When you have an hour, watch this video. An amazing discussion of a corner of aerodynamics most of us have never heard of. Five Hundred mph and twenty Gs on an RC glider......

https://www.youtube.com/watch?v=nv7-YM4wno8&authuser=0

Definitely going to watch that. When I stopped flying RC gliders to learn to fly about 12 years ago they were at 300 mph and thought it was about the limit. Amazing the progression.

daedaluscan wrote:Definitely going to watch that. When I stopped flying RC gliders to learn to fly about 12 years ago they were at 300 mph and thought it was about the limit. Amazing the progression.

At the end he was asked what he thinks the limits are, and he suggested that human response time may be limiting at about 500 mph.....freaking amazing.

Although the focus for these RC gliders is speed, this is the same principle that the albatross uses to cross oceans without flapping wings or landing. They dynamically soar around the waves. So, it doesn't have to focus on the high speed potential of the process, it can also be used at slower speeds to recover enough of the wind energy to cover long distances. I doubt the process would be viable for manned gliders because of the steep learning curve and the serious consequences that could accompany mistakes. Still fascinating stuff. On a similar note, the glider builders at Windward performance were working on an electric motor glider called the Goshawk. One of the concepts they were pursuing was using prop windmilling to generate electricity to charge the battery when diving in lift. The hope was that you could take off under your own power, fly around for a couple of hours and come back to your home field with a fully charged battery. Updates stopped coming in on the Goshawk, so I don't know what the current status is, but here's the presentation they made at the sustainable aviation symposium back in 2018. The discussion of regenerative battery charging starts at 22 minutes and 25 seconds into the 45 min video.