Flyfunston

I'm curious about pre shear conditions and would like to hear from as many of you as possible regarding the lift lately. I think it's interesting to show up and the air seems good, however, there are gliders on the ground . Seems like the lulls or holes in the lift will sometimes send you to the beach. It's more solid in the morning, however, in the afternoon the lulls become more pronounced. The way to keep from going to the beach is to fly earlier and stay high to ride out the holes? thoughts?
hope this pattern goes away soon. Tom Jensen (I need more airtime)

There will be much to say about pre-shear conditions but I first want to say something about landing in post-shear conditions;

After the shear passes, the wind in the LZ is sometimes calm, or light out of an odd direction. You might need a real flare!

It is more common for the wind after a shear to be strong out of the north, north-west, maybe 30 plus mph. This can make top landing quite challenging to say the least. Many good pilots have had hard or scary landings due to rotors generated by the cliff, bushes, and vehicles in the parking lot. One pilot this year even broke his arm.
This turbulence can be avoided by landing on the beach! The best place to land is at the north end of the cliffs at Ocean Beach where you will have easy access after breaking down. The wind off the ocean will be more laminar than on top of the cliff, though you can expect a dramatic wind gradient so keep your speed up on approach.

Even if you can't make it to the north end, *as long as the tide is out*, you can land in front of the bowl south of launch or near the other sand trail at the north gap. Having to carry your glider up is usually better than crashing on top.

Now, about how to get into the shear to begin with........

Well I'll tell you how to miss it.....get there and notice all the gliders on the ground and the wind not too strong, but whitecaps out on the water.....think about what glider to setup, high performance or slow boater (depends on if the wind comes in or not)....
Then when it finally does come in, scramble to setup and launch before it gets crappy sand strong...nope too slow of a setup...so just watch everyone WHO WAS READY FOR IT launch and go straight up.......
After awhile I had to fly (it had been 3.5 weeks) so I launched into some nasty air and played (got tossed around) in that nasty air for about 20 min before calling it quits and doing a nice fast top landing.....it was a short one yesterday and I still missed it...

Yeah...it was a short one yesterday, but I was one of the fortunate one's who was set-up and got into it...I guess it helps to only have one glider to choose from...

I was able to kiss 1155' MSL above the north bunkers...the air was glass smooth for a good hour or so and the overall sweet spot seemed to be around the 900 to 1000+ foot range...I could ease the bar forward, gain altitude and fly backwards, or just sit motionless at the north end...talk about getting into a trance...

The City, east bay, and all over was crystal clear...there was a little blue helicopter zipping about that appeared to know our whereabouts, but I still felt compelled to keep a close eye on him...

Then I could feel it getting a bit more textured, so I top landed after a little over an hour...the winds began to gradually increase throughout the day and into the late afternoon from what I could tell...

~Chris

So Chris,
Could you help us recognize a pattern for sucessful shearing? What were the conditions like before the shear arrived? On what did you base your decision when to launch? What were the conditions like right after launch, and later on landing? How many others got up in it?

"Could you help us recognize a pattern for successful shearing?"

I'll do my best, but there are others who could do much better explaining this...

First, my glider was set up [another blatant jab at Diev ]. The conditions appeared blown out as early as 9AM Sunday morning. By noon the wind had turned light and more from the south. So the wind direction was switchy that day and velocities varied. There were medium-sized white caps, though, from the bowl on up north as far as the eye could see. Something appeared to be rolling in. The wind sock was reading SSW by about 2PM, but upper layer winds and cloud wisps were NW, so there was some mixing going on. Then the wind sock slowly started inching its way W and WNW matching more the upper layer winds. A couple pilots started suiting up and I soon followed...a NW shear was upon us as the velocity picked up, too.

"On what did you base your decision when to launch?"

What convinced me it was time to launch was the matching of the lower level wind (the wind sock) with the upper level winds (the upper layer wisps of clouds from the NW). Rather than being at 90 degrees to one another, they were now in-sync with each other, but along with that came the increase in wind velocity. It was time to launch before it became too strong...Also, the birds were specking out at the north end above the bunkers and not getting jostled about...

Right after launch, it was a bit of a rodeo ride to the north end, but once we reached the bunkers the elevator ride became apparent...it was going to be a good day. Almost all of the pilots who launched stayed near the north end working the lift / elevator ride. That appeared to be the sweet spot. I think I was about the 3rd pilot in the air with a total of about 1/2 dozen others...maybe a couple more.

After about 45 minutes, I felt the air cool off considerably and the velocity picked up quite a bit. The air became less smooth and more "textured". The "sweet spot" of ultra smooth air seemed to be disappearing. I noticed a couple people landing and could see the wind sock whipping around much more than before.

The winds were WNW while landing and strong, maybe in the high 20's or thereabout. I let myself drift pretty deep, almost over the road that runs by the clubhouse while landing. Personally, I like to be far back from the setup area in these conditions and planted my glider well enough back to not incur any rotor...

This is my take on the shear conditions on July 1st, 2007. Each shear has its own characteristics and can deliver goodness or misery in a moments notice...

Chris

hi chris, and everyone,


thanks so much for these posts! super informative for a newbie like me


i have a question for ya though. you spoke of waiting until the upper level and lower level winds were aligned before launch. first off, how high were the upper level winds. if you were using cloud wisps as your gauge, i'd think they're pretty high. would those come into play in your flight?

and what's the problem if the upper level winds and lower level winds aren't aligned? do you get rotors or turbulance at the meeting of the two winds? unsafe?

thanks!
josh