Booming thermals. Rare?

[Wildewinds]

My thermalling experience is pretty limited. I've specked out a few times with a handlaunch and 3m sailplane, but I mostly fly slope.

This morning was a new experience for me. I was messing around with a Slow Stick park flyer (fitted with an old Psyko HLG 1.5m wing) and I saw some red tailed hawks circling. I headed over there and cut the engine. Within a minute I was so freaking high that I scared myself. Two of the three hawks that were in the thermal with me were already out of sight. I was WAY specked out. FAST. It was like an express elevator straight up. Anything with wings would be able to ride that sucker up.

So, the question is, how often do thermals like that happen to you guys?

[Freddy Bear]

I was flying around trying to get a thermal after an engine run of three minutes :)
And there was nothing going. As I made an approach the wings fluttered and I was in lift. Within minutes I was at that place you spoke about but my glider went on up through the cloud and to a place I didn’t know for two days. :eek: I lost it vertical. I got it back but a lot was broken and the receiver cost eighty dollars to fix. PCM 7 Channel. ;)

[solo6796]

It doesn't happen often enough, but we get some of those here in Texas. Sometimes, you can do aerobatics coming down and then go right back up...

I like to work light lift, too, but it is pretty amazing to see a sailplane rise 50+ feet with each circle.

Lets go Flying!

AJ

[Keith Watson]

How often? Never as often as you would like. :)

When I run into those around here they are usually higher up. Doing spiral dives is sometimes not enough to get down! I also lost a plane once that way when a low cloud came along after I had spent a couple of minutes trying to get down. Never saw that plane again.

This summer I was in light lift when a vulture came to check out the lift. He only made one turn before leaving. Then 2 vultures circled a few hundred yards away. By the time I got my plane to their thermal they were dots next to some clouds a few thousand feet up.

[Whorges]

You guys that have gotten thermals like that, where were you flying (what state, over what type of surfaces)?

[Mirage1]

I fly in a county park in Georgia next to a elementary school with a steel roof and a big blacktop parking lot. On the other side there is a bunch of house trailers. Both of those generate big thermals that take a sailplane up like a rocket.

[BMatthews]

I've had both my RC sailplanes as well as some of my free flight models in those. I find it's not so much where you are but what the weather is like that day. Generally the temperature needs to be warm to hot and the winds in the medium range with lots of lulls and gusts. The lulls and gusts indicate how strong the thermals around you are. The deeper the variation in wind speeds between them the more likely you'll find of these super thermals.

It really sucks when one of my FF modesl hits one of these because even with teh DT popped the model still goes up. If I've got my binos (usually do on moderte and stronger wind days) then I can follow it until the thermal finally kicks it out but occasionally it just won't let my toy go and then it's time to sigh and walk back empty handed. That's happened about 5 or 6 times in my years.

[SilentEric]

I fly at an open field in Poway California (TPG club thermal field). I've caught thermals like this a few times and they make you just want to keep climbing (better than sinking). I tend to get too high, but luckily I have not lost a plane yet (knock on wood). I once flew in the early morning with some dense fog (we call it Marine layer here) with my 3m Sapphire. I launched very low from the winch and caught an incredible thermal. I watched my plane coimb at least 50ft in a single circle and start to disappear. I had to make a quick dive out as it entered the fog. In hind sight, I should have landed, but it sure was fun riding that thermal for about 5 different climbs into the fog.

Eric

[Keith Watson]

I'm south of Portland, OR. The area is a bunch of condos surrounded by big fields. The real massive air, when you can just wander around the sky and keep going up, are on days with low cumulus clouds.

[corndog]

There are four of us work with slow sticks. We started playing a fun game. Climb for thirty seconds and see who stays up the longest with no throttle. I stayed up for over five minutes after climbing for only thirty seconds! I think the only reason I started coming down was because I left the good spot and had trouble finding it again. Its funny you mention the hawks because there were about three of them circling in the same area. My slow stick is stock right now and we were flying over a construcion area that has had alot of dirt moved recently for a new building.

[sleipnir]

Here's a question: When I fly full scale I look for at least .5 meters a second (ms)on the vario to just stay up, 1-3ms for half way decent XC speeds and 4MS and above for fast cruising. What do you think is needed for an RC sailplane? Floater, TD, Scale...?

Bob

[Whorges]

The usual sink rate on an RC sail plane is roughly 100 ft/min for a floater and probably 150 ft/min to 200 ft/min for ships built heavier for more penetration. In my hang glider in CT/NY air on good days the vario reads 800 ft/min, but I'm happy if I get to go up at 200 ft/min. For me flying RC the hardest thing is to know if the plane is going up or not. In the hang glider being in the ship and having the vario makes thermaling much easier IMHO.

