Which Way is That Thermal?

[ContestID67]

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?

2) What do you use to determine if the thermal is on the left or the
right? This is the wing up or down when its near the thermal debate.

Thanks, John

[[email protected]]

It's an old idea. Past attempts have failed because the temperature
gradients were too small to be detected reliably. Perhaps modern
sensors will work better.

As for number 2, there's really no debate. For conventional gliders,
the wing that goes up points in the direction of the thermal. Flying
wings may be a different story.



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?
>
> 2) What do you use to determine if the thermal is on the left or the
> right? This is the wing up or down when its near the thermal debate.
>
> Thanks, John

[Frank Whiteley]

Regarding apparent rising wings, that may not indicate anything
regarding the direction of the core of the thermal, other than a turn
may indicated.

That is, there is another school of thought on which way to turn,
especially if the goal is to center as quickly as possible in a
thermal.

Frank Whiteley

wrote:
> It's an old idea. Past attempts have failed because the temperature
> gradients were too small to be detected reliably. Perhaps modern
> sensors will work better.
>
> As for number 2, there's really no debate. For conventional gliders,
> the wing that goes up points in the direction of the thermal. Flying
> wings may be a different story.
>
>
>
> 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?
> >
> > 2) What do you use to determine if the thermal is on the left or the
> > right? This is the wing up or down when its near the thermal debate.
> >
> > Thanks, John

[BTIZ]

Which wing tip goes up? turn that way. Finger tips on the stick.. feel the
pressure...
Use the Force Luke..

BT

"ContestID67" > wrote in message
ups.com...
>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?
>
> 2) What do you use to determine if the thermal is on the left or the
> right? This is the wing up or down when its near the thermal debate.
>
> Thanks, John
>

[[email protected]]

Really? I had never heard of the "turn away from the thermal" school
of thought.



Frank Whiteley wrote:
> Regarding apparent rising wings, that may not indicate anything
> regarding the direction of the core of the thermal, other than a turn
> may indicated.
>
> That is, there is another school of thought on which way to turn,
> especially if the goal is to center as quickly as possible in a
> thermal.
>
> Frank Whiteley
>
> wrote:
> > It's an old idea. Past attempts have failed because the temperature
> > gradients were too small to be detected reliably. Perhaps modern
> > sensors will work better.
> >
> > As for number 2, there's really no debate. For conventional gliders,
> > the wing that goes up points in the direction of the thermal. Flying
> > wings may be a different story.
> >
> >
> >
> > 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?
> > >
> > > 2) What do you use to determine if the thermal is on the left or the
> > > right? This is the wing up or down when its near the thermal debate.
> > >
> > > Thanks, John

[flying_monkey[_1_]]

Yes, Frank, please explain this to us. I never heard that that there
was any other theory than turn toward the uplifted wing. Sure, there's
lots of theories about what to do after that. Bob Wander's "book" has
the 4-circle search method, and it seems like I read something in
Knauff's stuff somewhere, maybe in "Breaking the Apron Strings." I'm
still early in the learning process, and seem to have the best results
with "tighten the turn in decreasing lift, loosen the turn in
increasing lift. This works so well that I'm frequently seeing people
in roughly equal gliders climbing past me, so I'm always looking for a
better way. Enlighten us.

Thanks,
Ed

wrote:
> Really? I had never heard of the "turn away from the thermal" school
> of thought.
>
>
>
> Frank Whiteley wrote:
> > Regarding apparent rising wings, that may not indicate anything
> > regarding the direction of the core of the thermal, other than a turn
> > may indicated.
> >
> > That is, there is another school of thought on which way to turn,
> > especially if the goal is to center as quickly as possible in a
> > thermal.
> >
> > Frank Whiteley

[Ray Lovinggood]

Suppose I'm flying along straight and level and I feel
the left wingtip rise. Where is the thermal? Is it
on the left and is it lifting the wing?

Or, is the right wing in sink and the wing is being
pushed down?

Does that mean there is a thermal further to the right
and the sink that pushed my wing down is the sink that
surrounds the thermal?

Which way should I turn?

For me, the answer is sometimes straight forward:
Turn the way my friends are turning because they got
there sooner than me!

