Engineers have historically faced two obstacles when designing electric aircraft. Batteries that run the electric motors have been too heavy and not energy-dense enough to provide sufficient power. And the consequences of failure were too high: Running out of power would all but assure a crash landing.
But in the past several years, says Paul Peterson, the founder and CEO of the Portland, Oregon, aeronautics company Volta Volare, off-the-shelf electric-car batteries and motors have become light, powerful and efficient enough to make electric—or at least hybrid—flight viable. This spring, Volta Volare will begin testing its four-passenger GT4. Constructed around a standard airframe, the plane runs on a hybrid powertrain similar to the one in the Chevrolet Volt, with batteries plus a backup gasoline engine.
An electric plane could be significantly less expensive to operate than a conventional aircraft. A 200-mile electric-powered flight in a single-engine personal plane would consume about $20 of electricity, compared with about $80 worth of aviation-grade gasoline, and an electric motor has only one moving part, so it would be largely maintenance-free. Peterson says that such cost reductions, combined with shared-ownership models, could make personal aviation vastly more accessible.
Canard Pusher Airframe: Peterson's team settled early on a canard pusher airframe—so named for the canard, or short cross-wing near the plane's nose, and the rear-mounted propeller, which "pushes" the craft through the air. The airframe's "three-wing" design affords engineers a multitude of places in which to stash batteries.
Carbon-Composite Propeller: The GT4's four-blade carbon-composite propellers are lighter than those made of metal or wood, but they are strong enough to handle the heavy, instantaneous torque that electric motors produce.
Hybrid Powertrain: The GT4 can take off, climb, and cruise up to 300 miles on battery power alone. When the power supply approaches 25 percent full, a battery controller signals the gas engine to kick in. The engine generates electricity, which recharges the battery.
Electric Motor: The GT4's electric motor, which is made from the combined cores of two smaller motors, sits in a sealed aluminum housing. It can generate 600 peak horsepower and sustain 400 horsepower throughout flight. Unlike an internal-combustion engine, which requires a mechanic to spend a week dissecting and then reassembling the powertrain during annual inspections, the electric motor on the GT4 would involve just a quick electronic diagnostic by connecting a laptop to the plane by USB cable.
Electric-Car Batteries: A 900-pound lithium-polymer battery array—236 individual cells, each the size of a paperback book—powers the electric motor. The GT4's hybrid powertrain is lighter than the gas engine that the canard pusher airframe was originally designed to carry, so engineers added extra batteries to balance the craft's center of gravity. "In the old days," Peterson says, "the pilot would move bags of lead shot in and out of the luggage compartment. Now we can use batteries for that."
Range-Extending Gas Engine: A supercharged 1.5-liter gasoline engine backs up the electric system. A 23-gallon tank in the center fuselage holds enough unleaded gas to extend the GT4's range up to 1,000 miles. Once batteries improve, engineers could remove the gas engine, converting the GT4 into an all-electric craft.
This article should have given the firm EVDrive credit as an engineering partner on the design of the GT4 aircraft's drive train. We regret the omission.
Well, it's a baby step. 200 miles won't even get you from New York to DC. We've got a log way to go before we can replace commercial flights with electric motors.
I'm also kind of curious as to what happens when one of these things crashes. As I understand it, the batteries are actually a bit more toxic than regular fuels.
Just to let you know:
"...The GT4 can take off, climb, and cruise up to 300 miles on battery power alone...."
"...A supercharged 1.5-liter gasoline engine backs up the electric system. A 23-gallon tank in the center fuselage holds enough unleaded gas to extend the GT4’s range up to 1,000 miles...."
I think this an awesome step upon fuel efficency of airplanes; very cool!
See life in all its beautiful colors, and
from different perspectives too!
It all sounds very good, but what I don't understand is why they didn't cover most of the plain with solarcells to enhance the efficiency to charge batteries while flying. 17% efficiency is now common, but it will increase.
I think it will take more small range extenders and more extreme engineering to make this kind of project truly a compelling choice over a traditional aircraft.
One range extender that could be very economically feasible these days is solar cells on all non-moving top and side surfaces, under a protective transparent layer. Lots of good sunshine at altitude. Might be good enough to extend your range 20%.
As for extreme engineering, there are lots of little things that reduce efficiency, and I don't know that a standard airframe will get us there.
Best of luck to this team in figuring out how to develop it further.
Now we just need the electric car-plane. And the Jetsons will be real.
