Rafter Rat (oz10500)

About this Plan

Rafter Rat. Indoor model for radio control with electric power, using GWS geared motor.

Quote: "Just an enlarged Hangar Rat! Flies just like the smaller one, too, but under full control! Simple to build, cheap to power - and easy to fly! What else do you need? Rafter Rat by Ken Sheppard.

Having seen quite a few novices cutting their indoor FF teeth with Harry Barr's Hangar Rat (oz10107) over the last few years, it seemed a natural choice to steal Harry's excellent design, double it up and fit micro radio, for an ab-initio indoor RC model.

The result, shown here, is a model that flies just like the rubber-powered original - and just as slowly. The wing incidence is variable, so you can try out different angles to find a flying speed that suits you - and the size of the hall! Powered by the very popular GWS geared electric powerplant on 7 x 300mAh cells, and steered by two of their Naro micro servos, it must be the cheapest way of getting started in indoor R/C slow fly. Built from simple balsa stripwood and a few balsa sheet ribs, it certainly is one of the easiest!

Key Elements. Flying as slow as it does, it doesn't need nicely rounded leading edges or tapered trailing edges - just use medium grade strip (light, but firm) for the outlines, 1/4 in sq for the wings, 3/16 sq for the tail. The fuselage stick and wing mounting pylon needs to be fairly hard, but not too heavy - choose carefully. Wing 'ribs' are just cut from soft 1/4 in sheet.

The covering used on the prototype was Airspan, applied with Balsaloc and shrunk very gently with an iron set on low heat - just enough the tighten the Airspan. Top surface only for the wing and tailplane, both sides of fin and rudder.

Cocktail sticks are used to locate the fin onto the fuselage stick, passing through the tailplane. These sticks are also used as control horns - pushed into the balsa surfaces at an angle so that the closed loop nylon fishing lines are attached exactly above the hinge gap lines - and a tail skid!

The wing incidence shown on the plan worked well for me, with the CG in the position indicated and the motor thrustlines as given. All these are variable and will effect individual models differently, so there is plenty of opportunity to experiment. For that purpose, the wing is retained by just two pins, one through each of the fore and aft pylon uprights..."

Rafter Rat, Model Flyer, July 2001.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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