Saturday, December 27, 2008

Two nice dual flights

Today the air was crystal clear, providing wonderful views of the snow on the mountains to the north and east. But due to about 50% cirrus cloud cover, it never got warm enough for good soaring. I was determined to fly regardless of lift! (Also, I got a tiny new camera recently and wanted to try it out.)

N, one of the students in the club, has passed his written test for the Private Pilot license and wanted to start to practice for the Practical test. He asked me to fly with him and tell him what maneuvers to demonstrate. I have a list of them, so after going over the list in some detail, up we went. (You can just see the towplane and the mountains in this shot.)

We found just a little lift on the first flight, keeping us up for 30 minutes from a 4000' tow. The second flight was not so lucky, essentially no lift and a 23 minute flight.

The list of tasks for the Practical is pretty long - it's quite a bit to accomplish in a single flight. N did nearly all of the tasks on both flights.

1. Aero tow
a. Box the wake when above 300' AGL
b. Slack line control
c. Signal the tow plane for turn, speed up, or slow down
2. Release at 5500' MSL (4000' AGL)
3. Steep turns
a. One 360 degrees
b. One 720 degrees
c. Complete turn on a specified heading
d. Final turn serves as one clearing turn
4. Stalls
a. Straight ahead with and without dive brakes
b. Turning (left and right) with and without dive brakes
5. Slow flight - 35 knots
a. Straight ahead flight
b. Left and right 90 degree turns
6. Straight ahead flight
a. Minimum sink speed
b. Best L/D speed
c. Speed to fly if in sink
7. Thermal soaring
8. Approach to glider area of runway 22
a. Slip on base or final without dive brakes
b. Use of radio
9. Land in designated box

So I got to fly for nearly an hour with a friend, practice some instructor skills, and split the tow fees. Not bad! The only downside to dual flights with students is that I can only log as PIC the time that I am actually flying the plane, which in today's case was only about 5 minutes per flight.

Tuesday, December 16, 2008

Thinking about lift

I've been thinking a lot about lift lately. Not the kind of lift that glider pilots seek out (upward moving air), but the kind of lift that both airplane and glider pilots care about: the lift generated by the wing.

All pilots, and most passengers, at some level want to know "What makes an airplane fly?" The wing, obviously! Since I want to be an instructor, I should be able to explain what enables a wing to fly. I've read a number of sources, and am still unsatisfied with the explanations.

Most sources talk about Bernoulli's principle (why the top of the wing causes lift) and/or Newton's law of reaction (why the bottom of the wing causes lift). Some synthesize the two, and speculate on what proportion of each effect causes the most lift. Some introduce "circulation". Eventually they all start getting vague and say that the reason a wing accelerates air that flows over the top surface can't be easily explained and mumble something about Euler's equations, as if that will help.

Stick and Rudder, otherwise a fantastic book, simply says "It shoves the air down with its bottom surface, and it pulls the air down with its top surface; the latter action is the more important." Langeweische says a lot about how lift varies with Angle of Attack - he is much more concerned with how to fly the wing than with why the wing flies.

See How It Flies Section 3, Airfoils and Airflow, is filled with wonderful diagrams of stream lines:

and talks a lot about the timing of the parcels of air. Like other books, it tries to correct the false notion that the air flowing over the top of the wing "must" move faster in order to meet up with corresponding parcels flowing below. That makes sense - there's nothing tying the two flows together.

Later, Denker talks about circulation but never explains it. He starts with the idea of air circulating around a stationary wing on the ground (artificially stirred by a paddle), then expects us to accept that circulation continues during flight. I'm sorry, but I don't think there's any air making its way around the trailing edge from the top to the bottom and flowing forward - it's all flowing past the trailing edge. In fact he makes that point himself by discussing the stagnation point at the trailing edge. He and other sources seem to say that circulation is a mathematical construct to explain pressure differences, not a real circulation around the wing. Huh?

Aerofoils and Wings explains a lot about how different wings behave, but as far as lift generation goes, Brandon just refers us to Denker. Later, "As the air accelerates away from the stagnation line, the local airflow over the upper surface gains a greater speed than the lower." We're supposed to take this on faith? What makes it accelerate so much? OK, it accelerates upward because the leading edge forces the air up over the top surface. But why would air flowing below the wing not also accelerate? It's being pushed down, just as the air over the top is being pushed up (due to the Angle of Attack), but I suppose not as much.

In the January 2009 issue of AOPA Flight Training, "The Magic of Lift" can't seem to decide whether or not air meets up at the trailing edge at the same time. Christensen spends some time trying to explain why air traveling faster has lower pressure, using a car-traffic analogy. That's a useful analogy, but only if you assume that the air above must move faster because it has to get to the trailing edge at the same time as the air below. He starts to debunk that idea and then reverts back to it.

But at least Christensen considers the wing from what I think is a better point of view. Most texts describe a stationary wing, and a moving flow of air. I think that's because wind tunnels have been used for years to study airfoils (it's easier than observing airflow by looking down the tip of a moving wing!). But in flight, the wing moves and the air is still. Most texts would claim that the two situations can be described by the same laws. But I'm not so sure... I think the behavior of the air may be different, primarily because of inertia and ambient pressure.

The air has stationary inertia (it must be shoved out of the way by the wing), it doesn't have inertia of motion. As the air is shoved out of the way, wouldn't its pressure be increased, rather than decreased as is assumed in the air-moving-faster-over-the-wing model? He states that as the air comes back down after the wing has passed, it "now possesses momentum, causing the air to overshoot ... resulting in the downwash." I get that. But what started it moving downward - isn't it the ambient pressure of the air above it that is being shoved against? I think of the air as squishy, and once the wing gets out of the way, the air is squished back downward.

According to Bernoulli, moving air has lower pressure. But it seems to me that it may not have lower pressure in all directions. A parcel of air moving upward, being shoved out of the way by the top surface of the leading edge, may have lower pressure horizontally, but wouldn't it have higher pressure vertically? After all, it's being squeezed between the wing and the air above it. Once it gets moving at a constant rate, maybe... but as it's accelerating, it seems to me the pressure in the vertical direction would be higher. (I remember reading a description of pitot tubes and venturis that made me think of it this way... I'll have to look for it.)

NASA cops out and fails to provide a good explanation, too. They spend a lot of time explaining flow patterns and have some great interactive illustrations, but in the end they just say "The real details of how an object generates lift are very complex and do not lend themselves to simplification. For a gas, we have to simultaneously conserve the mass, momentum, and energy in the flow. ... To truly understand the details of the generation of lift, one has to have a good working knowledge of the Euler Equations."

But equations merely quantify physical phenomena. Mass is moved around by energy, not by numbers. There must be a way to explain what the air is doing, without getting into the details of how much. Langeweische did such a tremendous job of explaining phenomena and behaviors without invoking mathematics - I wish he had tackled this aspect as well.

Some texts also get into bound vortices (the full extension of what we pilots usually call "wingtip vortices"), and I think this aspect is far more important in explaining lift than most authors do. To put it as simply as I can, if some air is shoved downward (whether by Bernoulli and suction on the top, or Newton and deflection on the bottom), that displaced air must be replaced by air from above. You can't leave a hole in the air - that's a vacuum, and as we all know, Nature hates vacuuming. The most natural way for the ambient air to fill it is from a circular region above and around the hole. Then that gap is filled by air from below the circular region (all around the original hole). Then that circular gap is filled by the original shoved-down air spreading out. Viola - a donut-shaped flow of air - like a smoke ring. And due to inertia, it keeps on vortexing until it's diluted.

I have to think about this a little more, and find some good diagrams of it. It's almost got me believing in circulation again. The BGA Gliding: Theory of Flight has a good diagram of the donut shape of the bound vortex (Chapter 3 Figure 40), but again I think the bound vortex is partly a mathematical abstraction. I really don't think air flows forward under the wing!

So, writing this out, I think I've arrived at a conclusion. Why does the air accelerate over the top of the wing? Because it's been given energy by the leading edge, shoving it out of the way. Where did it get that energy? In the case of an airplane, it comes from the engine shoving the wing forward. In the case of a glider, it comes from gravity pulling the glider and wing downward-forward. The ultimate purpose of the wing is to transfer energy from the (engine or falling fuselage) into downward-moving air at the trailing edge, which shoves the wing upward. Most texts talk about the flow of the air over a stationary wing, as if the air has the energy. I think the wing has the energy, the leading edge forces the air up, then the compressed air above forces the displaced air back down past the trailing edge. The displaced air takes the energy with it, causing a vortex. Somehow Newton's action-reaction law gets invoked to cause the wing to go up - still not sure why. I think air moves the wing up, not old Newton. I'll have to think on this some more.

