On Electric Aircraft

[Dan Marotta]

A couple of very good perspectives HERE
<https://www.avweb.com/features/reader-mail/top-letters-and-comments-february-7-2020/?MailingID=280&utm_source=ActiveCampaign&utm_medium=email&utm_content=Bryant+Crash+Prelim%2C+Drone+Certifica tion+NPRM&utm_campaign=Bryant+Crash+Prelim%2C+Drone+Certific ation+NPRM-Monday+February+10%2C+2020>.

Let the flames begin...
--
Dan, 5J

[kinsell]

On 2/10/20 8:43 AM, Dan Marotta wrote:
> A couple of very good perspectives HERE
> <https://www.avweb.com/features/reader-mail/top-letters-and-comments-february-7-2020/?MailingID=280&utm_source=ActiveCampaign&utm_medium=email&utm_content=Bryant+Crash+Prelim%2C+Drone+Certifica tion+NPRM&utm_campaign=Bryant+Crash+Prelim%2C+Drone+Certific ation+NPRM-Monday+February+10%2C+2020>.
>
> Let the flames begin...
> --
> Dan, 5J

Yep. Came across an article from COPA (Canadian Owners and Pilot's
Association) filling in some the the details of the Harbour Air plane.
It was so stuffed full of batteries there was hardly any useful load
left. Which puts it more in the category of publicity stunt than a
serious attempt to develop an electric plane. And of course calling it
the first all-electric commercial aircraft is disingenuous in the extreme.


https://copanational.org/en/2019/12/12/harbour-airs-e-beaver/?utm_source=wysija&utm_medium=email&utm_campaign=COPA%20eFlight-20191212&fbclid=IwAR2Z79lsJpXKCXr5s5wW5naWosNSSiK7OAgzMDVKL-c09zQBJD3aCPb93FA

[Eric Greenwell[_4_]]

kinsell wrote on 2/10/2020 7:59 AM:
> On 2/10/20 8:43 AM, Dan Marotta wrote:
>> A couple of very good perspectives HERE
>> <https://www.avweb.com/features/reader-mail/top-letters-and-comments-february-7-2020/?MailingID=280&utm_source=ActiveCampaign&utm_medium=email&utm_content=Bryant+Crash+Prelim%2C+Drone+Certifica tion+NPRM&utm_campaign=Bryant+Crash+Prelim%2C+Drone+Certific ation+NPRM-Monday+February+10%2C+2020>.
>>
>>
>> Let the flames begin...
>> --
>> Dan, 5J
>
> Yep.Â* Came across an article from COPA (Canadian Owners and Pilot's Association)
> filling in some the the details of the Harbour Air plane. It was so stuffed full
> of batteries there was hardly any useful load left.Â* Which puts it more in the
> category of publicity stunt than a serious attempt to develop an electric plane.
> And of course calling it the first all-electric commercial aircraft is
> disingenuous in the extreme.
>
>
> https://copanational.org/en/2019/12/12/harbour-airs-e-beaver/?utm_source=wysija&utm_medium=email&utm_campaign=COPA%20eFlight-20191212&fbclid=IwAR2Z79lsJpXKCXr5s5wW5naWosNSSiK7OAgzMDVKL-c09zQBJD3aCPb93FA
>
The article made clear it's _test_ plane, not prototype for the commercial
version. That version will use a different chemistry Li battery that is
significantly lighter.

"The flight was not in a commercial aircraft in the sense that it was certified to
carry passengers – it is a prototype used in the certification process. As such,
the flight was made for ‘proof of concept’ purposes only."


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Steve Bralla]

On Monday, February 10, 2020 at 7:43:11 AM UTC-8, Dan Marotta wrote:
> A couple of very good perspectives HERE.
>
>
>
> Let the flames begin...
>
>
> --
>
> Dan, 5J

The first two of Clark's laws may apply here.
1)When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
2)The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
3)Any sufficiently advanced technology is indistinguishable from magic.

Steve

[Martin Gregorie[_6_]]

On Mon, 10 Feb 2020 08:43:04 -0700, Dan Marotta wrote:

> A couple of very good perspectives HERE
> <https://www.avweb.com/features/reader-mail/top-letters-and-comments-
february-7-2020/?
MailingID=280&utm_source=ActiveCampaign&utm_medium=email&utm_content=Bryant+Crash+Prelim%2C+Drone+Certifica tion+NPRM&utm_campaign=Bryant+Crash+Prelim%2C+Drone+Certific ation+NPRM-
Monday+February+10%2C+2020>.
>
> Let the flames begin...

That was an interesting read.

For fun, I dug up the numbers on a 7.2 AH SLA, Gasoline, and a SAFT Li-
ion cell and lobbed the lot into a spreadsheet. I picked on SAFT cells
because they made the cylindrical Li-ion cells used in the Antares, and
used the numbers for their highest capacity cell.

Here's what it showed:

Parameter Yuasa NP7-12 Petrol (1 litre) SAFT LS133600

Chemistry SLA Hydrocarbon Li-ion
Voltage (V) 12 3.67
Capacity (AH) 7 17
(w.hr) 84 9600 62.39

Weight (Kg) 2.200 0.755 0.090
Volume (litres) 0.739 1.000 0.323
Density 0.976 0.755 0.278

To hold equal amounts of energy, we need
Units installed 114.286 1.000 153.871
Weight (kg) 251.429 0.755 13.848
Volume (litres) 84.497 1.000 49.728

I hope the formatting doesn't get too mangled by the wonders of NNTP.

