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Thread: Lesson and Flight Report - April 12, 2014

  1. #1
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    Lesson and Flight Report - April 12, 2014

    I am having a problem getting the SSA Tracker to display the tracks tonight. I move the time slider on the bottom but the tracks do not show up. Any one else have a solution or have the same problem?

    It was a good day, with some having more fun than others.

    I snapped a few photos to show the conditions.
    Lift was a few miles west of the clouds, in a convergence line. Clouds were minimal, but the lift was there.

    There is a lesson to be learned here and I will start the lesson on the next posting to this thread. First, an abbreviated report of the day.

    I had a good run up to T-15 and back as did most of the others. Coming home, I flew the convergence line down towards Arbuckle and could have flown Arbuckle to Colusa if I had tried. Had to get back for the BBQ - and the talks. It was a good day and a nice evening.

    Some photos and the track... ...

    A real lesson in finding the right place to fly.
    Off tow, I discovered the convergence early as I flew over Goat. I went west of Goat a mile or so and was able to climb an extra 2 or 3,000 feet.


    Snap shot of front panel of the Duo at 2:31 - at 12,000 looking to the south on the Clear Nav
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    Ten seconds later, same place, but looking out the window.
    See the ratty cu over Sheet Iron, St John and Snow Mtn.

    You can see that flying in the convergence line 3 or 4 miles west of the clouds was the place to be.
    Near the clouds, and you were lucky to be above 8,000 ft.


    Click image for larger version. 

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    An hour and 20 minutes later it was 3:40 and I was coming south from T-15. Yolla Peak is behind left wing and Anthony is below right wing.
    You can see there were not a lot of clouds to mark the way, but the convergence allowed me an easy ride back to Tree Farm.


    Click image for larger version. 

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    Here is the Flight Log
    Same route essentially flown by at least six of us ... Ray, Guy, Jim, Key, Peter D.


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    Last edited by Peter Kelly; 04-13-2014 at 02:11 PM.
    Peter Kelly

  2. #2
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    Re: Lesson and Post Flight Report - April 12, 2014

    I am always apt to comment on my flights, because I think that we each should share our sport with others. I like to try to help others to learn how to do cross country soaring. I am extra-motivated today, due to last night's fine presentation by Pat Alford, taking us through his last 10 plus years of his training, experience and discovery.

    A lot of cross-country training cannot be "taught" per se, because it is more self-discovery, but if you know what to look for - before you launch into the sky, it might be helpful. Keeping your eyes closed and wandering in the dark is not the most efficient way to find your goal. Having a bit of light, will help you tremendously. Let's shed some light on this challenge.

    How do you discover such a phenomenon as "convergence lift" upwind of the clouds?

    Me? I study the weather charts before launch.

    Others? National champions such as Peter D and Ray G are national Champs because they have the ability to quickly recognize what is happening in the atmosphere around them. They read the cues that are apparent to them - the same cues that are NOT so apparent to the rest of us mortals. A point right there is that you must be relaxed, not tense, not distracted with a lack of coordinated flying, etc. You need to be relaxed, and open to what is happening around you.

    I pay attention to the RASP products before takeoff.
    I have uploaded eight products from the RASP model - all for 2100Z, which is 2 PM, on Saturday 12 Apr.

    Look them over. Compare that to the clouds I displayed in the photos in the previous post on this thread.

    BTW, I have several other photos I could share.

    Others of you who see different bits of info in these products, please share your thoughts.

    With the stronger wind coming from the west, as compared to the east wind, and the fact that the ridge is abrupt on the west side, vs fingers of ridges coming east from the crest of the Mendo Ridge, and the changes in wind direction as you ascend, and look at that dotted line and the dryness of the air above 10k on the sounding - it's no wonder the evidence was evaporating as the thermals went up through 10,000 ft.
    There is so much info in these products.


    see surface wind and BL wind


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    see convergence lines and top of thermals (H-Crit) - not really the tops, as we know.

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    see bases of the cu, and the wind strength and direction and Vert Velocity of the air at 5 and 10 K

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    and finally, see the sounding. This tells is all.

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    And sometimes you just need to observe more. See the cu on the horizon and remain aware all that is in between you and those cu.

