aircraft and for how much correction is required. This will develop with time.
Final Thoughts
As a pilot advances his or her flying skills and more aerobatic maneuvers are flown, the importance of the rudder is evident. Flying when wind is present can be one of the most challenging things a pilot can do, but you must remember that the wind conditions on competition day are unpredictable. Practice makes perfect!
