Step 2

Cut (with a pair of pliers or a saw) along the lines to form 4 identical curved strips.

Step 4

For each strip: drill the two holes with a 3mm drill bit and cut along the line with a tin snips, working from end to end.

Sand to refine the shape.

Step 5

Place a blade with the curved side up on one of the branches of the cross and pierce it using the two holes as guides.

Pass two M3 x 1cm screws through the back and fix on the other side with washers.

Do the same for the other 4 blades.

Mark and pierce the centre of the cross and pass an M3 x 1.4cm screw through the other way and fix firmly on the other side with a nut.

Step 6

Assemble the motor reducer kit.

Cut the metal rod to 1.5 cm and insert the rod through one of the large gears.

Insert the small gear onto the motor shaft.

Push the motor through the hole in the motor reducer housing.

Place a large gear so that it connects with the motor shaft and then place the gear with the metal rod on top of it.

The rod should just protrude from the other side of the housing.

Spray some grease on it and then close the housing with the other part by tightening it well.

Step 8

Drill a hole in the plastic connection tube with an 8mm drill bit just before the centre.

Step 10

Pass two M3 screws 3cm through the two holes of the reducer block and screw nuts on the other side until they touch the reducer block without tightening too much.

Step 11

Use a cutter to clear the connector and its two screws from its plastic sheath.

Step 12

Cut one of the two screws in half to reduce its length (this prevents the screw from hitting the long screw that goes through the motor reducer, which would prevent the shaft from turning).

Pass a cable connector over the motor reducer shaft and screw the connector in place, making sure that there is no gap between the connector and the surface of the motor reducer.

Step 13

Drill a hole with a M5 drill bit at 5cm from one end of the smaller 35cm tube.

At the other end, cut two slits of about 4cm exactly in the same alignment as the hole with a pair of pliers.

Step 14

On the M5 screw 40mm long, place 1 ball bearing, 1 washer and 1 nut.Tighten the nut making sure the screw remains in the centre of the ball bearing.

Step 16

Wind turbines are today mostly three-blade models.Theoretically, a single-blade wind turbine would be the most efficient, but would induce an imbalance that would be very difficult to control.In principle, two-blade wind turbines would also be more efficient than three-blade ones, but in practice they can experience annoying oscillations that reduce efficiency and increase wear and tear.On the other hand, wind turbines with more than three blades create more resistance to the wind, are necessarily heavier and therefore less efficient.For all these reasons, three-blade wind turbines are currently considered the best possible compromise.To illustrate this reality, here is an alternative way to make a three-blade propeller with these additional materials :

• 1 piece of forex 10 x 10 cm (same type as for the tail) 
• 2 small washers