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Old Sep 15, 2012, 09:18 PM
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Soaring hints.

Hi, guys.

I have seen a number of newer fliers asking for hints over the last several days and figured I would start a thread where we pool some of our best advice. I'm not going to attempt writing a manual but rather just offer tips that can help. Please feel free to contribute either hints or questions. So? I'll offer a couple very basic hints to start the ball rolling.

1. CG and trim. Get it right. A successful sailplane pretty much has to be able to fly hands off. Newer pilots might want to get some help if there's any experienced pilots available but keep in mind that we develop our own styles and it's very hard for one pilot to fine tune the trim for another. One also wants to trim for best glide performance while trim under power is secondary.

2. Speed control. It's a bit counter intuitive but controlling speed is a real key to soaring. In very simple terms: one wants to fly a little faster at the optimum lift to drag angle (a bit nose down) when searching for lift while one slows down to the speed of maximum lift (more level or even a bit nose up) while actually in lift. Finding the speed and angle for maximum lift to drag is very much like trimming a power boat so that it is "on the step" where one has the least amount of hull in the water and are creating the smallest wake. The type of airfoil, streamlining, and wing loading will affect the best glide angles.
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Old Sep 15, 2012, 11:08 PM
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The best lift is always directly under the sun because the ground is hottest there.
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Old Sep 16, 2012, 07:58 AM
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If the wind direction changes suddenly it ususally means there is a thermal being 'fed' by the moving air. Go down wind to find the lift.

Iain
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Old Sep 17, 2012, 03:35 PM
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I like the tip the best lift is under the sun ;-)

HI guys,
(Its raining here in Kentucky and so I was checking out the sailplane section and came across this thread.)

There are a lot of quips like that when it comes to thermal lore, but in fact Lain has the best tip...the one that is useful to us rc sailplane guys.

Having hand tossed a 147" sailplane (that means no motor) into lift and keeping it up for over 2 hours and a couple of 8 hour flights, one thing for sure is that everything on the daylight side of the Earth is directly under the sun.:-)

Diagnosing where and how lift is generated is also interesting and helpful, but again its Lain who has the info that will put you into lift.

Rising air pulls air to feed it. Rising air is warm and the feeder air is cool.

Stand in a field, close your eyes and feel the air on your face, arms and legs. Launch toward the place the air hitting you is heading and likely....you'll have a good day.
Gordy
PS, as far as trim and balance etc goes...houses fly just fine in Kansas with out any attention to those things. Put just about anything in lift and its going to go up. However, properly balanced will help your model tell you the truth about lift and sink, versus lying about airspeed changes.
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Old Sep 17, 2012, 03:44 PM
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Good stuff, Gordy.

I might also add that thermals are caused by contrasts in temperature. One doesn't really need warm temps for thermals to form but rather places where local heating occurs. Big chunks of asphalt like roads and parking lots can be very consistent sources of thermals. (Note: Please don't fly over busy roads or parking lots. Find a spot down wind and let the thermals blow to you.) Plowed fields in spring or fall can provide great lift. I've even had some great flights flying over an open spot on a frozen lake.
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Old Sep 17, 2012, 04:49 PM
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Pay attention to the birds... When they start to circle go join in
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Old Sep 17, 2012, 05:48 PM
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The only problem with following the birds, in my experience, is that they almost always make me feel inadequate and want to get a new and very expensive sailplane! I have also seen a couple of birds in videos that don't like to share their airspace though I've never suffered from a hostile response myself. I've had birds get curious and follow me around but generally they seem to ignore gliders.
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Old Sep 18, 2012, 10:27 AM
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This may seem super obvious but pick a sailplane with a 6 - 8ounce wing loading. Use that same sailplane and practice practice practice practice practice !! Don't get discouraged if you can't find lift at first. After a while you'll swear you can SEE lift (and you actually can if you pay attention to the little tell-tales) Successfully flying a sailplane is one of the bigger challenges but I feel has the BIGGEST rewards also.

