Swamp Rat electric

• Based on Gary's original styling, Swamp Rat by Peter Miller is the free plan with RCM&E's August 2013 issue.

I was asked by Peter Miller if I would like to convert his Swamp Rat from i.c. to electric and this is what I did and have called it RATATAT.

First I made a few small changes to the model – servos were put on the outside for rudder and elevator and the wings had two servos, one for each aileron. The undercarriage was from aluminium with fibreglass spats from my scrap box.

The first part of the conversion concerned the motor. After a good look around I found what I needed – a 650watt outrunner and 4S 4000mAh Li-Po combination spinning an 11 x 5.5 APC-e prop and a 60amp ESC with a UBEC. I found 650 watts to be very practical for this model the all-up weight came out a little lighter than the i.c. Swamp Rat.

The conversion was very easy I had to make a battery tray and a removable bottom unit for both motor and battery with servos going in the wings and fuselage to keep them away from the battery installation. On the electric model the cowl can be made all-in-one as the motor and other parts can be got at from underneath.

The removable panels! There are three altogether, one for the motor one for the ESC and on for the Li-Po.As per plan, cover the bottom of the fuselage from the tail to f4 and leave the rest open. From f4 to f2 is for the Li-Po and from f2 to f1 is the ESC and from f1 to the nose ring is for the motor. F3 you will not need and F2 will have the bottom half cut away this will become clear why when you fit the battery tray.

A battery tray is made from 1/8” light ply and ½” triangular stock. Make the tray so it fits between the inside of the fuselage sides as per drawing and reinforce the top side of the tray with ½” triangular stock (see photos below). You need to put triangular stock around the bottom of the opening to hold the magnets, then make up the bottom hatch and glue in the magnets as required.