Sunday, February 06, 2011

3 Days of Thermal Research - a New Pilot's Perspective

Some serious thermal research was completed over the last three days here on Oahu during a cycle of light and variable winds accompanied by a light southerly flow. Day one of my journey began at Koko Crater with visiting pilot Markus, and included some serious scratching, a bomb-out, and an eventual successful high flight. Days 2 and 3 were spent at Nanakuli in strong thermic conditions, with JK and visitor BC Brad. I hope to share a few insights from my flights, or just amuse anyone who chooses to read this article.

A note to the reader, you may want to read this article in three installments (Day 1, Day 2, and Day 3) as it is quite long. Thom, this means you will have three days of coffee reading ahead of you.

Day 1 - Thursday - Koko Crater Miracle

Day one of my thermal research started at Koko Crater with visiting pilot Markus during a pilot's brief. The two of us met up after some discussion of the flying potential with the light SSE conditions, which tend to be tricky. Since Makapuu was in the rotor, the usual check of conditions at Sandys was in order, and to my delight, we found them to be very favorable for Koko Crater, although on the light side. "Is there any reason we should not fly?" After a short conversation, neither of us came up with a single reason. It's a go. So I volunteered to be the wind dummy. Launch … scratch … getting low … scratch some more … don't land in a thorn tree … ended up sinking out to the hot and windless field of grass behind the sewage treatment plan.

One good piece of information was gained from the experience -- the location of a strong thermal where I least expected it. While sweating in the field folding my glider I decided to give it another go. Decided to climb straight back up the face of the crater from the field where I landed. At least I would get some more exercise, right? I also thought that this could not be nearly as difficult as my last hike with Gavin from the Blow Hole to the rim of Koko Crater and back down the crater's MILLIONS of stairs. Started up the hot rocky slope and made it back to launch in record time, to the surprise of Markus who had not yet launched. Markus launched and maintained his altitude but eventually headed for the beach and landed. He got some good pictures which I will include with this story.

I was now focused on that rogue thermal that I had discovered on my first bomb-out. Launched during a light thermal cycle, but the lift was just not near the hill. Flew along the crater, getting nothing, then past where I had launched and away from the hill and out into the field behind the sewage treatment plant, telling myself, "this is not ridge lift." As I approached the low altitude of 75 ft, I hooked a good thermal, and suddenly was able to fly figure eights and then circles, until I was at 2,200 ft and well above the crater, looking down at a site I had never flown before. I was up!

The air was nice up high, and there was really no wind, so flying over the Blow Hole and even over the crater was very peaceful, a stark contrast to my next two flights at Nanakuli. [Editor's note: really nice use of foreshadowing here!] Not wanting to leave my partner in crime stranded, I steered a course out over the water and practiced some wing-overs and spirals, landing near Markus in the park, and getting a ride back to our cars at the trail head. First successful flight at Koko Crater was celebrated with a much needed gatorade, courtesy of Markus, followed by a Makapuu site intro to finish off the day.

Lesson learned: sometimes doing thermal research by oneself requires bombing out once before the strategy for the day becomes clear. When it's exceedingly light and thermic, I fully expect to hike twice when on my own.

Day 2 - Friday - Nanakuli Rough and Rowdy

Day two of thermal research came about rather unexpectedly as well. While at the office working diligently, a check of the winds led me to the conclusion that we had classic "light and variable" conditions with a high cloud base, and the possibility of some cross country flying at Nanakuli. During lunch it felt like a hole was burning through my chest, telling me not to miss this chance. I made the strategic decision to head straight for the promised land, whether anyone else was going or not. Time was of the essence -- no overdevelopment for me.

While driving like a bat out of hell, I received the text "NAN! NAN! NAN!" from an unknown number, as I was passing the H2 exit. Was this a sign from God? Called the unknown number, and it turned out to be JK, who had the same idea and was 10 minutes ahead of me. We met and left a car at KFC in Waikele, with dreams of flying over the back. Got to the base of Nanakuli ridge at 1:00 pm and we were up and launching by 1:45 pm. JK launched just below high launch on the School Side, while I opted to go to high launch to give myself the best chances for staying up. Right off launch I was hit by a thermal and instantly found myself 200 ft over launch and looking for more of the same. Struggled for 30 min near high launch height before I got up above the peak and to cloud base. Conditions were very rowdy with punchy lift and thermals that were quite small but strong, with equally strong sink located predominately away from the ridge. As I gained altitude over the summit, there seemed to be quite a turbulent convergence of thermals from three sides of the peak, resulting in several collapses and rough conditions even up high at 3,200 ft.

