My answer began to get too lengthy to stick in comments so I'm posting it here, and thanks Thomas for your enthusiasm.
I talked over this very subject this week with Randall Fishman, the award-winning electric flight pioneer. His take on where we're at right now is in my Profiles in Vision column, coming in the July issue of P&P.
Randall's whole trip is to get people up in the air with electric power right now, and not for 150,000 clams either. To summarize his own one-man research and development plan, it's all about lightweight motorgliders.
There are two key factors -- light weight and a good low sink rate. The less power you need to get airborne and maintain flight, the better contemporary electric flight technology works.
Randall hopes to debut his latest design, a composite two-seat LSA called ElectraFlyer X, at Oshkosh this year. It's a very cool looking airplane...and a motorglider.
Previously, as I've noted here more than once, he rocked the electric world with the ElectraFlyer Trike, currently available for sale, and the prototype ElectraFlyer C, a single-seat model (more below). He's also in test mode with newly designed motors he's had built for the X and other projects.
There are lots of other electric motorglider projects out there, for this basic reason: the less amount of thrust you need to stay airborne, the more viable electric propulsion is. For now that has to mean less transportation-style flying and more "pure enjoyment" local flying.
Can we live with that? Hell yes...how cool is it that we are able to fly this completely revolutionary technology right now?
My favorite story of Randall's recounts the time he took his electric trike off from Ellenville, NY's little airport, motored over to where the hang glider guys were soaring the popular ridge a couple miles away, turned off the motor and joined the thermaling gaggles.
Typically, and I've done this myself, you work up into ever-stronger lift bands at E-Ville by ramping up the sloping ridge, which can get you good and high but also back half a mile or more from launch.
That particular day, some guys were way high but way back. Randall, because he had the boost of electric power when he needed it, was able to penetrate out in front of the hill and catch some really strong lift that the pure soaring craft couldn't risk trying to reach for fear they'd land out from the LZ, the landing zone.
He flew two hours that day -- and landed with plenty of "juice" to spare.
This is one highly doable scenario for electric powered flight. No, it's not 100 knot A-to-B flying, but we've got plenty of gas-powered aircraft for that already.
|The Electric Swift. Photo from Icaro. No, that's not a tail, but a folding prop!|
On a good soaring day, you can take a current-tech electric, whether it's a hang glider trike or a lightweight motorglider or a flying wing like the Swift at left, motor up into the lift, and fly as long as the lift holds out. That's possible right now.
And to repeat my electric-flight mantra: no mess, no smell, dramatically less noise, no vibration, no annuals, no oil, no gas, long-life motors, rechargeable battery packs that cost under a buck to charge, and will last many hundreds of hours, and will get increasingly affordable as more people jump on the electric bandwagon, not just in the air but also for ground vehicles like cars, bikes and cycles.
We're in the beginning stages of a paradigm shift that will outlast all the greed-based attempts to forestall it. It's here, it's growing, and it will be glorious.
Okay, down with the pom poms and back on topic.
There are more pure "muscle" electric aviation projects out there as well, of course. Before those become reality, before the "higher, faster, more payload" visions become reality, battery efficiency will have to improve by a few scales of magnitude.
|Electric Swift's cockpit view. Photo courtesy Icaro.|
Bigger motorgliders will work but are more exotic and complex to deal with (trailers, special hangars, elaborate feathering/streamlining systems, and higher costs for sure.)
Meanwhile, the electric powered hang glider trikes that Randall and others have developed work, and work very well.
They serve up more than an hour of flight and don't require 130 lb. pilots to do so (Randall weighs 200 lbs. and has consistently had 1 1/2 hour and longer flights.)
Some other notable projects, including the video below, are popping up around the world. Search for "electric trike" to get an idea. Here's a link to get you started learning about various electric projects already for sale or imminent.
Let's take a closer look at Randall's ElectraFlyer C prototype (which he is selling for $49,000, see my earlier post). The C is a single-seat, converted all- aluminum Monnett Moni motorglider he built from a kit. And Randall also gets 1.5 hours and more on a full charge too, along with 70 mph cruise and 90+ mph top speed.
|Manfred Ruehmer's electric trike (see video above). Photo courtesy Icaro.|
Some time pretty soon, certainly in the next year or so, we're going to have a lot of electric aircraft on the market, to suit a broad range of budgets.
This will not be solely another rich person's hobby, although it will take time to get the electric industry up and running because important technologies need to be developed and proofed, such as higher-storage batteries and more sophisticated, safe electronic motor controllers.
It is happening. It is happening now. We will be flying electric globally in a rich variety of planforms and applications before very much longer, you can count on it.
This year's Oshkosh, in particular, should bring more exposure and new electric aircraft to a broader audience.
Keep a lookout for my survey of electric flight projects around the world, also coming in the July issue of P&P.