Electric Powered Aircraft

[Icarus2001]

Yes, look how far we have come. Last year in Australia 0.3% of cars sold were electric. In the USA 2.1 % and in Japan 1%.

[Wizofoz]

Originally Posted by Icarus2001

Yes, look how far we have come. Last year in Australia 0.3% of cars sold were electric. In the USA 2.1 % and in Japan 1%.

That's a 26 fold increase in 7 years. You think that insignificant??

[DaveReidUK]

Originally Posted by KelvinD

According to a former RAF pilot, now working for Rolls Royce assured us TV this evening that RR would be demonstrating an electric plane at Farnborough.

Rolls-Royce is leading a highly specialised challenge to build the world’s fastest all-electric aircraft

Due to fly next year, though whether it's in time for Farnborough remains to be seen.

[Deltasierra010]

Statistics can be made to prove or disprove anything, the reality is that over the last 4 yrs electric cars have hardly increased their share at all. Lack of government incentive is one reason along with initial cost and limited range, EVs will be the norm in maybe 10yrs time, at present we just have early adopters.

As for electric aeroplanes, short duration trainers maybe and recreational planes but the energy density is far to small it needs a 10 fold increase to be really useful and thats a long way off

[netstruggler]

Originally Posted by Wizofoz

That's a 26 fold increase in 7 years. You think that insignificant??

It depends where you're starting from.

Try buying 26 lottery tickets and see if that significantly increases your chance of winning the jackpot. Mathematically yes it does, but not to the point where you have a significant chance of winning during your lifetime.

Also, during that period the number of all vehicle sales has increased 100 times more than the increase in the number of electric vehicles. So things still aren't going in the right direction.

[beardy]

The environmental effects are based on absolute numbers of units not proportion of total.

[horizon flyer]

Of course China is the biggest market for electrics, about 30,000 a month in sales and rising. The Chines government wants electrics. The biggest manufacture of EVs world wide is a Chines company called BYD ( Beyond Your Dreams ) in fact you may own one of their, products the battery in your mobile phone. As of today electrics with 250 plus range are available at around £32,000 from several manufactures, the Kia being about the best at this price/range point. In aircraft it is not really viable until a battery of 2.5Kw/hours/Kg is available. So I believe all these electric aircraft so far are, just getting ready for this battery when ? may be another 10 years.

[futurama]

Originally Posted by Icarus2001

Yes, look how far we have come. Last year in Australia 0.3% of cars sold were electric. In the USA 2.1 % and in Japan 1%.

The above chart is a blatant lie.

1. Look at the fine print. The chart "excludes Tesla, which does not reveal sales data". That's a lie. Tesla is a publicly traded company and reports sales data every quarter (example). In 2018 Tesla produced 254,530 vehicles and sold 245,162. For the chart to exclude Tesla -- the #1 EV car manufacturer in the world -- is beyond misleading.

2. The chart compares apples vs. oranges, because it includes vehicle categories (such as large trucks) with no EV equivalent yet. But if we compare by market segment, EVs have been doing very well, and in some cases (such as Tesla) EVs sales are surpassing the competition:



As we can see in the category Tesla competes in (Small & Midsize luxury vehicles) Tesla outsold all competitors in the US during Q1 2019, and looks to repeat the same for the full H1 as they reported record production and sales in Q2.

[tdracer]

Originally Posted by futurama

As we can see in the category Tesla competes in (Small & Midsize luxury vehicles) Tesla outsold all competitors in the US during Q1 2019, and looks to repeat the same for the full H1 as they reported record production and sales in Q2.

The other side of that is Tesla lost over a billion dollars in the process (~$700 million 1st quarter, ~$400 million 2nd quarter). More worrisome is that, while they delivered more cars in the 2nd than the first, income was down by a billion dollars. In short, Tesla is having to cut prices to maintain demand, when they are all ready selling for less than their costs of production. Not even Musk can keep that up indefinitely...

[futurama]

Originally Posted by tdracer

The other side of that is Tesla lost over a billion dollars in the process (~$700 million 1st quarter, ~$400 million 2nd quarter). More worrisome is that, while they delivered more cars in the 2nd than the first, income was down by a billion dollars. In short, Tesla is having to cut prices to maintain demand, when they are all ready selling for less than their costs of production. Not even Musk can keep that up indefinitely...

