Electric Helicopters
Agile,
I have worked on this for two major manufacturers and in terms of the electric drivetrain it is and has been for a long time far superior to piston/turbine engines and gearboxes in every conceivable way. Power-to-weight has long since been good enough...however, the problem remains energy storage. Will still don't have a sufficiently energy dense way of storing electricity. The latest battery technology is still too heavy and while fuel cells themselves are light enough, reliable enough and extremely efficient, the problem is the volume of hydrogen that you have to carry around with you which leads to a huge heavy fuel tank. Hydrogen has a density of about 70.8kg/m^3 as a liquid!
There will be an almost overnight switch to electric cars and electric helicopters the moment we can store electricity in an energy-dense manner, it will be just as quick as the mobile phone and satnav revolutions. However, progress on the battery front is very incremental as is the issue of storing hydrogen efficiently for fuels cells.
It will come, but I don't know when.
CRAN