Clarky (oz15533)

About this Plan

Clarky. Radio control sport model, for electric power.

Quote (google-translated): "A 3-axis model for Speed 400. Clarky, by Patrick Martin.

After having presented you a small electric plane for beginners (the 'Easylec' in Modele Mag n?631 of April 2004), here is a new model more sporty but designed with the same type of propulsion. The 'Clarky', that's its name, is thus intended for modelers mastering 2-axis piloting and wishing to progress without being afraid with a more scalable electric plane.

Based on my experience with propulsions based on reduced Speed ??400s, the Clarky was designed for the Speed 400 6 volts, reduction 2.33/1, with 9 x 6 propeller. Powered by a 1000 mA/h Ni-MH battery, this provides sufficient traction for a 900 gram aircraft, Piper style, and 600 to 700 grams for a so-called transition model. The flight duration is then between 12 and 16 minutes depending on use. With 830 grams and 24 dm2, the Clarky is halfway between a glider and an aerobatic aircraft. Slow flight is therefore easy and safe, but you just have to push the watt stick if you want to let off steam a little or try your hand at aerobatics. The Clarky then adopts a livelier look and can turn something other than flat eights.

To obtain a lightweight aircraft, all-wood construction is of course the order of the day. The classic rectangular wings with ailerons use a good old profile, not really cut out for aerobatics but which remains a sure value: the Clark-Y (which gave its name to the aircraft). The fuselage is largely made using rods. The empennage is also in structure, all this leading to a reduced weight guaranteeing good flight qualities.

The construction is a little more delicate than that of a beginner's aircraft and should only be considered after two or three other achievements. The fuselage and wing strips are made of hard balsa (the plane is made to be moved). The stabilizer and rudder are made of medium balsa, as well as the formwork. The construction uses mostly white glue: it is less light and less fast than cyano, but it guarantees good mechanical resistance and reliability over time.

Since the wings are rectangular, all the ribs are identical except for the root where the thickness of the intrados and extrados formwork will have been subtracted. After having easily made these ribs, the spars, intrados formwork and trailing edge strip in 6 x 6 balsa (to be profiled before its installation) are pinned on site. Next comes the gluing of the ribs, leading edge strip and upper spar, then the spar reinforcement cores in 15/10 vertical fiber balsa. The salmons take a little while to make because they are made up of many parts, but this saves a lot of weight for a satisfactory aesthetic result. Since we are talking about weight, it is quite advisable to make a few recesses in the ribs (before construction!) and a little everywhere where the rigidity of the plane will not be compromised.

The wings are finished with the extra-back formwork, before assembling them with a 6° dihedral. The wing key is glued after having carefully cut out its location using a hacksaw blade. It should be noted here that the intrados formwork is therefore not done in its entirety: it is necessary to leave a small part unformed at the location of this key and then finish the formwork once it is in place. The assembly of the aileron controls will be done according to the classic torsion bar system.

These wings are finally provided, for their fixing, with a beech dowel at the front and two spacers at the rear for the passage of the screws. The gluing of these spacers is done with fluid cyano which hardens the wood at this location. Finally, a generous sanding puts the leading edge in shape, erases a few residual defects..."

Direct submission to Outerzone.

Quote: "Dear Steve and Mary, Another from France, this time a sports low winger designed for a Speed 400 electric motor, although it would benefit from the installation of a brushless power train. It would make a good first aileron model or a fun sports model for club flying. The French language article from Modéle magazine describing the model is also attached. All the best, Dilwyn."

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