Blade Manufacture

For the 12 Watt machine, the blades were made from wood and hand crafted. They are strong, light and virtually silent and I have been delighted with them. However, they required a large investment in time, taking in excess of 12 hours to manufacture. As I am unsure about the size/number of blades required on the new design, I looked for a faster solution I could use during testing. When the blade size has been finalized, it would then be worth expending the effort to produce some more wooden blades.

I read an article here that gave instructions on how to make blades from plastic waste pipes so I set about trying that to produce something to test with. I found a six-inch diameter waste pipe at a local DIY store and as they were sold in 2 metre lengths, it looked like making each blade 1m long would yield the results I was after giving a total blade diameter of just over 2 metres.

Here is the quartered pipe:

The blades were mounted on a small hub using 6mm bolts

Here are the completed blades. I confess they look a bit flimsy and I think they should be much wider. They seem to work ok though, I managed to test them in a wind and they do rotate. However, I'm unsure if they will generate the torque required. As they took less than an hour to make, I can easily produce a fatter set if these are not suitable.

After mounting on the hub, there are a few more mechanical/welding jobs to finish off on the frame and then after wiring up the stator, we are just about ready for a test flight.