Monday, May 31, 2010

Tehachapi Day 3 - Mystery Partly Solved

Very few people flying today, so hard to tell if anyone stayed up. It was a bit breezier but not bad. Conditions didn't look good for a retry of my long flight for Silver. I dawdled trying to decide whether to try to fly shear line (due to the wind) or wait for it to heat up. Someone asked me, "What's that little box on your hat?" I replied that it is a mini audio variometer which I can use if the one in the ship fails (or in Blaniks that don't have built-in audio varios.) She asked me, "Do they fail often?" I said no, but I had the whole battery fail once (the PW5 has no pneumatic-only vario), and I had definitely used it then. (See my first Dust Devil Dash post.)

One club member stayed up about a half hour, working shear line lift at about 6000' MSL, so I figured I'd at least give it a try. As I was pushing out, he came back, which was not a great sign.

During the tow, I noticed the vario needle swinging wildly, something I had seen yesterday but attributed to the bumps we flew through. I let off at 3000' AGL, well upwind, where I thought I would start hunting for shear line (convergence) lift. But something wasn't right. I was seeing sink on the vario, but it didn't feel like I was sinking nor was the altimeter unwinding. I thought to turn on my clip-on electronic vario and sure enough, it beeped to indicate lift. I also checked the "Vario" number on the display of my PDA/GPS, and it showed "up" as well. (Not sure if it's calculated from GPS info, or fed from the pressure sensor in the Volkslogger.)

So I had conclusive proof that the vario or the pneumatic system that drives it was faulty. Yesterday's terrible flights were not entirely my fault. Thinking I was in sink, I sped up to try to get out of it, which only made things worse, since the PW5's polar curve drops off pretty steeply with speed. I had slowed down to minimum sink speed a couple of times to try to reduce the drag and see if I was fooling myself, but maybe at those times I really was in sink, because it didn't help. I don't know why I didn't think of checking against the other vario and the GPS yesterday - I guess I believed the instrument too much.

I ignored the bad instruments and flew by feel and by my clip-on vario. I found some moderate lift and then a halfway decent thermal. I worked it back up to 7100' MSL, nearly my release altitude. I couldn't seem to get higher than that. I don't think it was shear line lift, because it was wide enough to circle in pretty consistently. I left it in search of other lift, but kept coming back to it to "tank up". Eventually I went downwind to circle under another glider that was higher than me, but that didn't work out and I came back for a landing after 33 minutes. I didn't care that it was fairly short - I had solved yesterday's mystery and successfully worked the lift on a not-so-great day. (And I experimented with another way of working lift in wind, but that's a story for another blog post.)

My landing on runway 27R was terrific - really smooth touchdown, and I worked hard to get a very long straight rollout with a light gusty wind about 40 degrees off my nose. That's tricky in the PW5, with its non-castering wheels and tiny rudder. The runway was completely clear so I was able to roll all the way to the west end, and use the favorable crosswind to roll off gently, wings level, into the dirt right in front of my tie-down spot. Nice!

Back on the ground, another club member and I worked on diagnosing the problem. To make a long story short, we found a kink in the Total Energy probe line, and think it's pinched or caught somewhere under the cockpit floor. Another member who's staying over at Tehachapi is going to pull the floor and look for problems.

Sunday, May 30, 2010

Tehachapi Day 2 - Skunked Twice

My plan for today was to try for a very long local flight in the PW5, if weather conditions were favorable. I need a 5 hour flight to complete my Silver badge, and this was the first opprtunity where the glider availability, my preparation, and the weather might all come together. It looked possible according to the forecasts and models, with decent lift as high as 10,000' in the Tehachapi area (but not very far north), and light winds from the east: up to 15 knots on the ground, but only about 5 aloft. I planned to stay local if possible - I didn't see any reason to complicate the goal by going cross-country.

For a long flight like that, I made sure to take plenty of water, some snacks, fully charged battery, and a full oxygen tank. I planned to take off by about 11:30. A few other gliders launced before me, but no one had yet stayed up very long. I took off to the west (runway 27) at 11:15. I thought the tow pilot would take me over the mountains, but instead he took me over the valley upwind of the airport. The vario was all over the place - way up and way down. We encountered some lift, and I let off at 3100' AGL. I did a tight circle to "notch" the flight trace and to work the lift. Nothing but sink everywhere I went. I couldn't get up over the mountains so I tried to explore the valley. The sink was anywhere from 6 to 10 knots. Very soon I was forced to land, I think after 13 minutes.