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    Last edited by Peter Kelly; 04-13-2014 at 12:52 PM.
    Peter Kelly

  3. #3
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    Re: Lesson and Post Flight Report - April 12, 2014

    I have to admit not checking the convergence before I took off as I expected the clouds to mark the convergence. Not that it would have made much difference in my case, Kempton and I were simply too early and could not connect. We couldn't go any further west as we were quickly below the ridges. But I don't see any indication in the RASP charts that the convergence was west of the crest.
    Lesson learned for me, after launching too early twice in a row, is fly the weather, not the forecast. If the great cloud street we expected by 11AM wasn't there yet, it is better to wait for it a little longer. But then we only had 1.5 tow plane so someone needed to launch early

    Ramy

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    Re: Lesson and Flight Report - April 12, 2014

    Thanks Peter and Pat! I am closely following all this and am sure that this will help me better understand the conditions and make improvements.

  5. #5
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    Re: Lesson and Flight Report - April 12, 2014

    Quote Originally Posted by Frans67 View Post
    Thanks Peter and Pat! I am closely following all this and am sure that this will help me better understand the conditions and make improvements.
    Thanks Frans for the post/ feedback. This "lesson" may serve as a reminder to those who are experienced x-c flyers, but this is mostly oriented towards people like yourself Frans. People who know how to fly, have no trouble thermaling or making the ship do what you want it to do, etc, but have NOT YET logged thousands of miles doing cross country flying. Round trip from Goat to T-15 is about 140 miles, so doing that a couple of times, after having accumulated 7 or 800 miles flying in and around Goat, Snow and St John, would easily put you into the 1,000 mile category. Yes, this lesson is more for those who are still in the 300 to 700 mile club, if you will allow me to establish "club levels" in x-c. Reminds me of the conversation two pilots with big (humongous) egos famously had - each taking a position that landing out north of St John was/ was not a legitimate event. Pilots need to learn to fly x-c near safe places to land, but at the same time, once you have the confidence to venture out (a big step in itself), a land out or two is inevitable as you build up your experience level. In any case, keep your landing options open as you test your knowledge and skills of finding the lift.

    I really don't know Frans' experience level, but I do occasionally watch the traces of many pilots who fly out of Williams. I can see it would be helpful to a lot of pilots if we talked more about predicting conditions and reporting conditions.

    As for taking off too early, that's always a gamble for others, but for me, when I owned a motor glider, not so much. I always enjoyed working the first thermal and staying on top of them, as they rose to, and above, "normal" tow release heights. Ramy, Kempton, and Sergio paid the price for going too early, but like Ramy says, you need to fly conditions, not the forecast.

    However, that being said, there isn't any rationale that I can think of for a pilot not being knowledgeable about the forecast conditions that are expected during a flight. If nothing else, pilots should be aware of the forecast surface winds that are expected for the planned landing time. You may not have radio contact with the airport when you start the final glide, and yet you always want to take into account what the winds may be when you glide those last five or ten miles towards the runway, at minimum altitude. If the office is open and you are within radio range, Cora always does a nice job of reporting the winds, when you ask.

    Back to analyzing the conditions on Saturday, for those of us that were at the field, we all saw the high level of moisture in the air. Poor visibility. It was extremely difficult to see the sky over Snow and Goat. You probably couldn't see small cu, even if they were present, until you were on tow above 5,000 feet, but then it was too late to turn back. But looking straight up from the runway, we could see the sky was blue, not grey. Looking now at the sounding, it is obvious why the visibility was that way. The blue line is touching the red line from about 7,000 to 10,000 feet. That is nearly 100 % moisture level. the dry bulb temp (red) is the same as the wet bulb temp (blue). Then you see the dotted line, which I am guessing is the expected rise in a parcel of hot air from the surface, and you see it rises along the red line to about 5,000 ft and then goes nearly vertical. Wow. If there were no horizontal mixing (contamination/ dilution) of that parcel of hot air, and it had been big enough to start with, it would ascend to some really good heights. That would be something, but you can see the winds increase in strength at about 10,000 ft (see the inversion (knee) on the red line), thus with winds over 15 kts at 12,000, you wouldn't expect to see the thermal keep rising very much. Besides that, you can see the dryness of the air (as I previously mentioned) (blue line shooting off to the left), thus the clouds that did form would quickly evaporate above 10,000 ft.

    So why no clouds on the west side of the convergence line?

    Most all pilots who have flown convergence lines with cu marking the line have seen the "shelf". Several of us have documented it along the Mendos with smoke lines as well. We know the two sides of a convergence have varying levels of moisture, as well as varying levels of instability. It seems to me that the air mass on the west side of the convergence line on the Mendos is always more dry ( and more unstable) than the air mass on the valley side. The wind is normally always stronger from the west as well. Maybe the side with the stronger prevailing wind is riding up the side with the weaker wind - thus higher levels on the side with the stronger prevailing wind.

