Hi there all

Just a quick scribble to help explain the directional movement of gears;

In figure 1 – that is 2 gears ‘meshing’ and the motor directly drives one prop shaft – and the other prop shaft is driven by the ‘meshing’ gear. These 2 shafts drive in opposite directions; the only disadvantage with this, for model boat purposes, is the distance between the prop shafts, e.g. if the distance between the 2 prop shafts were say 50 mm; each cog would have to be 50 mm diameter. Think about this one.

In figure 2 – you will see 3 cogs driving – the centre cog being the one driven by the motor and how it turns the 2 outer cogs (or the driven cogs) in the same direction.

In figure 3 – you will see a 4 cog set up; with cog number 3 being the ‘idler’. The idler cog changes the direction of rotation on cog 4.

Hope this is of some help.

One last thing; if this is still not clear; get 4 round coins of equal size; place them on a flat surface; all edge to edge (in a straight line). Turn one coin whilst butting another coin against it, and see which way it turns that coin. This may help to understand.

As mentioned before, when we are dealing with belts and pulleys; the scenario changes a little, because we can twist the belts into a figure of 8 which does reverse the rotation of the pulley.

Just out of interest; if we think back – or look back – in some cases :) to the ‘older’ industries and ‘old’ workshops, where there used to be one driving steam engine, in a steam engine house-building; driving what was called a ‘line shaft’. This line shaft would run the full length of the workshop/mill whichever the case and off this line shaft they would take belt drives off on various size pulleys to drive various machines. So, the one line shaft could drive as many as say, 100 workshop machines at once.

Aye

John E

Bluebird