Which Way is That Thermal?

Here is a way to solve two problems with one action:

When you approach the thermal drop a lot of aluminum confetti. When you
circle around, just fly to the spot that is climbing. At the same time, the
radar operator will spot you on the screen so jets can avoid you.

The problem I have yet to solve is the littering - but you cannot have
everything. Maybe the confetti can be coupons that can be redeemed and the
nearby store operator will pay you to drop them.

I am putting my broken aircraft back together and need to get back in the
air - going stir crazy.

Colin

flying_monkey wrote:
I never heard that that there
was any other theory than turn toward the uplifted wing.

Try doing that below ridge height.
Better yet, think about what happens if you would do that, and don't.
Jim

I agree.

Given that you are in an area of likely lift.
Training stage 1 seems to be how to stay in the thermal when you are
already in it.
Training stage 2 seems to be how to centre in the thermal when you have
found it.
Training stage 3 seems to be how to decide which thermal to centre in
when you are in a likely area.

I have flown a number of legs with Justin Wills on Competition
Enterprise and it is interesting to see our different responses when we
reach the same cloud to climb. I find a good thermal and start centreing
like mad, whilst Justin seems to wander off exploring the area. When I
approach an area already full of other gliders, I will often look around
before joining their thermal.

I often wonder when I meet a thermal whether my first reaction should be
to concentrate on centreing or check that I am in the right place, often
I do the daft thing of first centreing then exploring then re-centreing
which is probably not very efficient.

As for the Immelman, this seems to result from a pull-up from 80kts+ in
neg flap to 50kts in positive flap and a near stall in order to roll the
glider rapidly into the turn. Difficult to achieve in the company of
others.

I am increasingly concerned at my own ability even to manage stage 1.

Rory

Author: Bill Daniels bildan@comcast-dot-net
Date/Time: 20:00 06 September 2006
------------------------------------------------------------
Or, as I've seen in OLC .igc files by top pilots, fly straight through
the thermal to evaluate it, then turn 270 degrees AWAY from the side
where they think the thermal is and then reverse turn direction thus
placing the final

circle two turn diameters back on track offset to the side where the
strongest lift was. The emphasis seems to be good thermal selection vs.

fast centering.

Alternatively, at least one pilot will sometimes perform what must be a

modified Immelmann since the course reversal, as seen on SeeYou's map
view,

is a zero-radius turn while gaining 800 feet in the pull-up. This entry

showed an 80 knot IAS reduction in 12 seconds.

However, it's more likely these guys don't use any specific maneuver -
they just KNOW where the lift is and they're not shy about going for it.

Bill Daniels

ContestID67 wrote:
I was sent a link to a gadget some college engineers-in-the-making
built. http://engenius.sece.rmit.edu.au/Abstracts/Page601.htm. It
tries to detect which way a thermal is based on temperature differences
between wing tips. Bright boys.

I have two questions;

1) Have there been other gadgets created to do the same thing? How
well did they work?

Dear Sir:

Look at the Themi:
http://www.themi.de/Themi%20Centering%20Device.htm

And, I've been told that the Zander flight computer --
http://www.zander-variometer.de/ -- has similar capability, but don't
see evidence of this on their web site.

After hearing about the Themi, I *had* to buy one to see how it works.
Having said that, I have been using one for 2 years, and have some
experience with it -- it's a fun toy -- but I"ve been unable to find
any description of how it operates. Some things are obvious: It has a
GPS engine, and probably has a barometric sensor and/or accelerometers.

In any case, the maximum it coiuld do is to use 3-D GPS data to
calculate climb/descent; it could have accelerometers as well; and
sense pressure changes. It could calculate, therefore, the movement of
the glider, make some assumptions about flight, calculate wind, and on
this basis estimate where the best lift *was* so you can go back to it.

In my experience, if I fly in non-erratic circles, it does a pretty
good job of re-finding the last spots of lift after I've wandered away
fruitlessly looking for something better, and in doing this it seems to
compensate for wind.

Obviously, it can't predict the future, so I use my own judgment on
where lift is *going* to be.

It is useful? After 2 years with it, I do feel that I'm better than it
is. I look at the ground and the cloud (if any) and think about the
wind (my SN-10 is invaluable in this regard --
http://www.ilec-gmbh.com/sn10.htm ) and am reliably able to find lift.