Why not add solar cells above 20% efficiency, double the battery size and remove the gas engine? Removing the gasoline (23 gallons) saves nearly 200 lbs, and the gas motor at least 200 more. That's 400 lbs for more batteries.
That would improve the range to >400 or more miles and make it possible for many short hops from DC to other places, etc.
In fact, very few small planes would require more than 400 mile 'hops' so just make the batteries removable and voila you have a cross country possible small planet hoping from airport to airport!
Were very close to making gasoline small planes obsolete and cars too. Once those Northwest University batteries get mass produced (http://www.sciencedaily.com/releases/2011/11/111114142047.htm)--range of current LiON will improve by a factor of 10!
Then the gas plane and gas auto are obsolete!
From the description of the systems in this article, this should be termed a "Hybrid" airplane. It still has a tail pipe! When it can loose the gas tank and tail pipe, then it can be call an electric plane.
For those of you asking for more mileage, this is a commuter plane. For the most part, only the larger piston powered, and jet aircraft, can make coast-to-coast jumps.
A 300 mile range is pretty good for commuter plane, and only $20 worth of "fuel." To extend that to a full 1,000 miles is even better because filling up the fuel tank at today's prices brings the total trip to only $100 + landing fees. With this plane, I could take my wife on a weekend trip from Detroit, MI to Virginia Beach, VA on $100 worth of fuel (way cheaper than driving) and a fraction of the time spent driving means more time enjoying each other.
That's the spirit of this plane, not long-haul business trips, but short, quick, cheap commutes. Dinner in NYC? Easy. Atlanta for a concert? Forgetaboutit!
What will REALLY be exciting is when IBMs Lithium-Oxygen batteries get incorporated into this vehicle. the LiOxygeN (LION) batteries have an energy density of 12 kWh / kg... gasoline is 12.7 kWh / kg, thats a 94% equivalency to gasoline / weight. Probably slightly less when you figure in the fact that the battery does not decrease in weight as you consume the charge, whereas gasoline is consumed and no longer weighs down the vehicle.
But still, even at 90% equivalency, it starts to make sense to not have a backup gasoline-powered generator. I could see an 800 mile trip on all electric power, costing maybe $50. That's still $100 roundtrip for two from Detroit, MI to Virginia Beach, VA.
12 kWh per kg is a bit of a stretch don't you think? We're going to magically jump from from 0.2 kWh per kg all the way to 12? Then you're forgetting about the biggest issue with batteries. If you now have 90% of the specific energy of gasoline in a battery something will eventually fail, better not be around when it does. Current Li-ion batteries with 0.2 kWh per kg already cause large explosions. So you're trading a homogenous fluid (gas) for a battery with thousands of failure mechanisms, most of which are on the microscopic scale. But I digress, because 12 kWh/kg battery technology doesn't exist.
It also includes an ipod charger which drains the battery so much that you'd be able to fly from the airport and crash into your local supermarket.
You apparently haven't been keeping up with the news as of late. Google these terms:
ibm, lithium air, kwh / kg
Or just visit this site:
IBM's Battery 500 project actually just finished a working prototype. Though they haven't actually released specs yet, countless sources will tell you that the potential for a lithium-air battery is 12 kWh / kg.
Looking at their website, they'll have some of these in the air by the end of the year.
Full cost is apparently going to be a little over $500K for the aircraft itself, which includes transition training and FAA airworthiness certification. They also have an upgrade program to assist you in integrating future upgrades into your aircraft.
I actually work in the lithium battery field. Theoretical potential for a battery chemistry does not even come close to equating what you can produce for market. Companies have been touting "miracle" batteries that enchance specific energy by 10x for over a decade and yet we're still moving along slow as and steady with marginal increases, not leaps and bounds of 0.2 to 12 overnight. Thanks for providing a list of some relevant terms though as I am blatantly unaware of what I'm talking about ...
Mine's gonna have that classic shark mouth detail.
But anyways...Won't this bring about a new breed of DMV?
And flying a plane is much more dangerous than a car. Insurance must be killer.
I like nonsense, it wakes up the brain cells.
very nice looking aircraft. looks like it naturally produces alot of lift like a glider. get to cruising altitude and cut back the throttle and glide through the air. important because if theres an electrical short ur up there with no power. even the best airplanes can stall out with varing factors.
so what happens when u get to a few thousand feet and cut the engine? do drop like a rock or glide down?
This is where aviation is going, and it's getting there. A practical craft, for a larger market, would be a smaller, lighter, single and two-place plane, short-winged speed model and a long span motor-sailplane, two motors.
