File: 08glezellis.ht1.doc
[Headline: Mastering IMAC sequences with rolling elements]
To the seasoned aerobatic pilot, there is a major difference between being able to perform a maneuver and being able to perfect it. Many will agree that some of the most difficult figures to execute are those that have integrated rolling elements.
Because many maneuvers found in current aerobatic sequences contain these components, aerobatic mastery is a must to ensure that a pilot receives the highest possible marks. For those who are unfamiliar with these types of figures, they include the rolling circle and loops with various rolling segments.
I will explore maneuver number nine of the 2014 Advanced International Miniature Aerobatic Club (IMAC) sequence. This figure is the ideal topic because it combines an outside and inside loop into one with an integrated rolling combination at the top of the maneuver.
In this column, multiple flight and judging techniques will be discussed in addition to a few aircraft setup tips to guarantee success in any loop that contains an integrated rolling element. It is not only crucial for a pilot to have a firm understanding of the judging criteria against which he or she is being scored, but also to understand and utilize proper aircraft setup techniques so he or she can fly the perfect sequence in all weather conditions with any aircraft.
Without further delay, let’s begin!
Flight and Judging Basics
Throughout a sequence, a pilot is graded on proper airspace control and should place the maneuvers in such a way that they can be observed by the judges. With respect to maneuver nine, flying the figure directly in front of the judge ensures that it can be optimally evaluated. Beginning from inverted, the pilot performs a half outside loop with an integrated half roll followed by an opposite direction full roll at the apex, then a half inside loop to upright level flight.
In addition to the looping sections being wind corrected and appearing perfectly round, the combination roll element must be centered at the apex of the loop and flown within the arc of the loop. This simply means that there must be equal amounts of the roll element before and after the apex, regardless of where the pause between the half and full roll occur. The pilot can perform the first roll in the direction of his or her choice, but the second roll must be in the opposite direction.
For a maneuver such as this, the roll rate will determine the amount of rudder, elevator, and throttle input needed to keep the roll integrated over the top of the figure. Having a slow roll rate will require more rudder, elevator, and throttle inputs to keep the rolling element moving along the arc of the loop.
Throttle will also play a major role in how the aircraft will keep the arc over the top of the loop. By decreasing throttle as the aircraft is at the top of the maneuver, the airplane will naturally fall along the arc of the circle.
At all times, the pilot must focus on the fact that this figure must be perfectly round in shape and the first 90° radius performed at the beginning of the maneuver will dictate the size of the figure. No flat spots and shape irregularities should exist, and a large penalty will be assessed if the rolling element results in a flat spot on the loop.
Integrated rolling elements must be centered at the apex of the loop and if the roll is not centered, it will be downgraded approximately one-half point per 5° that it is not centered. The roll must be flown over the arc of the loop and if a line segment exists, a two-point deduction will be given. Points can easily be lost because of the many elements that exist throughout a figure.
Looping figures that contain combination roll elements (more than one type of roll combined) require that the entirety of the combined rolls be centered at the apex of the loop regardless of where the break between the roll types occurs. If the pilot begins the roll element at the 10 o’clock position, if perfectly centered it will be complete at the 2 o’clock position.
Flying an aircraft when there is a fair amount of wind can become challenging. If a model’s flight path is being judged, and there is a 10 mph crosswind, the airplane should be oriented in such a way that it is leaning into the wind so the flight path of the model will be parallel to the runway when viewed from the top. Wind correction must apply toward the roundness of the loop so that a constant radius exists within the aircraft’s flight path.
Aircraft Talk 101
Now that you are familiar with this aerobatic figure and a few of the critical judging elements that exist, it is important to evaluate the setup and programming of a specific airframe. Taking time to customize an aircraft to the pilot’s needs ensures that he or she will be able to consistently perform this maneuver and others.
High-quality hardware and servo selection are mandatory. Using titanium pro-links, aluminum servo arms, heavy-duty ball links, and powerful servos are critical components for the ultimate airframe, but it is important to fully understand how to properly program the radio system to cater to your needs. If a fair amount of play exists and the servo does not have accurate holding power, the pilot will not have a consistent feel of the aircraft at different flight speeds, which could result in a differing roll rate.
Most current aerobatic airframes feature large control surfaces because they are built to perform extreme maneuvers with ease. Having large control surface deflection amounts may work well for maneuvers such as the tail slide to ensure that the aircraft falls a certain direction, but for every other maneuver found in IMAC schedules, this is never needed. A pilot should always take full advantage of dual and/or triple rates that are common in all high-end radio systems.
Because this maneuver only contains rolling elements, you should always use your low-rate control setting. I prefer to have my low-rate settings tuned in such a way that I will not be able to perform a positive snap roll while on this rate. Only rolling and looping maneuvers will be flown on this rate, which is the rate that is needed for the looping figure of the month.
On this rate, it is common for an aerobatic aircraft to have 12° of aileron, 15° of elevator, and 30° of rudder deflection with the proper amount of exponential to soften the aircraft’s feel on that given control surface as the control stick nears the center position. Adjust the exponential amount so the aircraft has a smooth and constant feel throughout the figure and is not erratic. If you are unsure of how to use exponential, consult the instruction manual provided with the radio system or seek the advice of an experienced modeler.
Final Thoughts
It is necessary to have not only a firm understanding of the various judging elements and flying techniques needed to perform a maneuver with utmost perfection, but it is equally important to take the time to tune your aircraft. A pilot must know how to consistently perform well with any aircraft.
Until next time, fly hard![dingbat]
SOURCES:
IMAC
www.mini-iac.com