Challenge 2015 - "A no. 1 Clockwork Tractor Pull"
During this competition, each machine will compete individually to pull a weighted trailer. The trailer has wheels at the back but smooth skids at the front. On the trailer is a cradle which holds a weight. The forward motion of the trailer causes the cradle to slowly move forwards along the trailer so that the weight transfers from the rear wheels of the trailer to the front skids. As you will imagine, this means that (regardless of the weight being carried) the trailer gets harder to pull as it is pulled forwards. Philip Drew has kindly constructed this trailer, which all competitors will use in turn. Please see photographs.
1. A straight course will be marked on a piece of vinyl flooring on the hall floor, with a starting line and a finishing line, marked by tape and four feet apart. In the first round, each machine must demonstrate that when not pulling the sledge, it can drive at least four feet (ie to the finishing line). Any machine which cannot do this will be knocked out of the competition at this early stage (so don't get caught out by making a machine that is geared down too far - this contest requires a mix of pure power and endurance but you will not be required to go further than four feet).
2. In the second round, each surviving machine (hopefully all of them!) will perform one at a time, now pulling the sledge (with the sledge carrying a small weight) as far as possible before the machine stalls. Each machine will be stopped at the finishing line (assuming it gets that far) to avoid damaging the trailer mechanism which is designed for a maximum run of around five feet. The machine pulling the sledge the shortest distance will be knocked out of the competition - but if all machines reach the finishing line then they will all survive to the next round.
3. In successive rounds the surviving machines will again pull the sledge with its sliding weight but carrying a slightly greater weight in each round . Again, the machine travelling the shortest distance in each round will be knocked out of the competition if it also fails to reach the finishing line.
4. This challenge has been tested and will work and the idea is that in the final round, two 'super machines' will be left and may only pull the (by now heavily laden) sledge a few inches each. The Machine which travels the furthest will be declared the winner of the 2015 Scrapheap Challenge!
Technical design rules are as follows:-
1. Each round will be performed on the vinyl flooring on the wooden floor of the hall.
2, Each machine will be powered only by a single Meccano Number 1 clockwork motor.
3. There is no weight limit to your machine.
4. Each machine will use only standard Meccano parts (from any era)..
5. Each machine will only contact the ground via Meccano rubber or plastic tyres (of any type) and these tyres will turn in order to propel the machine forwards.
6. Machines cannot be touched once initially set in motion (so no rewinding of the motor, no manual gear changes etc).
7.Each machine will have a simple tow hook on the back - something like a bracket or trunnion with a vertical bolt over which the sledge can be hooked. This tow hook must be 1" from the floor.