Meanwhile, JK was scratching low for some time, before making it to within 200 ft of me at 1,700 ft, and then he hit a pocket of extreme sink on the school side of the ridge and landed out in Nanakuli Valley. Looking down, I was unsure if I would suffer the same fate, so I just kept thinking, "Where is the lift?" It seems if you get trapped below ridge height on one side or the other, chances are you will eventually get flushed.

Clouds were providing abundant lift up high, and I needed a break from the rough convergence at the peak. At 3,400 ft, I set a course to cross Nanakuli valley following a cloud street towards the Power Plant ridge, hoping to arrive on the top of the ridge where I dreamed of regaining altitude and heading towards Ko'olina. In the middle of the valley I was at 3,000 ft, and on half speed bar. Still not sinking … can this really be working? The answer turned out to be a resounding no. As I got directly above the flat top of my upwind destination, I hit a wall of 700 ft/min sink, and watched my dreams of crossing the valley fade away in 120 seconds of defeat.

I would suffer the same fate as JK, just along a slightly different route. Within a few minutes I was landing at the baseball field in Nanakuli valley, and got a warm reception from the caretaker of the park, who offered to give me a ride back to my truck in his golf cart. The promise of landing at Ko'olina to a warm reception of beautiful women, cold beer, and a beachside massage will have to wait for another day. JK and I headed back to KFC in Waikele, where he treated me to a much needed drink.

Lesson learned: stay along the spine of the ridge, not sinking below ridge height at any time, and be patient even when getting low. Sometimes it only takes one thermal to get up to cloud base. The convergence of thermal lift over the peak can be very rough to say the least.

Day 3 - Saturday - Nanakuli Solo, 1,100 ft/min Up

Finally it was Saturday. Could I get lucky and fly again? Conditions were indicating strong sea breeze all over the island. Would it be too strong at Nanakuli? Only one way to find out -- the drive to the promised land. Arriving in Nanakuli Valley alone, the wind was light and there was barely a sea breeze at the base of the trail up to launch. Made the hike for the second day in a row, to high launch on the school side, in record time, 30 minutes. As I arrived at the top, BC Brad called, and was interested in flying thermals. I gave him directions, and told him I could guide him up the trail from the air, as he was still in Kaneohe when he called.

Remembering my lesson from the previous day (shooting up 200 ft above launch in a thermal directly off launch), I chose a lighter cycle to launch in. Got off the hill smoothly, but immediately sank down to just above mid launch and was stuck between 700 ft and 800 ft for the next 45 minutes, scratching along the lower portion of the ridge. BC Brad arrived, and I had a few brief radio transmissions between my huge ups and downs, fearing the whole time that I was sure to sink out. Where is the lift?

About an hour into my flight I started making some progress, and finally found an extremely strong thermal that was big enough to core up past the summit of the mountain. This process was aided by a secret weapon, JK's vario. It was surprising how much those beeps helped me to stay in the core and locate the thermal all the way up to cloud base. The day before, without the reassuring beeps, I would fly in and out of a thermal 10 times while trying to stay inside the core, looking like a rag doll flailing all over the place.

As the conditions got stronger, I started getting huge lift and sink. Several times the vario pegged at 1,100 ft/min with a solid tone while in the core. Had I just pegged a vario to the upper limit of what it was made for? Are these legitimate strong thermic conditions which I have been reading about and dreaming about for the last 6 months? This was for sure my best experience with large and very strong thermals. At the same time the sink would take me right back down 1,000 ft nearly as fast as I got up. It was as if I was in an elevator up and an elevator down for nearly an hour, and this was hour two of my flight. When venturing over the peak, I found that the convergence there was a little unsettling. Wing would get hit by what seemed to be a shot of hot air which on several instances collapsed my wing. Got a full 50% collapse, but the glider recovered quickly. I was high enough not to worry, however my heart was still racing and I repeated, "Where is the lift?" to myself to calm back down.

