Speed-400 electric motors have been popular for many years. It was the primary choice for electric power when the first parking lot sized models hit our market about eight years ago. The Cox Corporation, makers of all those wonderful small size, glow-fueled engines and plastic, Ready-To-Fly (RTF) Control Line models has moved into the RC electric-powered Almost-ready-To-Fly (ARF) and RTF market in recent times.

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The subject of this review is their new Cox “EP-380”, speed-400 powered “EP-380” Advanced Trainer. It is an ARF model that comes with a geared “380” size electric motor. This essentially ready-built and covered model and motor presently (June 2006) sells for $114.95. The 400-Speed motor and gear box are included with the “kit”.

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The basic framework is built-up balsa with a lot of plywood added in the critical areas. The entire airplane is covered with an iron-on covering material in red, with white trim. By the way, during shipping much of this covering material became very loose or wrinkled. I would advise you to carefully re-shrink this material with either a modeler’s iron or heat gun. Don’t apply too much heat or you might run the risk of melting the material.

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As received the wing panels are separate and require joining using a plywood dihedral brace (photo 4) and 5 minute epoxy cement. Apply the epoxy inside the wing sockets and onto the brace itself. Slide the other wing half in place and remove any excess epoxy. Tape, or hold, the wing panels tightly together making sure both halves are aligned to prevent warps. Allow the epoxy to dry for at least 10 minutes.

The EP-380 is intended for full, four-channel control using ailerons, elevator, rudder and electric motor throttle via an Electronic Speed Controller (ESC) with a Battery Eliminator Circuit (BEC) that allows the motor battery to power the on-board radio system.

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The ailerons, elevator and rudder come pre-hinged. But, as an ARF and not an RTF, the hinges are not glued in place. The first thing you must do is cement these plastic hinges in place. The instruction booklet recommends that you pin the hinges while applying the CA cement. Do not use accelerator when gluing the hinges in place. I found it easier to first apply the cement to one side of the hinge (like on the actual control surface). After quickly curing, install the control surfaces to the wing, stab and vertical fin. Then again apply some thin CA while holding the control surfaces tightly in place. When installing the two ailerons, you will also have to apply some 5 minute epoxy into the two torque, or aileron, control arm holes in the wings.

(Ed. Note: While Bob’s method will work well for this and other similar electric-powered trainers, larger aircraft or those powered by glow engines require a stronger bond. Read how to do it in “Installing Mylar Hinges” in Sport Aviator’s Flight-Tech Section.)

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Once the hinges are taken care of you can install the wire landing gear with 5-minute epoxy cement. Put the epoxy into the landing gear mounting slots and then insert the gear legs.

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The stab and vertical fin are installed next. I spot cemented both of these surfaces first with thin CA to hold the correct position. Then I applied a liberal amount of 5 minute epoxy.

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There is also a plywood tailskid mount that gets epoxied underneath. The photos will show how the tailskid and bracket are assembled at the same time that the vertical fin/rudder is installed. If you wish, you can make a tail wheel wire bracket from some 1/16 in music wire available at any hobby shop. You will also need a small tail wheel and 1/16 in. wheel collar. This provides a steerable tail wheel that enhances ground handling, especially on paved runways. This is a nice touch but not critical since most takeoffs will probably be via hand launching anyway.