[schrederman]

In really good lift in West Texas, I've seen the variometer pegged at 10 knots (equal to about 1000 ft./min.), and had to use my watch to figure out how fast I was climbing. In just solar produced thermals I've seen 13 knots up. In the plume of a large brush fire, I've seen 17 knots. I have to say it was tough to stay in the fire plume, mostly because of the smoke, but the turbulence was awsome.

With my R/C stuff, I've seen some pretty fast rising stuff. I don't use electronics so I can't say what the climb rates were.

Jack Womack

[sleipnir]

Jack

Yeah, Gotta love those 5ms and above thermals. I fly just north of the Alps in Southern Bavaria and on a good day the thermals in the mountains are awesome. If anyone is interested and are in my area next spring and would like to go soaring, you pay for the launch (4.50 Euro winch launch) and the rides free. Of course it might cost you a dinner. The club has a Grob Twin III and I don't pay for usage so soaring is cheap, the more I fly the less it costs per flight. Is it a wonderful world or what?

Oh, and I can fly RC sailplanes at the field when the full size are'nt flying! What a deal!

Bob

[1-26 Flyer]

One thing to keep in mind about those "Frog Suckers" or as some of you may call them "big thermals" is that usually where there is big lift there is big sink. I had an interesting flight a few years back. I was flying on the slope with a handlaunch and the wind increased to about 25 mph. but the lift went away. I had to fly it right on the face of the hill just to keep it in the air. I remember thinking " man with this bad of sink there must be some big lift somewhere" so I flew off to the right about 300 yds. to the end of the slope and when I turned to come back I stuck a wingtip into a monster thermal. I tried 3 times to get into it but it kept spitting me out finnally I managed to get in it and within 4 turns I managed to go from about 100 ft. below me to "dang I can barely see it" high. I had to put it into a spin to get it down low enough to see what it was doing and about that time I hit the sink again. Needless to say it came down faster than it went up. Total elapsed time about 2 min. But what a ride

Dale

[guy mckenzie]

My first glider was a Graupner Uhu, about 36" in span. I was about 12 years old and with a little help from my Dad, towed it up with a piece of fishing line. It went up and up and I never saw it again.
My second plane had a DT activated on tow release.......I learned fast about the invisible power of a boomer. Still haven't quite learnt how to find too many.

[trashmanf]

I can't wait to find some big booming thermals! I have a very very heavy 3.3M carbon hotliner I'm building, well its a slope sailplane that I'm planning on powering, but until I have the money I want to winch or high-start it, it'll probably be a short ride down, but if I could catch one of those hella big thermals, I would be LOVING it! aerobatics on the way down, then right back into the thermal!!!

[lenrev]

I was flying near a landfill with a friend several years ago. Bored with little lift, I decided to shoot a Zagi LE up the hi-start. My friend launched his 100" Prophet at the same time. He landed at six-minutes and I rode a freak thermal from the land fill for over twenty-minutes!

[Ollie]

Are the thermals rare?

It depends on the hunter. If it depends on luck, the city boy in the wilds doesn't get much game for food. If the city boy hires a guide, he gets game almost every day. With much practice the city boy becomes a very good hunter without needing a guide.

[seeker]

Here, in Sin City, we get huge thermals in the fall and spring. I have seen many 600' per minute climbs. I fly from a 200' slope. there is a dry lake in a large valley( 5 miles across) directly in front of the slope. The valley creates a wind shadow that allows the lake to heat up and spit out BIG thermals. I have thermalled a 60" carbon mini blade(20 oz wing loading) to speck height.
Landing on rocks in Vegas.......Jon

[wingsnapper]

Truth is most people run into lift all the time.. the real trick is just knowing when it happens and sticking with what you've got. Sometimes you have to play with the decent air long enough for it to lead you to a core. Just last month I circled a few min in air that was just keeping me alive at about 35' then suddenly the thermal had drifted to an area that gave it more energy and boom.. up my plane went. This is a more typical account of thermal flight and may expose one of the most common errors in soaring.. lack of patience.
JS

[Gemarl]

Want big thermals? Park your car on the downwind side of the field and leave it running. Any thermals generated upwind will combine with the heat from the car to make an even bigger thermal. Good luck getting back!

[Tuomo]

I have seen many 600' per minute climbs....

I have logged 5-6m/s climbs 2 or 3 times. To you in US, that is faster than 1000 ft per minute.

