First of all, I am a dealer for Themi in the USA.

Bernd Scheffel, the designer of Themi, came to our gliderport several years
ago with his Themi device and installed it in our Duo Discus. We flew
together for an hour or so, and I considered the device as "interesting."

With my vast hours of thermalling experience, I had developed certain
Pavlovian responses to bumps in the air and beeps of the audio. I considered
my thermalling methods to be at least above average, fully understanding the
typical turmoil of the thermal air-flow. I doubted if Themi would be a
useful tool - at least for me or any experienced pilot.

One day, I decided to find out just what Themi was capable of. I doggedly
followed the blinking lights and discovered to my amazement that it was
unerringly correct. Often, my resposnes to bumps and beeps would have been
different than Themi indicated.

One must understand Themi does not look out the window. Using simple
variometer and GPS signals, it only tells the pilot where the center of the
lift was as experienced during the last turn.

For this reason, I find Themi most valuable when there are no clouds, or
iwhen low and disassociated from the clouds. At these times, Themi is
invaluable.

Themi uses two bright LED lights to signal when to steepen, shallow turns or
fly straight to the better lift. When the pilot is centering correctly,
there are no light signals. No distracting audio, nothing to distract the
pilot. There is no reason to look anywhere except outside the glider,
observing conditions outside for visual clues and collision avoidance.

The trend towards devices inside the cockpit which can be distracting, and
often provide lots of "interesting" information rather than the few things a
pilot really needs to know is an important issue when considering adding any
device to your cockpit.

More information about Themi can be found on our web site.

Tom Knauff
Knauff & Grove Soaring Supplies
www.eglider.org