Flying in and out of thermals, and thermal turns.

[soholingo]

First off I am flying a photon II R/E dlg. No flaps, no camber mode, just simple RE poly...

I am not sure if anyone can help me but I have been flying through thermals. I have progressed to point where I can tell I just flew through a thermal, and I can circle and fly BACK into the thermal, but I can not figure out how big the thermal is and I can see the plane 'falling' out of the thermal.

Any thoughts on how to gauge the size of a thermal, so I know how tight to turn? Also any tips on doing thermal turns so that the circles are tight and so I don't stall then speed up, then stall then speed up.

Thanks for any help you can offer...

Jay

[becsta]

With R/E only models, the key is to be smooth on the sticks, and not use so much deflection on the rudder and elevator. You're probably using too much elevator, which will eventually cause the plane to stall, and drop its nose, so you put more elevator in, and it does it again....

I was/am still like that sometimes, but I'm trusting my planes more and more to lay off the elevator, and use trim more - a couple'a clicks o' down trim, and she'll speed up, and a couple'a clicks o' up trim, and she'll slow down a touch

To see the thermals more, you need to move your plane's CG back a bit (so she becomes a bit more unstable, and react a bit more when she hits sink/lift). That, and "feeling" with your eyes what the plane is doing - if she doesn't look like she's in sink, then she has to be in neutral air, or lift, and vice versa.

Cheers,
- bec

[Curare]

When i was learning to pick thermals I'd fly though one and straighten the plane all the while cursing that it's "twitchy" to fly.

Nowadays I don't touch anything, and look for those telltale twitches, both in attutude and wing deflection.

The only real key to getting lift cored is watch watch watch.

another thing that's worth mentioning as bex has, is overcontrolling.

I remember being told as a kid by my old man that his gliders were always weak on rudder, and never turned right. I used to think that of my planes too. I was flying them a little too slowly, and as such everything got really mushy. I couple of clicks of down trim will help your turns, and keep those control imputs to a minimum. I used to fly my R/E on high rates, and could get about 4 minutes in still air. I was flapping rudders and yanking elevators the whole time. Nowadays I fly on low rates and just breathe on the sticks, and in still air with the same plane I've picked up a good minute.

food for thought.

[Andy W]

There's no way to know how big a thermal is unless you fly through it. There's no way to know if you're in the strongest part of the lift unless you fly through it into weaker lift. It's all about what you're willing to live with..

If you're scratching down low, you have to stay in whatever lift you find to get up to a safe altitude. If you're up high to beging with, you can afford to hunt around a little until you find the strongest area of lift.

It's exactly the same in full-scale, except we get the benefit of a vario chirping to indicate lift strength (although you can feel it in the seat of your pants.. :) ).. You encounter moderate lift, you wait a while before you initiate a turn. If the lift drops off, you're either turning the wrong way, or you've passed through a little bubble instead of a nice thermal.

Patience, and practice, will help. Do you have Paul's "Secrets of Thermal Soaring" DVD? If not, I'd get it..
..a

[Ollie]

First find the lift. Second, keep the plane in the lift. Third, map the lift with the plane. It is very important to trim the CG so that it is sensitive to lift. It is very important to keep the mass from the wing tips and tail so that the plane is sensitive to lift.

The air is invisible most of the time. The pilot must be sensitive to wind changes in speed and direction. The pilot must be sensitive to air temperature changes. The pilot notices clues of smoke, trash, grass, leaves and dust moving due to air movement. The pilot notices clues of birds and insects. The pilot concentrations his mind about all of the above.


Learning To "See"

by Mike Lee

"While there is no doubt that a large number of people must wear glasses for perfect vision, there is a little-known fact that people only see what they want to see. Most of the time, we see only those things which are in close proximity to us and ignore the rest. But when we fly aircraft we must be able to see or we are lost. There is a way to help yourself.

"Good eyesight doesn't require you to borrow the eyes of an eagle to be great. Even if you wear glasses, the trick to seeing well is to train yourself to do so. This is really easy to do, and you can do this anytime that you are awake and looking around.

"The first thing to do is try to notice everything around you. Look especially for details of items like the leaves in the trees, not just the trees. Look for the name emblem on a car as well as the entire car. Watch for the things within your peripheral vision without moving your eyeball from the spot it is focused on. After awhile you will find that you are seeing things you didn't see before.

"Next, move on to more distant objects. Don't just look at a mountain in the distance, look at the detail of the mountain in the distance. When you are out driving, look ahead, way ahead, for the street signs and read them. You will soon find that you are teaching yourself to see better. Your eyesight was always there for you -- it just wasn't fine tuned to see everything.

"If you practice seeing with your eyes, you will soon find that your ability to identify the altitude of your aircraft at distance is easier than before. You won't worry about whether that last control input should have been left, or was it right? Consequently, you will recognize lift faster and run from sink sooner. It is a very conscious effort to train your eyes to see, but the results will last you the rest of your life."

[becsta]

I'll tell ya a bit of a story, that might make you think a a bit about what's happening up there, so bear with me a sec here...

I remember back a few months when I was flying my 2M R/E glider (a Blejzyk First) in a comp. One of the guys I really look up to, was timekeeping for me, and he was also doing some coaching. Anyway, I launched it, and Carl told me to head downwind a bit, coz we felt a thermal go through.

I was at the stage in my flying where I was flying pretty much hands off, and that was how I was flying my plane that day. Anyway, she's flying downwind a bit, nice and straight, hands off, and Carl starts going off his head!

"What are ya doing?"

"Flying it, Carl, I'm going where you want me to go?!"

"No, you're not! She's meandering around all over the place up there", he says, getting a bit exasperated

"... but she's flying straight, Carl?"