While at cloud base, a wind front converged on the valley from a SE direction, and I decided it would be prudent to land. I had just cored a thermal to 2,200 ft finding myself on the dump side pointing back at the ridge without much forward penetration. Made my way down the ridge while sinking, and was not able to make the beach, so choose to land in a field near the dump, but out of any possible rotor cast by the Nanakuli ridge. I chose what I thought to be a grassy field, but it turned out to be an industrial dump with giant concrete chunks and twisted metal hidden in the deep grass. Not the best choice of landing sites. I was committed now to my chosen landing zone, and did a PLF with a few tumbles and I was down, with only a few scratches.

Now what? A hike back over the mountain seemed in order, from the dump side to the school side on a trail Alex had pointed out during our last visit to the promise land. BC Brad was still at launch, however my radio had run out of enough power to transmit, so we used two presses of the radio transmitter to indicate I was fine. Made the vertical climb back up the top of the ridge and up to mid launch, where BC Brad was making his way down. As we hiked back down to the cars, BC Brad checked the log for the last two days at Nanakuli on JK's vario:

Day 2: JK, +730 ft/min, -840 ft/min, 1,720' max ASL - 45 mins
Day 3: Allan, +1,100 ft/min, -730 ft/min, 2,200' max ASL - 2 hrs

The gust front that forced me to land seemed to only last 20 minutes, and subsided as we hiked down the hill. However, BC Brad and I decided that we had had enough of Nanakuli for the day. Lessons learned: coring a thermal is much more efficient with a vario; being patient sometimes pays off; and, do not spend the whole day hiking and flying at Nanakuli without eating breakfast or bringing water.


The west side seems to offer a complex flying environment, different than anything that I have experienced on Oahu in my short 6 month and 75 flight career. It has shown me that flying in such conditions is far more complex, and requires adapting quickly to conditions that change continuously. I have found that there are not many similarities between my approaches to ridge soaring and thermaling. The rules are different, and I am trying to develop an appreciation for this difference. I hope to continue my thermal research as conditions allow, and develop an approach for dealing with the strong turbulent convergence over the top of ridges I have experienced over the past two days.

Aloha to all who have chosen to read my story. It turned out to be longer than I had anticipated.


JK said...

Take from these few photos, Allan.

Thom said...

Thank you Allan. I did not find your story long at all and unfortunately it was so good that I read it without stopping for a refill on my coffee.

Your insights and abilities are beyond your short career. I hope you continue your ventures and eventually get that big west XC.

I hope that Doug gets to read this one.

Duck said...

Great flights Allan! You made the right call on flying sites with the L&V southerly flow--we did some KNA research. Confirmed that you can fly in weird conditions, but you might not want to.

Sounds like you are learning a lot and having a great time! Sooner than Later, I am sure we will be following you on some epic XC! Thanks for the read and the thoughtful insight for guys like me who have yet to fly NAN or Koko...

Waianae Jim said...

Great story Allan, at the rate you're going you'll be out flying many more "senior" pilots in the near future. Your enthusiasm and excitement really help remind me of why I like this sport so much

Alex said...

The great thing about the Oahu flying community is we don't have any "senior" pilots, with or without quotation marks. New pilots here get as much or more respect for a good fun flight than us grizzled old farts, and that's how it should be. I've never been part of a group of more humble guys than this one. We are not focused on outflying each other, but more on helping the new guys join us in the air to outfly their own hopes and dreams. Allan is a great example, and he obviously doesn't dream small.

Allan, your story was exciting and well written to boot. I can't wait to read your next gripping tale. I especially like the part about the hole burning in your chest. I try not to talk about that feeling because it would make me sound like an addict, god forbid, but coming from you it sounds like a normal metaphor. I feel like I have a hole burning in my shoulder right now, but as soon as I'm healed up, I'll join you up there and we can explore some of those thermals together. There's nothing I've done in the air that was more fulfilling than turning circles across from my buddies in the same column of rising air, wingtip to wingtip, watching each other's grinning faces as we mapped out the quickest route to cloud base.

allanc said...

