Friday, October 23, 2015

Flapping Freebird Almost Flies Away

Yesterday was one of those perfect fall days that I just had to take advantage of for some outdoor model aviation fun with a wind forecast of 2 mph and plenty of sunshine. I also wanted to get some video and images for some projects.  In the demonstrations I have done I bring along a rubber powered ornithopter; a model that flies by flapping the wings. This is to demonstrate that man first tried to fly by trying to emulate birds. The model I use is the Freebird which can be built from plans found on the Internet.

Freebird Orinithopter

Normally I fly the Freebird indoors but the wind was so light I thought I would try to get video of it flying outdoors. To get a good number of winds in the rubber motor you should use a rubber winder but I just turned the front of the cranking mechanism. The first couple of flights were really short so I cranked in a couple of extra turns in a rubber motor that is really short. I launch again and it is flying around my head, I struggled to get the camera focused on it. 

As I continue to watch it through the video camera view finder, I think why is it still flying? The Freebird is getting smaller too so I keep trying to zoom in on it. Finally I realize it is in a thermal air current and it is getting higher and farther away. At this point which just shy of one minute I put down the camera and start running towards it. By now it was beyond a small hill with small trees, from on top of the hill I was able to spot it in tall grass.

I was so happy that I had video of this even with small sections of it not in focus. For something with such a poor glide ratio I would not thought it could fly so well in thermal lift. It did and I had the proof. After this I flew my Allegro Lite RC sailplane and encountered thermal lift that was fair but not real strong.  The lift appeared to diminish as the afternoon slipped away so I flew several rubber powered free flight models.

Bill Kuhl

Related Links

Freebird Plans

Freebird Ornithopter Blog Post

Pioneers of Aviation Blog Post

Leonardo Da Vinci Ornithopter Blog Post

Allegro Lite Blog Post

Video of Freebird in Thermal Lift


  1. Cool... Next thing on a good thermal day is to fly your hat... I lost one once, to a BIG thermal!

  2. Hi Jim, when the flight boxes start going up, then I will be worried.