I pushed the glider aside to think about the conditions and see if anyone else was staying up. Soon there was a line of about 8 waiting to launch. I was advised to try to get away from the valley and head north, that by this time of day often the thermals die off. This time I asked to go over the mountains, as I felt the chances were better there because I could see a couple of gliders. I took off to the east at 12:25. At 3000' AGL there was nothing. I held out until 3800' and let off in some lift. Again, I could not get back into the lift. I tried the bald spot - nothing. I tried the ridges, looking for anabatic lift (unlikely) or orographic (more likely). Sink over the foothills. Sink over the valley. At 2000' AGL I found one weak little thermal that I worked for quite a while but it only gave me 100'. This flight only lasted 27 minutes.

Another pilot took off in the PW5 at 2:07 and stayed up for two hours and reached 11,700' MSL. And some guys went up at 2:00 in the Grob and got 90 minutes. So I guess I was just unlucky.

Saturday, May 29, 2010

Tehachapi Day 1

Several club members are at Tehachapi with the Grob 103 and PW5. I spent the morning and early afternoon doing maintenance on the Grob and figuring out the new Borgelt vario in it.

One club member brought a friend who wanted to go for a ride. We took off and let off in good lift. Although I caution newbies about thermal flight (see May 9), he wanted the whole experience, so I worked it for a while, gaining 900 feet pretty quickly. The view of the desert was spectacular! Although I kept to 30 degree banks, he did get queasy so I straightened out and cruised around over the mountains. We encountered two other gliders thermaling together but did not join them. I was able to fly through little bits of lift without circling, but eventually had to go out over the valley.

My passenger was feeling uncomfortable - said his hands were going to sleep - so I pulled the spoilers and brought us down. There was a bit of crosswind which made the last bit of final approach interesting, but it was not too bad. The runway was clear so we were able roll all the way to our tiedown area. Total flight time was 28 minutes.

Tomorrow is supposed to be even better conditions. If all goes well, I'm going to attempt a 5 hour flight in the PW5 to complete my Silver badge. My longest flight so far was about 2:50 I think. I won't go very far from the airport - probably just around and around the valley. The goal is to stay up, avoiding sink, not to do a cross-country flight over variable terrain I've already completed the distance and altitude requirements. I'll take along food, lots of water, oxygen, and the Volkslogger for proof. Music would be nice!

Sunday, May 23, 2010

Landout / survival kit

At our club meeting yesterday, I led a discussion about landout & survival kits, and opened up my kit to show one can look like. The idea is that when you're engaging in cross-country soaring, there are several scenarios that could place you in the wilderness on your own for some time, so you should take along some gear to make your stay more comfortable... or even survivable. And even on our "local" flights, we go over some fairly remote areas of the Santa Ana Mountains. A bailout or crash there could mean a long walk or an overnight stay. My kit is full of stuff I'll probably never need, but it's all so small and light that I decided it's worth including I take the kit along on nearly every flight in the PW5.

There are three scenarios I can think of where landout/survival gear would come in handy:
  • A routine, safe land out on a remote airstrip, dry lake bed, or other flat place in the desert or mountains. Even if the crew knows where you are, if it's late in the day, you may be staying overnight. In this case, you and the glider and the kit are together. Landout gear is important to protect the glider. Survival gear can make you more comfortable, first aid gear is probably not needed.

  • A survivable crash. These happen... pilots fly into trees or get forced down by mountain downdrafts. Rescue can take some time. In this case, you probably have access to the kit. Landout gear is not important, but first aid supplies might be, along with survival gear.

  • A bailout, due to collision or mechanical failure. You may or may not land close to the glider and your kit, so in this case your "survival kit" includes whatever minimal stuff is on your person, and your parachute and whatever's attached to it.
There are lots of resources on the web and in books and magazines to help you select landout and survival gear for your kit, so I won't go into the "why" for any of this stuff. If you have any questions or comments, please post a reply.

All this stuff fits into a single cloth bag which fits under/behind the seat in the PW5. It would just as easily fit in the cargo area behind the rear seat in our Blanik L13 or Grob 103. It weighs 4 pounds (of which 1 whole pound is a windbreaker jacket) and takes up 0.4 cubic feet. I started with a survival kit and a first aid kit I bought at a sporting goods store. I added tent stakes and ropes (the "landout" part), a flashlight, some granola bars, and personal items such as contact lenses.

I always wear "cargo" pants which provide some additional pockets. I should get a very small bag which fits into a leg pocket, and transfer some of the very small essential stuff into to cover the bailout scenario. There are also small packs that can strap onto a parachute, and I should look into that as well. On one side of the chute I strap my Personal Locator Beacon, but there's room on the other strap.

