Daemon
Sep 08, 2002, 04:16 AM
I posted a version of this over in one of the threads in the Slope forum, but I thought it an interesting story for the Thermal forum.
Today I was flying my Miraj F3F (98" 72oz) in light to moderate wind on a big south facing slope. Very sunny, hot and fairly unstable air so I was supplementing the mediocre slope lift with thermals. Had a few Red Tail hawks go after me, then go after each other, and then I gave em all some thrills to establish the true pecking order (they really don't know what to make of loops). Buzzed a few mountain bikers who stopped to watch.. The usual stuff. Anyway, first flight was about an hour and a half with one climb to about 1600 feet over launch .. eventually brought it in to check the batteries, no prob, back up.
20-30 minutes into the next flight, the air gets WAY funky. The wind goes from 10mph SSW (against a south face), to 15-20mph West.. and within a couple minutes WNW and maybe worse, because it feels like I'm flying nothing but rotor. Getting pounded up/down/sideways.. stalling, spun, rolled.. Ugly. The closer I come to the LZ, the worse it gets, so I keep drifting out and downhill.
I'm standing 200 feet up a 550 foot slope and there's a couple little north/south ridges jutting out to the south below me, so I head out south hoping to maybe catch some lift on their west faces before I get smacked into the ground..
Then BAM.. I go from about eye level in severe turbulence to 2000 feet over in less than 3 minutes, and by now the wind has shifted all the way around full on from the north so I'm standing on the backside of a 500 foot tall mountain with the rotor just hammering the only viable LZ. Obviously I've got major cloud suck, and can probably expect over development lasting the rest of the afternoon so the wind's not going to come back around to the south. I'm cruising around with the 98" wing span visibly about half the width of the button on the end of my TX antenna, standing in a hellhole of nothing but turbulence. The Miraj is still rising, sometimes flying smoothly, and sometimes getting tossed around like a rag doll. Hit hard.. 2-3 rolls in a blink, a dive, a loop, full stall, recover, and it's still rising. I've seen my HLG do that, but don't expect it from a foam cored mouldie weighing 4 lbs.
What to do. Hmm.. Pack up, walk down the mountain, and try to keep it up until I can land it well behind the rotor on the flats? nah. I can't carry the other two gliders with me, and fly at 2000 feet over, and I don't want to hike back up to get my stuff. I don't feel comfortable trying to land it past/near the powerlines at the base of the slope from where I'm at either.
Thinking..
Well.. the one thing we know about thermals is that all thermals are followed by sink. Generally speaking, the bigger the thermal, the bigger the sink. Judging by the size of the boomer I'm in now, the sink should be fairly impressive. If I'm lucky, the sink will be large enough to supress the rotor and just flow smoothly down the backside of the mountain over the LZ. (DS pilots learn this, sometimes the hard way, when they dive down the backside, and nearly get stuck there).
So I stay up over 1500 feet.. another 25 minutes. Banging around under the darkening clouds trimmed for high speed trying to minimize the effect of the turbulence (not that I'm worried an F3F glider is going to break). Finally it starts coming down on its own pretty fast. The sink is up there, the air temp at LZ is starting to cool off so I know it's happening at my level too. Down the glider comes.. faster now. I throw it into a dive when it's about 50 feet up, drive down the hill, back up into the wind, uphill, and the sink just plops it down not far from the LZ, with no rotor turbulence at all. The landing was a little hard because it was getting pushed down, but at least it was level and smooth.
20 *seconds* later, the sink has passed, and BOOM... 25-30mph winds from the north and the rotor is back. Man, that landing was pefectly timed. (in other words.. lucky)
Anyway, that's the first time that major SINK saved my butt. Haven't really had a problem getting out of boomers.. even my HLGs are strong and fast enough to dive out, but suddenly finding myself on the wrong side of the mountain in a big wind with my biggest crunchie was a new experience, and the thermal got me out of trouble in the first place, and the following sink got me down in one piece. Nice.
ian
Today I was flying my Miraj F3F (98" 72oz) in light to moderate wind on a big south facing slope. Very sunny, hot and fairly unstable air so I was supplementing the mediocre slope lift with thermals. Had a few Red Tail hawks go after me, then go after each other, and then I gave em all some thrills to establish the true pecking order (they really don't know what to make of loops). Buzzed a few mountain bikers who stopped to watch.. The usual stuff. Anyway, first flight was about an hour and a half with one climb to about 1600 feet over launch .. eventually brought it in to check the batteries, no prob, back up.
20-30 minutes into the next flight, the air gets WAY funky. The wind goes from 10mph SSW (against a south face), to 15-20mph West.. and within a couple minutes WNW and maybe worse, because it feels like I'm flying nothing but rotor. Getting pounded up/down/sideways.. stalling, spun, rolled.. Ugly. The closer I come to the LZ, the worse it gets, so I keep drifting out and downhill.
I'm standing 200 feet up a 550 foot slope and there's a couple little north/south ridges jutting out to the south below me, so I head out south hoping to maybe catch some lift on their west faces before I get smacked into the ground..
Then BAM.. I go from about eye level in severe turbulence to 2000 feet over in less than 3 minutes, and by now the wind has shifted all the way around full on from the north so I'm standing on the backside of a 500 foot tall mountain with the rotor just hammering the only viable LZ. Obviously I've got major cloud suck, and can probably expect over development lasting the rest of the afternoon so the wind's not going to come back around to the south. I'm cruising around with the 98" wing span visibly about half the width of the button on the end of my TX antenna, standing in a hellhole of nothing but turbulence. The Miraj is still rising, sometimes flying smoothly, and sometimes getting tossed around like a rag doll. Hit hard.. 2-3 rolls in a blink, a dive, a loop, full stall, recover, and it's still rising. I've seen my HLG do that, but don't expect it from a foam cored mouldie weighing 4 lbs.
What to do. Hmm.. Pack up, walk down the mountain, and try to keep it up until I can land it well behind the rotor on the flats? nah. I can't carry the other two gliders with me, and fly at 2000 feet over, and I don't want to hike back up to get my stuff. I don't feel comfortable trying to land it past/near the powerlines at the base of the slope from where I'm at either.
Thinking..
Well.. the one thing we know about thermals is that all thermals are followed by sink. Generally speaking, the bigger the thermal, the bigger the sink. Judging by the size of the boomer I'm in now, the sink should be fairly impressive. If I'm lucky, the sink will be large enough to supress the rotor and just flow smoothly down the backside of the mountain over the LZ. (DS pilots learn this, sometimes the hard way, when they dive down the backside, and nearly get stuck there).
So I stay up over 1500 feet.. another 25 minutes. Banging around under the darkening clouds trimmed for high speed trying to minimize the effect of the turbulence (not that I'm worried an F3F glider is going to break). Finally it starts coming down on its own pretty fast. The sink is up there, the air temp at LZ is starting to cool off so I know it's happening at my level too. Down the glider comes.. faster now. I throw it into a dive when it's about 50 feet up, drive down the hill, back up into the wind, uphill, and the sink just plops it down not far from the LZ, with no rotor turbulence at all. The landing was a little hard because it was getting pushed down, but at least it was level and smooth.
20 *seconds* later, the sink has passed, and BOOM... 25-30mph winds from the north and the rotor is back. Man, that landing was pefectly timed. (in other words.. lucky)
Anyway, that's the first time that major SINK saved my butt. Haven't really had a problem getting out of boomers.. even my HLGs are strong and fast enough to dive out, but suddenly finding myself on the wrong side of the mountain in a big wind with my biggest crunchie was a new experience, and the thermal got me out of trouble in the first place, and the following sink got me down in one piece. Nice.
ian