Am I thermalling correctly?

[Wildewinds]

I've been trying out this thermal duration stuff for about six months now. I seem to do okay. My thermalling technique up to this point has been to fight the model the whole way. If it wants to turn right (left wingtip goes up), I'll turn left and vice versa.

However, I hear about people talking about how sometimes the glider will center itself in a thermal (core), and I believe that's the whole point of what the free flight guys do. So, am I right in fighting it the whole way, or are there times to let the model decide where to go? If so, how can I tell the difference?

[Robglover]

If the airplane is going up you are thermaling correctly. If somebody elses airplane is going up faster than yours is then they are thermaling more correctly than you are. If somebody who isn't flying with you says that you could be going up faster listen and maybe try what they say, but be skeptical. Some of us enjoy contests because you can gage your skills in comparison to others.

[Sparky Paul]

The direction of circling can change with wider thermals.. Just get up high enough so the bank angle to stay in the thermal isn't too steep.
Today the thermals were so wide I could S-turn and go up!
Just get used to what the plane tells you is going on.

[flystoolow]

I've been trying for about six months now. I seem to do okay. My technique up to this point has been to fight the model the whole way.

Are there times to let the model decide where to go?

If she's cute, I'd say just lay back, close your eyes, and let the model do the work. :D

Hope I read your question correctly.

[Wildewinds]

If she's cute, I'd say just lay back, close your eyes, and let the model do the work. :D

She's a model. Of course she's cute.

Anyways, I think people are misunderstanding my question. I know how to thermal, and I do decently in contests, but I'm wondering about how to react to what the plane is doing in order to thermal and to find thermals better.

[Ollie]

There is no standard thermal. Most thermals are invisible. You must have indrect clues like wind direction changes, temperature changes, insect seen, birds, dust, grass, leaves, etc. Once you encounter the thermal, probe with your model. The sensitive of the model depends on your flying skill in mapping the thermal. Since the thermal changes with time, you must continue mapping of small thermals or ready for shear region or gusty thermals.

I had a flying buddy. He was a experienced flyer but he was a poor user of thermals. He liked the his model's set-up for high stability not for sensitivty for probing thermals.

[Phil Barnes]

RC gliders don't self center in lift. Centering in lift is your job as the RC glider pilot. You are correct to recognize an un commanded wing tip rise as a possible lift indication. You should force the glider to turn towards the raised wing tip. You then look to see if the glider begins rising in lift. If no lift is seen you can assume that it was only turbulence that the model encountered rather than lift.

While circling in lift you should always be assesing which part of your thermal turn is in the best lift. Adjust the thermal turns to keep the model in the strongest lift. You may also find that a tighter turn is needed to keep the model in the thermal core. This would be especially true closr to the ground. You may find that the thermal gets wider as you climb and you can flatten your turns at higher altitude.

Is that getting close to the type of answer you wanted?

[Wildewinds]

Is that getting close to the type of answer you wanted?

Yeah, that's exactly the response I'm looking for. Thanks Phil.

[Phil Barnes]

Correct thermal technique and how to read air is a huge topic. Ask some more questions if you have other areas where you doubt your'e own technique.

[slopemeno]

I would add to FLY with other fliers and watch their technique- share a thermal and see if they are specking out quicker than you. I've found the best way to improve in a hobby like ours is to spend a day with someone better than you at it. Ask questions, let them fly your plane, show them your setup.

[flystoolow]

Great advise from everyone.

I think another response to your question is relevant with regard to how much you should control the glider at either end of the thermal strength spectrum.

In a large, very gentle thermal, where the glider is barely maintaining altitude, or even descending slowly while you bide your time, it is generally best to basically let the plane fly itself just above stall speed, touching the controls only minimally. In this case most of your neuron activity should be working on keeping the glider flying level at mimimum sink speed without turning too much.

On the other hand, strong, small, violent thermals often have cores only 20' across. In these one needs to carry more speed (sometimes loads of speed) and not be afraid to really throw the plane around with full control movements if needed. In this case the glider can stand on it's wingtip 60% of the time, and cartwheel out of the thermal 40% of the time and still go up, and your brain should be working on constantly trying to enter/stay in the core of the thermal no matter what it takes. Losing 50' in a heartbeat is no big deal if your next pass through the core slams the glider up 100' in three seconds.

I think the best advice I ever received was:

Never leave lift!