@ JK - Thanks so much for flying with me and for posting the photos. Had mostly solo airtime over the last four days and it was great to share the air with you at Nanikuli for those epic 45-minutes. Didn't it seem like about 3-hours though.

@ Thom - Again thanks so much for your inspiration to write the last three days up and for your excitement for the sport. I have some questions to ask Doug Hoffman about flying convergence thermals and will post his responses here.

@ Duck - It is great to discuss your experiences thermaling in Europe and how they may relate to flying out at Nakikuli. You guys need to remember that I have never done an XC from Kahana and have not made it past the Pali so I will be following YOU sometime in the future.

I have been learning alot lately and really thinking and planning possible flights. I am half way done reading "Understanding The Sky" which is very helpful. Most of my learning does come by doing so we just got to get out there and try.

@ Waianae Jim - I really appreciate your comments and the love you have for the sport. You, Thom, and Alex just have this genuine excitement for flying that comes from the heart every day. I have seen you flying fast and far above my head and am sure that is not going to change any time soon.

@ Alex - I think that you put it perfectly. It is all about helping the members of our community fly better and keeping that drive to fly better than I did last week or last month (conditions permitting).

You may need to give me a refresher on developing a good stylistic approach to story telling. Loved the observed [Foreshadowing]. Want to include more style in my writing and get away from using I so much. I once knew how to write in such a way but AP English in High School was over 10-years ago for me (damm I am getting old). My only writing has been for engineering reports and e-mails lately.

I know we all try to hide our addict ways. That is why it is kind of embarrassing admit that I flew 4 afternoons (Wed, Thurs, Fri, Sat) alone except for one 45-min shared flight at Nanikuli. I sometimes don't post up because it feels like I am "stabbing other pilots in the heart" by telling them that I am flying but they are not (not a very humble thing to do). On the flip side posting to the cbox before a flight might give someone information which could get them a flight.

MauiDoug said...

Great flights and great story Allan! The Nanakuli sensor looked flyable on those two days and I'm glad you got a chance to soar with her! Thanks for the NAN insights and flying adventure story! AWESOME AllanC!!!

Louise said...

Allan - Great write up! Really enjoyed reading it, even from over here in BC. Looks like the thermal research has really taken off ;) And as Thom said it - well done summarizing the conditions here, for 75 flights you're doing awesome!!!

Looking forward to meeting up with you and the rest of the gang when I come out again 3 weeks.


Doug said...

Great to see someone taking an interest in my old girl :) I think you will find that Nanakuli will open doors to your flying that you didn't expect. After flying there for so many years I was just starting to begin to expect that flights like the one you had at Koko Head were possible at many other places on the island. Kahana, Mariners, etc.

About bombing out over the far side of the valley. Remember the triple points we talked about they work much more consistently than the high flats out toward the power plant. I don't know why but I think it may be partially because it is closer to the ocean without enough area heating to produce good thermals. Stick with the ridges.

Most varios will register 2000fpm. The bars will start disappearing when you pass 1000 fpm. I have found it useful to set the averager at 20 seconds. I have always thought it was about the time it took me to complete a whole turn in lift. The 20 second average means much more than the instant reading you see and hear. Use the instant and the beeping to help you center the thermal but the averager will tell you if you are climbing and how fast.

Last tip. The house thermal often lurks a bit behind the Haleakala peak. You would think it would be directly over the peak but it often gains strength as it fades back toward Lualualei.

Have fun

Thom said...

Wow, Great comments too. I would like to read "Understanding the Sky" but I am hoping they'll make a movie I can play on the dash.

Oh, about flying alone, never recommended, but IF...ahh oops, WHEN your gonna do this make sure you always call someone. Like you did when you called me so that we know where you are and check in with same contact when you land or post up.

The stabbing us in the heart thing when you get a flight in.......well we will tell you it does not bother us ground walkers and bomb outers......but it does. You should throw it out there so we can get more monkeys to gang ride NAN. She just seems to never get enough.

allanc said...

@ Louise- You the first pilot to comment on my story from off island. Thanks for the comments, it is really neat to hear that others outside our small community use Windlines.

I look forward to learning more from visiting pilots who have a wealth of knowledge and have been very willing to share with me. BC Brad's insights into the flying potential out at Nanikuli and his sharing of things he has learned was great.

