ORIGINAL: ZERO-322
If you know how to effectively hunt for thermals then you could probably stay up ther even longer then 40 min , I have flown for as long as 90 min on a single charge with the engine at idle , flying a 3 ch glider
And trust me, the first time you get into a good thermal the plane just keeps going up and up you'll be hooked on it!!!!
That's what happened to me!!!!
Ken