As a pilot begins an RC Aerobatics competition career, he or she will start in the Basic category and advance to the Unlimited class. This requires dedication to perfect the sequences being flown and to learn the techniques required to tune competition airframes. Although all basic core maneuvers are the same between categories, the elements found within them can differ—which brings me to this month’s topic.
The first maneuver of the 2015 International Miniature Aerobatic Club (IMAC) Advanced Known program is identified as a Horizontal-S. Not only does this figure contain numerous individual aerobatic elements—such as rolls in different directions and a positive snap roll combination—it also stresses the notion that a pilot should always execute each aerobatic maneuver while following the Aresti figures. All maneuvers, unless noted, are continuous after the pilot begins a sequence.
The size of one figure will impact another. In the case of the Horizontal-S, immediately after this maneuver is flown the modeler must execute a Split-S. If enough altitude is not gained during the first maneuver, there may be downgrades on the Split-S. The airplane could run out of altitude, changing the radius size!
In this month’s column, I will provide an overview of the Horizontal-S from the 2015 Advance Known schedule, then transition into various flight, basic setup, and judging techniques to help fliers improve their scores on competition day. Without further hesitation, let’s begin!
The Horizontal-S combines two Half Cuban maneuvers so they share a 45° line with different entry and exit altitudes. A pilot begins flying from upright level flight and will pass the aerobatic center. When ready, he or she will execute 11/2 positive snap rolls to inverted flight and will then push 5/8 of an outside loop to establish a 45°downline.
The longer a pilot waits to perform the snap-rolling segment, the larger the overall maneuver will need to be. This maneuver should be an appropriate size for a given aircraft so the model will fly at a constant flight speed for the best presentation.
After the 45° downline is drawn, a brief line segment should be visible. The person flying the aircraft will then perform a half roll followed by 11/2 rolls in the opposite direction. There should be a brief hesitation between the rolling elements. Also, the rolling segment should be centered on the downline.
When complete, another line segment equal to the first must be shown. The aeromodeler will begin to pull 5/8 of an inside loop to exit at a high altitude. Both of the two 5/8 loops must contain the same radii and the rolling combination must be perfectly centered on the 45° downline.
Control Surface Deflection
This figure contains many individual maneuvers. The first step is to show a locked heading with no altitude deviation. A few moments after the aircraft passes the pilot, the snap-rolling segment will be flown. The model must be stalled while performing the snap roll, which requires the modeler to “load” the wing by adding elevator input.
As the wing’s angle of attack changes, the aircraft’s operator must apply aileron and rudder deflection in the same direction for the snap rotation. After the desired number of rotations has been completed, the flier will release stick inputs because the wings are level. The modeler then begins the first 5/8 looping segment with no visible line between the snap roll and the loop.
Flying an airplane that is overly sensitive makes it difficult to perform a maneuver with consistency. The judges will notice any small corrections made by the pilot and downgrade his or her score.
When it comes to control deflection amounts, it is best to have only enough control throw to make the aircraft accomplish a given task. Although it is always best to start with the recommended control surface deflection and exponential settings, the modeler should adjust the settings to cater to the needs of both himself or herself and the sequence.
Because this maneuver contains different aerobatic elements, use either a flight mode, dual rates, or the mixes I have discussed in the past to allow flying on only one rate, but accomplish what is similar to an “automatic dual rate.” This will simplify a pilot’s workload.
During the 11/2 positive snap roll, a pilot should use only enough control deflection to execute the perfect snap roll. If the aircraft is difficult to keep up with, decrease aileron for overly sensitive ailerons, rudder if the aircraft becomes too deep in yaw, etc. The flight mode or dual rate switch should be flipped (if applicable) before proceeding with the rest of the figure.
Some pilots forget to change rates after a snap roll and only find out when they are in another segment of the figure. Battling an overly sensitive model can be difficult when the competition nerves kick in!
Wind Correction Basics
Flying when wind is present can be challenging for pilots of all experience levels. The figure’s pace will change, depending on wind speed. Imagine that this figure is being performed from left to right with a 15 mph crosswind blowing away from the flier. The model’s flight path will be judged, so the aircraft must be yawed in a manner that allows it to remain parallel to the runway (in the flight path).
Depending on the aircraft’s attitude, this will require rudder use in both directions so the model’s nose is always pointed slightly toward the modeler. For any drifting caused by wind, a judge will penalize the pilot approximately 0.5 points per 5° of deviation. During a 5/8 partial loop, the flight path must be round and remain parallel to the runway.
For 45° lines, judges will make an allowance for the aircraft’s position relative to where they are sitting.
You have now learned some of the basics when it comes to the control inputs, judging elements, and setup fundamentals with respect to the Horizontal-S.
Attending local competitions is the best way to gain experience because your problems, questions, and experiences can be discussed with pilots who have similar interests. Always remember to enjoy your model and everything this fine sport has to offer!
Until next time, fly hard!