I have no aerodynamic training, just what I've read along the way to becoming a pilot and an instructor. If you have some insight into this topic, please comment! If I'm all wet, I'd like to know where I've got it wrong. But I really care about what mass and energy do. Analogies don't hold wings up. Equations quantify but don't explain. It has to make sense.

Saturday, November 22, 2008

Some work and a sled ride

Today the weather forecast was really iffy. Light winds, and lift could go to 7000', but incoming cirrus clouds could spoil it.

The PW5 needed a little work, so I tackled these in the morning:
  • The battery wires were fraying. A and I put new lugs on the ends.
  • The gust locks for the ailerons needed new foam and bungee cord. We'd been using rags as padding for a few months!
  • Replaced the long rear bungee cord on the canopy cover.
  • The O2 system had been left turned on, so the battery was dead. A kindly went to town for a battery.
Some of the student pilots are coming to me with questions about procedures and resources. Without actually getting into ground school, I explain what I can. As one pointed out (and as I've blogged about), many of the books tell you what but they really don't explain the why. For example, one wanted to know about radio procedures on the UNICOM frequency in the landing pattern. What do you need to say, and in what sequence? Why in that sequence?

1. First, say who you're addressing, e.g. "Hemet traffic:" Why first? To get the attention of people who may not be fully listening. You're saying, "Hemet traffic, listen up!"

2. Next, who you are. "Glider two papa delta..." If you said this first, then who you're addressing, people would miss your call sign because they didn't start listening until they heard "Hemet traffic." Listeners aren't fully listening all the time.

3. Where you are. "Entering 45 for..."

4. What you are going to do. I get really specific because we gliders share the airport with power traffic, and they are most of the radio traffic. They're on the other runway (23) and they do a left pattern (which they don't specify). I want them to understand where I am going and that I'm not conflicting with them. "... right-hand pattern to runway two two." I emphasize the second two because they're normally listening for "two three".

5. Finish with who you're addressing. "Hemet". In case #1 got cut off, or was garbled, or they really weren't listnening at the beginning.
Once you understand the why of the sequence, it's easy to remember!

A had not flown the PW5 for a while so I went over the controls and features with him. He took off before noon and had a nice hour-long flight. Unfortunately, he used up all the lift. ;-)

I let off in lift but could not get back into it. The cloud cover had gotten thicker and there was very little sunlight hitting the ground. All I found was about 3 knots of sinking air. Near the Initial Point at about 1300' AGL I found a little weak lift but it was not even big enough to complete a circle in. I ended up with an 18-minute ride. Bummer! After about 2:00, most people were not staying up any more.

At least my landing was good. There was maybe a 4-knot headwind at most. I think I touched down right on the line, and stopped well within the first box. I think what made the difference was that I picked out my aiming point as soon as I turned base, and kept checking my angle to it all the way on the base leg. I think I've been looking elsewhere on base leg, and then not being at the right altitude when turning final. By establishing my aim point on base, the base and final legs are all part of the same glide slope.

Saturday, November 08, 2008


One of the requirements for the Commercial practical test is landings twice as precise as for the Private certificate. The Practical Test Standard says "stopping short of and within 100 feet of a designated point". I'm told that at our field, that translates to touching down and stopping within the first of our two landing boxes, which I think is about 500 feet long. I've had some issues with touching down too soon, i.e. short of the box, and I've been planning to work on this for some time. But the weather conditions have been pretty good lately, so I've tended to go soaring rather than spend time (and money) on landing practice.

I really need to practice this in a Blanik, since that's what I'll take the test in, but one was busy with students all day and the other had its control surfaces removed for replacement of the fabric, so I decided to practice in the PW5. It's different from the Blanik: lighter, doesn't have flaps, and is different in many ways, but my problem hasn't been with those aspects. My problem has simply been the glidepath to the aiming point. For some reason I tend to pick an aiming point too far downwind from the box border, making it so I have to float too far. In other words, I have tended to come down too steeply during the base and final legs.

Flight #1: I let off at the Initial Point at 1000' AGL. In lift! By the time I got to the point of turning base, I was STILL at nearly 1000'! I extended my downwind leg much further than usual. Full spoilers and forward slip and turning slip brought me down steeply, but again my roundout point was too far downwind. The standard advice is to not adjust spoilers after rounding out, but sometimes I do close them slightly to slow the sink rate. At least with the PW5, that's hard to get right, and it's easy to balloon up a bit. I touched down about 15' short of the line. Braking on the ground was very good (there was about a 6-knot headwind component), and stopping smoothly within the first box was easy. (Speed control is crucial to touching down with little energy, making for a short rollout. This I seem to have no problem with.)

Flight #2: This time I didn't have a bunch of lift on downwind, and had a more normal pattern and approach. Speed was right on, didn't have to mess with spoilers, just kept easing the stick back and floating... floating... floating... touched down about 1-2 feet short of the line. Good rollout again.

Flight #3: I decided to do a normal tow and do some soaring. Gotta have some fun, right? Uneventful flight: let off in lift, went up to about 5800' MSL, didn't find any other major lift. Nice clear day! A bit of lift on downwind, but not nearly as much as the first flight. Speed was a little high but I fixed it. Touchdown was... hmm... I don't really remember, I think still about a foot short of the line. Rollout again was nice and short. The wind was just right to "ground fly" balanced on the wheels for about 30 seconds or so.

On all three flights, I think I only used about 2/3 of the first box - the PW5 really stops short and smooth. So... I should definitely move my aiming point even more upwind on the field, to float further into the box, at least when there's a light headwind. I think that's part of the problem: trying to estimate how much the wind will help kill the float - maybe I'm underestimating that aspect. And flying all three different aircraft doesn't help. They're all different weights and different glide ratios, so adjusting for multiple variables is tricky. When I can nail landings in the first box in both Blanik and PW5, in varying wind conditions, then I'll know I'm ready for the practical. (Not a chance in the Grob - it's way too heavy and its wheel brake is weak. I was lucky to stop it in about 1200' a few weeks ago.)

Saturday, November 01, 2008

First Mountain Wave - well, hill wave anyway

Very interesting weather at Hemet today. A low pressure system to the east was to bring rain in by evening, and there were lots of thin cumulus clouds hanging around. The thermal forecast looked good, though no CU were forecast. The temperature profile looked good - no inversion at all. Driving in, I could see occasional little lenticular clouds, indicating wave activity. Huh? There were big "lennies" on the west side of Mt. San Jacinto and smaller ones to the north and west of the valley, but only CU and clear areas over the valley. The tricky part for me has been to figure out from the lennies which direction the wind is actually blowing, and therefore where the upwind side should be. The sounding map showed the wind at about 240, and driving in I was able to observe the trailing edge of a lennie dissipating, and that was the northeast side, which confirmed for me that the wind aloft was from the southwest.

The thermals were only supposed to go up to 7300' MSL, not high enough to reach the big lennies... but maybe the little ones?

The temperature was about 90F, higher than forecast, and way over trigger temperature. The wind at ground level was 13 to 16 knots, and was forecast to be about 20 at 5,000'. By the time I took off in the PW5 about 2:00, the sky was 90% obscured, and I was afraid thermal activity would shut down. But I let off tow in lift at 4500, and worked up to about 5500, and headed southwest toward the closest cloud that looked lenticular. To get there I had to head directly into the wind (approaching what I thought would be the lift area by flying under the cloud - watch out for rotor!). That's usually a killer for altitude, but I was in zero sink much of the way. Groundspeed was way slow! (I didn't bring my PDA, so I didn't have any true wind or groundspeed info.)

The cloud was further away than I thought, beyond the hills beyond the little town of Winchester. Thinking there might be rotor directly under the cloud, I skirted the edge between it and the next cloud. Wrong idea: there was no lift, even a little sink between the clouds, and the zero-sink or 1-knot lift had been under the cloud. I turned around and headed back toward the airport. I was fairly low, but I knew I'd be flying downwind to get back, so I would not lose too much altitude.

Close to the airport, I found lift again and worked it up to 5800'. My drift in the thermal confirmed the wind direction. I headed off toward the lennie again. This time, I was starting higher and closer, so I had a better chance of making it all the way. The minor lift was there again, all the way over to Winchester and beyond. I stayed under the cloud and drifted up, though I never reached cloudbase (which AWOS reported as 7,500'). But the cloud was still further southwest of the airport than I was comfortable going, so I did not go all the way to the leading edge. I eventually turned back and headed home, planning for about a one-hour flight duration.

Under a cloud, it's hard to see the actual shape, but earlier I had been able to see it was a combination of lenticular and CU: smooth and curved at the upwind side, then broken and puffy and going upward on the downwind side. And the next cloud over was definitely smooth and lens-shaped, clearly a wave cloud. So I conclude that I was flying in wave lift, not "cloud suck". It was not as smooth as most wave is described, but then I was not at the leading edge. And these clouds did not quite fit the classic lennies caused by wind blowing across a ridge. The hills upwind that created these waves are small and isolated, so the waves were not wide areas, more like small points. Since I was only up at between 5 and 6 thousand feet, I also conclude that the wind was probably bouncing off the ground, not off a stable air layer. So when I was flying under the cloud, I was essentially flying upwind in a huge updraft between the ground and the condensing moisture. Really a strange flight: I flew about 7 miles directly into a 20+ knot headwind, and actually went UP!