Ray Lovinggood
Carrboro, North Carolina, USA

At 10:48 06 September 2006, Flying_Monkey wrote:
>Yes, Frank, please explain this to us. I never heard
>that that there
>was any other theory than turn toward the uplifted
>wing. Sure, there's
>lots of theories about what to do after that. Bob
>Wander's 'book' has
>the 4-circle search method, and it seems like I read
>something in
>Knauff's stuff somewhere, maybe in 'Breaking the Apron
>Strings.' I'm
>still early in the learning process, and seem to have
>the best results
>with 'tighten the turn in decreasing lift, loosen the
>turn in
>increasing lift. This works so well that I'm frequently
>seeing people
>in roughly equal gliders climbing past me, so I'm always
>looking for a
>better way. Enlighten us.
>
>Thanks,
>Ed
>
wrote:
>> Really? I had never heard of the 'turn away from
>>the thermal' school
>> of thought.
>>
>>
>>
>> Frank Whiteley wrote:
>> > Regarding apparent rising wings, that may not indicate
>>>anything
>> > regarding the direction of the core of the thermal,
>>>other than a turn
>> > may indicated.
>> >
>> > That is, there is another school of thought on which
>>>way to turn,
>> > especially if the goal is to center as quickly as
>>>possible in a
>> > thermal.
>> >
>> > Frank Whiteley
>
>

[Mal[_2_]]

"Ray Lovinggood" > wrote in
message ...
> Suppose I'm flying along straight and level and I feel
> the left wingtip rise. Where is the thermal? Is it
> on the left and is it lifting the wing?
>
> Or, is the right wing in sink and the wing is being
> pushed down?
>
> Does that mean there is a thermal further to the right
> and the sink that pushed my wing down is the sink that
> surrounds the thermal?
>
> Which way should I turn?
>
> For me, the answer is sometimes straight forward:
> Turn the way my friends are turning because they got
> there sooner than me!
>
> Ray Lovinggood
> Carrboro, North Carolina, USA
>
> At 10:48 06 September 2006, Flying_Monkey wrote:
>>Yes, Frank, please explain this to us. I never heard
>>that that there
>>was any other theory than turn toward the uplifted
>>wing. Sure, there's
>>lots of theories about what to do after that. Bob
>>Wander's 'book' has
>>the 4-circle search method, and it seems like I read
>>something in
>>Knauff's stuff somewhere, maybe in 'Breaking the Apron
>>Strings.' I'm
>>still early in the learning process, and seem to have
>>the best results
>>with 'tighten the turn in decreasing lift, loosen the
>>turn in
>>increasing lift. This works so well that I'm frequently
>>seeing people
>>in roughly equal gliders climbing past me, so I'm always
>>looking for a
>>better way. Enlighten us.
>>
>>Thanks,
>>Ed
>>
wrote:
>>> Really? I had never heard of the 'turn away from
>>>the thermal' school
>>> of thought.
>>>
>>>
>>>
>>> Frank Whiteley wrote:
>>> > Regarding apparent rising wings, that may not indicate
>>>>anything
>>> > regarding the direction of the core of the thermal,
>>>>other than a turn
>>> > may indicated.
>>> >
>>> > That is, there is another school of thought on which
>>>>way to turn,
>>> > especially if the goal is to center as quickly as
>>>>possible in a
>>> > thermal.
>>> >
>>> > Frank Whiteley
>>
>>
>
>
>

The only way is up.

Normally the thermal is the opposite way to the way you turn.

You guys must be coming towards winter tonight we are having our first taste
of summer thunderstorm in Sydney.

Summer bush fires blow fly's dust and 10 knot plus thermals bring it on.

[flying_monkey[_1_]]

Gee, thanks, Ray. :-)

I think it's safe to assume in this discussion that we're talking about
flying alone. If there are other gliders in a thermal, we're required
for many reasons to turn in the same direction that they're turning,
and the presence of other gliders gives us a good idea where to look
for the center. I have my best performance when I can use my neighbors
as thermal indicators. :-)

But this is a serious question. How can I improve my performance
centering thermals? Are all thermals surrounded by this ring of sink
you mention? And what if I fly straight into the middle of a thermal,
so that there's no lifted wing? What's the best technique to use then?

