How to trim your model for rock&roll (part 1)

You can make the difference between a good model and a superb acrobatic machine, it will take only few steps to do it, and we can tell you how.

Step 0: first the first, if your model is not assembled yet, it is a good investment to spend time assuring that all the surfaces are properly aligned. Wing alignment and is easy if it comes with a spar, if not we need to align it and glue it with 45 minutes epoxy in order to allow us to make corrections before it dry. Tail alignment is may be the hardest part of the job, but still not difficult if we use slow cure epoxy and we align the tail with the wing properly installed. Commonly the motor incidence are given by the manufacturer, and we only have to respect them.

Step 1: radio set up. To program your radio properly helps a lot and makes the training easier. If you are going to learn 3D, a dual rate configuration it’s a must. We need full range movement for the 3D acrobatics, and a partial rate for the rest of the flight, 60% of the travel is an usual value. Together with this we need to add some –30% to –40% of exponential for a linear feeling in the low rate and –60% to –75% for full range travel. It will help to be more precise around the center without loosing the power at the end of the travel. This values are a starting point, probably rudder, aileron and elevator need different values depending the model and our tasting. No mixers are set yet. After this you need to fly the model and be comfortable with it before doing the next step. May be during this step you need to change mechanically the center or the travel of the surfaces, and this is the best moment to do it. If you are not going to flight 3D, the use of 3D rates is useless and affect adversely the resulting servo torque and precision. Then try always to flight with the radio rates at 100% and the trims centered.

Step 2: Now it’s time to select the best propeller for it. A prop with more diameter will give us more trust, and a one with more pith more speed, the limit will be given by the power plant. For example if the motor can handle a 10×6 prop, we can try with a 9×7 and a 11×5 and see what happen. In my experience rigid props are better for acrobatics than the floppy ones, as well as more efficient. With this set up we will proceed with our path to excel, but keep in mind that a change in the power plant means to trim all the model again.


Acerca de Adrián Muiño Ing. Adrián Muiño Educación Ingeniero en Electrónica (UTN, Argentina) Maestría en Dirección de Empresas (EOI, Madrid) Postgrado en Marketing (UCA, Bs. As.) Project Manager Professional, PMP del PMI (USA) Actividad académica (10+ años) Profesor de Postgrado en la Univ. Católica Argentina Instructor en gestión de proyectos Actividad profesional (10+ años) Program and Project Manager (BGH SA, Neoris, Petrobras, Ericsson) Escritor de artículos (PM y aeromodelismo) Beta tester
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