If the glider is only maintaining, not going up or down, that's fine. Stick with the weak lift for 2 or 3 minutes, and usually it will improve.

"Self centering" in a thermal.

An old trick some hang-glider and paraglider pilots use is to release a length of toilet paper into a thermal. If it is in the core, it will stay in the core and rise. Now that would be fun to rig up on an RC glider...a TP bomb bay.

[kevin6Q]

"If the glider is only maintaining, not going up or down, that's fine. Stick with the weak lift for 2 or 3 minutes, and usually it will improve."

The classic zero sink condition. A friend who flies full scale had a great quote about hanging out in zero sink waiting for the thermal to mature. I don't remember it exactly but it was something akin to:

"Remember, zero ain't nothin'"

[Ollie]

EVERY moment, the flier must concentrate on the signals from the plane. A brief bobble might miss the thermal if you don't concentrate. Once you fly into the gusty thermal, you concentrate when the (negative) signals are away from the core. Fight the plane to the core.

[becsta]

One of the pieces of advice that our top flyer in the club said to me not long ago was "fly straight". I looked at him strangely, and he repeated his advice "fly straight"!

My glider at the time was flying straight, but it was meandering across a course I was flying. A wing would raise a touch, and the glider would turn to one side, then the other wing would push up, and the glider would turn back, and slowly it was meandering from side to side down a straight line.

Carl was saying to me, quite angrily some times, "fly straight"!

When I eventually landed, he explained his advice - my plane was flying from the edge of one thermal, being pushed away, flying to the edge of another thermal, being pushed away ad finitum.

So, the next flight, I flew the plane straight, and wouldn't let it meander. My plane would fly straight and level hands off, so turning indicated lift, and I ended up hooking some boomer thermals as a result.

So my advice to you is: "fly straight" :)

[Jurgen]

"What is going on in the air ?"
To know there are your body sences and there is this stearable device often called a RC glider :)

For (self) centering in lift the Free Flighters had to meet the obective another way, like Histarter (RC group member) putted it before:
My low launch thermal huggers have followed FF programs. They utalize CLA (center of lateral area - controlled by vertical stab area) behind the CG reference - to insure inward tightening of a spiral turn with lift vector. The stronger the lift the tighter the natural spiral until I have to retard the forward slip by holding it off with opposite rudder (to avoid a spiral dive). This thermal sniffer action tells me how strong the lift is; while it is auto centering at the same time.

[Phil Barnes]

Jurgen

If you truly do understand that Histarter quote then I am very impressed with both your technical knowledge and your English language knowledge. Could you translate that quote for the rest of us please?

[BMatthews]

RC gliders don't self center in lift. Centering in lift is your job as the RC glider pilot......

It's not a common thing but it does happen on a resonably regular basis depending on the conditions. I have had the models do better when trimmed to a stable turn and letting then do their own thing than by trying to help out. Mostly when dealing with very light lift Mind you it's something best done with a poly model like a Gentle Lady or similar with the deeper free flight roots. I doubt that it would work as well with many or most flat winged aileron models.

The only rule you can make abour thermals and lift in general is that there are no rules... :D

[Jurgen]

If you truly do understand that Histarter quote then I am very impressed with both your technical knowledge and your English language knowledge. Could you translate that quote for the rest of us please?My own modest experience with thermalling is also like "fight yourself into the core".

I point to Highstarter's phrase because there are other views out there, just to complete the record. I do not have FreeFlight planes, nor do i practise their self centering know how. Actualy they stay a mystery to me Phil, therefore i do not dare to explain. So i had to quote someone in his own name in his own words, opening an interesting can of worms.

Other phrases pointing to self centering:

Highstarter:
I add a FF gimmic onto my sailplanes in the form of a large dorsal fin. The purpose is to shift the CLA back, and thus tend to make the craft overly stable i.e. wanting to spin in relitive to the strength of the lift. This eliminates holding rudder for the spiral, but feeding in offset (opposite rudder) to match the lift intensity. Cost of LD is negligable, and unimportant when centering in strong lift. Best of all, it is metering the air you are in.

BMatthews:
One time I put up my electric powered RC Record Hound old timer at the same time a buddy put up a sparky 60 free flight model of the same size. I flew over to his location with mine after the engine quit and the Viking was in a stable turn pattern. I trimmed my model for the same size turn and we watched. As it turned out my model drifted INTO a very light thermal while his was pushed away.