And what about speeds. Lets say I'm flying a Standard class glider,
with a min sink in the mid 40s and a best L/D of 38 at around 57 kt.
What should I be thermalling at in a typical eastern thermal? And what
angle of bank? I typically try to use around 45 degrees, but it isn't
constant until I get the thermal fairly well centered.

TIA (Thanks in advance),
Ed

Ray Lovinggood wrote:
> Suppose I'm flying along straight and level and I feel
> the left wingtip rise. Where is the thermal? Is it
> on the left and is it lifting the wing?
>
> Or, is the right wing in sink and the wing is being
> pushed down?
>
> Does that mean there is a thermal further to the right
> and the sink that pushed my wing down is the sink that
> surrounds the thermal?
>
> Which way should I turn?
>
> For me, the answer is sometimes straight forward:
> Turn the way my friends are turning because they got
> there sooner than me!
>
> Ray Lovinggood
> Carrboro, North Carolina, USA

[Bill Daniels]

"Frank Whiteley" > wrote in message
ups.com...
> Regarding apparent rising wings, that may not indicate anything
> regarding the direction of the core of the thermal, other than a turn
> may indicated.
>
> That is, there is another school of thought on which way to turn,
> especially if the goal is to center as quickly as possible in a
> thermal.
>
> Frank Whiteley

Yup, if you always turn toward the lifted wing, I guarantee you will be
right at least half the time.

Bill D

[Lew Hartswick]

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?
>
> 2) What do you use to determine if the thermal is on the left or the
> right? This is the wing up or down when its near the thermal debate.
>
> Thanks, John
>
Nothing new there, That system has been tried at least 25 years ago.
It intrigued me, as an electronics engineer just beginning to fly,
but the consensus of the "big boys" at the time was it wouldn't
be sufficiently accurate or too sensitive to random variations
or some other problems.
...lew...

[Eric Greenwell]

Lew Hartswick wrote:
> 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?
>>
>> 2) What do you use to determine if the thermal is on the left or the
>> right? This is the wing up or down when its near the thermal debate.
>>
>> Thanks, John
>>
> Nothing new there, That system has been tried at least 25 years ago.
> It intrigued me, as an electronics engineer just beginning to fly,
> but the consensus of the "big boys" at the time was it wouldn't
> be sufficiently accurate or too sensitive to random variations
> or some other problems.

It might be more practical with today's sensors, far greater computing
power, and electronic attitude indicators that might let you remove
temperature changes caused by bank angle. Or maybe there is a cheap
lidar unit that can detect nearby air motion: mount 3 of them in the
cockpit, pointed in different directions, and maybe get a clue about
where the air is going up and down.

--
Note: email address new as of 9/4/2006
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Frank Whiteley]

While cruising, one wing raises and the other lowers, left or right?
For discussion's sake, let's say the right wing's up and left wing
down. This can be caused by lift at the right wing, or sink at the
left wing.

When we have good thermal indicators in clouds, most of the time while
heading for that marker we encounter sink upon entering the thermal,
and sink again on exiting it on the next cruise.

So a down wing may well indicate that the thermal is just a bit further
in that direction. If you turn towards the raised wing, you may, as
Bill points out, also find the thermal about half the time, but the
thinking is that you've already flown past the core and will take two
or three turns to center. Or, you won't find the thermal, as it was
toward the down wing. By turning toward the down wing, you'll find the
thermal, or not. If not, you continue the turn through 270 degrees and
fly back to the raised wing indication which should be nearer the core
than if you'd originally turned that direction.

The concept is that you will reduce uncertainty in locating the thermal
initially and core more quickly at least half the time and that the
strategy saves 15-30 seconds or more per climb, or quite a lot during a
XC event. Perhaps a winning strategy.

