Great! Thanks for posting this, Dave. Looks a lot safer than putting a match to AvGas - you check all your fuses right?
Interestingly there is no real performance disadvantage, in terms of power to weight, with LiPo over internal combustion. Hybrids using LiPo & fuel cells seem to be hitting the mark in fixed wing aviation. There are already some other fixed wing projects going "commercial" with fuel cells now that the concept has been demonstrated by Boeing/Diamond/Intelligent Energy:
ENFICA-FC - ENvironmentally Friendly Inter City Aircraft powered by Fuel Cells
Actually, there may be some serious benefits to electric power in helicopter pilot training. If all you need to do is hover around the airfield, along with a couple of circuits, then this may be a much more cost effective approach. No more TBO to drive costs up and no more expensive development into ancilliaries like cooling and govenor control. The powertrain can be relatively simple with minimal vibration mounting, ideally with rotor system optimised for hover efficiency over cruise efficiency. Just make sure there are a couple of power packs on standby near the hangar, even recharge time is no longer a big headache.