But -- in weak or windy conditions, or when, as sometimes happens, I
lose my mental image of the thermal and where I've been, I will
somtimes turn my brain off for a couple of minutes and just "fly the
lights," and more often than not get back into lift.

I do wish that someone who knows the theory behind this gadget would
speak about this, as it would help me understand how best to fly with
it.

wrote in message
oups.com...
ContestID67 wrote:
Look at the Themi:
http://www.themi.de/Themi%20Centering%20Device.htm



I do wish that someone who knows the theory behind this gadget would
speak about this, as it would help me understand how best to fly with
it.


I'm not a Themi expert either, though I've flown with one for 6 years or so.
I don't think the Themi uses accelerometers, as mounting the main box is not
position sensitive. It does have a flight logger, barometric pressure
sensor, gps engine, and computer. Thus it can determine wind when circling,
the best lift encountered during the circle, the direction of that lift from
current position, and which way to turn in order to center the lift. Also,
returning to a previous thermal, but at a different altitude, the Themi does
a credible job of determining where the thermal center is based on its
previous experience with that thermal.

The Themi isn't always right, but it's a useful tool nonetheless. Is it
worth the money? If you needed a logger anyway, maybe. Some soaring computer
interface software (Winpilot Pro w/ climb maximizer) already has most of the
Themi thermal centering features. Since I bought Winpilot Pro after the
Themi, I'm flying with both. The Themi has some features WP Pro doesn't
have, and Themi's display requires almost no head down time.. However, if I
already had WP Pro, I wouldn't buy the Themi.

bumper

In article .com,
writes
ContestID67 wrote:
I was sent a link to a gadget some college engineers-in-the-making
built. http://engenius.sece.rmit.edu.au/Abstracts/Page601.htm. It
tries to detect which way a thermal is based on temperature differences
between wing tips. Bright boys.

I have two questions;

1) Have there been other gadgets created to do the same thing? How
well did they work?

A long time ago, a Dr Brennig-Jones suggested that, because
thermals apparently produce sub-audible sound, you could use the
glider's wings as a directional microphone to "hear" where the thermal
is.

I don't think anyone took up this idea.

--
Mike Lindsay

Here is their patent.. http://tinyurl.com/hswdy



Larry Goddard

"01" USA






" wrote in message
oups.com:

ContestID67 wrote:
I was sent a link to a gadget some college engineers-in-the-making
built. http://engenius.sece.rmit.edu.au/Abstracts/Page601.htm. It
tries to detect which way a thermal is based on temperature differences
between wing tips. Bright boys.

I have two questions;

1) Have there been other gadgets created to do the same thing? How
well did they work?

Dear Sir:

Look at the Themi:
http://www.themi.de/Themi%20Centering%20Device.htm

And, I've been told that the Zander flight computer --
http://www.zander-variometer.de/ -- has similar capability, but don't
see evidence of this on their web site.

After hearing about the Themi, I *had* to buy one to see how it works.
Having said that, I have been using one for 2 years, and have some
experience with it -- it's a fun toy -- but I"ve been unable to find
any description of how it operates. Some things are obvious: It has a
GPS engine, and probably has a barometric sensor and/or accelerometers.

In any case, the maximum it coiuld do is to use 3-D GPS data to
calculate climb/descent; it could have accelerometers as well; and
sense pressure changes. It could calculate, therefore, the movement of
the glider, make some assumptions about flight, calculate wind, and on
this basis estimate where the best lift *was* so you can go back to it.

In my experience, if I fly in non-erratic circles, it does a pretty
good job of re-finding the last spots of lift after I've wandered away
fruitlessly looking for something better, and in doing this it seems to
compensate for wind.

Obviously, it can't predict the future, so I use my own judgment on
where lift is *going* to be.

It is useful? After 2 years with it, I do feel that I'm better than it
is. I look at the ground and the cloud (if any) and think about the
wind (my SN-10 is invaluable in this regard --
http://www.ilec-gmbh.com/sn10.htm ) and am reliably able to find lift.

But -- in weak or windy conditions, or when, as sometimes happens, I
lose my mental image of the thermal and where I've been, I will
somtimes turn my brain off for a couple of minutes and just "fly the
lights," and more often than not get back into lift.

I do wish that someone who knows the theory behind this gadget would
speak about this, as it would help me understand how best to fly with
it.