"No, she's meandering around, bec"

"... but I'm not touching the sticks, Carl! The plane always does that..."

His point was that my plane was getting pushed away by one thermal, flying straight for a bit, then getting pushed the other way by another thermal.

"When I tell you to fly straight, you fly straight, straight, straight!", he said, and I got what he meant after that! I would fly it straight, then whenever a wing lifted, I would force the plane around, and we'd found lift.

I was thinking that the wing wasn't straight or something, and the plane would gradually meander around the sky doing its own thing, but it wasn't - the plane was quite capable of flying straight as an arrow if I wanted it to, hands off, and I was misreading the signs.

The next time I flew, we did the same thing, worked out a plan of where I was going to fly before launch, and I'd immediately head off in that direction (typically downwind at a 45degree angle to the wind). He told me to fly straight, so I did, for a long time, before the plane started doing its meandering bit again, but this time he just smiled at me, and I knew what to do - I ended up doing about 9 minutes that flight.

Another word of wisdom from him was to not leave lift if you're in it - why leave it? The only time you'd leave lift is if the plane is getting a long way away, and you're uncomfortable with where it is.

What else did he show me? Oh! When circling in lift, DS the back half of the lift in the circle - ie, use up elevator when going around the downwind leg of the turn, and not use the elevator when you're turning around the front half of the turn. When I was watching him circle in lift, he was methodically pulling up elevator through half the turn, not the whole turn (up, centre, up, centre, up, centre...). He'd use rudder (and ailerons) to keep the turn going.

One final thing, never exit a thermal out the front of it, always out to one side. The reason is that the strongest sink is directly upwind of the thermal. There is sink out to the sides, just not as strong.

[Curare]

Exactly

[Ollie]

A deaf person can learn to read lips!

So, you can learn to read lift with concentration!

Focus your mind.

[atjurhs]

What are you're all thoughts on for R/E only birds, programming in a little bit of down elevator when making a rudder input?

My thought is (for new T/D pilots anyways) to try and keep the airspeed up as you're making the turn.

[dr.E]

Jay... Get a pair of 1970's vintage running shorts (go comando :D ), wear some comfy sandals and go to the field........ You'll really feel the wind around you...... Toss towards the warm side :D

I'l try to make a dvd copy of Dave Thornburg's Old Buzzard Video or Joe Wurt's Vector Sum Video (I think it was Joe)

I think you might be a little nose heavy, this will accentuate the elevator throws also and the possible stall while coring....

Once you get in the thermal, the coring circle radius is dictated by your elevator because you're banking rather than yawing..... Evaluate the path you're coring by dividing the core into 4 quadrants and giving each quadrant a qualitative value of - , 0 , +, (sink,neutral,lift) and adjust the radius of the core with your elevator imput...

[BMatthews]

What are you're all thoughts on for R/E only birds, programming in a little bit of down elevator when making a rudder input?

My thought is (for new T/D pilots anyways) to try and keep the airspeed up as you're making the turn.

That's the wrong thing to do if the model is trimmed correctly. Adding rudder tends to move the model into a spiral dive so the speed tries to go up automatically. The trick for smooth level turns is to add UP elevator at the right time. The right time is dependent on the model. Some need up immediatley along with rudder input and others need the wings to reach a few degrees of bank before the elevator is smoothly added.

The only time I could see some small amount of down being needed is PERHAPS with a model that has a very sharply swept back hinge line where there's some geometric up elevator coupling due to the angled surface. But none of the swept hinge models I've ever flown showed any signs of this. But with a racy looking shark like sweep angle it's possible.

Becsta, a great story and lots of great hints in that.

Soho, when I'm circling in lift I'm still constantly watching the model to see where it tends to climb the best (or sink the least). I then alter the circle smoothly to try to coax the model towards where the larger amount of lift seems to be. That's one method of mapping the thermal and works well once you're already commited to circling flight. If you're still flying straight and you think you've passed through some lift then turning back into it is the only option. At that point you want to turn towards the side that seemed to lift a wing with a larger open first circle and then tighten it up a little as you come back through your original heading. This SHOULD put you back into the part of the moving airmass that produced the lift sign. From there keep circling while looking for signs of that lift. Alter the circle size to move around if you don't see it but keep circling to avoid further control movement drag. If you can't find it within a circle or two then you either missed it or it was just a local turbulence bump. On blustery days you can get a lot of those.

And this sort of thing along with all it's variations is what makes thermal flying both so much fun as well as often frustrating.... :D

[Curare]

If it was easy, I don't think I'd enjoy the thrill of getting it right.

[soholingo]

If it was easy, I don't think I'd enjoy the thrill of getting it right.

I think that's what keeps me coming back for more. Since I can't stay in lift, I have been working on my other skills, getting the plane back to me, flying smoothly, launching higher, etc... I just figure that so long as I am out there, stayng in thermals will come. What's unfortunate is that I am seeing the limits of my photon II. I can't launch it over 60 feet, it doesn't come back to me from long distances, etc...
I will keep at it...

Jay

[jcats]

hey soho,

are you still flying your fast electrics?
Is the photon considered a beginner dlg?

Since you know when you're entering and exiting a thermal (that's the approximate width of the thermal) then it's just a matter of getting back between the entrance and exit points and staying in it. At around 25 to 75 feet my circles are very tight. Even at higher altitudes my circles tend to be tight--as long as the plane climbs.
I noticed that when you're in a thermal the plane seems to have the speedup-stall-speedup-stall tendency (without even touching the elevator stick) so i give it some down to compensate. I see this on my supergee even with a very rearward CG.

Just keep at it and have fun!
I've been flying for over 4yrs. Getting into DLGs has been the most fun to date.

jun