Basic Thermal Knowledge Required

[simonbryant]

Hi all,

I have a Swift Vee which is approx 1.76M

Can someone give me some basic guidlines to thermaling....ie being in the UK do i need to wait for a Hot day in August or our their thermals about in Winter and spring?

Thanks

Simon

[lrsudog]

Hot days are not required. Some of the best days are the ones that start out cool with little or no breeze, but with very clear skies.

This allows the sun to rapidly heat the ground, even while the air temp remains lower. The heated ground will heat the air close to the ground, causing bubbles of lift to break free and rise, starting thermals.

[wrhinehart]

There are many sources of help about soaring. I've listed a few below.

The very best method is to find a Master Pilot in your area to assist you for your first flight.

He (or she) will check out the build, make sure the electronics are correct, hand launch and trim it for you.
Then he will launch it to altitude and give you the reins.

That is the best way.

http://www.moneysmith.net/Soaring/soaring.html

http://www.quicktechhobby.com/articles/thermal_surfing%20part%201.htm

http://www.quicktechhobby.com/articles/thermal_surfing%20part%202.htm

http://kohlin.com/air/soar-faq.htm#589931

That ought to keep you busy for a while.

Bill

[Yardbird]

Knowledge of thermals is important, equally important is recognizing when the sailplane encounters one.

For me, I look for a wing suddenly lifting, a drop of the tail or the feeling that the plane is being turned away from its path in the sky.

Of course, circling birds are always a good clue :D

[Garvey]

Beg, borrow or buy (if you can) a copy of 'Old Buzzard's Soaring Book' by Dave Thornburg. A true classic which will tell you all you need to know and more besides.

[Ollie]

Get the Old Buzzard’s Soaring Book (A11560) Thornburg from:
http://www.carstens-publications.com/

What do Thermals Look Like
http://www.rc-soar.com/tech/thermals.htm

[Ollie]

More:
http://radiocarbonart.com/Pages/asecthermalmain.html

[aeajr]

The best conditions are low wind, hot sun and low humidity. Some big dark
areas surrounded by lighter areas will help to create thermals, so look to see
if there is anything like that on or around your field. A freshly plowed
field with dark earth is good. A parking lot works. A large building with a
black roof is
awesome.

However I have caught thermals at 35 degrees F in 15 mph winds. They can be
weak and they move fast, but they are there!

Here are some thoughts on the hunt!

Weather by motor, winch, hi-start or hand launch, get your plane as high as
you can.
Trim the plane for nice level flight. Now, focus on watching the plane
and keeping it on a nice steady glide. Steady as she goes. Try to keep your
hands off the sticks as much as possible.

Let the plane ride with the river of air, giving it only occasional input to
keep it going in the general direction you want to go, but don't be a stickler
about it. Let it drift like a fly on the surface of the river, waiting for a
trout.

If you listen with your eyes, it will speak to you, but you have to listen
patiently.

Glide across the wind, not into it and not with it. Sort of a 45 -60 degree
left for a while then a 45 to 60 degrees to the right. this will give you the
best view of the plane and give you a good hunting pattern. Nice and slow and
easy. You want to cover the sky and search the moving river of air, like a
bird looking for food.

As you are flying watch the wing tips the nose and the tail. If a wing seems
to bump up, or if the nose or tail seem to bump, it could be a gust, or you
might have just brushed a thermal. Go immediately into a turn in the
direction of the wing that rose. If you think you went right through it, fly
on for a moment then turn to circle back into it. keep in mind that thermal
move down wind, so make your turn to circle down wind maybe 50 feet.

Try to make a circle, but not too tight or you will lose too much altitude.
Try for about a 75-100 foot diameter at first. Complete a couple of turns and
see if the plane seems to be rising. If it is, just stay with the turn but
give it a little up (back) stick. Not a lot, just a little. We don't want to
scare the thermal, we want to bond with it.

Try to observe if the plane is rising steadily, or if it seems to rise and
fall. If the second, that means you are not entered in the thermal so work
your way more toward the side of the circle where the plane rises.

Remember that thermals move with the wind, so you are not trying to stay in
one place in relation to the ground. The air is like a river and you are
trying to stay in a little whirlpool that is moving with the river.

If you go into the turn and make a couple of turns with no success, then just
resume the search pattern I mentioned. Angle across the wind, not into it
and not with it.

A sailplane in lift
http://www.rcgroups.com/articles/liftzonemag/2004/mar/ava/Ava2.wmv

If you are getting out too far, work your way back the same way, angles to the
wind.

Unless you hit a boomer, very strong lift, you are not going to immediately
know you are in lift, so you have to watch the plane. Sometimes it becomes
apparent because you realize that your not sinking but appear to be holding
altitude. The only way to do that is to be in lift.

It is a hunter's game, if you are up for it.

Good luck pilot! May your hunt go well!

[simonbryant]

Wow, some very good knowledge here to help me.

I have a lot of reading to do, then i guess its practise, practise, practise...

Thanks to you all for your time in sharing your knowledge with me.

I shall report back in due time on my progress....

Simon

[Garvey]

I'm sure you know of West London Models which is just north of Heathrow. The staff there are very helpful and should be able to point you to a gliding club in the area where you can get some first hand advice.

[simonbryant]

Great thanks...yeah West London Models is just down the RD from me, i will give em a call.

Simon

[Batmanwpg]

http://www.apogeerockets.com/education/detecting_thermals.asp
Try this article

[wingsnapper]

Great video! I'm glad to see that this kind of footage is out there. This is exactly what a newbe needs to see. A plane that is just barely holding it's own.. pilot keeps cool and works with what he has untill the core is found. Also notice that the pilot is flying an AVA (one of the easiest to fly planes out there). No need to take on a delicate dance like this with a plane one has to "fly".
Poly all the way.
JS

[simonbryant]

Hi Which Video are you refering to?

Does anyone know of an AVA supplier in the UK?

[Garvey]

The AVA is available from Brian Anderson. His phone number and email address are on the FVK website. I have dealt with him a couple of times and he is a very knowledgeable and helpful guy.
http://www.fvk.de/Englisch/FVK-Modell-English-Version.html

[simonbryant]

Great thanks for your help.

Simon

[wingsnapper]

Video was in Aeagr's post. JS