Half track Transporter


This project was first published on 1st April 1999

Introduction

This vehicle was devised to help with the transport of equipment across muddy sites. It should not be used for carrying passengers unless proper seats/seat belts are fitted.



Equipment


- 1 bicycle fitted with stunt pegs
- 4 rubber bands cut from an old car inner tube
- 2 old cycle inner tubes
- 1 large cycle tyre
- 52 lashing lengths
- 4 ropes 4 metres long (for tracks)
- 50 small spars x 0.6m long (for tracks)
- 18 spars x 1.4 metres long
- 6 spars x 1.7metres long
- 4 spars x 2.0 metres long
- 4 spars x 2.8 metres long
- 4 cable drums 0.6 metres diameter

Method

Construct the two chassis side members using 4 x 1.4 and 2 x 2.8 metre spars for each (a).

Join the side members using 4 x 1.7 metre spars at points 1 to 4 (a).

Prepare the track wheels:

cut 12 equi-spaced notches around the perimeter of each cable drum - the size of the notches should match the small 0.6 metre spars but only be 3/4 of the depth of them (b).

the tracks are made in a similar way to a rope ladder using a marline hitch ( c).

the wheels are fixed to the axle by drilling through the centre of the cable drum and the axle and forcing a tightly fitting peg through.

The drive to the tracked wheels is achieved by removing the usual rear tyre and inner tube from the cycle, turning the large tyre inside out so that the tread is on the inside and fitting this to the rear wheel of the cycle. The front axle of the vehicle is then passed between the cycle wheel and the tyre (d).

To locate the ideal position for the front axle, stand the cycle between the front ends of the chassis so that a spar lashed at point (a)5 is in contact with the cycle down tube (e).

With the front axle positioned, thread a rubber band made from a car inner tube on the axle either side of the cycle. Lash 2 vertical 1.4 metre spars to each chassis side, one either side of the axle to allow it to move vertically but not horizontally. (f)

Thread the suspension beam through the rubber bands and lash it across the chassis under the axle. The rubber bands will restrict the vertical movement of the axle.

Repeat the last two steps for the second axle.

The two cycle inner tubes tension between the front suspension beam and the rear stunt pegs on the cycle.

Add two spars as cross bracing on the top of the chassis and two further cross braces vertically between the chassis side members.

Note

due to the uneven condition of many sites, it is necessary to have a reasonable amount of axle articulation.