Coming back to the airport, I hit some fairly strong turbulence and some 8- to 10-knot sink. It was either rotor, or all that air that went UP coming back DOWN.

The thermal forecast certainly got the condensation level wrong - it forecast 18,000' and the cloudbase was actually 7,500.

Thursday, October 30, 2008

Two thirds of Silver

I received confirmation today that my Silver Badge distance and altitude claims were accepted! Now all I need is the 5-hour flight to complete the badge.

The Badge Lady pointed out that I had miscalculated the height penalty, but I still had enough distance to meet the requirement. I'll have to go back and reread that rule... something about flights over 100 kilometers.

She also pointed out some helpful things about dealing with the Volkslogger. I had entered various landing spots into SeeYou on my PDA, to help with navigation along the way. Well, SeeYou uploaded all those into the Volkslogger which treated them as turnpoints. For this badge flight, that's not important, but for other badge or record flights, those turnpoints would be part of the official declaration, which complicates things. So I'll have to try uploading a simple task for the declaration, and then using a more complex task just on the PDA for navigation.

Saturday, October 25, 2008

Passenger and Contest Flight

Today was the second half of our club's "Family Soaring Contest". We have several events, including accuracy landing, altitude gain, speed triangle, and timed flight. By coincidence my daughter N (age 20) wanted to go for a flight. (She's been up with me in Blaniks twice before.) So off we went.

The forecast was for good soaring weather. The NWS forecast said 739 fpm lift to 10,376' MSL, which I thought was optimistic. My Thermal Forecast spreadsheet gave a thermal index of -2 up to 7,500' MSL. Clear skies and very light winds were expected, with a maximum on the ground of 94F. The air was very clean!

We planned to use the Grob 103 because our main purpose was a pleasure flight, not a contest flight. Most pilots were flying Blaniks and trying for the accuracy landing. I figured that was pretty hopeless since the Grob has such a long rollout (it's heavy and the brakes are weak). No one in our club was staying up, though some other pilots in glass ships were doing OK. Not knowing if the conditions would be strong enough to do the triangle course, I decided to just enter for the 1-hour timed flight and the altitude gain.

We launched at 14:21, and let off at 4,500' MSL in decent lift. Using no more than 30-degree banked turns because of my passenger, I worked it up to about 5,200, then soon to 6,000, and eventually topped out at 7,200' MSL (very close to my forecast). At times the lift was up to about 5 knots, though the thermal seemed pretty narrow. We saw only one other glider get very much altitude, and he was never more than about 1,500' below us. So my altitude gain was 2,700'... not anything great, but I'm sure it was more than anyone else in our club today. It will depend on how people did on the other contest day(s).

Since we seemed to be topped out, and had been up about a half hour, we just flew over to Diamond Valley Lake for some sightseeing. N was doing fine with the circling. I offered to let her fly the ship but she declined. We encountered a big string of helium balloons obviously from a car lot or somewhere, and circled it at a safe distance. Soon enough we needed to plan our descent to try for exactly 60 minutes. I was still up over 6,000' so I used airbrakes and faster speed to get us down. (This was the first time I've heard the Grob's gear-up warning... I had the gear up for most of the flight, and opening the air brakes sets off the beeper.)

Trying for an exact flight duration is an interesting challenge. You have to estimate how long the aproach pattern and the landing will take (I guessed 4 minutes), then get to the Initial Point at pattern altitude at exactly 4 minutes before the target touchdown time. As it worked out, we landed 1 minute early for a 0:59 flight. Again, I don't think anyone else tried the duration flight today, so we'll have to see how people did on other contest day(s).

The landing rollout was long, as I expected. There was little or no headwind to help us stop, which was also expected. But I forgot to back my aim point up before the landing area, so we rolled out the far end almost to the taxiway, thereby blowing the spot landing part.

N had a great time flying! The visibility in the Grob is so much nicer than the Blaniks. She had no motion problems, and was glad to get up in the cooler air.

Saturday, October 11, 2008

Good stuff today!

As often happens, the first day after a cold front made for very good soaring today. The forecast was for lift up to 6,800' MSL in the morning, and then up to 9,000' or so in the afternoon due to further cooling aloft. And that's exactly what happened. The early pilots stayed up and reported getting over 6,000. And late in the afternoon, one of our instructor/student flights did indeed get to 9,000'. There were small CU clouds to mark the lift in the early part of the day, but most of them disappeared by midday.

We assembled the PW5, since we had trailered it for the planned trip to the desert. We replaced the safety harness with a new one that the club just bought. T took it for a flight and got to 8,500 and nearly two hours.

As I mentioned, I was planning to just fly a Blanik and practice landing to the tighter tolerances required for the commercial test. I told the tow pilot I'd go to 2,000' AGL... I didn't want to just release at 700' and land, since I had not flown a Blanik for a while. I figured I would do 2 or 3 patterns. Well, at 2,000' AGL I was in strong lift, so I let off and decided to go up for a little while. That very first thermal took me up to well over 6,000' MSL, with 6 knots of lift at times. I decided that landing practice could wait. This was too good to pass up! I practiced 45-degree banks, did a couple of stalls. My maximum altitude was 7,800' MSL, and I could see gliders and cloudbase about 1,000 feet higher than me.

I flew over to the little town of Winchester and back. I thought (correctly) that another student might be waiting, so I eventually forced it down with 60-knot circles and spoilers. So many days we scratch to find lift... and then days like this, we just have to waste it!

Approach and landing was weird. I hit some heavy sink on the downwind leg, and ended up turning base really early because I was quite low. I knew from looking at a flag and the wind socks that the wind was from the left (south) side. But then after flaring to land, I floated... and floated... like I had a tailwind. I touched down, did not bounce it, but suddenly I was in the air again and yawed to the right! Apparently the wind abruptly shifted, got under my right wing (it would have been up slightly due to the original left crosswind) and launched me into the air again, and "weathercocked" the glider to the right - at least 25 or 30 degrees! I got it under control and landed safely, but certainly not within the space I had been planning. And after I touched down, a strong crosswind from the right was blowing a bunch of debris my way. I let the glider weathercock into it, kept flaps and spoilers deployed, and stayed inside the glider until crew came out to help. (In strong wind, it's better to stay in it and be able to control it than to get out and have it get away from you.) So apparently I landed into a thermal. It certainly wasn't visible as a dust devil, but it caused a lot of shifting wind. It was probably responsible for the sink on downwind, too.

A very fun flight on a nice, easy day.

Friday, October 10, 2008

Winch trip canceled

There's a cold front moving through the state this weekend, and fairly high winds were forecast. So the club pres canceled the trip. We had set aside next weekend as a "rain date," but now it appears not enough people are able to go... so that's off too.

The winds aren't supposed to affect Hemet, so it looks like some of us will be going there tomorrow to put the gliders BACK together, and hopefully fly. It's supposed to be cold, so I'm probably just going to practice precision landings in a Blanik.

Saturday, October 04, 2008

All work and no fly #2

Today we needed to disassemble two gliders and trailer them to get ready for next weekend's club trip to Coyote Dry Lake. We plan to spend next weekend winch launching using a new two-drum winch that is being developed for sale by a fellow from San Diego. The disassembly of both the PW5 and a Blanik went pretty quickly.

The day was gray and cold, with a storm coming in. I had thought that I might do a few pattern tows in the Blanik to practice my precision landings (needed for the commercial practical test), but by the time we were done most everyone had left. And as I drove out of the airport, it started to drizzle. So... no flying this week.

I'm hoping next weekend to do one or two refresher winch launches in the Blanik with an instructor, and then fly in the PW5. The times I've been to Coyote, there have been no thermals. The last time the club went (and I didn't), the thermals were great. If I can get cell phone signal out there, I'll post updates during the weekend.

Monday, September 22, 2008

All work and no fly

Saturday had the potential for good lift according to the weather forecasts, but the wind seemed to break up all the thermals. Very few gliders stayed up for more than a few minutes, so I decided not to fly. There was lots to do at the field, though:
  • Deliver a new spare tire for the PW5 trailer. On the trip back from Tehachapi to Hemet, one of the trailer tires lost its tread. Fortunately it wasn't a blowout, and we had a good spare, so it wasn't too bad.
  • Assemble the Grob 103 after it returned from Tehachapi. Boy, are those wings heavy.
  • Find the calibration certificate for the Volkslogger, to file with the SSA along with my Silver badge application.
  • Move trailers and gliders around for maintenance.
  • Brag about my Dust Devil Dash flight at the club general meeting.
  • Run the wing for and push back several gliders.
Some days are like that in a club...