Not quite. With a company in growth mode, we have to look at the reason behind the numbers. Tesla actually has positive gross margins (around 20%); they are making money on each car sold. And their revenue jumped 60% compared to last year, which is remarkable since the bulk of the federal subsidies expired last year.

So why the big loss? It's largely because Tesla is making major capital investments to expand: building a new factory in China, preparing for another in Europe, and in developing a brand new car (Model Y). They also took an accounting charge to restructure their sales channel (going from a dealership model to primarily online sales).

For sure Tesla has a lot of risks. E.g., the high-end Model S is getting old and will need a design refresh. But if we dig deep, then we that Tesla's free cash flow actually swung to positive this quarter. And despite all the capital investments they're making, Tesla will likely become profitable (again) this year. Plus with $5 billion cash in the bank, they have some wiggle room to spare.

[Machdiamond]

Originally Posted by tdracer

The other side of that is Tesla lost over a billion dollars in the process (~$700 million 1st quarter, ~$400 million 2nd quarter). More worrisome is that, while they delivered more cars in the 2nd than the first, income was down by a billion dollars. In short, Tesla is having to cut prices to maintain demand, when they are all ready selling for less than their costs of production. Not even Musk can keep that up indefinitely...

Q1 revenue was 4.5 billion and Q2 was 6.4 billion, I don't know were you are taking that billion dollars down. More crucially, free cash flow was positive 614 million in Q2 versus negative 920 million in Q1.

Tesla is making money with a pretty decent gross margin of around 20%. And it was capable of sustaining that margin in Q2 in spite of mostly selling the lower priced Model 3 now.

The main reason it loses money overall is because it is financing a growth rate of more than 50% (average of last 5 years), more typical a tech company like Amazon or Google and nothing like any other car company. The long term financial outlook of Tesla is excellent, being the undisputed market leader of the fastest growing automotive market segment (73% growth globally in 2018) . As an investor in the company, I prefer to see them grow relentlessly rather than pull accounting stunts like they did with their highly profitable Q3 and Q4 quarters last year.

There is an amazing amount of Tesla bashing in the media because electric cars are jeopardising some well entrenched interests with deep pockets. I find rather unfortunate that a lot of the false narrative about electric cars is spilling over to electric aviation, and especially in the PPRuNe threads on electric powered aircraft.

To be honest, the fact that most (not all !) of the electric aircraft startups we hear about nowadays are total fantasy from a physics standpoint is not very helpful either.

[horizon flyer]

Again all the comments so far on electric vehicle have not taken into account the Chines market the biggest in the world for vehicle and electrics and BYD produce more than Tesla which is second. See https://www.bloomberg.com/news/featu...ing-like-tesla

Note Warren Buffet has a shares in this company and he is not known for making bad choices.

On aircraft they will still need an engine to power them even if the propeller or Fan is driven by an electric motor till batteries reach 2.5Kws/hours/kg. But using an electric transmission means propellers/fans can be positioned about any place on the airframe. Also the ic engine generator set can be optimised for high power density and placed in the best place for weight and balance. If the genset can run on Diesel/turbine fuel with lower fuel burn then the weight saving in fuel would compensate for any overall increase in power system weight plus the better aerodynamic would result in lower fuel burn another help.
So I think there are benefits to this system even if it still burns liquid fuel.

[futurama]

Electric aircraft updates from Oshkosh (via CleanTechnica):

1. Bye Aerospace has 624 “customer commitments” for its electric eFlyer training aircraft, with no less than 170 deposits, 318 memoranda of understanding (MOUs), and 136 MOU options
2. XTI Aircraft TriFan 600 hybrid-electric VTOL aircraft will use GE Aviation’s in-development Catalyst turboprop engine
3. Ampaire announced plans to bring hybrid-electric conversions to more types, including the Cessna 208B Grand Caravan and Viking Twin Otter. The conversions will cut fuel consumption by 70%-90%, reduce maintenance by 20%-50%, and result in quieter flight.
4. Texas Aircraft Manufacturing demonstrated its converted and certified Colt S-LSA at Oshkosh. The company is also working with Rolls-Royce Siemens to create a new electric light-sport aircraft based on the =Corp]SP55D electric motor.
5. Continental announced a partnership with VerdeGo Aero and its electric-VTOL powertrain. VerdeGo has been working on a 2 to 3 seat tilt-wing eVTOL.