@ a2011: Don't trip too much on it. You know how it is. So many of us, all wanting the world to be better NOW, and seeing all the newer tech advances, more and more of them each day; it's easy to lose sight of the idea that there's a very long way sometimes between the discovery and it's maximized potential. People see these great sounding potential gains and think that this is the new standard, because it would have to be wouldn't it? With gains that significant realized.
For those looking at this in the nuts and bolts aspect of FAA certification? It's going to be a long process before use of anything other than existing powerplants are being used outside an R+D setting.
I would think a small turbine engine would be better than a piston engine for the fossil fuel burner. Isn't it true that turbine engines are more efficient and lighter than piston engines? The slow spin up and down of a turbine engine is not a problem for this application.
I think the backup engine should be a Cyclone,a modern external combustion engine that burns anything flammable.See: http://www.cyclonepower.com/
Hey guys ,i know this airplane. Go to www.v-raptor.info for more information
Just one question? Do they have a working prototype? We've been burned so many times before.. They should have at least on working prototype before they start selling anything.
I'd love to have one of these, but... demonstrate... then sell..
It's experimental, they don't need FAA approval to fly a prototype..at least not much...
Until I see it flying, I'll keep my vintage 182...
Its surprising how little data the volta Volaire website releases. So here is what I can reconstruct from the data above. At roughly 1MegaJoule/kilo the 900 pounds of laptop batteries yield about 408MJ of stored electrical energy in the plane. The energy density of gasoline is 46 times more (!).
The plane has a 220Kw engine, so the batteries will last 30 minutes at full power. But batteries may not be fully depleted, and there are other losses, so its probably more like 20 minutes in practice. Assuming the engine runs about 70% power on average (like regular light planes do in cruise), that gives an electric endurance of just over 30 minutes. That is not more than 60 miles in practice and a far cry from the claimed 300 miles.
The built-in generator is 180HP. Lets estimate that its able to produce about 100Kw of electrical power, which is about half of the rated power of the prop motor. That's probably just enough juice to keep it in the air (but likely not at the advertised 160 knots). 23 Gallons leaves some 20 usable, which is enough for 2 hours of generator humming at 10gal/hour.
So total endurance is about 2 and a half hours, or about 250 miles, so I'd be really surprised if the Volta Volaire really has a range of 1000 miles.
A shorter range is really pushing the practical usability down because it will need many hours to recharge again.
This back-of-the-envelope calculation could be wrong, but I highly doubt that this is a good value proposition. It might be if batteries get twice as good.
AVGas is expensive but still only about 20% of the overall airplane cost.
Anyway, I hope they success, but the odds are not high given the current state-of-the-art in battery energy density.
@ a2011, and neuzelaar:
As others have pointed out, both IBM and Northwestern University have prototype batteries that far outshine the best batteries available today, and they are not the only ones. Check MIT, who is also working on a lithium-air battery... and I meet every month with a couple of fellows from Clean Tech Institute of Garden Grove, who have a working prototype of a lithium-air battery that yields in excess of 8 times the energy density... my memory fails me, but there are many others, just look and you'll find plenty of them.
Air batteries are nothing new, and there are companies and institutes of higher learning all over the planet working on them feverishly, spending many billions of dollars in this effort because they know what's at stake-- such technology will be the foundation of a TRILLION dollar industry.
Air batteries operate on a very simple principle: in a conventional battery, you have a cathode, an anode, a separator and an electrolyte; but if you can ditch the heavy metal cathode and replace it with free oxygen in the air to exchange charges with the anode of the battery, you can save most of the weight and expense of the battery. The problem is that lithium reacts vigorously with moisture in the air, so the separator has to achieve two things: it must allow a free flow of charge between the air and the anode, yet present a reliable barrier for moisture. Everyone I know that are working on air batteries are taking similar approaches: they are using newly found understanding of chemical behavior on the nanoscale, and using computers to model molecules that are capable of giving them the performance they need.
Each battery team has a slightly different take on the answer. They must balance the cost and availability of prospective materials; the battery must be reliably safe; it must be able to supply high energy density; it must be able to be recharged quickly; and it must survive many years of use.
Aside from air batteries, there is another approach that is also capable of dramatically increasing energy density. You can take two plates of dissimilar metals, shove them down into a lemon, and voila-- you have a battery that is just powerful enough to do a few minutes of light work... turn a fan, light an LED, tickle your tongue. But if you drill thousands of tiny holes in those same two metal plates before poking them into your citrus battery, they'll give you much greater energy, because there is much more surface area for the ions to move away from one plate, and attach to the other. By devising a way to increase the surface are of the plates, you can dramatically increase the battery's energy density.
