5 ms·

All-electric trainer aircraft, cheaper than Cessna

34 points by vinnyglennon 10y ago

mdorazio 10y ago
Does anyone have more specifics about the actual capabilities of the prototype? I'm skeptical they're able to get 3 hours of flight time out of a battery pack without sacrificing just about all the weight capacity for things like... a pilot. It's great to see that companies are actively working on electric-powered flight, though, especially in the small aircraft space where it has high potential. Also a small beef with the article - it makes it seem like there just aren't enough pilots to fly commercial planes, which simply isn't true. There are plenty of pilots, they just don't want to work for the terrible pay and life-destroying hours most carriers are offering, while at the same time often having to cover their own massive training costs. Some more info on the situation: http://time.com/4257940/pilot-shortage/ http://time.com/4257940/pilot-shortage/
- ams6110 10y ago
  Agreed, very little real information here. Nothing about range, top speed, weight, etc. A big part of training is doing "touch and goes" to practice approaches, landing, and taking off (the most dangerous phases of flight) which I would think would tax the battery a lot more than just cruising around for three hours.
- throwaway_xx9 10y ago
  > There are plenty of pilots There used to be plenty of qualified pilots before the knee-jerk Colgan 1500 hour rule. Now an ATP is required to start as an airline pilot, so there's basically no qualified pilots available who aren't already flying for an airline. All of the regional jet airlines will be filing bk in the next year because of this - their planes will sit on the ground for lack of pilots.
- highd 10y ago
  It's not stated very directly, but it appears the article is referring to hybrid propulsion systems much like in hybrid cars. That certainly makes sense for reducing fuel costs, as well as reducing the volume of fuel you'd need, thus reducing weight as well.
Zombieball 10y ago
My concern about training on an aircraft of this fashion is that you get no exposure to controls such as carb heat, fuel mixture, etc. I wonder if a distinction will be made (in the not so far future) between getting rated on a combustion plane vs. electric? Much like you get rated for high-performance or twin engines today.
- wp1 10y ago
  I would gladly pay for 5 hours of training for a combustion endorsement, if I could avoid fuel costs for 40+ hours of training to get my private certificate.
  - sokoloff 10y ago
    Fuel for a typical 4-cyl trainer will be around 8 gph at < $5/gal. 40 * 8 * 5 is $1600. 5 extra hours of dual in a rented piston plane is going to run you more than half of that possible savings. The net savings will be several hundred dollars, pretty much a drop in the bucket for flying expenses.
    - jessaustin 10y ago
      Why would it have to be "extra"? ISTM they could just train as they do now, except that they would concentrate all the ICE issues in the five hours in which they're flying with ICE.
      - sokoloff 10y ago
        Every new airplane type takes some type-specific instruction. True, it could count towards the FAA-minimum 40 hours, but almost no one takes a checkride with 40.0 hours in their logbook. I was a pretty dedicated student and at least a fair stick, and I was still in the 55-57 hour range when I took the checkride. Most people training at towered fields are in the 60-75 hour range at the ride. Fuel isn't the dominant cost in flight training. (Source: I bought my first airplane during flight training and have been flying for almost 2 decades now. Fuel is more than a rounding error, but tends to run around 1/4 of my all-in costs.)
yompers888 10y ago
As someone who really would love to get into general aviation but finds the fuel costs off-putting, I'd love for this to be successful. Isn't the big problem with electric planes supposed to be the energy density per kg? Wikipedia is showing 46MJ/kg for jet fuel, vs only ~1MJ/kg for lithium batteries [1]. Is this a lesser concern than I've been led to believe, is there recent development that improves lithium batteries by at least an order of magnitude in this property, or are they using some different battery technology entirely? I'm disappointed that there's no mention of the battery tech.
- ams6110 10y ago
  No, petroleum fuels still have a vastly higher energy density than batteries.
  - yompers888 10y ago
    I believe you're agreeing with me, but there seems to be some confusion.
    - csours 10y ago
      No, he's agreeing with you.
    - sokoloff 10y ago
      He was answering your "Is this a lesser concern..." question.
    - ams6110 10y ago
      I am agreeing. The "No" was in answer to your question "Is this a lesser concern..."
      - yompers888 10y ago
        Ah, then the confusion was mine. I apologize.
- 10y ago
DrScump 10y ago
It seems like an obvious feature would be to have solar cells on the upper wing surfaces... I guess the energy payout isn't sufficient for the area?
- dmd 10y ago
  That might be sufficient to power half of the avionics (i.e., maybe 0.01% of the power consumption. )
  - sgnelson 10y ago
    I can't say anything to the power efficiency of solar cells, but I can see how they could be useful for when you're not flying. "Free" energy for when you're ready to fly if you don't fly the plan daily, but instead just fly on the weekends or such. In the middle of nowhere without fuel or electric hookup? Wait a few days and at leas the plane will have energy to fly out of there. I'm not saying that will be the case, but an interesting aspect of solar panels on wings.
    - djrogers 10y ago
      You'd be much better off to simply have a few panels on a rack that you put out next to the plane. Being forced to haul around the extra weight of the panels on the top of the wings would be counterproductive, and if you really wanted the panels with you one day, you could pack them up and take them with you.
  - comicjk 10y ago
    To be more serious, a Cessna 152 has an 82 kW engine and a wing area of 14.9 m^2. On a sunny day (1 kW/m^2) with 20% efficient panels and a 90% efficient motor, the solar panels would supply 3.2% of that power. So it's not possible to build a solar plane this way, but it's not 0.01% either. https://en.m.wikipedia.org/wiki/Cessna_152 https://en.m.wikipedia.org/wiki/Cessna_152
pingec 10y ago
What about this one: http://www.pipistrel.si/news/wattsup-the-new-2seat-electric-trainer-took-its-maiden-fligh http://www.pipistrel.si/news/wattsup-the-new-2seat-electric-... Not an expert - don't know if they can be compared and the article lacks any actual specs to compare by, but the pipistrel's electric plane seems to be much cheaper. "Pipistrel expects to bring the final product to the market in 2015 with a target price below 100,000 EUR."
- DonaldFisk 10y ago
  There are some videos of the Pipistrel Alpha Electro on Youtube: https://www.youtube.com/watch?v=WiADDbeFanU https://www.youtube.com/watch?v=WiADDbeFanU https://www.youtube.com/watch?v=txBBl8Y1lHg https://www.youtube.com/watch?v=txBBl8Y1lHg
- AdrianB1 10y ago
  50% of the cost of a plane sold in USA is put aside as reserves for litigations; that doubles the actual cost of the plane, so the Pipistrel that is sold in Europe for 100,000 EUR may be $220,000 in USA. The Cessna 172 is 300k; a modern Pipistrel with better flying capabilities is 100K (there are a couple of 2015 Pipistrel planes on my base airport). Cessna does not sell lots of 172's, but neither Pipistrel does not sell in USA at 100k. The aviation in USA is mostly based on cheap old 1950-1970 planes, the cost for new is astronomical.
  - nkurz 10y ago
    Are you sure about this? I'm not in the market, and don't know the details, but it looks like Pipistrel USA is advertising "Ready to Fly" prices (denominated in Euros) that are much less than you say. For example, the Sinus shows a base price of 78500 EUR, and the Alpha Trainer Electro Experimental shows 110000 EUR: http://www.pipistrel-usa.com/price-list/RTF-price.html http://www.pipistrel-usa.com/price-list/RTF-price.html Is there some large undisclosed fee that is added to this? Or do the "add ons" actually required to have a flyable plane?
joosters 10y ago
I wonder how long the batteries will last for? Not the flying time, I mean instead their useful lifetime. It might become extremely expensive if you have to replace the batteries every year or so...
- DrScump 10y ago
  Then again, newer technologies resulting in better energy-per-unit-weight could drive battery replacement sooner, anyway.
ams6110 10y ago
An electric powerplant with effectively one moving part should also have dramatically lower mantenence cost than a traditional, gasoline-powered engine of more than 1,000 components I see this sort of statement made about electric cars also, and I think it's really not true. Modern internal combustion engines are very reliable, and need very little maintenance. Yes they need oil changes every so often, and I guess that's "dramatically" more in a divide-by-zero kind of way, but realistically it's not going to make a huge difference in the operational expense of a GA aircraft. Also not addressed in this piece, how long do the batteries last and what does it cost to replace them?
- coredog64 10y ago
  GA engines require a teardown inspection on a pretty regular basis. Not only that, but the liability tail for GA emphasizes the use of older designs.
  - ams6110 10y ago
    Presumably electric motors would require the same, then, in an aviation application?
    - djrogers 10y ago
      The teardown and inspection of an electric motor is trivial compared to that of an internal combustion engine. Generally speaking, you'd undo a few fasteners, pop off a cover, and check/clean the rotor/windings. 15 minutes tops - heck, you could do it before every flight and it'd still be cheaper than paying for the 100-hour maintenance on a GA plane.
  - sokoloff 10y ago
    Absent a propeller strike, a teardown inspection is almost never indicated between overhauls. Yes, the airframe and engine get inspected annually, but the engine is not "torn down" during those inspections.
- sintaxi 10y ago
sgnelson 10y ago
Very interesting. But sadly the article mentions the same old line: not enough airline pilots. The truth is that the airlines are not willing to pay for airline pilots. That's how capitalism works. You want workers? You pay workers. Simple as that.
- throwaway_xx9 10y ago
  No it's not that simple. Under the new Colgan 1,500 hour rules, there's no qualified pilots to work for the airlines. And don't get me started about capitalism - no businessman in this world wants a level playing field.
AdrianB1 10y ago
The big problem with the small planes is not the engine and fuel (still can't beat AVGAS in term of efficiency), but price; any part that exists in the automotive industry gets a 3 time price increase if it is used in aviation, 5 times if it is certified. A 1.4 liter 4 cylinder engine with 100 HP, that would be maybe 15-2000$ in a car, is ... 17.000$ for a small plane. A mobile radio for aviation starts from $300, a fixed one from $1500. That makes me believe the simple to maintain electric engine will have a 10 times price increase when used in an aircraft, just because they can and also because of all the crazy litigation system in US where 50% of the price of a new plane is put aside to pay for future litigations. In Europe we have huge taxes, so the price is even higher.
- cpncrunch 10y ago
  The FAA's Part 23 rewrite should help this. Just this month Dynon managed to get their D10A EFIS STC'd even though it isn't TSOd. Basically we will be allowed to put avionics designed for the experimental/homebuilt market into certified aircraft, resulting in a huge cost saving.
sgnelson 10y ago
my next question is: When will we have these small planes with true autopilots, which would allow a true novice to fly them? And surely people are working on them, but you don't hear about that as much as you do automobiles. Anyone know anything about this?
- slavak 10y ago
  Probably not in the foreseeable future; the market just isn't there, and in large part- the technology isn't either. For one thing, the technology for truly automatic or nearly-automatic landing (takeoff might be simpler) requires a lot of equipment at the airport, which the vast majority of airports a hobby pilot would fly from will never install. Since takeoff and landing are by far the most difficult and dangerous parts of the flight, this pretty much automatically precludes the possibility of an untrained pilot. Add to that, the stance in aviation is that the pilot must be capable of taking control of the aircraft if there is any problem with the automation. I don't know the statistics, but presumably the sensors and automation by itself are not reliable enough to function completely autonomously and without supervision 100% of the time. And if you're gonna have a hobby pilot that is perfectly capable of flying the plane manually, full automation is just a massive waste of money.
TheIronYuppie 10y ago
I know every one is talking about the energy density of gas, but wouldn't there reduction in moving parts in the engine offset? How does a Tesla compare to an average cat?
- qbrass 10y ago
  A Tesla's motor saves 200 lbs over a 4 cylinder engine but the battery pack adds 1000lbs over a 12 gallon fuel tank which would allow you to drive that 4 cylinder car twice as far.
deleted 10y ago
[deleted]
peteretep 10y ago
I was on a little Cessna Caravan twice this weekend, and both times was struck by how much less the torque on them is than a Tesla...
- sokoloff 10y ago
  Early PT6-114s (the turboprop engine on the early 208s) have a takeoff torque limit of 1658ft-lbs. Later PT6-114As (the current engine on the 208s) has a takeoff torque limit of 1865ft-lbs. The Tesla P85D has less than half of that. The Caravan has much less initial acceleration than a Tesla, but far more torque.

34 points by vinnyglennon 10y ago

Does anyone have more specifics about the actual capabilities of the prototype? I'm skeptical they're able to get 3 hours of flight time out of a battery pack without sacrificing just about all the weight capacity for things like... a pilot. It's great to see that companies are actively working on electric-powered flight, though, especially in the small aircraft space where it has high potential. Also a small beef with the article - it makes it seem like there just aren't enough pilots to fly commercial planes, which simply isn't true. There are plenty of pilots, they just don't want to work for the terrible pay and life-destroying hours most carriers are offering, while at the same time often having to cover their own massive training costs. Some more info on the situation: http://time.com/4257940/pilot-shortage/ http://time.com/4257940/pilot-shortage/

ams6110 10y ago
Agreed, very little real information here. Nothing about range, top speed, weight, etc. A big part of training is doing "touch and goes" to practice approaches, landing, and taking off (the most dangerous phases of flight) which I would think would tax the battery a lot more than just cruising around for three hours.
throwaway_xx9 10y ago
> There are plenty of pilots There used to be plenty of qualified pilots before the knee-jerk Colgan 1500 hour rule. Now an ATP is required to start as an airline pilot, so there's basically no qualified pilots available who aren't already flying for an airline. All of the regional jet airlines will be filing bk in the next year because of this - their planes will sit on the ground for lack of pilots.
highd 10y ago
It's not stated very directly, but it appears the article is referring to hybrid propulsion systems much like in hybrid cars. That certainly makes sense for reducing fuel costs, as well as reducing the volume of fuel you'd need, thus reducing weight as well.

Zombieball 10y ago

My concern about training on an aircraft of this fashion is that you get no exposure to controls such as carb heat, fuel mixture, etc. I wonder if a distinction will be made (in the not so far future) between getting rated on a combustion plane vs. electric? Much like you get rated for high-performance or twin engines today.

wp1 10y ago
I would gladly pay for 5 hours of training for a combustion endorsement, if I could avoid fuel costs for 40+ hours of training to get my private certificate.
- sokoloff 10y ago
  Fuel for a typical 4-cyl trainer will be around 8 gph at < $5/gal. 40 * 8 * 5 is $1600. 5 extra hours of dual in a rented piston plane is going to run you more than half of that possible savings. The net savings will be several hundred dollars, pretty much a drop in the bucket for flying expenses.
  - jessaustin 10y ago
    Why would it have to be "extra"? ISTM they could just train as they do now, except that they would concentrate all the ICE issues in the five hours in which they're flying with ICE.
    - sokoloff 10y ago
      Every new airplane type takes some type-specific instruction. True, it could count towards the FAA-minimum 40 hours, but almost no one takes a checkride with 40.0 hours in their logbook. I was a pretty dedicated student and at least a fair stick, and I was still in the 55-57 hour range when I took the checkride. Most people training at towered fields are in the 60-75 hour range at the ride. Fuel isn't the dominant cost in flight training. (Source: I bought my first airplane during flight training and have been flying for almost 2 decades now. Fuel is more than a rounding error, but tends to run around 1/4 of my all-in costs.)

yompers888 10y ago

As someone who really would love to get into general aviation but finds the fuel costs off-putting, I'd love for this to be successful. Isn't the big problem with electric planes supposed to be the energy density per kg? Wikipedia is showing 46MJ/kg for jet fuel, vs only ~1MJ/kg for lithium batteries [1]. Is this a lesser concern than I've been led to believe, is there recent development that improves lithium batteries by at least an order of magnitude in this property, or are they using some different battery technology entirely? I'm disappointed that there's no mention of the battery tech.

ams6110 10y ago
No, petroleum fuels still have a vastly higher energy density than batteries.
- yompers888 10y ago
  I believe you're agreeing with me, but there seems to be some confusion.
  - csours 10y ago
    No, he's agreeing with you.
  - sokoloff 10y ago
    He was answering your "Is this a lesser concern..." question.
  - ams6110 10y ago
    I am agreeing. The "No" was in answer to your question "Is this a lesser concern..."
    - yompers888 10y ago
      Ah, then the confusion was mine. I apologize.
10y ago

DrScump 10y ago

It seems like an obvious feature would be to have solar cells on the upper wing surfaces... I guess the energy payout isn't sufficient for the area?

dmd 10y ago
That might be sufficient to power half of the avionics (i.e., maybe 0.01% of the power consumption. )
- sgnelson 10y ago
  I can't say anything to the power efficiency of solar cells, but I can see how they could be useful for when you're not flying. "Free" energy for when you're ready to fly if you don't fly the plan daily, but instead just fly on the weekends or such. In the middle of nowhere without fuel or electric hookup? Wait a few days and at leas the plane will have energy to fly out of there. I'm not saying that will be the case, but an interesting aspect of solar panels on wings.
  - djrogers 10y ago
    You'd be much better off to simply have a few panels on a rack that you put out next to the plane. Being forced to haul around the extra weight of the panels on the top of the wings would be counterproductive, and if you really wanted the panels with you one day, you could pack them up and take them with you.
- comicjk 10y ago
  To be more serious, a Cessna 152 has an 82 kW engine and a wing area of 14.9 m^2. On a sunny day (1 kW/m^2) with 20% efficient panels and a 90% efficient motor, the solar panels would supply 3.2% of that power. So it's not possible to build a solar plane this way, but it's not 0.01% either. https://en.m.wikipedia.org/wiki/Cessna_152 https://en.m.wikipedia.org/wiki/Cessna_152

pingec 10y ago

What about this one: http://www.pipistrel.si/news/wattsup-the-new-2seat-electric-trainer-took-its-maiden-fligh http://www.pipistrel.si/news/wattsup-the-new-2seat-electric-... Not an expert - don't know if they can be compared and the article lacks any actual specs to compare by, but the pipistrel's electric plane seems to be much cheaper. "Pipistrel expects to bring the final product to the market in 2015 with a target price below 100,000 EUR."

DonaldFisk 10y ago
There are some videos of the Pipistrel Alpha Electro on Youtube: https://www.youtube.com/watch?v=WiADDbeFanU https://www.youtube.com/watch?v=WiADDbeFanU https://www.youtube.com/watch?v=txBBl8Y1lHg https://www.youtube.com/watch?v=txBBl8Y1lHg
AdrianB1 10y ago
50% of the cost of a plane sold in USA is put aside as reserves for litigations; that doubles the actual cost of the plane, so the Pipistrel that is sold in Europe for 100,000 EUR may be $220,000 in USA. The Cessna 172 is 300k; a modern Pipistrel with better flying capabilities is 100K (there are a couple of 2015 Pipistrel planes on my base airport). Cessna does not sell lots of 172's, but neither Pipistrel does not sell in USA at 100k. The aviation in USA is mostly based on cheap old 1950-1970 planes, the cost for new is astronomical.
- nkurz 10y ago
  Are you sure about this? I'm not in the market, and don't know the details, but it looks like Pipistrel USA is advertising "Ready to Fly" prices (denominated in Euros) that are much less than you say. For example, the Sinus shows a base price of 78500 EUR, and the Alpha Trainer Electro Experimental shows 110000 EUR: http://www.pipistrel-usa.com/price-list/RTF-price.html http://www.pipistrel-usa.com/price-list/RTF-price.html Is there some large undisclosed fee that is added to this? Or do the "add ons" actually required to have a flyable plane?

joosters 10y ago

I wonder how long the batteries will last for? Not the flying time, I mean instead their useful lifetime. It might become extremely expensive if you have to replace the batteries every year or so...

DrScump 10y ago
Then again, newer technologies resulting in better energy-per-unit-weight could drive battery replacement sooner, anyway.

ams6110 10y ago

An electric powerplant with effectively one moving part should also have dramatically lower mantenence cost than a traditional, gasoline-powered engine of more than 1,000 components I see this sort of statement made about electric cars also, and I think it's really not true. Modern internal combustion engines are very reliable, and need very little maintenance. Yes they need oil changes every so often, and I guess that's "dramatically" more in a divide-by-zero kind of way, but realistically it's not going to make a huge difference in the operational expense of a GA aircraft. Also not addressed in this piece, how long do the batteries last and what does it cost to replace them?

coredog64 10y ago
GA engines require a teardown inspection on a pretty regular basis. Not only that, but the liability tail for GA emphasizes the use of older designs.
- ams6110 10y ago
  Presumably electric motors would require the same, then, in an aviation application?
  - djrogers 10y ago
    The teardown and inspection of an electric motor is trivial compared to that of an internal combustion engine. Generally speaking, you'd undo a few fasteners, pop off a cover, and check/clean the rotor/windings. 15 minutes tops - heck, you could do it before every flight and it'd still be cheaper than paying for the 100-hour maintenance on a GA plane.
- sokoloff 10y ago
  Absent a propeller strike, a teardown inspection is almost never indicated between overhauls. Yes, the airframe and engine get inspected annually, but the engine is not "torn down" during those inspections.
sintaxi 10y ago

sgnelson 10y ago

Very interesting. But sadly the article mentions the same old line: not enough airline pilots. The truth is that the airlines are not willing to pay for airline pilots. That's how capitalism works. You want workers? You pay workers. Simple as that.

throwaway_xx9 10y ago
No it's not that simple. Under the new Colgan 1,500 hour rules, there's no qualified pilots to work for the airlines. And don't get me started about capitalism - no businessman in this world wants a level playing field.

AdrianB1 10y ago

The big problem with the small planes is not the engine and fuel (still can't beat AVGAS in term of efficiency), but price; any part that exists in the automotive industry gets a 3 time price increase if it is used in aviation, 5 times if it is certified. A 1.4 liter 4 cylinder engine with 100 HP, that would be maybe 15-2000$ in a car, is ... 17.000$ for a small plane. A mobile radio for aviation starts from $300, a fixed one from $1500. That makes me believe the simple to maintain electric engine will have a 10 times price increase when used in an aircraft, just because they can and also because of all the crazy litigation system in US where 50% of the price of a new plane is put aside to pay for future litigations. In Europe we have huge taxes, so the price is even higher.

cpncrunch 10y ago
The FAA's Part 23 rewrite should help this. Just this month Dynon managed to get their D10A EFIS STC'd even though it isn't TSOd. Basically we will be allowed to put avionics designed for the experimental/homebuilt market into certified aircraft, resulting in a huge cost saving.

sgnelson 10y ago

my next question is: When will we have these small planes with true autopilots, which would allow a true novice to fly them? And surely people are working on them, but you don't hear about that as much as you do automobiles. Anyone know anything about this?

slavak 10y ago
Probably not in the foreseeable future; the market just isn't there, and in large part- the technology isn't either. For one thing, the technology for truly automatic or nearly-automatic landing (takeoff might be simpler) requires a lot of equipment at the airport, which the vast majority of airports a hobby pilot would fly from will never install. Since takeoff and landing are by far the most difficult and dangerous parts of the flight, this pretty much automatically precludes the possibility of an untrained pilot. Add to that, the stance in aviation is that the pilot must be capable of taking control of the aircraft if there is any problem with the automation. I don't know the statistics, but presumably the sensors and automation by itself are not reliable enough to function completely autonomously and without supervision 100% of the time. And if you're gonna have a hobby pilot that is perfectly capable of flying the plane manually, full automation is just a massive waste of money.

TheIronYuppie 10y ago

I know every one is talking about the energy density of gas, but wouldn't there reduction in moving parts in the engine offset? How does a Tesla compare to an average cat?

qbrass 10y ago
A Tesla's motor saves 200 lbs over a 4 cylinder engine but the battery pack adds 1000lbs over a 12 gallon fuel tank which would allow you to drive that 4 cylinder car twice as far.

deleted 10y ago

[deleted]

peteretep 10y ago

I was on a little Cessna Caravan twice this weekend, and both times was struck by how much less the torque on them is than a Tesla...

sokoloff 10y ago
Early PT6-114s (the turboprop engine on the early 208s) have a takeoff torque limit of 1658ft-lbs. Later PT6-114As (the current engine on the 208s) has a takeoff torque limit of 1865ft-lbs. The Tesla P85D has less than half of that. The Caravan has much less initial acceleration than a Tesla, but far more torque.