When you are out here in Hawaii feel free to give me a call. I am a newer pilot but can share what I know about flying here on Oahu.

allanc said...

@ Doug Hoffman - I really appreciate the comments and encouragement. It is really helpful to get some insight from you and your experience. Really like the challenge of figuring it out or sinking out.

I look around the island and think that there are so many different possibilities. Just need to find safe conditions to fly in, and give them a try. Oh yeah, need also to find a place to launch. It is part of the challenge to not know exactly how you are going to stay in the air.

I will remember to stick to the triple points. Have you bombed out deep in the Nanakuli valley before. It looks like I could land back there and walk out if needed. Any advice on this?

Saturday was the first time I flew with a vario and it was borrowed. I am unsure as to how long the averager was set for but can check and see. All I know is that the thing was pegged with a solid tone while coring several thermals from below high launch to 1000-ft over the summit.

Last comment. I noticed that as I got directly above the peak (at like 3k) the turbulence would get quite strong. Do I want to avoid this convergence and focus on staying some distance on either side of the peak where the thermals are not colliding or do I just ride out the rough air until I get higher.

You also said this could have potentially been an inversion which could make for very turbulent conditions up high. I may have just needed to break through this rough area to get to better air.

Again, thanks for reading the story and for you insight. My approach is to try, learn, and try again always with a plan A, B, C, and D just in case the lift does not seem to make sense or defies logic.

JK said...


Great flying! You are definitely on a crash course in your first year. But of course, I don’t mean that literally. “Accelerated learning” is what I mean. You’re gripped by the flying obsession, but still have the discipline to walk down the hill. It’s easy to be “all thrust and no vector” when you’ve got the flying bug. But that’s not you. You’re good at taking home “lessons learned” from every flight, and that’s something we should all do every time we fly. I think that is the beauty of the blog. Sure, it’s an outlet for creative writing and a good way to “talk story”. But more importantly, it’s a way to share those lessons. When I write, I’m forced to organize thoughts, which solidifies the learning. Posting lets others pipe in with their experiences and in the end everyone gains. Of course, I’m looking for lessons that help me gain altitude, but also gain self-preservation. Those are the most important.

Perhaps my biggest lesson from that last NAN flight was that active air demands active flying. Thermalling is a very different animal from ridge lift and different rules apply. What we had that day was both, in my opinion. It was a hybrid day, and that kind of air will challenge pilots of any experience level. Do you remember those rocks we sat on up there? They were hot enough to fry an egg and undoubtedly spawning the thermals we were after. But the on-shore flow didn’t allow the air to linger around those rocks for long.

On launch, there were cycles for sure. But it wasn’t the typical cycle/calm/cycle that you get on a classic l/v day. The air flowing on those days is like a sighing giant.; long, slow, steady flow and then nothing. The air that day was more like a giant with a few broken ribs; short, punchy and frequent. The flow between cycles was certainly enough to pull up and launch. Perhaps not enough for ridge lift, but the cycles were frequent enough to be sure of catching one away from the hill and well before sinking out.

So, with that in mind, I think the best call was to hike to high launch with you, pull up between cycles and work my first thermal further away from the hill. Instead, I took the mid-high launch and launched IN a cycle and went straight up in my micro thermal. Then I flew out further and found one that was more developed. It wasn’t a problem, but hindsight is always 20/20.

And that kind of active air demands active flying as soon as the feet are off the ground. I could hear one of my early mentors calling out, “Do the Torpedo!” And I could hear myself say; “don’t be in such a hurry to get in the seat.” Active flying right off of launch cannot be done while struggling to sit. Fly first!

Oh, and my biggest lesson of the day. Try to avoid the leeside of ridgelines where there is -850 fpm of sink. The terrain was well suited to channel a nice thermal on a classic l/v day but as I mentioned before, this was a hybrid day and leeside rules applied. It was by far the smoothes air of the day, but incited the most awful sound from my vario. I don’t recommend it.

Allan, great post! Keep them coming and I’m looking forward to much more thermal research and XC adventures.

P.S. This is a good read: "Zen and the Art of Circles"

Doug said...

