This post is meant to be for the KidWind team that wants to go the extra mile and learn a bit more about the process and keep the engineering going. So what goes into designing and planning a tilt up tower for a 300 watt Air-X wind turbine?

I hear or read, I forget. I see or watch, I remember. I do it, I understand!

This will be about a guyed "tilt-up" tower. The big question. How strong is strong enough? Design and build your system to stand up to 50 m/s (110 mph) max force wind (worst case) with a safety factor of five and you will be able to sleep through any weather event!

Lets look at the F.A.T. (Frontal Area of the Tower) and swept area of the turbine. At 50 m/s you can count on a force of 250 kg/square meter of area to the wind.

We have a .1m wide by 6m tower = .6 sq/m and a .6m radius rotor on the Air-X = 1.13 sq/m

Total FAT = 1.73 sq/m x 250 kg = 432.5 kg (951.5 lbs) force at 50 m/s (110 mph) wind velocity. Times the safety factor of 5 means designing it to withstand 2162 kg (4757 lbs) of force.

This will help decide the rigging and anchor sizes needed for the tower guys.

Now the raising of the tower is another story...

In our example with a 6m (19.5 ft.) tower weighing 17.27 kg (38 lbs) and 11.36 kg (25 lb) 300 watt turbine for a total weight of 28.63 kg (63 lbs) you could probably just "muscle" the tower up to vertical and tighten up the guys. However this will help prepare you for bigger projects.

Anyway you need to think about the forces at play when you try to lift a hinged tower, to vertical, with a weight at the end of tower by pulling on a rope.

First, understand that lifting a 28.63 kg (63 lb) weight straight up with a rope would require a force of 28.63 kg (63 lbs)

Second, understand that lifting a weight by pulling at an angle is going to require more force than the weight of the object (the pole and turbine) you are lifting.

Third, the angles of the lifting rope to the weight determine the fore you will need to lift the tower and turbine.

The vertical line in the drawing represents the gin pole. The force will be brought down to the ground level (thick black horizontal line) forming another angle that will also impact the winching force needed to raise the tower and turbine from horizontal to vertical.