Frank Whiteley
flying_monkey wrote:
> Yes, Frank, please explain this to us. I never heard that that there
> was any other theory than turn toward the uplifted wing. Sure, there's
> lots of theories about what to do after that. Bob Wander's "book" has
> the 4-circle search method, and it seems like I read something in
> Knauff's stuff somewhere, maybe in "Breaking the Apron Strings." I'm
> still early in the learning process, and seem to have the best results
> with "tighten the turn in decreasing lift, loosen the turn in
> increasing lift. This works so well that I'm frequently seeing people
> in roughly equal gliders climbing past me, so I'm always looking for a
> better way. Enlighten us.
>
> Thanks,
> Ed
>
> wrote:
> > Really? I had never heard of the "turn away from the thermal" school
> > of thought.
> >
> >
> >
> > Frank Whiteley wrote:
> > > Regarding apparent rising wings, that may not indicate anything
> > > regarding the direction of the core of the thermal, other than a turn
> > > may indicated.
> > >
> > > That is, there is another school of thought on which way to turn,
> > > especially if the goal is to center as quickly as possible in a
> > > thermal.
> > >
> > > Frank Whiteley

[[email protected]]

Perhaps I'm fooling myself, but I believe in most cases that the
sensors in my butt can distinguish between a wing being pushed up and a
wing being pushed down.


Frank Whiteley wrote:
> While cruising, one wing raises and the other lowers, left or right?
> For discussion's sake, let's say the right wing's up and left wing
> down. This can be caused by lift at the right wing, or sink at the
> left wing.
>
> When we have good thermal indicators in clouds, most of the time while
> heading for that marker we encounter sink upon entering the thermal,
> and sink again on exiting it on the next cruise.
>
> So a down wing may well indicate that the thermal is just a bit further
> in that direction. If you turn towards the raised wing, you may, as
> Bill points out, also find the thermal about half the time, but the
> thinking is that you've already flown past the core and will take two
> or three turns to center. Or, you won't find the thermal, as it was
> toward the down wing. By turning toward the down wing, you'll find the
> thermal, or not. If not, you continue the turn through 270 degrees and
> fly back to the raised wing indication which should be nearer the core
> than if you'd originally turned that direction.
>
> The concept is that you will reduce uncertainty in locating the thermal
> initially and core more quickly at least half the time and that the
> strategy saves 15-30 seconds or more per climb, or quite a lot during a
> XC event. Perhaps a winning strategy.
>
> Frank Whiteley
> flying_monkey wrote:
> > Yes, Frank, please explain this to us. I never heard that that there
> > was any other theory than turn toward the uplifted wing. Sure, there's
> > lots of theories about what to do after that. Bob Wander's "book" has
> > the 4-circle search method, and it seems like I read something in
> > Knauff's stuff somewhere, maybe in "Breaking the Apron Strings." I'm
> > still early in the learning process, and seem to have the best results
> > with "tighten the turn in decreasing lift, loosen the turn in
> > increasing lift. This works so well that I'm frequently seeing people
> > in roughly equal gliders climbing past me, so I'm always looking for a
> > better way. Enlighten us.
> >
> > Thanks,
> > Ed
> >
> > wrote:
> > > Really? I had never heard of the "turn away from the thermal" school
> > > of thought.
> > >
> > >
> > >
> > > Frank Whiteley wrote:
> > > > Regarding apparent rising wings, that may not indicate anything
> > > > regarding the direction of the core of the thermal, other than a turn
> > > > may indicated.
> > > >
> > > > That is, there is another school of thought on which way to turn,
> > > > especially if the goal is to center as quickly as possible in a
> > > > thermal.
> > > >
> > > > Frank Whiteley

[Greg Arnold]

The vario also should indicate that. If one wing is being pushed down,
you won't stop to circle. If you do stop, it is because there is lift
at the wing that is going up.

It would be interesting to know which way the top competition pilots turn.


