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I am researching shear wave and thermal wave.
For example, the WI glider altitude record was set by Ted Clausing in thermal wave. For example, on 4/24/98, bases were 7000 msl, thermal wave took gliders to 16-20,000 msl over lower Michigan, and stacked lenticulars were seen. If you understand how to predict where shear and thermal wave will occur, I'd be delighted to hear about that! In any case, if you'll send me dates/locations of thermal-wave flights, and altitudes achieved, and a bit of story about the conditions, this would be wonderful. Attaching a log file would be a bonus. Send to: dleroyj AT gmail.com Thanks! DrDan |
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My Iowa state altitude record was recently exceeded by Don Gurnett using wave I believe. You can find Don he http://www.physics.uiowa.edu/people/donald-gurnett
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The Ohio record was set by Frank Paynter (TA) on wave day near Caesar Creek.. You would have to check what day that was, but chances are the flight is on OLC. A number of CCSC pilots were up and flying in it that day. From what i understood, it required having a decent cloud street with a 90-degree wind shift over top. The pilots essentially built up energy under the street then zoom climbed up on top of the Cu's to enter the wave above.
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Dan,
I assume you've read Chapter 6 of Rolf Hertenstein's "Thermals" Book, from Bob Wander. If not it has a good discussion on the conditions required for thermal waves. Unfortunately so far I've never been able to connect. |
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On Wednesday, 11 November 2015 15:18:02 UTC+2, danlj wrote:
I am researching shear wave and thermal wave. For example, the WI glider altitude record was set by Ted Clausing in thermal wave. For example, on 4/24/98, bases were 7000 msl, thermal wave took gliders to 16-20,000 msl over lower Michigan, and stacked lenticulars were seen. If you understand how to predict where shear and thermal wave will occur, I'd be delighted to hear about that! In any case, if you'll send me dates/locations of thermal-wave flights, and altitudes achieved, and a bit of story about the conditions, this would be wonderful. Attaching a log file would be a bonus. Send to: dleroyj AT gmail.com Thanks! DrDan Thermal waves are pretty well researched subject in meteorology. I did a short paper of thermal waves ages ago and still have a box full of printed articles. Well known glider pilot-meteorologists such as Joachim Kuettner and Tom Bradbury are good starting point for search. They observed thermal waves in 60's and 70's. There was at least one big measurement campaign in US during 80's or 90's. They flew fully instrumented plane several times over convective boundary layer and reported widespread wave occurrence. Model studies followed. |
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At 09:17 12 November 2015, krasw wrote:
On Wednesday, 11 November 2015 15:18:02 UTC+2, danlj wrote: I am researching shear wave and thermal wave. =20 For example, the WI glider altitude record was set by Ted Clausing in the= rmal wave. =20 For example, on 4/24/98, bases were 7000 msl, thermal wave took gliders t= o 16-20,000 msl over lower Michigan, and stacked lenticulars were seen. =20 If you understand how to predict where shear and thermal wave will occur,= I'd be delighted to hear about that! =20 In any case, if you'll send me dates/locations of thermal-wave flights, a= nd altitudes achieved, and a bit of story about the conditions, this would = be wonderful. Attaching a log file would be a bonus. =20 Send to: dleroyj AT gmail.com =20 Thanks! =20 DrDan Thermal waves are pretty well researched subject in meteorology. I did a sh= ort paper of thermal waves ages ago and still have a box full of printed ar= ticles. Well known glider pilot-meteorologists such as Joachim Kuettner and= Tom Bradbury are good starting point for search. They observed thermal wav= es in 60's and 70's. There was at least one big measurement campaign in US = during 80's or 90's. They flew fully instrumented plane several times over = convective boundary layer and reported widespread wave occurrence. Model st= udies followed. We have a bit of an advantage in the UK in that cloud flying is permitted and that makes it a lot easier to get into thermal wave. I've done quite a lot of it over the last 45 years. I've also discussed it with both Joachim and Tom. My experience is that very weak (reduced sink usually) wave, close the the up-wind side of the cumulus top, is there more often than not. It might even be more accurate to call this "cumulus ridge lift". Classic streets with upper wind, immediately above the inversion, at a significant angle to this (doesn't have to be 90 degrees, 60 or so will do), producing good usable wave (best I've ever seen was about 8 knots), is quite rare in the UK but I've experienced a fair number over the years. |