One of the very experienced cross-country pilots in the club quizzed me pretty intensely about my DDD flight, navigation, and landout. (I think he has his CFI-G rating but is not an active instructor.) He never came out and said so, but it seemed like he thought my choice of landing at the Olancha dirt strip was not a good one. I think his concern was over two points:
  1. The strip is not very wide, with tall bushes on either side that could damage wings. But I walked it last year, and it is fine for a short-span glider like the PW5. I think there were 6 to 8 feet of clearance on both sides. You certainly can't put a 15-meter or greater ship down there.
  2. If there was a strong crosswind, putting it down safely would be tough because you could get blown to the side. Well, maybe. In the case of my flight, the wind at altitude was only about 3 knots, and my crewman reported very light wind at ground level where he was. I had no trouble at all landing on that narrow strip.
Still, it would be good to have another spot to land between there and Lone Pine, which is 20 miles away.

Sunday, September 07, 2008

Dust Devil Dash contest

[To any readers who are experienced cross-country glider pilots, please remember that this is only my fourth real XC flight.]

The weather forecast was good for soaring, with thermals up to 13 or 14,000' predicted and not much wind. But the humidity was low, which meant that there would be no cumulus clouds to mark the lift. This made me pretty nervous, because so far all my real cross-country flights have been under CU, and I've gotten shot down on many "blue" days back in my home country at Hemet. I really did not have much confidence in my ability to find invisible thermals over the mountains. I waited until near the end of the launch order (about 25 gliders) in order to let the day really heat up. I decided to fly really conservatively: stay on the extreme eastern edge of the mountains, within safe gliding range of the landout sites in the Owens Valley.

The contest has a launch height limit of 3500' AGL (7700' MSL). I let off at that height but was not in lift. Turning back to look for lift we had flown through, I had to hunt a bit over the Tehachapi mountains but hooked a strong one without too much loss of altitude. It turned out to be really strong, with consistent lift of up to 8 knots. (I noticed that the SeeYou program on my PDA was not displaying the "Thermal Assistant" which usually pops up when circling to help analyze the strongest part of the thermal.) Two other gliders came in under me, and very soon I was at 13,000' and it was time to head northeast.

I was doing OK, staying at 9 to 10 thousand as far north as the Honda Track (where I landed last year). But I started going down a bit. I was really hoping I could stay at 12 or 13, but that wasn't happening. In looking for lift, I headed northwest a bit to stay over the mountains, and found little. Honda Track was looking pretty far away, and eventually I had to tell my ground crew (Irv) that I was diverting to Kelso Valley. I didn't say landing there, but that's what it was looking like. Now, the Kelso Valley dirt strip is a safe place to land, but (I'm told) it's a long drive to get into - about 2 hours. And that was the one place I had not documented in my ground crew materials, so Irv was starting to scratch his head about where he might need to go. And once I got below the ridge into the vally, the line-of-sight radios would not work and I would have to relay messages with other pilots. This was not looking good!

At about 2700' AGL (6700' MSL), I found a thermal near but not quite over the Rockpile, and it just kept going up and up, getting stronger and stronger. Within minutes I was back up at 13,000' MSL and was able to resume heading northeast, hoping to make Inyokern or at least the aqueduct road known as "Brad's landing road". This is where I started going into unfamiliar territory, as I could not see Inyokern airport at this point. Of course, my GPS / PDA showed me the course line, so I knew I would find it eventually. But I do like to be able to see my goal!

Although I came down to about 9-10K again, that was OK because I was within glide range of Brad's and Inyokern. I kept finding sustaining lift so I could mostly fly straight. I made Walker Pass pretty easily (that's where I turned around last week) and that's due west of Inyokern, which I could now see. (In case you're not familiar with the area, it's due east of Lake Isabella.) Along a steep ridge I found good, strong lift and got back up to about 11,500' as I recall. Now I was within range of Cinder Cone Dry Lake, although I could not see it beyond a ridge. So I told Irv I'd go to Cinder Cone. And then Coso Dry Lake is just a little further on... keep flying north in sustaining lift at about 9,000' (I flew under a hawk at that elevation).

OK, passing Coso I'm still at 9,000', so let's go on to Olancha. About this time I passed over a burned area of forest, and there was a small plume of smoke from a fire high on the ridge. I reported that to Irv, and he called it in. Maybe it was a known fire, or a hot spot from the recent burn, but I thought they might want to know.

By now it's after 3:00, and I'm on the east side of the mountains, so I'm thinking that the lift will start to weaken as the eastern slope loses the sun. Twice in a row my safety harness comes completely loose when something snags it. Try putting four pieces back together while flying at 500' to 1000' over the rocks! The second time, I just steered with my feet to have both hands free. Of course, when I'm doing that I'm not flying efficiently or looking for lift, so now I'm getting down around 8000', with not much hope of climbing back up to the top of the mountains.

So I declared that I would land at Olancha, and focused on that. It's a little dirt strip right by highway 395, quite long but not very wide. It's OK for a short-span glider like the PW5, but pretty tight for a bigger ship. I know from my planning that it's at 3600' MSL, so I have about 3000' to lose by circling. I turned a circle to let SeeYou calculate the wind speed and direction (nice feature!) and it favored a southward landing and was not strong. Once I was in the pattern, as trained, I ignored the altimeter and flew to a good, straight landing with just a bit of a bump. On the ground at about 4:00 after 2 hours and 50 minutes, about 72 nautical miles (83 statute miles) from Tehachapi. More than twice as far as last year's DDD flight, and almost twice as far as the farthest point of last week's out-and-return.

Now, here's why landing without reference to the altimeter (judging strictly by angles) is important. After I landed, my altimeter showed 3900', not 3600' as it really is at that location. So I was 300' lower at my pattern Initial Point than I thought, which is why I felt I had to abbreviate it a bit. (A 700' pattern is not really a problem with the PW5, it's pretty efficient.) So that means the atmospheric pressure had dropped by about 1/3 inch of mercury during my 3-hour flight. Not a surprise, just something we have to always consider - and why we ignore the altimeter close to the ground.

Irv arrived about 5 minutes after I landed. Disassembly of the PW5 was... er... eventful! When I pulled the main pins, they jerked out all the way instead of only halfway as they're supposed to, which let the wing drop and make it hard to pull the drag pins. And we spent quite a bit of time trying to get the drag pins move... the wrong way... Fortunately it was not too hot nor too windy, and after about an hour we eventually got it all sorted out and headed back to Tehachapi. Sorry 'bout that, Irv!

Before I flew, another pilot told me that my flight last week might not count for my Silver because I had not declared it, though that's not how I read the rules. So this time I made sure to load a flight declaration into the Volkslogger. And I had already calculated that Olancha is far enough even with a 3500' tow. The trace looks good, so I should now have Silver distance and altitude in the bag!

As for the contest - it will be a couple of weeks before results are posted. I know two guys from my club got as far as Minden, NV (240 nautical miles) and Fallon, NV (262 nm). Since it's a handicapped contest, and I doubled my distance compared to last year, I should not be as close to last place as last year. But then I never said I was a contender - the contest is just a convenient way for me to extend my XC experience.

And today I figured out why SeeYou's Thermal Assistant was not coming up. My fault - I had a configuration setting wrong.

So... I did OK flying a "blue" day into unfamiliar territory, without Thermal Assistant, and doubled my best straight-out XC distance.

Saturday, September 06, 2008

Dust Devil Dash quick recap

Today I flew in the Dust Devil Dash, a straight-out distance contest from Tehachapi, CA. This is the second time I've flown the DDD. I got to Olancha, a little town a few miles from Lone Pine, right near Mount Whitney. That's about 72 nautical miles, more than double my previous best distance. The flight was eventful but the landing was safe (only my second landout ever). About 3 hours, max altitude about 13,000 feet. I'll write more about it when I get home... the network in this motel keeps dying on me.

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!

Saturday, August 30, 2008

Silver Distance and Altitude!!

Our club is on a campout trip to Tehachapi for the weekend. I had a flight in the PW5 that went 41 nautical miles (out and back) and gained about 7000' in altitude. The Silver Badge requirements are 27 nm, 3xxx' altitude gain. And this time I got it all on the Volkslogger, so I should have no problem filing the claim.

Now I just need a 5 hour flight to finish the badge.

More details to come when I return home.

Saturday, August 23, 2008

A short flight and a bunch of work

Today I had a short flight in the PW5. Due to scheduling, I took off about noon, when the thermals were just starting to pop. On tow, all turbulence stopped at 4200' MSL, so I figured that was where the inversion layer sat at the time. Right after release, I turned back and found a thermal that went up to - yep - 4200'. Shortly thereafter I found some pretty hefty sink, and had to come back. I ended up with just a 20 minute flight.

