In this picture you can see that we are flying
just below the cloud level (3700ft) The instrament of the left
is the ASI or Air Speed Indicator) The middle dial is the height
of the aircraft and right hand dial is the vario that measurs
how fast the glider is going up or down. At the moment it is
falling at 1knt per minuet (100ft) this is normal. If we were
to enter a thermal it would indicate up. A weak thermal may
be 1 or 2kns where as a strong thermal would be above 4kns.