wrote:
> Perhaps I'm fooling myself, but I believe in most cases that the
> sensors in my butt can distinguish between a wing being pushed up and a
> wing being pushed down.
>
>
> Frank Whiteley wrote:
>> While cruising, one wing raises and the other lowers, left or right?
>> For discussion's sake, let's say the right wing's up and left wing
>> down. This can be caused by lift at the right wing, or sink at the
>> left wing.
>>
>> When we have good thermal indicators in clouds, most of the time while
>> heading for that marker we encounter sink upon entering the thermal,
>> and sink again on exiting it on the next cruise.
>>
>> So a down wing may well indicate that the thermal is just a bit further
>> in that direction. If you turn towards the raised wing, you may, as
>> Bill points out, also find the thermal about half the time, but the
>> thinking is that you've already flown past the core and will take two
>> or three turns to center. Or, you won't find the thermal, as it was
>> toward the down wing. By turning toward the down wing, you'll find the
>> thermal, or not. If not, you continue the turn through 270 degrees and
>> fly back to the raised wing indication which should be nearer the core
>> than if you'd originally turned that direction.
>>
>> The concept is that you will reduce uncertainty in locating the thermal
>> initially and core more quickly at least half the time and that the
>> strategy saves 15-30 seconds or more per climb, or quite a lot during a
>> XC event. Perhaps a winning strategy.
>>
>> Frank Whiteley
>> flying_monkey wrote:
>>> Yes, Frank, please explain this to us. I never heard that that there
>>> was any other theory than turn toward the uplifted wing. Sure, there's
>>> lots of theories about what to do after that. Bob Wander's "book" has
>>> the 4-circle search method, and it seems like I read something in
>>> Knauff's stuff somewhere, maybe in "Breaking the Apron Strings." I'm
>>> still early in the learning process, and seem to have the best results
>>> with "tighten the turn in decreasing lift, loosen the turn in
>>> increasing lift. This works so well that I'm frequently seeing people
>>> in roughly equal gliders climbing past me, so I'm always looking for a
>>> better way. Enlighten us.
>>>
>>> Thanks,
>>> Ed
>>>
>>> wrote:
>>>> Really? I had never heard of the "turn away from the thermal" school
>>>> of thought.
>>>>
>>>>
>>>>
>>>> Frank Whiteley wrote:
>>>>> Regarding apparent rising wings, that may not indicate anything
>>>>> regarding the direction of the core of the thermal, other than a turn
>>>>> may indicated.
>>>>>
>>>>> That is, there is another school of thought on which way to turn,
>>>>> especially if the goal is to center as quickly as possible in a
>>>>> thermal.
>>>>>
>>>>> Frank Whiteley
>

[Eric Greenwell]

Frank Whiteley wrote:
> While cruising, one wing raises and the other lowers, left or right?
> For discussion's sake, let's say the right wing's up and left wing
> down. This can be caused by lift at the right wing, or sink at the
> left wing.
>
> When we have good thermal indicators in clouds, most of the time while
> heading for that marker we encounter sink upon entering the thermal,
> and sink again on exiting it on the next cruise.
>
> So a down wing may well indicate that the thermal is just a bit further
> in that direction. If you turn towards the raised wing, you may, as
> Bill points out, also find the thermal about half the time, but the
> thinking is that you've already flown past the core and will take two
> or three turns to center. Or, you won't find the thermal, as it was
> toward the down wing. By turning toward the down wing, you'll find the
> thermal, or not. If not, you continue the turn through 270 degrees and
> fly back to the raised wing indication which should be nearer the core
> than if you'd originally turned that direction.

Couldn't you use this same tactic when you turn towards the raised wing,
and do the 270 to head back towards where the down wing was? It seems
like that's what I do, but much more than half the time, I'm satisfied
with the results of turning towards the raised wing.

Now, I don't immediately bank into a thermalling turn, but may bank only
10-30 degrees, based on how hard the wing went up - more bank the harder
it went up.

I could look through my flight traces, list the number of climbs and the
amount of centering needed in the first few turns, and get a % for how
well my technique seems to work, but I'm not an impartial data
inspector. I hope someone will look at my flights (and other pilots') on
the OLC and make this determination for me!

Generally, I say "aw shucks" only a few times each flight, so my
subjective belief is I'm getting it right most of the time. I also turn
right most of the time, suggesting most thermals occur on the right side
of my glider, and I think there are good reasons for that.

