Tuesday, September 02, 2008

Day 1 - Two flights: one lead and one silver

Saturday was hot and humid, promising good cumulus clouds. Mountain Valley Airport in Tehachapi is at 4200' MSL, so a 3000' tow starts you out at over 7000'. I launched about 12:20 in the PW5, let off at about 7400' over the Tehachapi Mountains, worked up to 8000' and could not get any higher. When I went in search of more thermals, I found nothing. There were some CU, but they apparently were already mature. I eventually ended up back in the valley and had to close in on the airport. Only 200' above pattern altitude, I found a thermal and went back up to about 6000', but that was all she wrote. I was back on the ground in 40 minutes - frustrated and angry.

After taking a break and thinking it over, I launched again at 13:42. Gotta get back on the horse, right? The CU were cycling up again.

This time I let off at about 7000' in strong lift, and immediately found two thermals that took me up to 13,500', still over the Tehachapis south of the airport. At some points I was above the base of some of the clouds - apparently some thermals went higher than others.

Whew! I do still know how to fly! That first "lead sled" flight was just bad luck. It's generally accepted that you need 10 to 11 thousand to hop over to the north side of the valley and make the mountains, so off I went across the hills on the east end of the valley (the "windmill ridge") hopping between scattered CU. I was fully prepared for a cross-country practice flight, and the CU over the Piute Mountains were looking nearly continuous. I lost only about 1500' getting to the good stuff, then was back up to 12,500' or so near cloudbase.

The air was very clear and I was able to look around and see some of the landout sites that were hard to see on previous flights. From my location and altitude, it looked like it would be easy to reach Mojave Airport, the Honda Track, etc., so I was feeling pretty good about going on. Some pilots reported rain and hail north of my position, and I could see it like a gray curtain. As I skirted around it to the west, I did go through a little hail, just for 10 or 15 seconds. It seemed to have no effect on the glider's flight. I also was watching the lift rate to make sure I did not get sucked up any stronger than was safe. But I was occasionally able to see the sides and tops of the CU, and they were not overdeveloping into thunderstorms, so I just cruised along below the clouds. That is the most amazing thing - cruising forward continuously, and not losing any altitude, just balancing the glider's sink rate with the lift, and doing about 50 knots. Way cool!

Another thermal and some cloud suck took me up to 13,500' and I kept going north over the Kelso Valley at up to 14,500'. Walker Pass and Inyokern were in sight. I had seen Walker on my earlier flights but had not made it that far. Last time, Inyokern was off in the hazy distance; this time I could see how close it was (about 13 miles), and a glide to there in an emergency certainly looked possible. I think I may have switched my task in my PDA to Inyokern to get the distance... don't remember for sure. I was using my marked-up sectional quite a bit, which showed 5-mile and 10-mile circles for all my landout sites. The clouds kept me up, and I turned back over Walker Pass at over 13,000'. That was far enough for this day - I did not want to tempt fate and a possible landout. It was about 15:00, and I expected the lift to start diminshing at any time. Most of my clubmates were going about as far as Kelso Ranch.

On the way back south, I made one mistake. I followed the same clouds that had brought me here, but did not realize that they had drifted east and so I was more over the desert foothills than over the mountains. Some of the CU started looking ragged, indicating that they were mature and the lift would be less. I started to lose some altitude, getting down to 11,500' by the time I was opposite Kelso Ranch. The margin was starting to look thinner, and my PDA lost its connection to the Volkslogger GPS. I got that fixed. Guys on the radio confirmed that they had found better lift on the west edge of the clouds, rather than where I was, and I got back to the west. One thermal took me back up a ways and so I had an easy glide from 12,500' back to the valley. By the time I made it into the valley, I was under 9,500'. That's an interesting aspect... you need a certain amount of height to get back and clear the final ridge, but then once over the valley, you have 5000' to burn off! So I did some lazy circles and landed after 2 hours and 21 minutes.

From my furthest point south (at the top of that great thermal) to Walker Pass where I turned around was 43 nautical miles, well over the 27 needed for the Silver distance. SeeYou calculated my total distance flown (not counting circling) as about 105 nm. I downloaded the flight trace from the Volkslogger to my PDA's external memory, and later my PC, for safekeeping. That night I re-read the Silver distance rules, and my south-to-north leg should clearly be acceptable for the flight claim. I wasn't really planning to go that far, so I had not uploaded a declaration into the VL before the flight, but the way I read the rules that should not be a problem. I have an Official Observer lined up to confirm that the trace from that day is mine. So I should have both Distance and Altitude for my Silver.

Back home, I found that SeeYou makes uploading the trace to the On Line Contest totally automatic - way easier than I was expecting!

So now I'm feeling pretty good about flying in the Dust Devil Dash contest next weekend. If you read my account of last year's contest, you'll see why I was not feeling so good about it before this flight. So if the weather is good, I'll go for it again.

Soon I'll write about the remaining days of the weekend trip - totally different weather conditions!


Julien said...

Hi Roger,

Thanks for the blog posts, I really enjoy reading about flying through the eyes of a glider pilot. I'm just about to finish my PPL and learning to fly gliders is definitely on my list of things to do.

In your post you mention altitudes in excess of 10,000ft. Do gliders pilots carry supplemental oxygen when they plan to spend extended amounts of time at those altitudes? Did you ever feel the symptoms of hypoxia?

I find it very ironic that without an engine you can go a lot higher than I can in a 172 :-) Makes me wonder what's the point of burning all that fuel.


Roger Worden said...

Yes, many gliders have oxygen systems. Our club PW5 and Grob 103 ships do, because both are used for cross-country flights. In the PW5 we have an EDS oxygen system which I have set to come on automatically at 10,000 feet. I noticed no ill effects before or after the flight. The club provides an O2 tank, but I bought my own so I can make sure it's always full when I need it.