About the Model:

During 2004 Nikko/Meccano launched their first remote Radio Controlled Meccano Set No.8700. which included instructions for three vehicles all using the same dedicated R/C 4 wheel chassis

This set received a lot of negative criticism in the UK due to the unique arrangement of the radio/motor/servo and wheels, envisaged as limiting any development or blending in with traditional Meccano.

However, as I see it, with a little bit of imagination the possibilities are limitless, the R/C chassis lends itself to a plethora of vehicles, from a simple Land Rover , through various military and earth moving equipment to truck type prime movers.

Having decided to model an amphibious army DUKW meant a third axle was required and to make it a true 4WD it had to be powered.

The Nikko/Meccano chassis has two lots of three ½" spaced holes on each side and a similar arrangement at the rear. The chassis was extended to the rear by bolting a 12 ½" angle girder to a small flat girder mounted in the center three holes on each side of the R/C chassis. At the front , 4 ½" angle girders are bolted directly to the forward side holes on each side.of the R/C chassis.

A 2 ½" angle girder connects the 12 ½" girders together and to the rear of the R/C chassis via spacers. Several 7 ½" angle girders are placed across the chassis to support the outer frame and body work.

A simple transmission arrangement was housed in a box consisting of two 2 1/2"x1 ½" flanged plates and two 3 ½" flat girders…the elongated holes of which allow the third axle a degree of movement, controlled by two shock absorbers, thus allowing some weight sharing with the original fixed rear axle over various surfaces.

The additional wheels ( from the Future Master series Set 8600 ) are not fixed to the third axle but are driven via threaded pins fixed in two 60 tooth gears. These gears are in turn driven by 15 tooth pinions fixed on the output shafts of the Paul Dale design miniature spur gear differential.

It was envisaged that this additional axle set up would have to have a similar amount of power and speed to the Nikko motor in the R/C chassis.

Initially it was thought that using the internal 6 volt ni-cad battery to power the third axle would simply involve extending a feed off the Nikko motor via two small holes drilled in the plastic housing of the R/C chassis. Several motors were tried including MO,MR and Emebo types with various gearing but none were satisfactory.

The problem was solved by using a PDU operating off a dedicated 12 volt supply, switched via two miniature relays in series with diodes to control its operating direction. The relays being operated via the above mentioned feed from the Nikko motor.

A bank of " C " cells housed in red plastic battery holders from the MR motor set supply the necessary 12 volts for the PDU which is set on the 3:1 ratio and drives via a chain to the differential.

Smooth interference free operation required the fitting of suppressor capacitors to the PDU.

Pictures of DUKWs were obtained from the net and a hobby magazine enabling a look-a-like model to be built.

Jack Parsisson supplied most of the kahki coloured parts used in the model which performs well and due to its weight of over 4.5Kg it is not as lively as the original jeep…which has to be a good thing.