As a result of discussions in other threads, I am opening this as a means of spreading around whatever knowledge (or BS) there might be on how folks can find lift, before they launch - in a contest, or just for fun. This sort of thread has been done before, and the ultimate source will always be for me "The Old Buzzard's Soaring Book" by Dave Thornburg. However, the day today where I am is unflyable, idleness is being enforced, and questions have been raised. So, here we are.

Here are some guidelines:

1. No question is dumb.
2. Replies should avoid sarcasm (which is far too easily misunderstood)
3. Pictures are worth thousands of words.
4. Only post if you are OK helping others (even questions can be helpful - you never know).

Here is the one, basic, fundamental question every RC sailplane pilot must ask him or herself before they launch an airplane, by whatever means:

"Just where can I send this airplane, so that it will rise?"

And so we begin.

This space is reserved to hold all lift sign that people identify, as a handy reference.

You post a good idea, and I will summarize it and list it here.

And so we begin:

1. Look for signs of other objects (dust, birds (that are NOT flapping their wings), insects, leaves) going up.
2. Other airplanes (going up, do NOT join the airplanes going down or coming home!)
3. Streamers (they will all point to the source of lift.
4. Sailplane activity - it will turn away from lift.

Here are a few things to remember about the atmosphere, and how it works.

We live at the bottom of an ocean of air, which is pretty much colorless, often odorless, invisible (at least sometimes), apparently weightless although it has mass, and is seldom completely still. It can be felt when it moves. When air is warmed by contact with heated ground, it will form a bubble or column, and rise. It sinks, too, but oddly, it does not form bubbles or columns when it does. It sinks, typically, over broad areas which flow in turn to the base of columns of rising air.

Your mission, once you grab a sailplane and step out onto the field, is to look around and catalog every single sign, indicator, hint, rumor and clue you can find to tell you what the surrounding air is doing. You have got to be just like a dog, which is the world's single most capable multi-spectral sensory integration system (sight, smell, hearing, touch and taste), and put everything you can see to work and figure out where the air (invisible, odorless, quiet, soft and tasteless) is going up.

Your own sailplane is an excellent indicator of what the air is doing. If you have it properly set up (i. e., once set in straight flight, it neither stalls not dives; turns neither left nor right unless commanded), you will find that it will neatly and calmly AVOID each and every thermal it encounters. Chances are, it will not strike a thermal dead center. Instead, one wing or the other will enter the lift first, and the airplane will bank away from the lift. Left wing rises? Turn left, and there you should find the love you have been seeking. If your sailplane stalls repeatedly, or seems to wander left and right, it is most likely flying too slow to show thermal presence. Give it a couple of clicks of nose down, and let it fly straight.

Good luck!

Before launch, what I look for in no particular order:

Circling buzzards or hawks (they're easy).
Some swifts or other insect eaters darting about in a particular area
Insect moving upward
Seeds, dandelion, cottonwood, or any other organic substance floating upward
Obvious directional wind shift from the prevailing breeze
Steady wind that suddenly dies...and picks up again
Wind indicators in the distance, weeds, trees, dust, that is in a different direction than my location.
A streamer indicating any of the above
I have actually seen thermals, more accurately, a column of dust(I assume) that is barely discernible. Just looks like a "column" that is slight different in appearance from the surrounding sky. I've only noticed this a couple times and only on really good lift days after a dry spell. Saw this twice on the same day this past Summer. Once before launching, I saw it and headed for it, caught it and specked out. Same day, I was flying and saw this phenomenon, headed toward it and caught the edge of it and drifted with it awhile downwind, still specked out but had to bail out to get back.

Any of these can also indicate lift while I'm flying.

But specifically while flying:

Obvious upward pitch of the plane with no input.
Tail lifting (probably flying out of lift)
The classic right or left wing lift, whic BTW, I've had my plane just refuse to turn in one direction, or require a lot more input than usual, which turns out was lift pushing it away, somehow without the obvious wing lift.
Just a strange little wiggle-waggle of the whole plane, like it was in some type of turbulence.

Most of those indicators are easy with moderate to strong lift. I find it more difficult to detect with weak lift.
I've also learned it's easier to see those indicator when I'm trying to fly as smoothly as possible. It it's relatively calm that's easier. When the plane is reacting to something obviously other than your input, that's a change in the air! When you're fighting wind and turbulence anyway, it's much harder for me to detect lift. Also harder flying fast. Can't imagine how the F5J guys search for and find lift under high speed motor run.

I've become quite adept at identifying sink. And oh that dreaded tail down parachute glide path, get ready to land.

If you happen to see me on your tail you might suspect what I'm doing

About streamers: very valuable clue-providers!

Having a variety of streamers around the perimeter of the field helps visualize thermals. The streamers (the best I've seen are made of audio tape pulled from tape cassettes) will all lean or point towards the lift.

Corky:

Ah, you are learning!

Crash:

Seeing thermals is more common than you might think, out here where it aint so wet.

Albuquerque is not a desert (it is officially "semi-arid grassland", receiving an average of 6-8 inches rain per year - sometimes) but there is plenty of dust for a thermal to lift. Even if there is not a dust devil sort of thermal, we can watch vehicles drive by, and if the dust rises in their wake, well.... Where do you think we might go?

