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Thread: X-country flights

  1. #1
    Join Date
    Mar 2015
    Location
    Santa Rosa
    Posts
    220

    X-country flights

    This is NOT a thread about racing.

    I am not Peter's "straight man". Most of you know now that I am a new glider pilot with lots of questions and Peter has responded with lots of answers. Others have responded also and I thank them as well.

    Quote Originally Posted by Peter Kelly View Post
    Russ,
    I evaluated the day's soaring conditions, and based upon that, I was confident that the ASW24 was not capable of completing that particular task, on that particular day. On other days, and on other tracks, it could easily be accomplished.
    Peter,

    I think I now understand that you are referring to the weather conditions Saturday which would not allow a Standard class glider to complete that task successfully.

    I would greatly appreciate your evaluation of the weather conditions Saturday, so us new x-country students, can have a better understanding of the issues involved?

    This is a discussion, so open for anyone to respond.

    Russ
    Last edited by Russ Pillard; 05-05-2015 at 04:41 PM. Reason: Minor edit

  2. #2
    Join Date
    Jan 2011
    Location
    Menlo Park, CA
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    933

    Re: X-country flights

    Russ,
    If you have not already, buy & read this book, Helmut Reichmann's Cross Country Soaring:
    https://www.cumulus-soaring.com/book...trySoaring.htm

    This is one of the best, if not the best book on cross country soaring. Lays out the theory with practical examples in an easy to read manner. I always point to examples in this book. This will answer many of your Qs while giving an overall context.

    Weather is a different topic, and for that, buy & read this book:
    https://www.cumulus-soaring.com/book...yAndFlight.htm

    Hope this helps, but keep asking Qs, while reading these books.
    Kemp
    ASH-25 (FNX)

  3. #3
    Join Date
    Mar 2015
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    Santa Rosa
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    Re: X-country flights

    Kemp,

    Thanks for the recommendations, I have ordered both books from Paul.

    Russ

  4. #4
    Join Date
    Jan 2011
    Location
    San Jose, CA
    Posts
    298

    Re: X-country flights

    Russ,

    I would also recommend this brand new book by G Dale (UK coach and Club Class Team pilot): The Soaring Engine Volume 1

    THE SOARING ENGINE series explains how the sun, wind and terrain combine to produce rising air for the soaring pilot to exploit. In this volume you will see how the wind flows over and around hills, ridges and mountains, how thermals form and evolve, the patterns that ridge and thermal activity create in the air an how to use the lift produced both in flat terrain and in mountains. Illustrated with clear simple diagrams, this book is a primer for soaring pilots flying anything from a paraglider to high performance sailplanes.

    http://wingsandwheels.com/pilot-supp...engine-v1.html

    G is planning on a 3 volume series. These volumes are expanded versions of the talks he gives while coaching.

    Hope this helps and keep the questions coming...
    Pete Alexander -- 98

  5. #5
    Join Date
    Jan 2011
    Posts
    620

    Re: X-country flights

    I understand peters conservative approach to a rental glider.
    That said, the difference in performance between modern standard class and 15m, such as 24 vs 27 is 10% or even less. I don't have handicaps in front of me to confirm, so feel free to correct me, but I think I am close. This means that standard class can fly as far as 15m but may take 10% longer time as those who flew standard class last weekend showed. so unless it is a day which require the whole soaring window, there is no significant difference. Flaps help, but in my opinion they are overrated unless you fly above 80 knots, which is not common in the Mendocinos. Even 18m only have slight advantage over 15m. Just my opinion, backed by handicaps.

    Ramy

  6. #6
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    Jan 2011
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    Re: X-country flights

    Quote Originally Posted by Russ Pillard View Post
    This is NOT a thread about racing.
    ....
    Peter,

    I think I now understand that you are referring to the weather conditions Saturday which would not allow a Standard class glider to complete that task successfully.
    .....

    Russ
    Ramy, Russ has it correct. And as Russ said - THIS thread is not about completing that racing task, on that day. I stand by what I said. BTW, the starting gate was not expected to open until after 1 pm.