The problem with these very powerfull thermals is that they usually happen when you are already quite high, around 300-600 meters. Loosing a plane is very easy.

[Peytr]

At our club field we have excellent thermal activity in spring, summer and fall. Boomers in the sense of max. climb speed are quiet common.

Rarer are the days when climb rate is less, but seems to be about everywhere. Have seen them a few times this year and it's crazy to see about all planes in the air, doing funny stuff like aerobatics without having to look where to fly, thermal activity all over the place. Off course the sink must be somewhere, but not over our field. These days are less common, so to speak. Nice every now and then, but thermal flying would become boring if it where like this all the time imho.

[flystoolow]

I took my friend out for his first flying lesson (thermal flying from a small mountain none-the-less), handed him the buddy box at 500', and....

well, 1 hour later he was still up there around 2000' and I never even touched the sticks.

I still just can't believe it. He actually never flew again; probably found this 'thermalling' stuff just too easy! :rolleyes:

[David Taylor]

The last monster thermal that I was in was about a half mile wide averaging 1500 FPM up with cores in the range of 2200-2400 FPM up. It would have been more fun if I was flying my R/C gliders but I was in my Hang Glider and the thermal was pretty much violent and it took a LOT just to stay in control. I was only about 1000 feet over the side of the mountain and was worried that if I tumbled and/or broke my glider and needed to throw my chute' I would get sucked up into the clouds whose tops were in the 40,000 foot range.
With my R/C gliders I have been in widespread lift and climbed extremely fast in a dust devil (about 20-30 seconds from 200' AGL to speck altitude, no kidding!) but the one in my Hang Glider was definately the biggest and strongest I have ever encountered.
In general your going to find bigger thermals in the mountains but on the flats you can still find hot spots that regurlarly pop off monsters, you just gotta go out and find these spots.

Dave T

[willfly]

I have logged 5-6m/s climbs 2 or 3 times. To you in US, that is faster than 1000 ft per minute.

The problem with these very powerfull thermals is that they usually happen when you are already quite high, around 300-600 meters. Loosing a plane is very easy.

Yep, I have experienced 1000 fpm lift, when your vario is pegged and each turn puts you 200' higher, and as you said it was almost a mile high.

[fprintf]

Truth is most people run into lift all the time.. the real trick is just knowing when it happens and sticking with what you've got. Sometimes you have to play with the decent air long enough for it to lead you to a core. Just last month I circled a few min in air that was just keeping me alive at about 35' then suddenly the thermal had drifted to an area that gave it more energy and boom.. up my plane went. This is a more typical account of thermal flight and may expose one of the most common errors in soaring.. lack of patience.
JS

Ain't that the truth. So many times I have seen my planes just poking along at telephone pole height or so, not going up but surprisingly not coming down. Since I dislike pulling back on the histart, I usually milk whatever lift I have as long as I can... sometimes to the point where I am in for a long walk and would have been better off setting up for a landing. But more times that I can count the plane has started going up, and eventually makes speck height. My 48 minute longest flight and my two 15 minute LSF II tasks were all done this way. Patience is often the key! Lift is everywhere!

[wingsnapper]

Yep it's exactly why I get so frustrated with planes that simply don't turn well. You have to be able to turn smoothly within a 8' - 10' or radius to be able to scratch down low.. If you have a plane that tip stalls or wants to tuck on one side and balloon up on the other in high angle turns things just become a nighmare. No matter what skill level trim, design, and good building means everything to a thermal pilot.

JS

[TLyttle]

Thermals are where you find them, and they are everywhere. Time of day often means a lot; one field we had would allow you to histart all morning and get nothing, then around 1:30pm, it seemed as if the whole area was going up. You couldn't miss. I would ride the 1:30 all afternoon, landing when I felt the batteries were running low, riding to the limit of my vision, then driving upwind until the model went up again, 1 1/2hr flights normal. That was with an Oly11, and some of the guys with glass jobs would do far better with their 50mph glide speed and better glide ratios.

Where I am now, one flys out of the ridge lift over the valley and away you go on huge boomers... Valhalla...

[bobthenuke]

No problem finding them here in Arizona. Flying my full size HP-18, the rudder pedals have straps to keep your feet from flying up when a "boomer" hits you. It happens all the time. Empty cement bags thermal great and sometimes go out of site when picked up by the dust devils. We call these "trash haulers". :)

[Ollie]

Frog Suckers
Hat Suckers
Boomers
Dust Devils
Trash Haulers
Great Vacuum Cleaners in the Sky
Super Thermals
Pop Off Monsters

Please add to our vocabulary.