My model gained, lost, gained, lost, etc in the turn so I thought I'd try to "help" it. Every time I touched the damn stick it made things worse. When I let it go the model would find it's own best spot where it seemed to make the most of the lift on it's own.

..... it was a humbling experience. Especially in light of the fact that I consider myself pretty decent at finding and riding light stuff compared to some. Not the best maybe but I've been complimented by others on occasion so it's not just me....

Batmanwpg:
Free Flighters have been doing the thermal autopilot for years!

FF models can be trimmed to fly out of neutral air and into the thermal and then tighten their circle to really centre it. The use of differential washout or washin and other factors helps to acheive this. Depends on the type of FF model being flown as to how the washin or washout is set up. They will actively seek any lift close by.

There is more but this gives a clue of possibilities, hopefully its not a hoax :)

Seems there is not 1 answer to: "Are gliders self centering in lift?" For myself i only experienced the 'NO' answer.
Jurgen.

[aeajr]

I have only been flying sailplanes for 2 1/2 years. I don't think I can add much to the knowledge of this group.

My observation is that the RES polywinged planes seem to find and hold thermals more easily and I seem to be able to center them more easily than the full house, mostly flat winged Legend. Perhaps I am over working the Legend or perhaps the lighter planes send me bigger signals that I can more easily recognize. Of course the heavier, faster Legend can hunt further and can handle wind much more easily so there is a trade-off here.

I have never tried free flight models. Your quotes have caught my attention. We have one free flight competitor in our club. Perhaps I should spend more time with him and learn about how he sets up his models.

Thanks for sharing these quotes. They have put the mind thinking and now I have to satisfy the curiosity. Free Flighters? Put the plane into thermals with no controls.

Sounds scary!

[Robglover]

Am I thermalling correctly?

Of course not. None of us are.

But, if the plane is staying in the air until you are ready to quit thermaling then you are thermaling well enough.

[TLyttle]

Lots of different philosophies here... I set up my Oly 11 so that it was closer to freeflight, ie, as soon as one wing flew into a thermal (usually weak) it would stall and pull the model into the core. However, if it hit something that dumped it well over, I would pull a quick 270deg turn and drive right into the core. Either way, I "usually" got what I was looking for: lots of up.

It doesn't cost a lot to trim a model to do exactly what you want: I fly the same model for years to make sure that it is doing what I want. Too many guys change planes so often that they really don't know what finding a thermal with it is all about. When I change planes it is only after I have exhausted every possibility of the model I am flying. And, I learned that the Hard Way, giving up on models that were capable of far more than I got out of them!!

[wingsnapper]

It doesn't cost a lot to trim a model to do exactly what you want: I fly the same model for years to make sure that it is doing what I want. Too many guys change planes so often that they really don't know what finding a thermal with it is all about. When I change planes it is only after I have exhausted every possibility of the model I am flying. And, I learned that the Hard Way, giving up on models that were capable of far more than I got out of them!!

I think the first commandment of thermal soaring reads:
"Know thy sailplane." ---- Thornburg.

JS

[Ollie]

Right on, TLittle and JS!!!!

[Peytr]

Self centering RC-planes:

I never got any real proof an RC plane can have a tendency towards selfcentering. When you think about it, it doesn't seem a logical thing to happen as well, so I tend to think it's a myth. Don't say I know, I just suspect it to be.

Fighting your plane to the core:

Where I fly we often have to fight to get and stay in a thermal at beneath something like 150m (that must be in the order of 420' for most people in here). When you're higher and still in a good thermal, it often is better to fly the plane a bit more relaxed. Signals are less visible (at least with my eye sight) and the thermal gets wider and often less turbulent. This way you often get rewarded bij a lot of altitude gain by just putting the plane in a stable circling flight. This might support the possible myth of self centering.

Knowing your plane:

Well spoken verybody. I often found that an older, well known mediocre glider can outperform almost anything, at least in thermal flying. When fighting you know the stall behaviour and minimum speed better. When trimming for the more relaxed flying you know how to let the plane fly with minimal sink. Signals are recognised easier. etc. Above all that, with an older plane you will have had the chance to get the plane decently trimmed for your preferred flying style.

Also a vario can help a lot in perfecting your flying. I use a vario sometimes and learned a lot from what I hear. It doesn't just indicate lift, but can also help to check if the last action was a win or a loose. (if you use an altitude reporting vario like the Picolario talk f.i., which I have). Very helpfull imho.