Winch Launch

Our club is joining with two others for two weekends of winch launching, one of which was last weekend. Our club just finished rebuilding a winch and loading it with Spectra cable. We have instructors who have extensive winch experience, but none of the members did, so we thought it would be good to learn from other clubs who do. Some members worked on learning to "drive" the winch, and most others worked on learning to fly the gliders. We have done autotowing before, and some of us already have our "ground launch" endorsement, which you can get via either auto or winch. Technically you don't need another endorsement to do the other kind of ground launch, but you'd be crazy not to get instruction in it before doing it.

Saturday I did one launch, and Sunday I did two more. All three were very straight. It's the speed control, the angle of attack, that is tricky. My first one was not very controlled, my second one was better although I let off early when my speed got low. My third was quite good, achieving an altitude of 1400' AGL.

Ground launching involves redirecting the forward-downward force of the cable motion, using the resistance of the bottom surface of the wing against the air, into a forward-upward force. The amount of force converted depends on the angle, so increasing the angle of attack (with the elevator) directs more of the force, increasing airspeed. This is the opposite of the action of the elevator when in free flight. So you have to reverse your thinking: if the speed gets low, pull back to increase the force... up to a point, of course.

Now, there are two schools of thought on this, so I inv1te comments. A few months before doing this for real, I studied it in books and on the Internet and RAS. Some highly respected instructors insist it does not work this way, that lowering the nose is the way to increase airspeed during winch launch, just as in free flight, that it is NOT reversed. In my limited experience, six autotows and three winch launches, it IS reversed. The HRI's say that if the winch is underpowered, the reverse method is true, and if the winch has excess power (big European diesel or diesel-electrics), it is false. All three winches in use at our event were traditional gas V8's... powerful enough to launch pretty darn high, but maybe not in the excess-power range.

The other tricky part is that since you're going up at a 40-degree angle, directional control is harder. Until you know the surrounding landmarks, you can't judge direction very well.

Things happen REALLY fast. Zero to 55kt in about 3 seconds. Off the ground in as little as 50 feet. Up to 200' AGL in about 5 seconds. Then up at 40-45 degrees for about a minute or less. Wow!

Our club did some launches with our winch and steel cable some months ago, and did not get nearly as high. With about 3500' of lightweight Spectra, launches of 1400 to 1600' were common. That's enough to snoop around for thermals until you're down to about 800' and need to enter a pattern. Some folks found thermals and went off for hour-long flights of up to 10,000'.

Usually where we fly no one is on the ground near the approach end of the runway. At this site, we took off from a taxiway and landed on the adjacent runway, so we were quite close to the round-out point. In this shot you can see the flaps and airbrakes open.

I'll have more to say about some critical things that I learned about safe launches... after our second winch event weekend is over.

Ups and downs

I launched in the PW5 a little before 3:00. There was some lift, and I almost let off at 2500' AGL, but didn't, and did not find more until 3500' AGL. I cruised around and eventually found lift over a rocky set of hills near a canyon. It was not terribly stong, but workable. Another fellow called over and joined me, at least a thousand feet lower. Two guys in one of our club Blaniks also came over, at nearly my altitude. So we circled together for quite a while, working our way back up to about 5000' MSL. At times we were closer than I have ever been when sharing a thermal, but we were on the radio and kept in touch. It was choppy lift, some up and down... sometimes the Blanik was higher than me and a few seconds later it would sink lower. Later J said he thought it was shear line lift, but I thought it was thermal.

We all took off in different directions from about 5000' MSL. I got right into some moderate turbulence and some serious sink! At times the vario was pegged at more than 10kt down (that's 1,000 fet per minute down). I don't think I've seen such sink in the Hemet area, although I've had it at Minden. It was everywhere! I tried to find lift again - found a little zero sink briefly - but it was really bad. There was sink and lift on my downwind leg. I ended up with just a 37 minute flight! The Blanik guys did not hit the same elevator I did, but they didn't find lift either, and landed right behind me. My landing was fine.

