Wednesday, December 23, 2015

Observations - Research - Going Fast in DS

One of the biggest thrills for me is when I can make an observation and through further research find the explanation for what I have observed and then use additional information to improve what I am trying to accomplish.  This past model flying season which has extended my flying much longer than normal; has given me a good chance to practice dynamic soaring with a few different radio control gliders from a small hill. The speeds my gliders obtain have not been measured but do appear to be increasing but probably only a tenth of the new current record just set by Spencer Lisenby in California.  Flying at 50 mph it is easier to observe what is going on.  During my flying last weekend I noticed at a certain part of my circle the glider would begin to accelerate and also coming back around.  My thoughts previous to reading an article in the April 2012 RC Soaring Digest by  Philip L. Richardson was that the glider sort of bounced off the separation in the boundary layer. 

Small Amount of Snow Last Weekend 

In actuality the glider accelerates as it passes through the layer; once going up through it and again when coming back through it going down the back side of the hill.   There is also an optimum period and diameter for the circuits the glider is making.  That is something I really didn’t know either but just kept experimenting with varying the size of the circuit.  In the article it also indicates that periods of wind gusts can increase the amount of shear, those have been the times I have avoided going into DS circuit in fear of crashing in the turbulence.

Passing Through Shear Layer

Besides the theory of how the physics works learning to fly your glider without stuffing it into the hill is important also. I do seem to be improving in part because of greater amounts of practice, I have become more comfortable flying the glider. When I first started learning just the thought of diving the glider over the back of the hill scared me.  Slowly it is getting to the point of I just can’t get enough of that initial first dive. 

Bill Kuhl

Additional Resources

RC Soaring Digest April 12  article starts on page 36

1 comment:

  1. I went flew again yesterday in 30 F weather but a better wind direction. Flying with gloves on I completed over 100 DS circuits and called it enough.