Old_dude
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Old Sep 18, 2012, 11:26 AM
AMA7224 LSF1832
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Quote:
Originally Posted by old_dude View Post
....... After a while you'll swear you can SEE lift (and you actually can if you pay attention to the little tell-tales).....
A very appropiate Yogi Berra-izm here would be "You can observe a lot by watching". You do get a second sense after a bit for finding lift,it comes with air time and may well be a revalation,a epiphany or just all the sudden you know what to do.

Quote:
Originally Posted by old_dude View Post
Successfully flying a sailplane is one of the bigger challenges but I feel has the BIGGEST rewards also.
This is what keeps me coming back for more.
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Old Sep 18, 2012, 03:08 PM
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Here's one that is so obvious it's easy to forget.

A folding prop will continue to windmill without setting the ESC to brake and said windmilling will kill any chance at a good glide performance. Remember; a prop is just a wing that spins and unless one brakes a folding prop the lift on that "wing" will keep the blades extended. Another thing to keep in mind with a glider or anything with a high lift airfoil is that any change in airspeed will have a big effect on trim and glide performance. I can't stress enough that "the faster you go the more it wants to climb". This is exacerbated by a windmilling prop
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Old Sep 18, 2012, 04:55 PM
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Read the plane. Right wing rises; rising air to right. Left wing rises; rising air to left. Nose rises; entering rising air. Tail rises; exiting rising air or it's behind.
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Old Sep 18, 2012, 05:08 PM
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So I know it's not a sail plane but I'm having fun learning the whole soaring thing with my dynamic s.......my flying field is in a very flat area so no slopes to play around with.
The max flight I have had out of this bird is around 25 mins but with loads of pack left. I'm so used to 7-12 min flight that I start to panic over that....I really need some telemetry to easy my worry.
I do get some good wind 12-20 mph at our field but no sure how beat to use it for lift, and whenever I see birds circling in thermals I just can't catch them....I seem to loose altitude in the tight turns.
I have no idea on wing landings so would anyone be able to say if the dynamic is a good plane for what I'm trying to do with it.

I have no problems with fast flight and love the fact the dynamic will pull vertical forever.
Do people switch flaps on when looking for lift or do you use them only for landing???
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Old Sep 18, 2012, 05:38 PM
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Welcome, blackbrabus.

I've never flown a Dynamis-S but, from my research, soaring is not it's strongest suit. It will probably climb in strong lift but will suffer compared to a lighter "floater". I'm still learning the characteristics of Li-po batteries and tend to chicken out before I use a whole lot of battery too.

Birds are much better at soaring than we are and I have only managed to out climb birds on three or four occasions in 40 years. I suspect those birds just weren't trying!

Based on the specs I would say that the Dynamic-S would be a real challenge to get a lot of thermal soaring but I don't see any reason it wouldn't be a good learning tool and loads of fun. You will probably be looking at stretching flight times a bit rather than staying up all day without power. Given the relatively high wing loading I would say that you would see more benefit from flying back and forth through a thermal rather than trying to circle inside it. Like ajbeebster says; "read the plane". If you see it start to rise? Pull a little back stick to slow it down and get the most out of the lift. Then? Let it go back to its normal glide angle and speed then try to make a controlled turn to go back through the thermal and catch a bit more lift.

Flaps can be used to optimize a sailplane for certain situations. One will see a lot of talk about "camber" and "reflex" with flap-equipped gliders. Camber is when the flaps and/or ailerons are pointed down a couple degrees to maximize the lift provided by the airfoil. This can be used to stretch out the glide in the absence of lift or to slow it down within a thermal. Reflex is when they are pointed up a bit to provide higher speed and better wind penetration.

Keep asking if I'm not making myself clear.
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Old Sep 18, 2012, 06:33 PM
Red Merle ALES
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I see this question asked periodically so I made a page on my website called "Tips" that may be of interest.

http://www.tailwindgliders.com/Tips.html

Make sure you fully understand "The Third Vector"

Curtis
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Old Sep 18, 2012, 07:31 PM
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Drift with the lift…

We are always flying in an air mass that is moving with the speed and direction of the prevailing wind. If you're circling in a thermal, that thermal is moving with the wind and you need to drift with it.

Oh yeah… read Old Buzzard's Soaring Book by Dave Thornburg about a dozen times.

Piper J3
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