We have two materials that are capable of doing exactly that-- carbon nanotubes, and silicon nanowires, although there are likely to be other similar materials adapted for this purpose as well. Carbon nanotubes and silicon nanowires are difficult to work with-- it's not as if you can simply sit down with extremely tiny tweezers and place billions of individual fibers where they will be needed-- we have to be clever about how we can coat the charge plates so as to provide the energy density these electric planes will need. But it's not much different than the challenges we faced thirty years ago with shrinking the space needed for our data.
Air batteries are capable of giving us batteries that sound like something out of Smallville, but they only rely on eliminating the need for the cathode-- imagine doubling up on these technologies, massively increasing the surface are of the anode-- imagine a battery with hundreds of times the energy potential of today's batteries.
I once had to help a friend tip a hard drive back on its end after an earthquake. We struggled for a half an hour to put this 500 megabyte hard drive upright again, yet today a tiny chip in my phone holds tens of millions of times more data than that gargantuan hard drive did, and it does it far more cheaply, with far less energy, far less effort, and more reliably. There is no way at that time I could have thought today's technology could be possible, and that is why it is so easy for me to see that we will soon have EVs traveling thousands of miles on a single charge, and electric planes capable of completely supplanting our current use of fuel for aircraft.
Be patient... do not embarrass yourself by preaching about what you are so sure is impossible.
Here's my take on any battery powered vehicle:
1. All batteries need to be manufactured. All machinery run to produce batteries run mostly on electricity and some on hydrocarbon fuel.
2. All batteries need to be charged using electricity.
3. Energy stored in the battery must be more than needed to operate the vehicle.
4. All energy transfer is less than 100% effiecient.
5. Only 11% electricity in the U.S. is produced using non-fossil (coal, natural gas, petroleum products) fuels.
6. Since the charge in the battery comes from the electricity generated by using fossil fuels mainly, a battery powered vehicle is effectively a fossil fuel powered vehicle. It only relocates the source of whatever the environmentalists consider as sources of pollution, man-made global warming, etc. (mostly hoaxes, IMHO)
7. The battery today cannot be recharged in the same time it takes to fill the gas tank, no matter what size the vehicle.
8. The battery cannot be replaced with the same ease as a part in the fossil-fuel powered engine, and costs an enormous amount.
9. The range of the vehicle is nowhere near the range of a fossil fuel powered vehicle.
10. Battery powered aircraft of the size of a Boeing 747 or the Airbus A380 are not even a twinkle in the eye of a designer.
Without a real technological breakthrough, a battery powered vehicle, which is indirectly a fossil fuel powered vehicle, will remain experimental, IMHO, for a long time.
I've been reading about the next generation of battery it uses air for electrolyte its still in the prototype stage but the weight to energy density promises to be very high its suppose to improve a 60 mile range electric car to over 300 miles
With the further advances in room temp superconductors and better battery tech as well as advanced materials tech and craft design, I can see this becoming a viable alternative in the future of civilian aviation.
But to tout electric vehicles of any type as being"low maintenance" due to lack of moving parts is largely a misconception.The home computer has few moving parts but if one chip or circuit path is corrupted the whole is largely useless.Plus the electronic components of electric/hybrid vehicles are to a larger extent more costly.But, as to the response that most of americas electricity comes from non clean un-renewable resources.....We have the technology to build and use liquid thorium reactors.less nuclear hazard safer due to lower pressure containment unit.
Anyone know why we don't use this tech for energy yet?
"so what happens when u get to a few thousand feet and cut the engine? do drop like a rock or glide down?"
You pull the release on the parachute attached to the top of the aircraft, that's what! The life saving aircraft chute has already been featured in Pop Science (Ballistic Recovery System) and has been demonstrated in real flight. It works! And this is the size aircraft it seems to have been designed for! With that little backup system on board, the risk factor goes way down, if there is a battery or engine failure, for this or any small aircraft.
I am curious why turbine alternators & carbon fiber flywheel storage aren't used with hybrid technology like this? I remember back in 1998 the Chrysler Patriot project had quite a menu of energy application. I'm surprised it doesn't appear back again. I enjoyed reading everyone's input here for years. Popsci has always been a venue of positive forward thinking and some of the best creative entrepreneurs in the world.
There was also a TAU Sterling engine, article titled "Thunder in a bottle". Another parasitic form of energy transformation I never heard of again. Using exhaust gases it would seem a good fit for energy retention.