The landing was weird. I had had some excess speed on downwind and base legs, but had it under control at 52 knots on final. I was on right track to my aiming point, and was down to maybe 20 or 30 feet AGL. Suddenly my airspeed dropped to the low 40's. I must have caught a tailwind gust or flown through a thermal or something - there had been some lift on downwind. I had to nose over to regain flying speed (and close spoilers), but there was not much air under me, so I had to quickly round out again. I touched down quite short of the landing zone, maybe 30 or 40 feet early.

Before taking off, we had a problem with the circuit breaker that powers the audio vario and its digital display. It kept shutting off. It worked OK during preflight checks, and worked fine later on the ground, so we think it was just too hot. The glider had sat in the sun for quite a while with the canopy cover off, and it was about 97F when we pushed out. Maybe the breaker is getting old and overly sensitive. We're going to make sure to cover the canopy to keep the cockpit cool when we have a long delay. I thought the Volkslogger was acting up. I wanted to test it once before using it at Tehachapi. As it turns out, I was misinterpreting the Volks display... I think it was working properly. But we also thought it was contributing to the breaker popping off, so we turned it off before flight, and I flew with my standalone GPS input.

Later, we disassembled the PW5 and a Blanik to transport them to Tehachapi for the Labor Day weekend campout. (The Grob 103 is already there - has been all summer.) We're planning to leave the PW5 there for another week, and I'll fly it in the Dust Devil Dash on 9/6. That's a straight-out contest. You can read about my effort in that contest last year here.

Thursday, August 14, 2008

A Minor Milestone

Saturday's flight was my 200th as a glider pilot!

Sunday, August 10, 2008

Soaring simulation software for training

I've written before about programs such as Sailors of the Sky and Condor, which are glider-specific PC-based flight simulators. Recently some instructors have described their experiences with students who have used Condor before or during their flight training. These students have required fewer flights before solo or testing for their PPG - sometimes quite significantly. PC-based simulation like Condor does not qualify as a "simulator" under the FAR's, and time on it cannot be logged, but it can be very helpful.

Our club Board decided to offer a Condor training environment to our student pilots. I donated a used PC of adequate power, another member donated a 21-inch monitor, and the Board funded the rest of the equipment and software. I did the purchasing, configuration, and installation. From concept to completion took about two months. Total cost to the club was about $450, since most of the hardware was donated.

We cleared out some dedicated space in our clubhouse, and bought a computer desk. The PC includes a force-feedback joystick, rudder pedals, and speakers. The force-feedback joystick allows some realistic aileron resistance, and provides a shaking warning to simulate pre-stall buffet. The rudder pedals are important to enable students to properly learn coordinated turns.

In addition to the basic Condor program, we got an add-on pack of gliders that includes a PW5. The basic Condor comes with scenery for Germany. I also found a scenery file for Colorado, but none for California. One of our club members is working on building one.

I made up a notebook with simple instructions for getting started with Condor, some next steps for more advanced students, and the Condor manual. Soon we'll demonstrate it to all student pilots.

We believe we are one of the first clubs in the U.S. to provide a dedicated soaring simulation station on site at our gliderport. We think it'll be a great benefit for students who may not want to invest in the hardware and software on their own. We're hoping our instructors will work simulation practice into the training curriculum.

I'd be interested in comments from other clubs who may have experience with the use of simulation in their flight training.

Steep turns

One of the requirements on the Practical Test Standard for the Commercial certificate is demonstration of steep turns. That means turns at a bank angle of up to 60 degrees. One trick that has been suggested to help gauge the angle of bank is to pick two screws on an instrument, diagonally opposite each other, and make them line up on the horizon. Using that measure, I realized some time ago that I usually don't bank very steeply, usually only up to 35-40 degrees even when thermalling. It just does not feel comfortable to bank more steeply.

So today that's what I planned to work on. Shortly after release I found a suitable thermal and intentionally banked steeper and steeper. I thought I remembered feeling that I would fall sideways toward the low wing, but that was not an issue today. This time I found two things that I needed to work on:

* The G force gets really noticeable beyond 45 degrees or so. If I recall correctly, it's 1.4 G at 45 deg, and 2.0 at 60 deg. When thermalling, we keep on circling for many turns, unlike when we turn just to change heading. So the G force is with us for a long time. Not a problem, but it takes some getting used to.

* I initially had some problems with speed control. In the PW5, at 60 deg, the optimal speed is 56 knots. It kept wanting to creep up to 62 kt or so, and it took a lot of effort to bring it back down. After some practice, I seemed to be more consistent.

After working a couple of thermals up to about 6800' MSL, I headed over to the hills to see if I could find some to take me higher. No luck - a lot of sink - and I ended up with just a 40-minute flight.

Earlier in the day, I spent some time briefing another pilot who's hoping to fly the PW5 soon. He's flown a single-seat glider a few times before, but it was quite a while ago. I recommended he work through Bob Wander's book "Transition to Single Seat Gliders", a terrific little book that really helps you get prepared in advance and suggests some maneuvers to practice in the air before your first landing.

Saturday, July 12, 2008

Cloud streets and TVs

We've been getting some heat and tropical moisture influx for a few days, so I figured we might get some cumulus clouds to mark the lift... normally Hemet is so dry that all we get are "blue" thermals. There were big CU over the mountains, and the cloudbase there was maybe 9,000' MSL. There were CU and some lenticular-looking clouds all around the valley. My thermal forecast at trigger temperature (88F) was for lift to 6300' MSL. When I took off, the temp was 99F.

I came off tow at 4300' MSL and joined a thermal about 1000' under a 2-33. I worked that one up to 6000', and the 2-33 headed away, so I figured that was probably the top. Just a short distance away was a dark little cloud leading to a "cloud street" along the ridge north of the valley. I easily followed that over to the "S" ridge, which was pretty good because that ridge often has no lift working. I spotted a turkey vulture (TV)... and then a big flock of them, probably 15 to 20, all circling in lift. Sure enough, right under them, I found lift again. I worked that one up to 6300' MSL (and the TV's scattered).

With all this good lift, I would have liked to attack Mt. San Jacinto, but the peak was quite obscured by haze and clouds. Plus, my PDA / GPS had failed due to the heat, so I did not have glide calculations available electronically. If I was seriously planning to go to the mountain, I should have studied the distances and altitudes so I would have a good idea of my range, which I had not done.

So with plenty of altitude, I headed south across the valley, over the lowest foothills. As I mentioned, there were some lenticular-looking clouds in various places, and one was just ahead of me, so I thought I'd see if there really was any mountain wave lift working. It occasionally does work in the Hemet valley, but I have not encountered it yet. I went just adjacent to what looked like the leading edge of the lennie, but I was at least 1,000' lower than it, probably 2,000'. Either I was too low, or it really wasn't a lennie, or the wind was going the opposite direction, but I did not find either lift or sink near it. Not finding any meaningful lift there, I continued to the southeast corner of the valley, where I found yet another thermal to 6,000' MSL or higher.

Heading west along the hills north of Diamond Valley Lake, I found no lift and not much sink. I played with correlating the sink rate to the airspeed. (I really found no serious sink all day.) I went nearly to the town of Winchester, thereby completing a modified version of the "cross-country practice triangle" that we use, about a 30-mile flight path. I didn't find much more useful lift in that area, so I planned to land. The wind had picked up at ground level... AWOS said 12kt gusting to 20kt, with some really bumpy, turbulent lift at about 2,000' AGL. I did a pretty darn good crosswind landing after a 1 hour and 10 minute flight.

A very good soaring day! And guess what - I topped out at 6300' MSL, exactly what my forecast indicated (though for the 88F trigger temp, not the 99F actual temp).

Saturday, June 28, 2008

Two dual flights

Today for whatever reason, no club instructor was available but three pre-solo students came out to the field unaware. I was planning to fly a Blanik because the PW5 is down for partial refinishing, and the Grob is away at Tehachapi. I'm not an instructor, but I'm studying to be one, so I offered to fly with them. Not as instructional flights, but at least to get in some practice and avoid wasting their day. I made it clear that the time was not loggable, and that we would split the tow fee. (One decided not to fly after all for minor medical reasons.) I looked at their logbooks to see where they are in their learning process. As PIC (responsible for the flight) and not an instructor, I planned to fly the takeoffs and landings.

Weather was favorable for thermals. While we were sitting waiting for the day to heat up, several dust devils rolled through the field. One of them picked up a whole bunch of yellow leaves from the ground and floated them up about 50 feet and dropped them on us. Crows were thermaling easily - time to get in the air!
  1. R. is a teenage boy with about 8-10 flights so far. I flew the takeoff and tow (to just above the top of the inversion), and then turned it over to him. After flying around and losing some altitude, we got into a thermal and went up 1000', back to about the release altitude. I wasn't teaching him anything new, just letting him fly and giving some pointers on centering, speed in turns, and clearing his turns. When he didn't find more sustaining lift, I took it back and did the approach and landing (not one of my best) after a 43-minute flight.