[phylosocopter]

even a hybrid drive has enormous potential fuel , cost and safety benifits

transmission losses.. remember the trend now for efficiency in jet engines is geared fans and these gear drives add weight, complexity, and consume power , electric motors are small, light (relative to a jet engine) and can be designed for any speed, torque relationship required .. the amount of gear creating wind-age is also reduced

motor size.. instead of fossil fueled engines designed to deliver TOGA power the hybrid engine needs only to deliver a bit more than cruise power, an insignificant amount of battery ( weight and volume wise) can supply TOGA (ludicrous amounts of, if required!) as well as power to land safely if main engine fails.

safety .. power from multiple fossil fueled engines can be (re)-routed to multiple drive motors so balance can be maintained in the event of an engine outage

cost.. the electric drives need a fraction of the maintenance and have far greater reliability . The generator engines can be modular and easier to swap (than a wing mounted engine/gear/fan assembly)

[Less Hair]

Eletric flight is nothing for heavy airliners. Batteries are to heavy and will remain so. The only power source would be nuclear power. But this has acceptance problems.
The smart thing with Alice is: They do what is possible today. Existing "Tesla" battery, lightweight structure, small, short range. It's not a fantasy like many others are it's build for FAR 23 right away.
It doesn't make sense to go bigger than that with available battery technology.

[Less Hair]

By 2040 Norway wants to move all short haul flights to all electric.

[Deltasierra010]

I don’t really get hybrid drives for aircraft, if you are going to have electric drive for a propeller you need a generator of some kind which is is going to weigh more than any gear box. In addition the current bypass turbine is compact, fairly light and uses the thrust from the turbine as well as the fan, the power source in any other position would provide less thrust and be no more efficient

There are plenty of examples of electric drives in locomotives, heavy plant and tractors using massive Diesel engines where weight is not an issue and mechanical transmission impractical, for large aircraft weight is a big issue and only a turbine gives an acceptable power to weight ratio. For light aircraft a piston engine could drive a generator to charge the battery to power the electric motor drive, replacing the direct drive propeller but as we have seen in cars fuel economy gains are difficult to achieve, the main advantage is less city pollution.

Any hybrid aircraft would need to carry batteries + fuel + piston engine + generator + electric motor, it will be interesting to see what payload is left.

[Icarus2001]

For light aircraft a piston engine could drive a generator to charge the battery to power the electric motor drive

So what would the advantage of this arrangement be? You are still burning fuel, still making noise and still carrying the weight. To achieve what?

A little like this...

[Machdiamond]

Hybrid aircraft have no technical connection whatsoever with hybrid cars.

Hybrid cars are mostly efficient in city driving because they can get some of the energy back in when braking (particularly for city busses). Plug-in hybrids are also nice where you get some cheap and short go-to-work city-range purely on electricity.

Aircraft can't use regen because when you descend, regen creates drag and increases descent slope which means your top of descent needs to be some further distance away and the energy you need cover that distance is ALWAYS (look up entropy) going to be more than the regen energy of the descent, with the exception of poorly planned mostly speed brakes deployed descents.

Where hybrids start to make sense on aircraft is when you consider the wildly different power requirements of flight segments like taxi, takeoff, climb, cruise and descent, and you discover that on short haul aircraft your turbine engine sucks terribly most of the time except when near full power (piston engines don't suck so bad at low power and are less desirable in hybrids). Then you can scale down the turbine engine and pair it up with electric power assistance, and if you do it right you end up with a significantly reduced block fuel - even considering generator losses. And that's only the beginning of possibilities.

[Less Hair]

The main problem for battery powered aircraft I see is their weight. Especially on landing. An empty battery is as heavy as a fully loaded one. That's like every landing will be a heavy landing. Combine that with short endurance and many short flights and you have a high structural fatigue and you will need more robust structure.