Themi thermal locator

[John Jones]

Anybody have information on the Themi thermal locator?
Check news at www.eglider.org

My guess is the device is using GPS position and altitude,
along with some math to determine which direction you
are currently turning, and then to 'guess' where the
thermal core is. The device then lights a light telling
you which wing to level so you will head toward this
thermal core location.

For example, if you turn away from the thermal (into
sink, for example), simple math on the GPS data will
show you with a decreasing climb rate along with a
bearing change (direction) that you are heading away
from the thermal. Would be very simple to monitor
the heading changes and signal (with a light) to raise
your wing (bearing change would tell you which wing
needs to come up), thereby stopping any further heading
changes as your swing around and point back to the
'good lift'.

Basically, do with software and the GPS data the 'circle
shifting' we do in our head.

Can this be programed into a PDA?

[Marc Ramsey]

John Jones wrote:
> Basically, do with software and the GPS data the 'circle
> shifting' we do in our head.
>
> Can this be programed into a PDA?

Themi also incorporates a variometer. Given the short-term errors in
GPS altitude, you can't get close enough to an accurate instantaneous
climb rate indication to be able to do the "circle shifting" trick using
GPS alone. Plus, I believe the Themi algorithm is patented in the EU
and US...

Marc

[Brian Penfold]

I've seen the Themi whilst here in the USA on business,
and although I haven't used it myself, it gets quite
a good recomendation with the pilots who have flown
with it saying that they belive their rates of climb/thermal
centering have improved by using it. The only downside
I can see, is that the lights needs to be mounted in
such a manner that they can be easily seen from the
peripheral vision and not so low down on the cockpit
that you need to keep your eyes inside to see gain
the benefit, and in doing so compromise safety and
lookout.

They are about $1300 in the USA (about 750 pounds),
but don't forget that it is a GNSS flight recorder
primariliy (although not approved for world records
yet).

More info at: http://www.themi.de/

If you need to spend 750 pounds or so on a logger -
why not get one which tells you where the thermal centre
is!

[CV]

John Jones wrote:
> thermal core is. The device then lights a light telling
> you which wing to level ...

Ahem. Interesting aerobatics, that. How do you level one wing
without levelling the other ?
CV

[Martin Hellman]

John Jones > wrote in message >...
> Anybody have information on the Themi thermal locator?
> Check news at www.eglider.org

I have one and find it very helpful. There is some prejudice of the
type "Maybe a beginner could benefit but me?"

Tom Knauff, who sells it, told me that was his initial reaction, and
when he was first given one for evaluation he determined how good it
was merely by seeing how often it agreed with his actions. Pretty good
he decided. But then, he related, he decided he ought to give it a
better chance than that and followed it even when it disagreed with
his long years of experience. And damned if it didn't out guess him
more often than not.

I too have found that the Themi agrees with me most of the time, and
when it disagrees with me, it is right more often than not. Still,
sometimes when it disagrees I will still follow my instincts. I think
you learn when that makes sense and when it doesn't as you use it. I
tend to agree with Tom when he told me that, low down, where the
thermals are not well organized, he finds it extremely helpful.

If the money isn't a problem and the pride issue isn't either, I'd get
one. A friend who has one too and is also a pretty good thermaller
agrees.

Martin

[Mike Borgelt]

On 29 Apr 2004 18:31:43 -0700, (Martin Hellman)
wrote:

>John Jones > wrote in message >...
>> Anybody have information on the Themi thermal locator?
>> Check news at www.eglider.org
>
>I have one and find it very helpful. There is some prejudice of the
>type "Maybe a beginner could benefit but me?"
>
>Tom Knauff, who sells it, told me that was his initial reaction, and
>when he was first given one for evaluation he determined how good it
>was merely by seeing how often it agreed with his actions. Pretty good
>he decided. But then, he related, he decided he ought to give it a
>better chance than that and followed it even when it disagreed with
>his long years of experience. And damned if it didn't out guess him
>more often than not.
>
>I too have found that the Themi agrees with me most of the time, and
>when it disagrees with me, it is right more often than not. Still,
>sometimes when it disagrees I will still follow my instincts. I think
>you learn when that makes sense and when it doesn't as you use it. I
>tend to agree with Tom when he told me that, low down, where the
>thermals are not well organized, he finds it extremely helpful.
>
>If the money isn't a problem and the pride issue isn't either, I'd get
>one. A friend who has one too and is also a pretty good thermaller
>agrees.
>
>Martin


What it won't do of course is get you to notice the nearby hawk or
eagle going up in a core or the other glider likewise.

I'm very skeptical that the software can do anything better than a
well trained pilot can for the simple reason that nobody seems to
consistently outclimb anyone else in contests once a thermal is found.

There is a fair bit of information processing in where the best lift
is and much of it hasn't got to do with the current or recent past
flight path/vertical velocity of the glider.

One day we'll even get varios that reliably tell us the current
vertical velocity of the air while still being total energy. That
doesn't happen now.

Mike Borgelt