BACK TO GRAVITY MOTOR

 

The AIRBRAKE

The AIRBRAKE frame is made by gluing two half lolly sticks to a drilled wooden block that's the same as the pulley bearing block.

Punch or drill 5mm holes in the lolly stick pieces as shown. A punch will be less likely to split the wood, especially if you punch away from the very end of the stick.

Put the horizontal shaft [same dimensions as drive shaft] through the holes before you glue them to the block, DO NOT glue the shaft to the lolly sticks - it must be able to turn.

Assembling

the parts

 

Cut two identical shapes from stiff card, The size and shape is up to you. Remember that their job is to 'catch the air' so don't make them too small. A 6 to 8cm square will work well.

Fit one to each end of the horizontal shaft. The tape shown on the diagram was put there to hold them while the PVA glue dried!
 As the axle spins the cards push against the air. When the card shapes are vertical the motor will run slowly - changing the angle of the discs will alter the speed the motor spins at. Turn the cards flat ie so that they are horizontal surfaces, and the motor will run fast.

By altering the angle you will be able to regulate the speed.