Hi Gary,
Re launching with high upper winds; yes, I agree – no point launching if you can’t even hold position in the wave. My rule of thumb is that, if your groundspeed whilst heading directly into wind is under 10 knots, then you will have very little ability to explore crosswind. Also, it is often hard to determine in the air whether such a low groundspeed hasn’t actually turned into a downwind speed. On moisture content and “wet waves”; I guess this depends on where you fly. I recall the Grampians (your turf?) often had good cloud cover and the occasional thick cloud wave in predominantly W-SW winds. I can recall almost getting caught in a closing Foehn gap when a small “pulse” of moisture arrived in the SW stream and closed the gap below us in about 2-3 minutes. Two or three of us were at 16,000’; luckily, I was in a Hornet and the trailing edge brakes meant I could descend rapidly. The others went downwind for outlandings. On “dry” waves; Winter post-frontal airmasses often have quite dry air above the inversion so you get clear blue sky above 6-7/8 cu, typically below 6-7,000’. As well, NW-N pre-frontal winds are often (but not always) very dry with no clouds evident. Most of my actual wave flying over Mt Donna Buang and down here over Mt Wellington are blue wave days with few lennies and/or cu. Of course, the good Lennie days often have very strong ground winds that preclude a safe launch. I agree an AH is vital and the knowledge and experience on how to rely on it. I have a full electric panel in the Ximango but only an inertial vario AH feature in the ASH26E. I believe one should know how one’s aircraft behaves using a “benign spiral” and practice it regularly. Ie full airbrakes at 50-60 knots in a 20-30 degree banked turn. On phone gyros, etc; the only comment I’d make is that the “6-pack” panel display feature in my GPSmap in the Ximango is usable as sole reference as a last resort. Ditto the AH feature in my ASH26E vario but more as a turn indicator than an AH. With lots of new inertial-type varios coming on the market, I believe we ought to expect a good AH feature to be built in. I suspect the issues are more non-technical around how to disable it for comps flying so pilots can’t cloud fly. How has the wave season been for you so far? Cheers John From: Gary Stevenson [mailto:[email protected]] Sent: Wednesday, 13 July 2016 10:37 PM To: 'John Gwyther' <[email protected]>; 'Gliding Australia Forum' <[email protected]> Cc: [email protected] Subject: RE: [gfaforum] Re: Wave flying Hi John, Nice to see a bit of practical reality (obviously from experience), infused into this scenario. I haven’t the slightest doubt that you are 100% right. Your comment on wind speeds aloft is very pertinent, but if high winds aloft are forecast , I suggest that you would not take a launch anyway??? Would you agree that in – just to pick to a number - 90% of cases, a wind speed of 80 kts at FL 185 is unlikely? High moisture content of the air in Victoria is not unusual on wave days. This can induce a high (95% plus), proportion of mid-level cloud formation. I call this situation “wet wave” and it can be deadly, when the Fohn gap closes under you. If you don’t have a dedicated AH - NOT a phone app – and know how to use it you could end up dead. If you intend to fly in these conditions , fitting a turn and bank indicator to your panel as well as the AH seems to be a good idea. Having said that, I recently heard a rumour that some phones are now fitted with some sort of gyro???/alternative system. All this is outside my experience, but this rumour seems somewhat unlikely. Does such a system exist? How does the average phone AH work anyway, and what are its failings? Comments please. Regards, Gary From: John Gwyther [mailto:[email protected]] Sent: Wednesday, 13 July 2016 8:08 PM To: Gliding Australia Forum Cc: [email protected] <mailto:[email protected]> Subject: [gfaforum] Re: SkySight and Wave Yep, very nice looking but, down here in Gippsland NW of Sale, we've had cu-nims and snow showers all day. Previous attempts to fly in these conditions resulted in getting cut-off horizontally and vertically from a safe return. Also, whilst the wave is there, the winds aloft (70-80 knots at FL185) would make it very hard to move along the wave without going backwards downwind. I've been tracking his wave forecasts on this site and they seem to line up pretty well with local experience. One can also get good visual confirmation with the new Himawari-8 BOM satellite. On Wednesday, July 13, 2016 at 11:04:15 AM UTC+10, Paul Mander wrote: Take a look at the wave display for today on Matthew Scutter's new forecasting package, SkySight. It shows the possibility of a flight in wave from Bunyan to Bairnsdale to Kempsey; 1020 km, if one could address the airspace issues. That possibility is exciting, but it also demonstrates the usefulness of the SkySight model. I recommend it. -- You received this message because you are subscribed to the Google Groups "Gliding Australia Forum" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected] <mailto:[email protected]> . To post to this group, send email to [email protected] <mailto:[email protected]> . Visit this group at https://groups.google.com/a/glidingaustralia.org/group/gfaforum/.
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