--
Note: email address new as of 9/4/2006
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Bill Daniels]

"Frank Whiteley" > wrote in message
oups.com...
> While cruising, one wing raises and the other lowers, left or right?
> For discussion's sake, let's say the right wing's up and left wing
> down. This can be caused by lift at the right wing, or sink at the
> left wing.
>
> When we have good thermal indicators in clouds, most of the time while
> heading for that marker we encounter sink upon entering the thermal,
> and sink again on exiting it on the next cruise.
>
> So a down wing may well indicate that the thermal is just a bit further
> in that direction. If you turn towards the raised wing, you may, as
> Bill points out, also find the thermal about half the time, but the
> thinking is that you've already flown past the core and will take two
> or three turns to center. Or, you won't find the thermal, as it was
> toward the down wing. By turning toward the down wing, you'll find the
> thermal, or not. If not, you continue the turn through 270 degrees and
> fly back to the raised wing indication which should be nearer the core
> than if you'd originally turned that direction.
>
> The concept is that you will reduce uncertainty in locating the thermal
> initially and core more quickly at least half the time and that the
> strategy saves 15-30 seconds or more per climb, or quite a lot during a
> XC event. Perhaps a winning strategy.
>
> Frank Whiteley

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

[[email protected]]

Lew Hartswick wrote:
> 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?
> >
> > 2) What do you use to determine if the thermal is on the left or the
> > right? This is the wing up or down when its near the thermal debate.
> >
> > Thanks, John
> >
> Nothing new there, That system has been tried at least 25 years ago.
> It intrigued me, as an electronics engineer just beginning to fly,
> but the consensus of the "big boys" at the time was it wouldn't
> be sufficiently accurate or too sensitive to random variations
> or some other problems.
> ...lew...

This measurement technique has never been shown to even work, let alone
be supperior to existing variometers (which it would have to be by a
large margin to justify running wiring thru our wings, although that
might be done by the manufacturer; but they won't do it unless there is
a demand for the device). Personally, I think there are other methods
that will work significantly better than present technology that don't
require you to run wiring in your wings (which would have to be
connected and disconnected every time you assemble/disassemble, which,
in turn, requires an additional preflight inspection).

On the direction to turn: at the last convention I listened to Tom
Knauff declare that most glider pilots don't know which way to turn
into a thermal; the correct direction, according to Knauff, is towards
the down wing because sinking air surrounds a thermal. I am like Eric -
I turn towards the up wing. If Knauff is correct, I should be missing
the thermal (on the 1st turn) well over half of the time, and I am not.
Most of the time I do not immediately commit to the turn (of course,
there is occassionally those 10 kt monsters where there is question),
and actually like to turn slightly away from the direction that I think
the thermal is. The concept here is to find the boundary of the thermal
and to stay inside of it; if you search for the center of the thermal I
think you will end up flying thru it and turning too late, forcing the
glider into the sinking air around the thermal. Once I know where the
boundary is I turn into the thermal, gradually tightening the turn
until I am getting optimum climb. Ideally with this technique you will
seldom fly thru the center of the thermal, making it easier to center
the glider in the thermal. This is also helpful in identifying
streeting, since you turn only once you detect that the lift is
definitely falling off.

Tom Seim
Richland, WA

[Gary Evans[_1_]]

At 18:36 06 September 2006, Eric Greenwell wrote:
I also turn right most of the time, suggesting most
thermals occur on the right side of my glider, and
I think there are good reasons for that.


OK I'll bite. What good reasons do you have?

[Eric Greenwell]

Gary Evans wrote:
> At 18:36 06 September 2006, Eric Greenwell wrote:
> I also turn right most of the time, suggesting most
> thermals occur on the right side of my glider, and
> I think there are good reasons for that.
>
>
> OK I'll bite. What good reasons do you have?

I thought you'd never ask! Part of it is some of the thermals will be
entered close enough to center that both wings will rise (20% of them?);
in that case, I circle in my favorite direction. So, if I just flew
randomly about, I'd be circling 40% to the left and 60% to the right.

But, I don't fly randomly: I often have a good idea of where the lift is
(cloud, bird, ridge, dust devil), so I fly slightly to the left of it.
That ups the percentage of thermals on the right (or center) to about
80% overall.


--
Note: email address new as of 9/4/2006
Change "netto" to "net" to email me directly

Eric Greenwell - Washington State, USA

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[COLIN LAMB]

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

[JS]

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

[Rory O'Conor[_1_]]

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

[[email protected]]

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.

[bumper]

> 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

[Mike Lindsay]

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

[01-- Zero One]

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.