I once launched a DLG into a dust devil. It was advancing onto the field like the Tasmanian Devil in the old cartoons ,and scattering things around. But, it was the middle of a heat, and no one was going to pass up lift.

I actually went around it, and entered the lift from the side, avoiding the dust itself. The airplane went up skyward, all tossed and tumbling. I was busy trying to regain control, but noticed something else in the lift with me: it was a lawn chair. My lawn chair, and it was out-climbing my airplane!

And yes, it landed after I brought my airplane back, too. I was out-climbed and out-flown by my own lawn chair.

A tip I got from my Dad at my first contest.

I was flying upwind in a Z pattern, Dad was timing for me.
Dad asked why I didn't turn to a bump up of the wingtip.
Why would I asked?
It is lift, "Turn into the rising wingtip dumba##."

Thanks Dad!! 2nd Saturday, 4th Sunday, 1st overall.

Joe


Balsa Breaks Better
Woodies Forever

I once tried to land in a dust devil. Bad idea. It kept sucking the glider back up. I made two or three passes before I dorked it much too hard and broke the fuselage. I should have waited or flown it to the other end of the field.

Once, I almost lost my student's .40 sized* trainer straight up in a thermal. Also saw someone thermal a Kadet Mk. 2** for two or three minutes, minus the cowling.

I find that a glider in lift feels more lively, but that's not much help before launching.

If you're at a contest and you see a bunch of sailplanes circling in the same area, the lift is probably dying unless the expert who found it is still there. If not, it's probably moved or is breaking up. If there are only two or three, maybe its still got some life left, depending on who the two or three are flown by. It takes time for a bunch of people to pile on. Time in which the thermal has probably changed or moved. If the expert is a mean person and has almost made his time, he may circle in sink to lure the unwary. ;-)



*A model designed for a 0.4 cubic inch IC motor that burned methanol and nitromethane, with a bunch of castor oil. I figured those of you who are neither Luddites or old might want to know.

**The most popular trainer when I entered the hobby, also .40 sized and with a higher wing loading than the other trainer I mentioned. Sig still makes the kit. They also still make the Kadet Senior, which is far larger but flies fine with a .40, and is fairly easy to thermal. This is handy for instructors who have just got egg on their face from not making the engine run right.

Good morning!
I am enjoying the various responses as I sip on my first cup of java! I wonder if the more experienced pilots can find and stay in lift with most of their sailplanes or do they find they have a favourite? The reason I ask is I seem to have the best luck finding lift in my old Wanderer 99. It seems to circle slower and tighter. With most of my other planes, it's up they go, circle around the field and all too soon they are landing. Does having a larger wingspan make it easier to find and stay in lift?

Cheers!
Lyle

Great forum topic , enough of the gloom and doom .
Pappy , I have found that bigger ships do signal and respond to lift in an easier to determine way and once into the lift , they're easier to keep there .
I had flown virtually only standard class 100" ships ( Aquilas etc ) for decades ,then I moved to
G/E's , Challengers at 144" . I don't think I'm going back.
I will say my big ones are light and enjoy very favorable wing loading.

Lyle,

Size, in this case, does matter. Usually a longer wing span can search more air to find the lift. However, the 100" size glider is a good compromise. I began my soaring in the '70's with a Wanderer 99 and completed many of my LSF tasks with it. It is a good trainer to use to start searching for thermals and performs well in light winds. The one problem with the 99 is the airfoil that does not have a wide speed range and as a result it has the characteristics you describe.

Mark

Size matters: a larger sailplane can be seen further away, and any wing rocking will be more noticeable.

But, the Big Boys flying DLG still find plenty of lift, and those airplanes are limited to wing spans of 1.5 meters. I learned thermalling from DLG, which I pursued with great passion for about ten years, and it has paid off in F3RES in spades. Toby confided in me that in the last F3K contest he attended, in the last round, he merely side-armed a launch into a passing gopher fart and rode that out.

Wing loading affects sink rate, yes. Low wing loading relates directly to low sink rate, but again, that is not finding a thermal.

OK, here is some anecdotal information about size and sink rate.

A couple of days ago, I was at the Balloon Fiesta Park on that rarest of days: calm. I could feel air movement, but the direction was always changing, and it was only movement, not a true breeze. I am getting back to F3K, and I was working on my launch "technique", which was always a joke but is now pretty sad. I can launch roughly 100 feet. Which is enough to generate a flight time of 1:30-1:45 if I (1) pitch over properly at the top; (2) transition immediately to full camber for minimum sink; and (3) don't touch the sticks, ever! after that.

In nearly the same conditions, a couple of years ago, we launched a wide variety of 2-meter F3RES airplanes under controlled conditions: no thermalling, minimum turns, every airplane launched from the same histart. The histart probably generated 200 foot launches. The usual flight time was - wait for it - never more than two minutes.

In other words, the smaller airplanes (the DLGs), from a lower launch, actually got nearly the same flight times.

There is all kinds of rationale to explain the two classes of performance, but the point is that size does not equate directly to performance. It can help, but a poor pilot with an excellent airplane will probably not see the same flight times (or have as much fun) as a good pilot (paying attention) flying a lesser airplane.