  2. S. is transitioning from power and has about 30 flights or so in gliders, including takeoffs and landings. I did the takeoff and then handed it over to him to fly the tow at about 800' AGL. Shortly we spotted a glider not far away, and about 1000' higher than us, so we hopped over to join him and found nice lift, up to about 8 knots at times. S. worked on centering the thermal and I gave him some pointers. Eventually we got up near the other ship and since I was not sure if S. has done many (or any) gaggles, I pointed out how to safely join the circle and keep him in sight. We gained 1500' in the process, way above release altitude.

    Eventually we topped out and went off in search of other lift. There was a visible convergence, so we tried to work that, and found quite a bit of zero sink - and then a lot of regular sink. He gave it back to me at about 1000' above the IP, and I did not find enough lift to rescue the flight, so we brought it back in and I landed it after a 37-minute flight.
So I got 1:20 of PIC time, some practice in flying and observing hands-off from the back seat, and flew for half price. And two students got to fly who otherwise would not have.

Monday, June 09, 2008

Club instruction operations

A reader wrote in a comment here about a frustrating club situation, and that our club's operation sounds a lot more productive for students. Here are some thoughts about what makes it work:
  1. Club's stated purpose is to train students to fly. Most people who join are either starting from scratch, or adding on to a power certificate. Few people who already have their PPG join just to have access to club gliders, though some do. (Many buy their own gliders after getting their cert, but many don't.) So if a PPG is on the field on a Saturday, they're often helping with student operations as well as flying themselves. Four of us are working on our commercial and instructor ratings.

  2. Multiple club gliders.
    • We have two Blanik trainers. Typically one is used by the instructor and student, and one is available for solo students or other pilots. If one is grounded for some reason, everyone pretty much accepts that the students have priority to use the one good one. When one Blanik got wrecked, our Board placed a high priority on buying another one ASAP.

    • We have one single-seat fiberglass PW5, which students can progress to after solo and before getting their PPG. Many don't, choosing to focus on the certificate first, but it is available. And most of the ground instruction (orientation) for the PW5 is conducted by PPG's, not instructors, 'cuz they're the most familiar with it. A CFIG has to sign off, but typically not much instructor time is used on these students.

    • We have a two-seat fiberglass Grob 103, which is the preferred ship for experienced PPG's to take pleasure flights and give passenger rides in. So when it's available, this keeps the Blaniks mostly available for students. Instructors have to train and sign off on this ship, so it does get student use. And if both Blaniks are down (rarely), the Grob becomes the trainer.

  3. Multiple towplanes (sometimes) provided by an FBO. We don't have a towplane, we pay Sailplane Enterprises for each launch. They will run two and even three towplanes when the demand is there. But sometimes they don't have enough pilots, and sometimes 3 to 4 glass private ships push out at once, and SE reserves the right to cut in line if they have paying rides (to 10,000' !) or students, and there's another club on the field, so there can be long delays sometimes. Usually it's no more than 30 minutes, but sometimes... Rarely is there a line more than 4 gliders long.

  4. Single instructor on Saturdays, but flexibility. When I started with the club, there were enough instructors that training was offered every Saturday and Sunday. We lost a few, so we cut back to only Saturdays. We have picked up more instructors, but I don't think they're willing to commit to twice as much work and resume a Sunday schedule. BUT... Sometimes two will come out on a Saturday. One of them is retired and instructs a couple of days during the week by appointment. One of them is a new instructor and comes out on Fridays. One of them is a commercial instructor and is able to make special arrangements. So... with our instructors' gracious flexibility, there's more instructing occuring than meets the Saturday student's eye. And as I mentioned, there are four CFIGs in the pipeline. If we all complete it, I bet we'll get back to Sunday instruction... or two instructors most Saturdays.

    Having the right student:instructor and student:glider ratio helps a lot. I suppose if there are just too many students, some will not get a chance to fly. I think we have about 8 active students, but not all show up every Saturday, so probably 5 or 6 need instructing, plus maybe a PPG checkride or something. If they all get through their turns, sometimes some will want to go again. So the instructor is busy from about 10:00 until 4 or 5:00... and they don't take long lunches or long breaks, 'cuz they want everyone to fly.

  5. Efficiency. Everyone who's on the field is expected to help push out, push back, run equipment around, and basically keep things moving. It's not a long push from the landing zone back to the line. Students sign up for 1-hour blocks, and if they move it along, they can get two pattern tows in an hour, three if it's early and there's no wait. Way back when, SE offered a discount for pattern tows before 11:00. That's gone, but the idea of getting started early persists. If students are needing pattern work, they plan to do it in the morning. If they're working on thermaling, they plan for the afternoon. And there's peer pressure to be ready to go when your turn is up... and to be flexible if someone needs to go next for some reason. Although they sign up for a specific time, it rarely works out that way, and people are pretty nice about it.
It sounds like the main problem at the reader's field is towplane capacity (1) and balance (20 private ships and 1 instructor). I think he meant that the towplane is owned by the club. Reading between the lines of his note, it sounds like the club does not place emphasis on instructing. If instructing is their priority, maybe they could consider letting instructional flights cut in front of private launches. But if that's not their culture, then students may very well have to find other situations to get training at a reasonable pace.

Saturday, June 07, 2008

Air work and ground work

Today's flying pretty well matched the forecast: weak lift, 2 knots, not going very high. There was probably an inversion at 5000' MSL or so, but the air was clear enough you could not see the inversion from the ground. Barometric pressure was low, and winds were light. I found a couple of thermals, never got much above release altitude. No heavy sink, some weak lift late in the flight, probably not convergence because it was localized and not spread out. (See, I remembered the possibility of a shear line!)

The PW5 is grounded, so I took a solo flight in a Blanik, the new one that I've only flown once before. (The other time was a dual flight.) I played with it a little bit, because last time I flew it it seemed to want to roll left. Well, this time when I released the stick and did not adjust with rudder, it tracked nicely straight ahead. After a while it did drop a wing, but it was very gentle and randomly chose left and right. So I would conclude that there is no problem.

I did notice that I could not trim it back far enough to stabilize at Minimum Sink speed, which is 42 knots. I also noticed it's a very quiet ship! And in this one, I was feeling the bump of lift well before the varios indicated any.

Usually in a Blanik, in weak lift, it's helpful to pull out the flaps about halfway. This expands the wing area, producing more lift, without dropping them down, which would add drag. Often this makes the difference between "zero sink" and usable lift. Today it did not seem to help. So I tried not pulling them out even halfway... still did not seem to help. I wonder if there's some difference with the flaps? Something to try again in this ship.

The PW5 needs its annual inspection, and we thought our local A&P was going to do it today. We usually do whatever minor disassembly is needed to make the A&P's job easier, and in the case of the PW5 that means removing the "seat pan". I'm one of the most frequent fliers of it, so I was designated. I've never seen it disassembled, but it turned out to be pretty easy: remove 22 screws and wrangle it out. He never returned, so the PW5 remains in pieces for now. I did get a chance to look at how the control stick mechanism works.

Tuesday, June 03, 2008

Two short flights

Saturday's forecast was for about 4kt lift up to 6-7,000' MSL, hot enough for thermals (about 87F, I think), but unfortunately with an inversion. Sure enough, I could see the inversion and watched it slowly lift through the early part of the day. We had some work to do (assembling a Blanik, other maintenance stuff), and I took off at 2:00 or so.

I adjusted my seat back position and trim setting to maybe compensate for the attitude/balance issues I noted last time (see last week's post). Takeoff and tow were normal, with maybe a bit more slack than usual to deal with. I did remember to use the trick of climbing immediately after release, converting excess speed to a little altitude. I figure if I can remember to do one additional thing every time, I'm gradually improving.

I let off near lift at about 4500' MSL. I never got higher than release altitude, though I did find some lift and zero sink. Not enough to keep me up very long... no soaring birds, no dust devils. I think it was generally stable, with occasional thermals popping off only the highest hills. I practiced steepening my turns and trying to center the weak lift with the help of SeeYou's thermal display tool. I ended up with a 28 minute flight.

When I came in to land, there was another glider right in the middle of the farthest part of the landing zone, and they were not moving. So to avoid them, I lined up early and to the right, nearer to the runway. I overdid it, and actually touched down to the right of the cone and then rolled back into the zone. Looking back, I should have just landed on the runway.

