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Thread: Micro-lift Wave Day Sunday, March 9

  1. #1
    Join Date
    Sep 2013
    Fremont, CA

    Micro-lift Wave Day Sunday, March 9

    I went to Williams yesterday fully expecting a not so great wave day, and that's exactly what I got! But the ETBF (Elapsed Time Between Flights) meter had just passed the three week mark and it was time to get my earthbound butt back in the air!

    I ended up making two flights. The first takeoff was at 14:00 and the second was at 17:00. It was purely happenstance that both takeoffs coincided with the times of the RASP Blipmap runs (Remember that while we are on DST that 13:00 PST=14:00 DST and 16:00 PST=17:00 DST). Here are the corresponding 850mb Vertical Velocity charts.

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    Both times I asked Mark Miller to tow me out to the vicinity of Walker Ridge and Bear Valley. On the first flight I ended up steering Mark into some rain (virga actually, but we were above the evaporation level). Mark later complained that I got him all wet. Sorry, Mark! I found nothing but 4-5 knots of sink after release and until I was out of Bear Valley.

    The second flight was a little better, as predicted by the orange and red areas on the 16:00 PST Blipmap. But the best I got was a reduced sink rate. But that was OK by me as the sky was beautiful and I enjoyed loitering over Bear Valley. The valley floor up by Stonyford was completely obscured by low clouds and the overcast ceiling was about 10,000'.

    Here are a few pics.

    Before the second takeoff.
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    Looking north from Bear Valley.
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    Better than the flying was the time spent with others on the ground. Before the first flight I met Ken Moore, who is working on his glider add-on rating with Ed. Ken lives midway between Williams and Montague and can't decide where he wants to do his glider flying. That's a rough problem to have! When I asked him how his training was going, he commented about how much rudder is required in glider flying! I've heard that from other power pilots. I also passed on to him what I have heard from a number of other power pilots. And that is that learning to fly gliders makes them better power pilots.

    In between flights, I got to spend some time with Ginny getting up to speed on the VSA. We truly are fortunate to have her as the President of the VSA!

    All in all, it was another great day at the gliderport!


    Oh BTW, I did post my flights to OLC. Nothing to write home about, but here they are:

    First Flight

    Second Flight
    Last edited by Pat Alford; 03-10-2014 at 08:20 PM. Reason: Added OLC links

  2. #2
    Join Date
    Jan 2011
    WSC, San Anselmo

    Re: Micro-lift Wave Day Sunday, March 9

    And then came Monday... Watched the clouds forming for a good part of the day while doing some ground chores. Kevin Ash was towing, and quite a few flights were made - some with sustained altitude, although I did not hear of any altitude gains. At about 3 PM, Kevin and I took a tow in the ASK 21 (Thank you tow pilot Noelle!) up to Maxwell under some clouds that were generating quite a bit of sink. But that was unbeknownst to us until we arrived there. Cumulus fakus I believe they are called. Maybe even rotor clouds, but unclear what could have precipitated wave in that location. We retreated downwind and found some sustainable lift over I-5, circled a few times and took in the views. The wind was getting stronger, and from the north, so we headed back and landed. A fun, if brief flight. It was great flying with Kevin - very enthusiastic glider pilot as well as ace tow pilot.
    Looking forward to next weekend.
    Ginny Farnsworth G3
    Past President
    Valley Soaring Association

  3. #3
    Join Date
    Sep 2013
    Fremont, CA

    Re: Micro-lift Wave Day Sunday, March 9

    Ha ha, Ginny! Cumulus Fakus! I love it. I had not heard that term before, but I certainly have experienced them first hand!

    I'm glad you were able to get in the air on Monday! As for what may have precipitated lift in the area you describe, I have heard Kempton describe (to Ramy, I believe) one possible explanation for lift in wide open areas such as the Sacramento Valley on north wind days where there is no obvious physical generator. And that is the phenomenon known as hydraulic jump. It happens in channels that fluids move through. In this case the channel is the valley itself, and the fluid is the air. Hydraulic engineers that design irrigation channels, aqueducts, dams, etc. have to take it into account. In a post I made from earlier this year, I postulated that maybe that is what was being predicted by the RASP Blipmaps (although it was 48 hours out and never did materialize). Check it out here:

    Hydraulic Jump Postulation

    What else would generate lift in that area? I don't know. Does anyone else have any ideas?


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