- I only bombed out in the valley one time...this means usually you will find lift! You can also glide a long way in the calm air that is usually in the valley. I have seen people land back there but only after scratching for way to long. Once you are below the ridge on the Lualualei side of the valley it is unlikely you will get up and its time to head out. Landing back there has been no problem the Lyman ranch is at the back of the valley and Bob the Father and Bob the son were very friendly when I visited. The Father came to the LZ one day and talked and requested photos of the ranch which I delivered shortly after. I think the valley is actually Hawaiian home lands but the ranch is the gate way to the valley.

The thermals can be tricky you should have an idea of how high they will take you based on cloud development. Remember cloud base will often be higher in the back of the valley because the air is starting from a higher initial altitude, this is true of the lift as well. If its rowdy and you are not to base yet hang in there. If you are high enough to leave the peak over Haleakala you will often find stronger more organized (smoother) lift that will take you higher further back in the valley. You will often get 1000 feet higher in the back of the valley, and can often just float around at 4000+ while guys are getting the crap beat out of them closer to the coast.

Something to think about is stability affects turbulence and on a given day the stability of the air will differ from place to place. For our little island closer to the ocean = more stable.

There is no right answer for where to fly, JK is right about different rules for thermal flying. When you are in the core follow it. If it drifts inland follow it, if it drifts west follow it, if it drifts into the lee you will have to evaluate how much wind there is and if you can safely return to the safe side of the ridge if you fall out of the thermal. When you are low look for signs of wind, grass moving trees shaking, what ever, they may indicate a prevailing wind you can ridge soar or the presence of a thermal.

If you are getting 3000 feet XC is possible the direction you choose to go will often determine your success. You will normally not want to fly into the lee side of the ridge. For example if the wind is clearly from the power plant to the ridge it is normally more fruitful to head down the Lualualei ridge if the wind if dominating from the dump side and the thermals are drifting toward down it will be better to cross to the town side of the valley. If there is no wind or it is straight into the valley you can go either way. Don't let the wind at launch determine which way you go. Get the feel of what the air at altitude is doing and go with it.

Spring flying is still a month off. Keep posting the cool stories, I need them :)

If you want that vario I was telling you about give me a call. If you want advice give me a call. I'd love to talk to you when you are on launch. I'll be the phone buddy Thom was talking about!

Brazilian Ray said...

awesome write up with LOTS of information from lots of pilots, this is what this blog is all about, but it takes someone starting a story!!! keep'em coming!!
Nanakuli is the hardest place to get people to go to... most people will choose parawaiting over thermal research, but if you keep going, learning and even getting some good flights and writing about it, maybe someday more people will join you.... (am I dreaming?) but the main thing is for you to set goals and chase them.... it won't happen for you to get to some 6000 ft from home (my highest there), so keep going (and writing about it).
on another note, I landed way back in the valley once, where they train their horses, and they were pretty cool about it! on another day I landed in waianae and got a ride back to my car, actually this have happened twice!, I do not know any other place on this island where the locals are so receptive to us, just show respect and they will give it back to you! drive slow, smile and take the time to talk to them and you will be pleased to meet such cool and curious people!

before, I would not miss a day at nanakuli (I'd even call in sick at work), but then I got busy, Doug left and less flying have happened there, but I can assure you every hike there is a learning experience and the most rewarding (XC) flights are to be had there. I hope to join you for some (more) of those!

Brazilian Ray

allanc said...

@ Ray and Doug - I really value both of your opinions and truly appreciate that you guys take the time to pass on the knowledge that you have. I have only heard legends of the incredible flights that have been flown out at Nanikuli and these have captivated my imagination and motivated me to learn how to fly.

I am going to keep exploring the valley, trying different approaches, and asking questions while staying safe in the process. I am looking forward to being in the air out there with all of it's complexity.

Doug, I will take you up on your offer and give you a call the next time I am on launch and it is a reasonable time in Washington. I figure that no one can teach me to become an exceptional pilot but with time in the air, reading and thinking about flying strategy, and learning what to look for from you and Ray I may be off to a good start.

Doug said...

If you're on launch its a reasonable time here :)

allanc said...

You are totally correct. I am embarrassed not to have seen the obvious.

Rob said...

Nice story. I'm back in Montana just jealous. Hope to get out there some time.