Monday, August 10, 2015

Memorable RC Thermal Flights

This weekend I continued testing of the Spektrum telemetry and vario installed in my Gentle Lady 2-meter sailplane. My previous blog post about telemetry had a large number of views.  Last Saturday I flew in not so great conditions until it was time to leave, and then the weather was improving. There was only one flight where the glider was climbing slowly in a thermal but I lost the lift before getting very high. I did get the vario unit changed to output in feet instead of meters however.

Gentle Lady in Flight

Really Low Wind

Sunday there was a forecast of sun and very low wind of only 2 mph in the afternoon. This time I used my longer hi-start with heavier tubing. On the first launches I did not pull back near enough to get much altitude at all but I did not want to break the wing. With an older larger glider I had, that is exactly what happened, pulled back just a little farther to get more altitude and snapped the wing. The heavy tubing on this hi-start also seemed to be hard for a 2-meter glider to lift launching into almost no wind. Many of the launches were 100 feet or less.

Heavy Tubing on Hi-Start

Result of Too Much Tension on Hi-start

After at least a dozen launches I managed to launch to 120 feet and encountered lift right away. The vario was constantly beeping. I kept the glider circling as smooth as possible and it kept gradually working upwards. As the altitude passed 200 feet or so the rate of climb improved somewhat also. I was starting to draw attention to a family that was bike riding in the area and turkey vultures flew in closer to join my glider briefly. The last altitude that I remember hearing was a little over 390 feet, after that the altitude was slowly decreasing. I started flying in a different area of the field looking for another thermal.

At about 60 feet of altitude the vario started beeping again so I started the glider in a circle. Circling rather tight seemed to work better now. The highest it reached from this thermal was about 260 feet but it was such a thrill to climb from a fairly low altitude. Soon after landing the gaps between clouds closed in and the sun went under.  I had one the nicest thermal flights I had in a while so decided I had enough flying for the afternoon.  Whether having the vario helped on this flight I do not know, it did help to be able to tell the story without having to use complete guesses to the altitude of the glider at different points in the flight.

Sun Goes Under a Cloud

Bill Kuhl

Spektrum Telemetry and Vario Module First Experiments

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