I wasn't done. That wasn't enough flying for the day. It seemed to me that there was lift to be found. And my first flight was free, thanks to a gift certificate from Daughter #1. So up I went again. This time I didn't find lift on tow, so I held out for about a 3500' AGL release. I did find some decent thermals and got up to a couple hundred feet above release altitude. It seemed I could see over the top of the dirty air, so I'm pretty sure I was at the top of the thermals, about 5200' MSL, and they were not punching through the inversion.

One of my strategies has been to try the hills to the south of the Hemet valley, as stepping stones to get to Mt. San Jacinto. So I headed across the valley to the Ramona Bowl. No lift in the valley... no lift over the hills... but I didn't lose much altitude getting there, either. One little bump on the way back to the airport. The flight was a whopping 31 minutes, with a fine crosswind landing.

One thing I should work on is remembering that there may be shear line (convergence) lift in the afternoons. Sometimes we can see it from the ground (regions of clean vs. dirty air), but in the air I don't think to fly back and forth looking for it; instead I usually assume all the lift is thermal.

Sunday, May 18, 2008

A Weird Flight

This should have been a great day. I'm still trying to figure out whether I was just off, or just unlucky, or whether there was something wrong with the aircraft.

We're in a heat wave, but the temperatures aloft were good, so the thermal forecast looked great. I forecast a thermal index of -3 at 5000' MSL, and thermals to 10,000'. The NWS thermal forecast was even more optimistic: 1100 feet/minute to over 14,000'. As I was driving in, I could see CU popping over the San Bernadino mountains to the north at 10:30. They were popping all around the Hemet valley, and over San Jacinto by 11:30, though small. I planned my flight as if I were going to the top - took all my cross-country gear. This would be the first time I used the EDS oxygen system that we just installed. I swapped my O2 tank for the club's tank.

It was hot. Forecast was 101F. When I pushed out it was 108. "But it's a dry heat." That's really true... 108 at Hemet feels like 95 to 100 at home. I make sure to drink a lot of water before and during flights. I had to spend some extra time squatting and bending working on some issues in the PW5 cockpit, but even so, the heat was not unbearable.

The audio vario on the flight computer was acting up. The volume control failed, as it has done before, and when that happens it squawks at full volume. I taped some cardboard over the speaker to make it tolerable. You can't turn it off separately... the computer, vario, and radio are all on one master switch.

The Volkslogger was gone - I assume it was packed up with the Grob for next weekend's campout. So I used my stand-alone GPS unit, and made sure to keep it out of the sun. This was one of the few times I had no problems with it starting up or accidentally shutting off.

Takeoff was the first weird event. I had a couple of equipment problems getting set to take off... just annoying stuff with belts and hoses. I knew that the density altitude would be high, what with the 108F heat. AWOS's altimeter setting and DA were missing, so I just assumed it would be high, and was not surprised that the tow plane consumed most of the runway before lifting off. But I was very surprised to find that the PW5 was still on the ground when the towplane took off! I eventually lifted off, but was way below the towplane. I glanced at the spoiler handle - it was forward. (I didn't tug on it to see if it was locked.) I've had one or two tows where the plane took a very low path, but that was not the case - he seemed to be climbing OK but I wasn't. I felt like I was going slow, likely to stall (unlikely on tow, and the ASI showed 50 to 55 knots), so I was reluctant to nose up too much. I considered aborting, and kept my hand near the release just in case. I think we were up to 700 or 800 feet before I was in "high position" where I belonged. Weird!

I let off a little below 3000' AGL after passing through several spots of 10kt lift. After losing some altitude and then finding a thermal, I gained 1000' and was back up to about 4700' MSL. But I was having to work for it. My plan had been to thermal up high enough to try the southern hills to get me to San Jac, so I headed that way. I found nothing but sink as I headed south, so I stayed over the little canyon where I started. I found ragged little thermals. I used the thermal helper on SeeYou to analyze where the best parts were, but never felt really centered in them.

Weird item #2: I seemed to be flying faster in thermals than I wanted, often creeping up to 55 or 60 kts. Once when flying straight, I went to pull the trim back to help keep me slowed down, and found that I had already trimmed back to #3 (I know it was at 5 or 6 on takeoff).

Weird item #3: I was hearing some wind noise from behind me on the right side, as if the canopy were ajar - and this was over the extra-loud speaker. I made sure no hoses or anything were stuck in the opening.

Weird item #4: I seemed to not be flying as coordinated as usual. When circling to the right in lift, my yaw string was usually off to the right. I was always having to take off some right pressure. That's weird because I had noticed over the last few flights that I was coordinating really well, effortlessly.

I began to think that there was something sticking out or open causing drag and noise (#3), maybe on the right side (#4), or somehow causing me to nose down (#1 and 2).

The sink was outvoting the lift, so I had to get closer and closer to the airport. I could see some other gliders thermaling over the Three Sisters (which is not far from the airport), but even that was too far for me. I spent a bunch of time at about 1200' AGL trying to work some pitiful lift, and eventually had to give up.

Of course, I found zero sink on the downwind leg, keeping me fairly high. My speed kept creeping up to 60-62 knots (no-wind pattern speed is 51), kind of reinforcing my feeling that the glider wanted to fly nose-down. I had a light crosswind on landing, and landed very well... but after just 32 minutes. Aargh! Very frustrating having such a short flight with the mountains beckoning! One other club pilot found very good lift (in the Blanik), and just came back when he ran out of water early. Another in the Blanik got beat down by sink and had an even shorter flight than I did.

I have to admit that I felt kind of "off" for the whole flight. Not enough to cancel takeoff, not enough to head back to the airport voluntarily. Partly the heat, partly the minor equipment problems, partly the annoyingly loud vario (couldn't hear the radio), partly feeling crowded by my stuff in the cockpit...

Back on the ground, I checked the stabilizer and it was latched properly and not at a funny angle. I looked under and around the wing roots, and found no tape gaps or foreign objects that would cause drag or noise. The PW5 had recently been assembled, but another pilot did a complete inspection, and I did a partial and had not noticed any problems.

When I was putting everything away, I noticed that my oxygen hose had pulled out of the socket on the EDS machine. And where it is placed, I can't see it due to the junk pocket. I probably would have noticed had I needed it, because I tested the system on the ground and the fresh, "cool" sensation of each EDS pulse was very noticeable.

  • Is the PW5 just much more affected by high density altitude than I've ever noticed before, and I needed to help it take off?
  • Is there something open or out of alignment, causing drag or nose-down attitude?
  • Was I just "off" due to the heat, and eating lunch right before flying?

Maybe something with the rudder... maybe it's misaligned slightly to the right, accounting for #4, and adding drag? I noticed during Positive Control Check that my partner was applying more pressure than I liked, so maybe I missed that it's staying right... I seemed to have more right rudder than I needed, but then I go by the yaw string action, and I never paid attention to whether my feet were not balanced. I did not notice any undue yaw during takeoff or straight flight or landing.


Sunday, May 11, 2008


Last week I completed a minor milestone: I filled up my first logbook. That's not very important as aviation milestones go, but it did make me think of a few things:

My experience now includes 192 flights, 81:34 hours, 63:46 as Pilot in Command.

In addition to my logbook, I enter my time and flights in an Excel spreadsheet. That makes it a little easier to total things up, check the math, and answer questions like how much time I have in each type of glider. It also handles a quirk of tracking time and flights: once you have your Private certificate, you can log instructional time as both Dual Received and PIC.

Whenever I fill a page of my logbook, I run a photocopy of it. This is really important! I had not thought of it until one of my instructors had several logbooks stolen from a car. The CFI went to a lot of trouble to try to recreate the records, by asking students for copies of their logbooks etc. We put in a lot of work to accomplish our training... to lose the records of it would make it very difficult to apply for certificates and ratings.

My first logbook was the red SSA one, my second is the new blue and white one. One big difference I see is a new column to track Ground Training Received. Also, the front of the new book lists requirements for various tests and ratings.

Saturday, May 03, 2008

Air Show and Air Work

I had a dilemma. I really wanted to go to the Air Fest at March ARB this weekend. I haven't been to a big air show in many years, and the Thunderbirds don't come around very often. But I also wanted to fly, since I've missed the last three weekends and the next three are iffy, all due to other family obligations. Most of the club is away doing winch launching at a dry lake for the weekend, and one of the ships they took is the PW5, so if I was going to fly it would have to be with the help of remaining club members, since the Blanik and Grob take more than one person to move. Fortunately J was planning to go today (giving his wife a ride), so I planned to make flying the priority.

I did go to March Field early, watched about four aerial acts, and quickly walked the static displays, going through a few big aircraft. And I mean BIG... C-5, C-17, and a version of a B737 that is used to train navigators - a flying classroom. Then I headed down to Hemet (about 20 minutes away). I figured if everything went well, I just might make it back up to March for the Thunderbirds at 15:15. But it would be tight: washing, preflighting, his flight, my flight, putting away...