Here's the list of what's currently in my bag:

Main bag
Stakes - 2
Ropes - 3
LED flashlight
Windbreaker (stuffed in quart Ziploc bag)

Waterproof bag - commercial survival kit
Small multitool
Light stick
Bright vinyl tape
Fire starting sticks - 2
Candle - heat-resistant
Tie-wraps - 2
Space blanket
Pad of paper
Tape strips
Plastic bag

Smaller Bag
Chemical pocket warmer
CD for signal mirror
Batteries for flashlight
Space blanket
Sunscreen packets - 2
Wipe packets - 3
Vinyl tape
Contact lenses
Eye drops
Trail mix bars – 3

Little stuff in Ziploc Bag
Waterproof matches
Golf pencil
$20 bill
Nylon rope
Safety pins
Razor blades
Fishing line

First Aid Kit - store-bought
Gauze pads - 2
Non-adherent pads - 2
Various adhesive bandages - 12
Tape strips - 2
Alcohol pads - 4
Iodine pads - 2
Sting pads - 2
Antibiotic ointment - 2
Advil - 8
First aid pamphlet
Gauze strip
More band-aids and alcohol pads


Wow, I just noticed that I've written 250 blog posts since starting this blog in 2005.

Coincidentally, I recently logged my 250th glider flight (in March). I started flight training in April 2003.

Sunday, May 09, 2010

An ideal intro flight

A longtime friend is visiting from out of state, and she wants to go for a glider flight. She's not exactly the adventurous type, so I'm a little surprised, but I'm always glad when a friend is interested. A first-time glider flight, especially for someone who isn't already a pilot or looking to become one, is kind of a balancing act for the pilot. I want them to have fun, with no motion sickness, but I also want it to be longer than just a "sled ride" and for them to experience soaring upward in lift. But working lift often involves steep turns which can be scary and induce motion sickness. So the question is always: to glide or to soar? To take off early when it's smooth but soaring isn't likely, or to wait until the thermals start but it can be bumpy?

Saturday's weather looked promising, with clear skies, mid-80's, no cloud cover, and moderate lift forecast: 3 knots of lift to about 5,300' MSL. We got to the airport early in case I had to wash and/or preflight the Blanik, or in case a number of us decided to assemble the second Blanik (still on the trailer after our winching trip). As it turned out, another member had washed it, and he and a new student did the preflight, and there weren't enough members to assemble the other one, so we ended up with a lot of time. The instructor had three students for the day, and some paperwork to do with them, so we decided I would take my passenger up first. After waiting in line for a couple ships, we took off at 11:37, pretty early for any thermal activity.

The takeoff was a bit slow and the climb-out was a LOT slow. Usually we climb to about 400-500 feet and turn south, but this time we kept going straight out over the lake and were only 300-350 feet AGL. Had we had a rope break there, we would have made it back to flat open land but probably not to the actual runway. I decided to hang in there and we eventually climbed normally up over the mountains. Later I talked with the tow pilot and he said we seemed to go through area of sinking air. Plus we had a tailwind instead of the usual headwind, so all together it made for a very flat flight path. Once we got onto the southbound leg over the hills, we started getting some turbulence which I hoped would indicate lift. My passenger was enjoying it so far.

As we approached 3000' AGL over the mountains we got into some lift. Between the towplane climbing and the lifting air, it was nearly 1000 feet per minute up, and it continued for several seconds, so I pulled off and turned into it. What luck! It was pretty strong, up to about 300-400 fpm at times, and very broad. Whether it was thermal or convergence, it was big. I was able to stay in it with about a 15-degree bank. That was the best of both worlds: a gentle bank for my passenger's first glider flight, and lift to keep us up for a while. We took that up about 800 feet very easily (to 5,100 feet, very close to the thermal forecast). With nearly 4000' in the tank, we could afford to fly around and enjoy the view. Although the tow plane went by once with a Schweizer, we never saw them again - we had the whole sky to ourselves. We never hit any serious sink, and we found 1 to 3 knots of lift occasionally, so it was a pretty relaxing flight. Jody was enjoying the flight, and the lift we found after that first boomer was weaker, and I didn't want to push it by trying to aggressively work the smaller thermals.

So I eventually turned back after about 35 minutes - I knew we had student pilots waiting to get in the air. Of course, as I started the 45-degree leg we encountered more lift and I had to use spoilers on the downwind leg to get us down. My landing was smooth and the rollout was nice, although I had to hold a fair amount of right rudder and aileron to keep aligned - that tailwind had turned a bit and was now about 30 degrees off our nose, but gentle. We rolled all the way up for an easy pushback, and ended up with a 43-minute total flight.

That strong and wide lift at 11:45 in the morning was really amazing, and made for a terrific guest flight that was long enough to be fun.