Thursday, June 28, 2012

Weird but it Worked

Sunday's forecast was for winds from the west or northwest north of the mountains, but from the south down in the L.A. basin. That made for a possible convergence at right angles right on the top of the mountains. It looked like there could be the possibility of mountain wave lift in places. It was warm enough for some thermal heating too, if the winds did not blow them out.

I decided to fly our Grob 103 Twin Astir because I wanted to check out some issues with how it handles. Our club members have been discussing how heavy the aileron controls are, and whether the stick forces are increasing or not. (If any readers have experience with this in Twin Astirs, I'd like to hear about it. This specific model is known to be different from other Grob 103 variants.) Since the winds were fairly light, I figured it would be a good day to experiment with it.

There were reports that lift was working well over Mt. Lewis. I towed to 3900' AGL (7300' MSL) over the "second ridge" and let off in decent lift, hoping to work my way up to the higher mountains. It was pretty patchy lift, though, and I had to drift down the ridge (westward) to keep sufficient clearance. I found more lift over the valley next to the Devil's Punchbowl than I did over the hills. It was enough to slowly creep up, but nothing very exciting. A couple of other gliders joined me, but none of us were climbing very fast. For the first hour I was up and down by just a few hundred feet.

The lift was puzzling, as it often can be in this area. Sometimes it was too narrow to circle like a thermal, and there was rotor-like turbulence next to it, but the lift was not smooth as one would expect if it was wave. For a while it seemed to be parallel to the second ridge, as if it was a small wave coming off of it, but other times it was perpendicular to it.

After about an hour of hard work, I found a big, wide area of lift that felt more like thermal, and shared it with (as I later learned) a DG-400. That is really one of the fun parts of local soaring: flying near, but not too near, other sailplanes. Watching each other swoop and turn big lazy circles, or tighter turns trying to core a thermal, you feel like you're weightless, and the ground far below is irrelevant. It's amazing how suddenly your companion glider can be a couple hundred feet above or below you, as you each get into and out of areas of lift and sink. Unfortunately I did not bring my camera along this time.

One of the great thrills is finally "ratcheting up" the altitude and finding that you're going up more than going down, and being able to relax and enjoy the flight. Eventually the lift was stronger and more consistent and I reached 9,000' MSL. By that time I had been up for nearly two hours, and I had kind of a time limit to the afternoon, so I called it a day. Not a spectacular day, but ultimately a successful one. I ended up with a total time of 2:08.

Talking with other pilots back on the ground, we all agreed it was a weird day. Some lucky pilots broke through to some good wave lift over the higher mountains and got to 14,000'. Others of us in thermal  lift topped out about 9,000'. Some of the lift was hard to categorize, so we figured it was some combination of convergence and moderate wave over the hills, and thermal over the flats. Whatever!!