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On Thursday, 12 November 2015 15:15:07 UTC+2, Chris Rollings wrote:
We have a bit of an advantage in the UK in that cloud flying is permitted and that makes it a lot easier to get into thermal wave. I've done quite a lot of it over the last 45 years. I've also discussed it with both Joachim and Tom. My experience is that very weak (reduced sink usually) wave, close the the up-wind side of the cumulus top, is there more often than not. It might even be more accurate to call this "cumulus ridge lift". Classic streets with upper wind, immediately above the inversion, at a significant angle to this (doesn't have to be 90 degrees, 60 or so will do), producing good usable wave (best I've ever seen was about 8 knots), is quite rare in the UK but I've experienced a fair number over the years. I've done it also, both before starting cloud flying and after. It is quite rare and lift is usually extremely weak. I remember some notable cases with approaching front and strong wind shear. I wouldn't call it ridge lift BTW, at least if term means same as anabatic slope wind. They are purely thermally forced, which is completely different phenomenom. |
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On Wednesday, November 11, 2015 at 11:18:02 AM UTC-2, danlj wrote:
I am researching shear wave and thermal wave. For example, the WI glider altitude record was set by Ted Clausing in thermal wave. For example, on 4/24/98, bases were 7000 msl, thermal wave took gliders to 16-20,000 msl over lower Michigan, and stacked lenticulars were seen. If you understand how to predict where shear and thermal wave will occur, I'd be delighted to hear about that! In any case, if you'll send me dates/locations of thermal-wave flights, and altitudes achieved, and a bit of story about the conditions, this would be wonderful. Attaching a log file would be a bonus. Send to: dleroyj AT gmail.com Thanks! DrDan Yes, thermal wave or convective wave! Neat! Where I fly, on the Canadian prairies, 500km downwind of the mountains and at least 300km from any substantive foothills, we see wave clouds occasionally (several times per season), and some times manage to contact the lift. The technique is to climb normally in a thermal till right snug up against the cloud, and then press forward into wind. Just upwind of the cloud, with luck, will be that magical smooth smooth laminar wave flow and up you go climbing the face of the cloud using the classic wave climb figure 8 pattern. Sometimes we just see lennies appear in one quandrant of the sky or another, either in some messy relationship to the cumulous clouds or, occasionally, clearly capping or bisecting a particular cu. More dramatic are the days, typically a day with a brisk wind aloft, perhaps 20 knots, with excellent streeting fully developed, when, within what seems a blink of an eye, the clouds re-orient themselves 90 degrees to form a series of bars across the wind. This happens mid to the later part of the afternoon. Good climbs are rare, but do happen. Unfortunately, I do not have any electronic examples. I saw one barograph trace of a sustained gentle climb over a period of about an hour and a half. On another day, three of us noticed convective wave northwest of the field and headed up there. That evening, one of my friends was particularly animated, reporting having climbed up and over the cumulous reaching "harruumpp-tin thousand feet". Despite his overwhelming need to clear his throat at the critical juncture, I am pretty sure I know what he was trying to choke out - if it would be useful to your research I could pass it on by private email. |
#9
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On Wednesday, November 11, 2015 at 8:18:02 AM UTC-5, danlj wrote:
I am researching shear wave and thermal wave. For example, the WI glider altitude record was set by Ted Clausing in thermal wave. For example, on 4/24/98, bases were 7000 msl, thermal wave took gliders to 16-20,000 msl over lower Michigan, and stacked lenticulars were seen. If you understand how to predict where shear and thermal wave will occur, I'd be delighted to hear about that! In any case, if you'll send me dates/locations of thermal-wave flights, and altitudes achieved, and a bit of story about the conditions, this would be wonderful. Attaching a log file would be a bonus. Send to: dleroyj AT gmail.com Thanks! DrDan the adds satellite can provide evidence of good streeting. just google adds satellite. also you can use the BAK40 soundings to predict the wind and lapse rates conducive to thermal wave. you can use them to predict conditions the night before, right up to taking off. just google bak 40 sounding, or go he http://rucsoundings.noaa.gov/ |
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