Miles M18 (oz16981)

About this Plan

Miles M18. Radio control scale model. Wingspan 1180 mm, for electric power with geared Speed 400 motor.

Quote (google-translated): "Practical, affordable, good. An affordable beginner's model. The Miles M-18, by Bruno Schmalzgruber.

When the author took a closer look at geared motors, static thrust measurements (published in Modell issue 2/95) revealed either a significant gain in performance or energy savings, depending on the desired outcome.

As a proponent of this type of propulsion system, I didn't want to stop at mere advice; practical testing had to show whether the concept could live up to the theory. The first production geared motors from the company Groß were already on store shelves—fortunately available with a choice of three different gear ratios. The next step was to select a suitable full-scale aircraft to model. A candidate was quickly found, and the size of the future model was determined by the expected thrust output.

The Miles M-18 was tailor-made for this project. It featured a simple airframe structure, large broad wings, ample dihedral, and wide landing gear with large wheels. What more could a modeler ask for? Although the model was originally intended merely as a testbed for various geared drive systems, its exceptionally docile flying characteristics eventually prompted me to draw up a set of plans.

Anyone who can read plans reasonably well - and is willing to put more effort into a model than simply installing an RC system into a 'fast-food' (or ready-made) model - is rewarded with a unique aircraft that isn't seen at every flying field. If the builder has also mastered RC control inputs, reacting instinctively without having to stop and think which way to push the stick, the Miles M-18 proves to be a remarkably durable model despite its lightweight construction (provided, of course, that you actually hit the runway). However, even rollovers in rough terrain usually turn out well, given the low mass involved.

A Speed 400/7.2V motor with a 3:1 reduction gear served as the initial power plant. Naturally, the motor is severely overloaded when running on 12 cells (0.7 Ah), but if one is going to experiment seriously, why not push the Speed ??400 to the limit as well?

To cut a long story short: it hasn't suffered any serious damage so far.

With a bit of sensible handling - though flying at continuous full throttle certainly doesn't qualify as sensible - the motor generates such a surplus of power when paired with a Graupner 25 x 15 cm propeller that even vertical rolls are possible. However, full-throttle operation should be limited to about 15 to 20 seconds. For general aerobatics or even scale-like flying, half-throttle is usually sufficient; this conserves energy and yields average flight times of 7 to 9 minutes..."

Direct submission to Outerzone.

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