Fortunately an instructor and student were planning to fly the Blanik, so preflight was already done. Then J decided not to take his wife up, for a couple of reasons, and we decided to fly dual. We ate lunch during the student flight, got in a 1 hour and 20 minute soaring flight, and I still made it back to March by 15:20!

Our flight was actually very fun. The weather was favorable for thermals, although the NWS soaring forecast was all wacky. I forecast thermals up to 9,500' with a TI of -4. Thermals were easy to find. They actually topped out at 5,300' (consistently) but lift was strong, up to 6 knots. (Sink was stronger - 8 to 10 kt!) We split duties: I took off and did half the thermals, J did a couple too and did the landing. Flying dual is fun and educational. The copilot can take over some duties (radio, thermal analysis) and helps with the lookout. We learn from each other and make suggestions. (Upside: we split the tow fee. Downside: we can only log half as much PIC time.) I worked on steepening my banks, he worked on speed control in thermals. We were flying the "new" Blanik that the club just acquired - neither of us had flown it before.

I made it back to March nearly in time, but could not get back on base - they closed the gate, since it was nearly the end of the show. But lots of people were watching along the road outside the base, so I found a shady spot and relaxed. The Thunderbirds took off about 30 minutes after the published time, so I did not miss a thing. Six jets in formation make a BIG noise! Of course the show is not confined to the airfield; they go out about 3 miles. So I could see most of the show, and they flew over us a number of times. (I decided not to try to futz with my camera, and just to enjoy the show.)

So my soaring "sandwich" worked out perfectly! I got to see the static displays, a few aerobatic and skydiving acts, got to go soaring, and then watched the Thunderbirds. And I was probably one of the few in the audience that actually flew an aircraft that day! It was a day of contrasts:
  • Visiting some of the largest, most powerful aircraft on earth, and then flying one of the smallest, without any power at all.
  • Flying in a very quiet aircraft, and then hearing some of the noisiest on earth.
  • Watching some of the best pilots do their toughest stuff, and sharing the cockpit with a pilot for a very relaxing flight.
  • Looking up from one airport, and an hour or so later later looking down on another.

A very fun day!

Sunday, April 06, 2008

First solo spins

Today the general weather forecast was not so great, so I guess that's why no other pilots were at the field. But the thermal forecast was actually not that bad, and a "marine layer with reverse clearing" meant that there was a lot of moisture to form clouds. There was quite a bit of CU over the hills, and it was working well, if not very high. Cloudbase was about 5200' MSL, so I got up to about 4700' most of the time. It started getting murky rather than being a very defined cloudbase. One time I got a thermal off to the side of a cloud and got to 5200'. One time I got down to about 1800' AGL and thought I might drop out, but I found more lift and was soon up to cloudbase again.

Other than a couple of commercial glider flights and a hang glider, there was NO ONE else up in the air. I ended up with a flight of an hour and 20 minutes, and I could have stayed up longer. (This was in the PW5.)

Since I had a consistent source of lift for a change, and enough altitude to be well above the 1500' AGL aerobatic floor, I took the opportunity to do my first solo spins. I've done them with two different instructors in Blaniks (a long time ago and recently) and as a passenger in a biplane, and I've studied several resources such as the pilot's manuals for all of our gliders. I've also studied some online articles to firm up my "book" knowledge of how spins really work. Some time ago I did spins (not always intentionally) in the SOTS flight simulator. I figure if I'm going to become an instructor, and I'll have to teach spins eventually, I might as well start getting more comfortable with them.

I started off with some stalls, and hardly noticed the wing-drop tendency I had seen in the PW5 some weeks ago. It took me a while to get my courage up to actually enter a spin... but I was as prepared as I was ever going to get.

The first time I tried, it did not spin, just kind of dropped off to one side and self-recovered. The next time I kicked the rudder fully left, and down we went. I came out of it after only a half turn... but it was fully spinning, with quite a nose-down attitude. Boy was my heart pumping!

Later in the flight, after nearly getting down to pattern altitude and then working back up to cloudbase again, I did one more spin. This time I came out after 3/4 of a turn. It seems to take forever to go around! Just before or as I was coming out, it seemed like I was pulling quite a bit of G force. I didn't get dizzy or anything, but did get a bit of a head rush. When I had completely pulled out I was doing about 70 knots. When I upload my flight trace, it'll be interesting to see what speed was recorded during the spin and recovery.

I've decided that the hardest thing I've done so far in the air was to NOT apply opposite rudder right away! All my training and instincts make me want to stay straight and level, to avoid spinning out of a turn. To do it intentionally, to watch the ground spin up at me, and to know there was no instructor along, and to STAY in the spin, was scary. I'm sure it will get easier the more I do it.


Update: I analyzed my flight trace, and found that my peak speed (as estimated by GPS) was 82 knots at the end of the spin; I had estimated it at 70. What I didn't write yesterday was that I was not sure whether that was faster than normal. I know that spins should have a stable speed, and spiral dives can increase in speed, so I wanted to be sure I was spinning and not spiraling, since that speed struck me as rather fast. But I went back to the PW5 manual, and it says spin recovery is at 81 knots. And it says the load factor is 4 Gs, so the head rush was not all in my head. So these spins were perfectly normal.

The GPS doesn't record anything that would indicate the glider position (and therefore turns) during the spin. The flight trace, recorded at 4 second intervals, just points straight down. But my ground track before and after the spins confirm about 1/2 turn and 3/4 turn, which I had visually estimated based on ground features.

Sunday, March 30, 2008

A little local dolphin flying

Saturday's weather was better than I expected, with nice scattered CU's from about noon until about 2:30, though not high enough to go very far from the airport. I took fellow pilot N for a ride in the Grob 103 - I did all the flying, he helped with lookout and strategy. As it turned out, I should have listened to him more.

We let off at 4200' MSL (2700' AGL) in lift under a cloud. The clouds were fairly constant to the north, and we were able to "dolphin fly" a few miles. That means that there's enough lift, and the sources of lift (generally marked by clouds) are close enough that you can fly straight and stay in lift, without stopping to circle. When you're in lift, you slow down to minimum sink speed in order to stay in it as long as possible - ride it as high as you can. Then when you get out of it, into neutral or sinking air, speed up to get to the next lift as soon as you can. So you end up going up and down like a dolphin. (Not at all the same thing as "porpoising," which is an uncontrolled up-and-down pitching - also known as a pitch PIO. Go figure.)

To stay clear of the clouds, the highest we could go was 4600'. When we reached the north end of this little cloud street, we headed southeast across the Hemet valley, moving between more scattered little clouds. We found that the lift was weaker, more narrow, and ragged. No more straight flying, we had to work the thermals, and could not get up to cloudbase as well. N kept telling me it was probably better to the west (over the hills). After getting back near the airport, we headed southwest to try to work some more lift, and didn't find anything useful. Soon we were back down to pattern altitude and had to come back in for a 36-minute total flight. Disappointing, since things were working, and others had longer flights.

The lesson sfrom this flight (seems like there's always a lesson) are:
  • The clouds over the valley were obviously more ragged, less well-defined, than the ones over the hills, but I failed to pick up on that fact. For some reason I thought that a cloud was a cloud, or that they were forming there. The valley clouds had no lift under them. They probably formed over the hills, broke off and drifted downwind over the valley, and then decayed there. Should have listened to N - should have bailed out of the valley back to the hills earlier.
  • When I was under the clouds over the hills, all I could see was the bottoms - they were so close together I could not see the tops of the ones futher ahead. The tops probably had the well-defined outlines that indicate growing CU, but I couldn't see them from below.
After we landed, a student pilot and I considered going up for another flight, but by then the cloud cover was getting much more prevalent. With the sunlight to the ground greatly reduced, we figured the lift would not be working too well, and it was starting to get windy.

On the ground, some of the new student pilots are approaching me with questions on weather and various other topics, which is great since I'm working toward becoming an instructor.

Saturday, March 15, 2008

Windy work day

Although I spent the day at the airport, I didn't fly today. Our club had scheduled both a morning ground school for student pilots and a work day. It was a post-frontal day with lots of cumulus, and presumably good lift, but lots of wind. The forecast was for increasing clouds and possible rain in the afternoon. I pretty much planned on not flying because of the work and the weather. We private pilots vacuumed, washed, waxed, buffed, installed, painted (and repainted), took off tires, put on tires, sanded, hauled away... but didn't fly.

On the plus side, after all the recent rains, the field is covered in flowers:

If we had not had work to do, the day would have been flyable. The wind was strong, from the left about 30 degrees. But it was pretty well shredding the clouds, so we figured the lift would be iffy.

The students finally got out of class about 2:00. (I guess there was a lot of wind indoors as well.) The instructor was willing to fly in spite of the wind. He just said "it's a challenging day" and proceeded to train students on crosswind takeoff and landing procedures. Notice how low he's holding the left wing compared to the right: