A British company, with funding from the U.K. government, says an electric-powered airliner could be in revenue service as early as 2023. Cranfield Aerospace Solutions says it will convert a Britten-Norman Islander to hybrid electric power for short hop service between Scotland and the Orkney Islands. Scottish carrier Loganair will be the launch customer. Pure electric flights in the nine-passenger aircraft will be available for those minutes-long short routes but the turbine-powered generator in the fuselage will power the motors on longer flights.
Building the prototype, called Project Fresson, will be funded by an $11.7 million government grant. After the concept is proven, Cranfield wants to get a supplementary type certificate to convert any of the existing fleet of about 700 Islanders to the hybrid system, promising a payback period of about three years. Using off-the-shelf motors, batteries and controls, Cranfield is targeting an endurance of 60 minutes with 30 minutes of reserves before the generator is needed. After the Islander project, it plans to convert a 19-seat commuter aircraft before it starts building its own designs.
I hope that they document actual efficiencies. It would be fun to see how hybrid systems are more fuel inefficient due to increased weight and complexity.
Don’t ask these technical questions, Mark … they’re saving the planet and that’s that … no discussion allowed.
“After the Islander project, it plans to convert a 19-seat commuter aircraft before it starts building its own designs.”
Building its own designs? What newly-manufactured ISLANDER could compete with a used one, on cost? Then why would any rational person think that a new DESIGN could compete?
As Mooney recently discovered, low-volume Design Costs + Certification Costs + Manufacturing Costs = bankruptcy.
Apend the DSM: Electric Derangement Syndrome.
Apparently “electric” is such a good idea that traditional economics, physics and regulations no longer apply.
“DSM” … good one, Yars
I spoke at length with four Tesla owners at the charging station in Oshkosh a few months ago. Their answers to technical questions were a joke. Between acquisition costs, usability, range, cold weather ops and more, the idea is ridiculous in all but a few niche environments / uses.
I just want to know where in the fuselage they intend to put the turbine generator. Seems like putting it in the nose would create the fewest W&B and systems interference problems, but where do you send the exhaust? Something like a Silver Eagle conversion?
Lots of Trilanders out there, too…
It’s my understanding (and I could be completely wrong here) that everything goes in the nacelle. An electric motor/generator is added to the shaft between the turbine and the gearbox. The battery packs will likely end up in the fuselage, but those can be spread out to minimize CG issues.
The article says, “the turbine-powered generator in the fuselage”
Does anyone know how many kilowatt hours of power will it take two electric motors with the equivalent of two 300 hp engines for an hour,with a safe reserve? To generate 300 hp will take about 220 kw of power,Times two. A generator capable of putting out what much power would need about 1000 hp to run it.
600 hp = 447.42 kw
At 38% efficiency, you’d need 1,177 shaft horsepower.
This makes no sense. The efficiency of generators (KW out vs SHP in) is close to 95%. (Google “electric generator efficiency”.) The 38% sounds like the thermodynamic efficiency of the engine running the generator (a plausible figure for a turbine). But it’s shaft horsepower, not energy input, we talk about in rating a turbine.
Whether you need to match the max electric power of the motors is a separate question. You need max power for takeoff and climbout, but if all you want from the generator is to match cruise power, that’s a ot less.
– Andy
Yars, you always use fact and sound engineering to kill feel good ideas. Perhaps since the flights are short, they could have a long extension cord plugged into the tail. For the trip back, they could just rewind the cord and pull the plane back using the the 1,177 shp turbine.
Aviation seems to draw in dreamers who can’t tell the difference between what THEY think is a good idea and reality. Filling an airplane meant to carry people with batteries, generators and etc is C R A Z Y !! Now then, when they find a way to box up Element 115 … maybe.
Trying to follow the math here. Why do we think we need a generator of 1000+ horsepower to supply two 300HP motors? Seems like a generator of 500HP would do the trick. The generator should be sized to provide only a little more than cruise power (600HP at 75% = 450HP). The “extra” 50HP available from the generator in cruise would go to recharging the batteries. The extra 100HP needed for takeoff and climb segments would come from the batteries. No extension cord required. Too many people here are using bad math to claim this experiment is a bad idea. Maybe it is still a bad idea overall, but your argument for needing 1177HP doesn’t hold water.
David,
As far as math, what happens to PAYLOAD when you have to carry an “auxiliary” 500HP engine/transmission and a heavy generator head that would be capable of handling at least 500shp (372 KW)? Oh, and lets not forget the dead weight of carrying fuel for an “axillary” 500+HP generator., and controllers, and exhaust system, and…
The math is that you lose payload, performance, and therefor you also lose efficiency.
Every time there is an article about another company investing in electric aviation there are a host of negative comments by people who think they know more than the engineers who have been working on these projects. If such negativity existed 120 years ago I wonder if we would have ever adopted the horseless carriage. And lets not forget about the masses of people who in the late 90s said that no one would ever make money on the internet.
There are approximately 170 electric aircraft in development today. Don’t you think that with all those projects going on, including the groundbreaking work at NASA that there is something real about the future of electric aviation.
OK, so here are some real numbers. The energy density of jet fuel is approximately 11 kWh/lb. Seeing has how turbine engines are only about 30% (+/- 2%) efficient, we can assume that for battery energy density to meet the equivalent needs would be about 1/3 (since most electric motors are 93% efficient), so let’s start with a target of battery energy density of about 3.7 kWh/lb. Current Li-Ion batteries used in vehicles are about 250 Wh/lb. However, current research has produced a Li-CO2 battery that promises 7x the energy density of Li-Ion batteries and has demonstrated 500 cycles of charging without any degradation (https://insideevs.com/news/373986/first-li-co2-battery-uic/), so we are now around 1.5 kWh/lb. At this rate we are getting very close to energy requirements to be competitive with current turbine propulsion.
But that’s just the energy side of the equation, which within time we will see even higher energy densities in batteries, but will we really need it? The answer is no. Because Electric propulsion has already demonstrated the promise of enabling more efficient airframes. Not to mention, the fact that electric motors can provide full torque over almost their entire RPM range which means the ability to mount more efficient propellers so rather than requiring 3.7KwH/lb of energy storage to match jet fuel, we would arguably require less. Add to that the fact that since electric motors do not suffer power loss at low density altitudes, most airframes would not need to amounts of excess power so the energy requirement drops even further.
I would love to be able to have an electric motor on my PA28-180. To think that I can replace my 308lb. O-360 (weight without all the accessories like exhaust, oil cooler, fuel system, etc.) with a 156 lb. electric motor that produces almost twice the power and never again worry about oil changes, spark plugs, magnetos, exhaust systems that must be inspected for leaks every year, etc., would significantly reduce maintenance costs and worries. To not have to deal with fuel would improve safety as well as reduce operating costs. And just imagine how much quieter it would be, not to mention the lower level of vibrations that not only reduce fatigue but also reduce wear on other components. Oh, and yes, it’s also good for the environment (I don’t know why some people think that’s a bad thing). I actually dream of replacing my fuel tanks with modular battery packs that could be easily removed and taken home to be charged extremely cheaply (I have solar so I only pay 4 cents per kWhr).
There is definitely a promising future in electric aviation. There are thousands of engineers who are likely much smarter than any of us commenting here who see that and are working on making it a reality. They are doing this now because they know that battery technology will only continue to improve so long as their is enough of a demand to make it worthwhile for research to continue. (170 projects is quite a bit of an incentive to promote this research.) And their are plenty of business people out there who see the real promise of genuine savings from electric aircraft. We can all post theoretical numbers in these comments, but there are people out their doing real work and proving real concepts. I’m more likely to trust their results than I am to trust the negative opinions often posted here.
“I would love to be able to have an electric motor on my PA28-180”
Daniel,
Dreaming is fun, but reality is that a powerplant “conversion” on a used GA airplane is cost prohibitive. There is no market to for a $125K conversion for a $37K airplane. Genuine savings is done by keeping your engine in good shape and have an interest bearing saving account for the next overhaul. You can fly for the next 40 years and still come out better financially by NOT doing an electric conversion.
As far as the environment, converting your PA28 to electric would be absolutely undetectable by any measurement by any government weather station on the planet. If you want to feel like it does, then the great philosopher Steven Tyler once said: Dream on, Dream on.
Putting $125K (an arbitrary figure you state) into a $37K airplane (yet another arbitrary figure) may not sound like it makes sense when you state it that way. But then again, I would argue that paying $400K for a new Piper Archer makes less sense. I have putt over $80k into my 50 year old PA28-180 making it just as good as a new (if not better) Archer because I like having a like new airplane that actually has a far better useful load than a new Archer for 1/3 the cost. So for me It would make sense to upgrade to electric because the benefits do not end as cost. (I have stated all of these benefits in my original post.)
And I reject your cynical comment about converting my plane to electric being absolutely undetectable on “any government weather station.” All change is incremental and it has to start somewhere. I am actually excited that there are over 1,000 engineers out there “dreaming on” while the cynics here lack vision. All change is incremental and it has to start somewhere. Why does everyone on Avweb think this is a bad thing? It makes no sense.
btw: in my original post I has stated many energy density figures as kWh/lb when in fact all figures should have been kWh/Kg.
$125K is NOT arbitrary; it’s was what it cost to convert a C172 to diesel ($78K + $47K STC/Labor) when AOPA ran the numbers last year. It’s not cynical, it’s an opinion based on experience.
I agree, $400K for a Piper Archer (whether new or paying used+expensive mods) does not make a whole lot of sense. If that’s what YOU want regardless of the route to get there; hey, go for it.
Just for ecological grins, you do realize that your gas engine will still be flying, right? The used and experimental market will see to that. Not cynical, just another opinion based on experience.