Driving home, analyzing my flight, I realized that although I get the wind direction from the wind sock (and occasionally AWOS), I'm forgetting to fully use it. I use it to plan for crosswind landing, lowering a wing if necessary and expecting drift. And I use it to confirm drift during the downwind leg. But I'm forgetting to use it to adjust my approach speed. I've pretty much just been using the standard approach speed (e.g. 51kt in the PW5) and not increasing it by 1/2 the headwind component. Something else to work on next time!

I just bought an oxygen tank for the PW5. The club provides one, but this way I don't have to worry about whether it is full or not. It cost $30 to fill the first time.

I also bought a kit to mount my PDA in the PW5. J had already mounted a base on the panel, so I got a compatible arm and a bracket for the PDA. But I'm having trouble with the battery and cover. When I got ready to fly, my PDA crashed. Not sure if it was due to heat or battery, but everything was lost from memory. So I was unable to use it today and need to restore it.

There's more than one way to climb a mountain

Yesterday turned out to be a booming lift day and I had a great flight. It almost didn't happen... I had stuff to do in the morning, I am trying to get over a cold, and I was just planning to do a checkride with an instructor in the Grob 103. But when I checked the thermal forcast, it was for over 10kt lift to 14,000', and I knew we had some assembling to do, so I headed out to Hemet. As it turned out, we didn't have an instructor, the PW5 had been reassembled (thanks, guys... I owe you one), and no one was planning to fly it. So after taping the wings, doing a thorough post-assembly inspection, problems hooking up my PDA, and resting a bit to make sure my cold was OK, it was nearly 3:00 before I took off.

It was 103 F! I had not done my usual detailed weather study, so I didn't know the forecast temperature profile, but as I was driving in I could see that the few clouds were only over the high peaks and the bases looked to be about 14,000', so wow - looked like great conditions. Some of the experts on the radio were reporting in anywhere from 12 to 15,000' MSL.

I released at 4500' MSL and hooked a nice thermal right away up to 7500'. Then it was off to the "S" ridge. I found some moderate thermal lift on the low ridge and worked my way up the side of Mt. San Jacinto. I had been here one time before, in the Grob 103 last July. Last time was pure thermal lift, strong and topped by lots of cumulus clouds at about 10,500'. The clouds were the reason I did not get to the top that time.

As they say, though, every flight is different. This time the lift was not so strong, and not so clearly thermal. I found some anabatic lift coming off the ridges, and rode that up a ways. That is really weird stuff. When it's working, you fly toward the ridge of the mountain and the lift pushes you up, keeping you a fairly constant distance above the "spine" of the ridge. I remember thinking it was like magic - but I don't quite trust it, and San Jac's ridges are steeper than where I learned it in the Tehachapis. I don't have a huge amount of experience in the mountains, so I made sure I stayed some distance off the ridge, and turned away when I seemed to be getting too close. I got as high as about 9,100' MSL.

I also knew that there was about a 10kt wind from the west-southwest, and since I was working the side of the mountain that was roughly perpendicular to the wind, there should be orographic ("ridge") lift. But this isn't a classic "ridge", there are lots of canyons to break it up, so I wondered how strong it might be. I have never had any dual instruction in classic ridge lift, so I was really careful. I went back and forth along a fairly steep, rocky cliff and found sustaining lift, but not enough to take me any higher.

By that time I had been up about an hour and a half, and didn't feel like trying something else to get to the top, so I headed back. There was some lift all the way across the valley, so even though I had a 10kt headwind, I got back to the airport at about 5000' AGL. I floated around for a while trying to lose altitude, and I just couldn't. I think the shear line had moved in, because everywhere I went I found sustaining lift. I wanted to stretch it out to a 2-hour flight, which turned out to be easy!

