[Amps] time to death...

[Roy]

About -

"you need a backup system - just in case your nifty micro controlled wonder 
goes south!"

If your exhaust port aims straight up, simply fly a little thin-paper 'kite' 
tethered by three threads above it. Since it moves around, your eye will 
instantly notice if it should crash due to lack of air flow. So basic it 
can't fail -- remember, "simplicity is ingenuity".

73,   Roy            K6XK