    Russ,
    you can see there are lots of experienced pilots that are eager to help, and you are getting some valuable inputs. Good work on your part. Others pilots should pose similar concerns.
    Peter Kelly

  7. #7
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    Re: X-country flights

    So I'm on a similar thread with a friend who's ramping up his gliding/soaring experience at Estrella, AZ. I've pointed him to this thread.

    Re: most valuable reading, while discussing thermal size and turn radius, I mentioned Moffat's "Winning on the Wind" book and looked for where to buy this. It's out of print, with only used copies to buy. I think there's one on the bookshelf at WSC, but I found this readable PDF as an alternate:

    http://www.lakesgc.co.uk/mainwebpage...The%20Wind.pdf

    Put it on your smartphone and read whenever you can!
    Kemp
    ASH-25 (FNX)

  8. #8
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    Mar 2015
    Location
    Santa Rosa
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    Re: X-country flights

    Quote Originally Posted by Peter Kelly View Post
    Russ,
    I evaluated the day's soaring conditions, and based upon that, I was confident that the ASW24 was not capable of completing that particular task, on that particular day. On other days, and on other tracks, it could easily be accomplished.
    I would greatly appreciate an evaluation of the weather conditions on that Saturday 5/2, so us new x-country students can have a better understanding of the issues involved.

  9. #9
    Join Date
    Jan 2011
    Location
    Schleicher ASW-24
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    Re: X-country flights

    Quote Originally Posted by Russ Pillard View Post
    I would greatly appreciate an evaluation of the weather conditions on that Saturday 5/2, so us new x-country students can have a better understanding of the issues involved.
    Russ, although I have the charts right here on my computer and could easily display the evaluation, let's leave that one alone. We have beat it to death. It is better to look at forecasts, do some real flight planning and then, after the flight, debrief to all what you found in the air. (put your money where your mouth is, as the saying goes). That is my preferred methodology. I think that approach is a better teaching tool. Anyone can tell you what the weather was (and where the lift was, or was not), but it's hard to say where the lift will be for sure.

    I told you my plans to fly on Friday (tomorrow) and if you looked at the charts I referred to yesterday you would have seen the lift and the how easy it would be to do that 400 k flight.
    However, our schedules have changed, so I won't be flying tomorrow after all. Thus, I stopped looking at the forecast for tomorrow. I am now looking at Saturday.
    Peter Kelly

  10. #10
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    Re: X-country flights

    Russ,
    To set basics, just cause I don't know what you know...

    Looking at the whole XC thing with a first order template, ideally, we want a day that has:
    - As much daylight as possible, "t time"
    - As high of lift as possible. Lift strength & lift height are roughly correlated. This is the main driver of "s speed"
    - Said lift over as wide an area as possible "a arena". I just note this as occasionally there can be one strong lift point with nothing anywhere else.

    So, t x s = max distance within the lift arena.

    Typically a "good" thermal days on the Mendos arena have bases at 10K or higher. Goat is 6K, Snow is 7K, and Yolla Bolla peak is 8K in height. On said good day, cloud base tends to rise higher to the north at about the same rate. Meaning at 10K over Goat, that's 4K AGL, and at Yolla, it's likely you are at 12K. That's a 4K working band of height to use to make distance. But in practice, subtract 1K resulting in 3K usable as when you get close to the ridge line, you start considering retreat or stopping forward progress to search for thermals.

    Of that usable 3K, with an ASW-24 you can reasonably go 15 miles or so to the next thermal, factoring in sink and not a straight path. You can see if cloud base drops 1K, you now have 2K of working band, so your working band was whacked by 33%!

    Conversely, if cloud base goes up by 1K, you now have 33% MORE altitude usable for going further. Hence, a couple extra thousand feet boosts achievable distance by a disproportional amount.

    Sorry if this is redundant, but wanted to make sure that base construct was there....
    Kemp
    ASH-25 (FNX)

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