So... that sustaining lift came back to haunt me during my pattern and landing. I hardly lost any altitude on the downwind leg. I extended my downwind leg so I would have some more room to lose height, and even used airbrakes on downwind, which I almost never do. I planned to try for a more precise landing by adjusting my "aiming point" closer to the field, because I've been landing just a bit short lately. Although my airspeed was a bit high on base leg, it was fine on final. I rounded out, and floated... and floated... and floated... Now, a bit of float is expected because of ground effect, but this was ridiculous. I didn't want to pull airbrakes too hard, 'ciz that sometimes causes hard landings. But I was near the end of the landing zone and still in the air. There's a taxiway that crosses west of the landing zone, and it's rough to roll over. At that low altitude and with decaying airspeed, it's not safe to "zoom" over it. So eventually I closed airbrakes and "hopped" over it, then pulled them out and landed on the other side. It's an approved landing area, but usually for downwind rope-break practice... unusual to land there upwind. I've done it before, with an instructor on board. It all worked out OK... it was the right decision for a safe landing. Pilots on the ground agreed. But it was weird. I played back the flight on my IPAQ, and I think my speed was right where it should have been. So... maybe there was lift in the landing zone, if the shear line was active all the way down to ground level? Maybe the wind died, or even reversed? Not sure why it happened, but I was glad to know I handled it correctly.

Some work and some fun

Saturday we did some more maintenance work on the Grob 103. We took out the seats and some of the interior coverings so we could clean and lubricate all of the accessible linkages. One of our club members has over the last couple of weeks installed several replacement instruments and repaired the landing gear doors. (He's qualified as an aircraft mechanic - it's great to have him as a member!) That's one of the nice things about being in the club: I get to learn to do minor work on the gliders, and there's always someone who has done it before. All that needs to be done now is to get the weight and balance recalculated. That was supposed to happen yesterday, too, but the inspector had a foul-up with his equipment, so it'll have to wait until next weekend. We're all eager to get the big ship flying again, for several reasons:

• It's a more attractive ship in which to take someone for a ride.
• It's more comfortable than a Blanik L-13 for some larger club members
• It soars beautifully. I think I can feel the lift much better in the Grob than in the others.

The afternoon shaped up into a really nice soaring day. Lift was plentiful and relatively strong. The ground temperature heated up to 86F, about 6 degrees higher than forecast and 10 degrees higher than my calculated thermal trigger temp. My thermal tops forecast was 5200' MSL and the NWS's was 6685.

I took off about 2:00, and had a weird tow. The tow started off fast, about 70 kt instead of the usual 60. I kept getting strong lift on tow, got out of position on the high side and got *lots* of slack. I never lost sight of the towplane but did have a big loop of rope under me. I was able to get it out but it was the worst I've ever seen - I usually have very little slack line. The next time the vario showed a really high rate of climb, maxing out at 10kt, I released, at 2600' AGL = 4100' MSL. I got into the lift right away and took it up to a bit over 5000' pretty easily and went in search of more lift. In three or four decent thermals I worked it up to 6000' MSL and that's where it seemed to top out. I cruised over to the Ramona Bowl and back... not very far, but in a different direction than I usually fly.

When my hour was nearly up, I tried some stalls, but the PW-5 doesn't really stall very much for me. It just kind of mushes down. I then tried pulling up more steeply, and it stalled but it pretty much recovered itself.

After I landed, with a 0:56 flight, the next fellow took off at 3:36 and got a 2.5 hour flight nearly to Elsinore, returing on strong shear line lift. I heard some folks got to 7 and maybe 8,000 feet.

Work day

Although the soaring forecast looked promising, I ended up not flying today. Our club had its general meeting, a guest speaker, and a work day.

We just got our Grob 103 back from some major repairs, so we put the wings on it, taped it up, moved it to a new tie-down, and did some general preparation. The new canopies are blue-tinted. There are still some things that need to be done before it flies, but we wanted to get as far as we could.

I did some other general maintenance on it and the PW5 well into the afternoon. There was lift, and eventually some shear, but it seemed more important to get the work done today. So no flight. Next week I'll be going to a soaring seminar... so maybe I'll fly again on March 31.