We're not getting as much altitude on the tows as I thought. Now that Ben is flying with the vario he's able to tell.
We might get 500ft. if we have a warming breeze.
Yes Bob, the vario did chirp UP. There were no Cumulus as you can see.
The ground was heating. Must have been heat convection.
We've been working in reasonably bumpy conditions.
If we'd had any real thermal action, Ben would have been

Here's his next flight that day. Another good one.

https://www.youtube.com/watch?v=WfcAhN_ ... DW&index=9