Monday, April 21, 2014

April 19, 2014 - A Day in the Convergence

Visibility: 10+ miles
Wind: NE 3 - 10
Altitudes: 8,100 ft
Time Aloft: 2.5 + hours
Max Lift: 8 Kts
Temperature: 75 - 80 F
Comment: Good day in the Mountains and Valley
Tow pilot: Yutaka Buto (Thanks Yutaka)

  This post is about a week late.  However, there are some details that are worth sharing, especially for anyone who has heard about convergence lift but has not had a chance to fly in it.  I will add that there were several players (Karl in GD, Julie in JB and Morgan/Eric Bick in 5H) along with others in the 2-33s.  I was not on the ground when they were aloft so please forgive me as I did not record your names.

  After pre-flight inspection of the 1-35 the first clouds started to form over the mountains.  These cycled through lunch, sometimes forming a large mass and sometimes disappearing altogether.  This cycling continued as other ships were assembled and lessons continued. 

  I was second in line and towed off a little before 1:00 pm.  This is the first time I could clearly see the convergence and I was anxious to connect and use it.  I was almost too anxious; I got off tow in a decent thermal that I thought would connect and spent the next 45 minutes working my way into the lift.  Lesson 1: tow directly into the lift; do not tow "near" the lift, and do not endure hearing others call "6,000 feet at 7 knots" while circling at 2,500 in 2 knots.

  Once in the lift, I ran south to Orchard Peak, observing the clouds and their alignment with the mountains below.  By this time I could hear 5H, JB and GD well on their way north and south.  JB was headed to Blackwell Corner, so I was interested as I was headed in this direction.  I made Orchard with plenty to spare but decided to run to 41/33 as it was the  next turn point on my task.  5H was headed south by then and called my position, crossing behind and below me.  Lesson 2: There is a lot of radio chatter regarding position and conditions; listen closely and do not be afraid to add your fair share.

  There was a finger of cloud pointing at 41/33 so I aligned under it and climbed.  I added up what the run from the lift to the turn and back would cost and headed out.  After making the 41/33 turn with only a few bumps, I rejoined the lift, climbed and headed north.  By this time there were many radio calls from other sailplanes transiting the area, as well as JB returning from Blackwell Corner and GD heading south.  Lesson 3: On that day, the convergence tended to group the traffic in a relatively small area.  Radio calls and good scanning are required (FLARM would be good; having a yellow sailplane doesn't hurt.)

  By the time I headed north, the clouds over the mountains were mostly continuous.  I spent some time trying different sides of the cloud to see if one side was better than the other.  I had mixed results, so there is something to learn here (the more experienced members can please comment as they see fit). 

Around Hidden Valley I turned around.  There was more traffic moving south and I was able to fly with JB for a little while.  I decided to run west to Parkfield and then head back to convergence.  What became very clear was the area to the west had smooth sink (-5 knots) so this task was quickly abandoned and I ran back to the mountains.

  I headed toward Avenal and found both 2-33s circling in lift along with JB heading back to land.  The lift that was not present during the run from the convergence to 41/33 was now in place and I was able to do a few turns with 45H.  JB landed then I touched down.

  Morgan informed me later that the OLC distance for the club this weekend totaled over 1,000 km.  Lesson 4:  I have been hearing about convergence flying for years before I had a chance to give it a try and I highly recommend it. 

Morgan's Report:

Classic great convergence day. I was scheduled to fly with a new contestant for the contest, Eric Bick.  He was coming up for the day and I had offered to give him an area checkout in the Duo and show him what I could of the contest area.  I didn't expect the kind of day we had though.  Due to a long drive, he didn't arrive until nearly 2pm, so we got a very late start.

Off tow the valley was working, but the clouds were clearly a bit to the west of the hills and it took a little effort to get into them.  Once on the convergence line, it was clearly a great day.  I stopped thermalling about 1500-2000 below cloud base and started to just dolphin fly the convergence heading south and climbing along the way.

There was a short gap between Orchard Peak and the temblors, but we jumped into it and had some small puffs indicate the line for us.  It was a milk run all the way down the CA Valley following the very well marked line.  A few stops in lift that was very strong.  It was a different kind of flying than Eric was used to.  The Mojave shear lines are much more rough and not so much like a well organized line of thermals like we have.

We jumped across the CA valley at Soda Lake, then across the Caliente Range near the Fellows VOR and across to the Sierra Madre range on the south side of the Cuyama Valley.  The clouds extended all the way across to the San Rafael range north of Santa Ynez.  We pushed partly across, but with bases around 8000, it's not somewhere I like to be that low and we turned.
Looking West up the Cuyama Valley on our way North.
Looking East down the Caliente Range and towards New Cuyama, note how wide the convergence line is.

The run north was even easier than the run south, at least until about 10 miles east of Orchard Peak. Then it was clear the day was starting to die.  It was probably 4:30 or 4:45 at this point, so no surprise.  I took the opportunity to teach Eric a bit about finding the convergence line in the blue.  Looking for small wisps and more importantly to just feel your way along the line.  Small intercept angles and turns as you bump along a narrow line of blue lift.  Using this technique we continued from south of Orchard to around Pine Canyon without thermalling.  Probably 20 miles of running in the blue without a real climb.

At Pine Canyon we found a climb to 7000 that gave us enough to jump across to the Juniper Ridge that runs up to Center Peak.  Here I made a mistake.  We had descended out of the NE flow and into the Westerly flow without any obvious transition.  I pushed west to Center Peak where BG had found a climb only 5 minutes before.  Nothing but sink.  Turning towards Coalinga at about 5500 it was clear that I was in westerly winds.  I told Eric that when it doubt, go downwind.  We headed downwind towards the Coalinga airport and sure enough, back into the convergence line and a 3kt climb to close to 8000.

TOR, Kurth Thams in the motor glider Carat, had been flying with us on the way north.  He was low near Coalinga and had to fire up the aluminum thermal.  If I had found reliable lift just a few minutes before he probably would have made it home, but had to light the fire before getting too low and lacking fuel reserves.  He did join us in our thermal for a climb boost.

We topped out, headed North to the San Benito Range, but it wasn't working. With that we turned for home and final glide back to Avenal.  I pretty much got to show Eric the entire contest area, except the central valley. I can only hope we get a few days like that during the contest.

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