    So back to the question of why no clouds on the west side of the convergence line... I suspect it is due to the air being more dry on the west side. If we had a sounding of the air on each side, I suspect we would see less moisture on the west side.

    Any one else have better explanations of why a "shelf" normally exists on a shear line, with the one side being higher than the other?

    And another point - this being about my comments above referencing the "about upwind side" of a convergence line. When you are in the line, there is not an up wind side. The wind is usually less - duh... its converging.... or at least it is an average of the two wind vectors. When I said upwind, I was thinking more about the side with the stronger wind, which is usually the west side on the Mendos and also usually the drier side, and the more unstable side.

    So if you lose the lift after being on the line, a good technique is to read your wind and then move downwind and see if it decreases, and changes direction. Once your wind decreases back to an average of the two wind vectors, you will probably be back in the convergence line.
    Last edited by Peter Kelly; 04-14-2014 at 02:11 PM.
    Peter Kelly

  6. #6
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    Re: Lesson and Flight Report - April 12, 2014

    Peter,

    Wow! Thanks so much for taking the time to write all this up! I have now read it all four times. There is so much valuable information in this thread and your willingness to share it is greatly appreciated! This is exactly the type of thing that I was thanking the Williams soaring community for at the end of my presentation. Some of the information you present is "instant learning" and some is "homework" for further study. I will undoubtedly refer back to this thread in the future.

    There are several points that I'd like to share with regard to this specific part of your post:

    Quote Originally Posted by Peter Kelly View Post

    So why no clouds on the west side of the convergence line?

    Most all pilots who have flown convergence lines with cu marking the line have seen the "shelf". Several of us have documented it along the Mendos with smoke lines as well. We know the two sides of a convergence have varying levels of moisture, as well as varying levels of instability. It seems to me that the air mass on the west side of the convergence line on the Mendos is always more dry ( and more unstable) than the air mass on the valley side. The wind is normally always stronger from the west as well. Maybe the side with the stronger prevailing wind is riding up the side with the weaker wind - thus higher levels on the side with the stronger prevailing wind.

    So back to the question of why no clouds on the west side of the convergence line... I suspect it is due to the air being more dry on the west side. If we had a sounding of the air on each side, I suspect we would see less moisture on the west side.

    Any one else have better explanations of why a "shelf" normally exists on a shear line, with the one side being higher than the other?

    And another point - this being about my comments above referencing the "about upwind side" of a convergence line. When you are in the line, there is not an up wind side. The wind is usually less - duh... its converging.... or at least it is an average of the two wind vectors. When I said upwind, I was thinking more about the side with the stronger wind, which is usually the west side on the Mendos and also usually the drier side, and the more unstable side.

    So if you lose the lift after being on the line, a good technique is to read your wind and then move downwind and see if it decreases, and changes direction. Once your wind decreases back to an average of the two wind vectors, you will probably be back in the convergence line.
    Devin and I had a great flight in convergence lift all the way to Mt. Whitney back in July, 2012. I did a blog post about the flight on the other blog I maintain (http://mindensoaring.blogspot.com/). I included one of the pictures from that flight in my presentation Saturday night. The post can be seen here:

    http://mindensoaring.blogspot.com/20...h-six-pit.html

    The flight was easy until we got down to Mammoth Lakes. It was completely blue the rest of the way. When we got to the end of the clouds I said "Ok, Devin this is where I would turn around and head back." He said "let's keep going a little and see what happens." Much to my delight, the lift continued! So when you say:

    Quote Originally Posted by Peter Kelly View Post
    We know the two sides of a convergence have varying levels of moisture, as well as varying levels of instability.
    We should be mindful that can include each side having no moisture (or not enough to make cloud)!

    And I love your hunting technique to reestablish the convergence line. I'm not sure which side (east or west) was a stronger wind on our flight, but what Devin and I did was more driven by the terrain we were flying over. We would first alter our course to the west while we had as much height as possible, and then to the east (as this was our "escape" side) if we did not find it to the west. We never had to search far. The important thing was to get back in it as soon as possible!

    And with regard to the "shelf" you write about, I now have a better understanding of what was happening in the last photo in my blog post. If you look at our flight trace, you can see that we returned from Mt. Whitney along basically the same path we had taken on the way down until we were just south of Mono Lake. At this point we diverted from the convergence line to good looking clouds that would take us the rest of the way home. That last photo is looking west back at the convergence line and the "shelf" is very noticeable.

    Thanks again, Peter!
    Last edited by Pat Alford; 04-16-2014 at 07:32 PM.

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