someAWE

Christof Beaupoil Administrator

Update on the OTS design

Dear all,

Some have asked for an update on progress on the OTS design. Here you go:

After successfully flying this little proof of concept:

https://www.youtube.com/watch?v=CWeu8aI2ofw

I started to build and test a 250W version of the base station:

A 24inch diameter version of the "Open Tensegrity Shaft" (OTS):

(Design files for the assembly stand can be found here)

And a test bench to see if it holds the torque and RPMs:

https://youtu.be/5wu3bggTH5U

Now I am in the process of building a “TipTurbine”:

 

 

Since the tips of a turbine make most of the power - and with an OTS you do not need to transmit the force to the center of the hub - the inner part of the blades is mostely obsolete. This way the TipTurbine leverages the benefits of cross wind travelling wings without me having to be smart enough to build a flying robot and without having to pull the ground tether cross wind.

The lifter kite provides passive control by “telling” the turbine where is “up” and by fixing the center point of the circular “flightpath”. You can find the design files of the TipTurbine here.

I went with four blades as a compromise between a high enough Tip Speed Ratio, a high enough RPM to not need gearing for the generator and low enough RPM to limit air friction losses of the OTS. 

The design allows to use different rotor blades and to adjust their pitch angle. The first blades that I will test are currently being built by the great guys of Kitewinder. As soon as they arrive I am ready for the next Flugtag!

Once Rod starts small batch production of his DAISY I will make sure to snatch one up and hook it up too the OTS.

Reinhart, any progress on the single skin rotor?

That's all for now. Enjoy!

/cb