I got some time in the field on Friday. Only 4 hours of wind over 4m/s. Where has it all gone?
First few tests were all single rigid rotor Daisy type.
(Should Daisy method just be called mechanical drag mode airborne wind energy?)
- Daisy method should be called mechanical drag mode AWES.
- No - Daisy is Dasiy and always will be
Gave me a chance to test out how the line tension based generation governor fits in… Was really good to see the difference between tension when the rotor is up and stalled at the start vs once the rotor is spinning. Read about 90N before and around 300 - 450N after.
Generation was fairly smooth on the whole, but I’m still ramping up and down based on trends and I think the software ramp downs were a bit over the top culling regen current to near zero… nervousness. SO yeah, there are power peaks but longer ramping up to them.
Like I’ve still only had a chance to glance at the real data. Weekend - Family.
I reconfigured the gen software in the field a few times But I do need to make it much more object-oriented and less linear. It’s butt ugly.
I made sure to have my emergency drive forward button on this time. It comes in handy for startup and just incase you haven’t started up enough … I think there was a lot of resistance down on the wheel because there was a very quick overtwist moment on one start which the forward drive sorted.
Then I got the dual rotor up. First run & It needed a wee bit of line balancing on the top cone lines, and trying lines between wing inner and lift line centre is… hmmm …maybe for a later wing type. but ok
Power was ok but the wind was dropping and gen control was still a bit timid on the brake current.
Got it back up and running again. bit more regen brake ask. but it was obvious the lift kite tension was now way down. The kite rings looked too heavy and as predicted, about 1min after spin up, the lower ring hit the ground. Yes I was wearing a helmet… no bad damage. one of the ring tubes folded just in front of the fuselage. Surprisingly little damage. I could have replaced the tube but wind was too low.
For finishing a test It’s easy when the rig is spinning, to pull the lifting kite around the wind window to stall the rotor. This will be harder in high wind. Another solution or 3 will help there.
The rigidised foam rotors are certainly fast once they’re flowing. You can see line blur at 1/500th second
Interesting also how straight up the lines are. very little twist and high tension = very efficient torque transfer with very little need for hoop material. You can see the non drive tethering clips on the lower ring being spun outward.