Its interesting that petrol (gasolene) is lighter than SAFT cells by a
factor of over 10 and takes up around 50 times the space - and this is an
underestimate because its the total volume of the cells and doesn't count
either the extra space needed because cylindrical cells can't be packed
without leaving air gaps or the space needed to cooling air to circulate
round the batteries, which are quite widely spaced inside the Antares
wing.



--
Martin | martin at
Gregorie | gregorie dot org

[Eric Greenwell[_4_]]

Martin Gregorie wrote on 2/10/2020 5:52 PM:
>
> That was an interesting read.
>
> For fun, I dug up the numbers on a 7.2 AH SLA, Gasoline, and a SAFT Li-
> ion cell and lobbed the lot into a spreadsheet. I picked on SAFT cells
> because they made the cylindrical Li-ion cells used in the Antares, and
> used the numbers for their highest capacity cell.
>
> Here's what it showed:
>
> Parameter Yuasa NP7-12 Petrol (1 litre) SAFT LS133600
>
> Chemistry SLA Hydrocarbon Li-ion
> Voltage (V) 12 3.67
> Capacity (AH) 7 17
> (w.hr) 84 9600 62.39
>
> Weight (Kg) 2.200 0.755 0.090
> Volume (litres) 0.739 1.000 0.323
> Density 0.976 0.755 0.278
>
> To hold equal amounts of energy, we need
> Units installed 114.286 1.000 153.871
> Weight (kg) 251.429 0.755 13.848
> Volume (litres) 84.497 1.000 49.728
>
> I hope the formatting doesn't get too mangled by the wonders of NNTP.
>
> Its interesting that petrol (gasolene) is lighter than SAFT cells by a
> factor of over 10 and takes up around 50 times the space - and this is an
> underestimate because its the total volume of the cells and doesn't count
> either the extra space needed because cylindrical cells can't be packed
> without leaving air gaps or the space needed to cooling air to circulate
> round the batteries, which are quite widely spaced inside the Antares
> wing.

Your chart doesn't account for the efficiencies in converting energy to
propulsion. An electric motor will deliver about 95% of the electrical energy to
the propeller, but only about 40% of the gasoline energy will be delivered to the
propeller.

Since it is propulsion we desire, not just stored energy, you should reduce the
lead acid and lithium battery sizes by 55% to account for their greater energy to
propulsion efficiency.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[kinsell]

On 2/10/20 3:38 PM, Steve Bralla wrote:
> On Monday, February 10, 2020 at 7:43:11 AM UTC-8, Dan Marotta wrote:
>> A couple of very good perspectives HERE.
>>
>>
>>
>> Let the flames begin...
>>
>>
>> --
>>
>> Dan, 5J
>
> The first two of Clark's laws may apply here.
> 1)When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
> 2)The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
> 3)Any sufficiently advanced technology is indistinguishable from magic.
>
> Steve
>

He needs to add one more:

4) If you're looking to defraud investors, or land huge government
grants, then you won't find more fertile hunting grounds than electric
airplanes.

[Martin Gregorie[_6_]]

On Mon, 10 Feb 2020 19:12:42 -0800, Eric Greenwell wrote:

> Your chart doesn't account for the efficiencies in converting energy to
> propulsion. An electric motor will deliver about 95% of the electrical
> energy to the propeller, but only about 40% of the gasoline energy will
> be delivered to the propeller.
>
> Since it is propulsion we desire, not just stored energy, you should
> reduce the lead acid and lithium battery sizes by 55% to account for
> their greater energy to propulsion efficiency.
>
Fair point, but SLA still shows as a non-starter while SAFT cells are
still six times the weight of hydrocarbon and occupy at least 25 times
the volume.

The one thing we both missed, though is that a good brushless motor plus
its controller will be a lighter and smaller than the equivalent ICE
piston engine driving a propeller. Has anybody got numbers for this? IOW,
is motor+controller+prop+Li-ion battery still heavier than petrol+piston
engine+prop? It will almost certainly be heavier than a Jet-A+turboprop
engine+propeller.

And, or course, empty fuel tanks are a lot lighter than full ones but a
flat battery weighs the same as a fully charged one.


--
Martin | martin at
Gregorie | gregorie dot org

[Tim Newport-Peace[_6_]]

At 12:33 11 February 2020, Martin Gregorie wrote:
>On Mon, 10 Feb 2020 19:12:42 -0800, Eric Greenwell wrote:
>
>> Your chart doesn't account for the efficiencies in converting energy to
>> propulsion. An electric motor will deliver about 95% of the electrical
>> energy to the propeller, but only about 40% of the gasoline energy will
>> be delivered to the propeller.
>>
>> Since it is propulsion we desire, not just stored energy, you should
>> reduce the lead acid and lithium battery sizes by 55% to account for
>> their greater energy to propulsion efficiency.
>>
>Fair point, but SLA still shows as a non-starter while SAFT cells are
>still six times the weight of hydrocarbon and occupy at least 25 times
>the volume.
>
>The one thing we both missed, though is that a good brushless motor plus
>its controller will be a lighter and smaller than the equivalent ICE
>piston engine driving a propeller. Has anybody got numbers for this? IOW,

>is motor+controller+prop+Li-ion battery still heavier than petrol+piston
>engine+prop? It will almost certainly be heavier than a Jet-A+turboprop
>engine+propeller.
>
>And, or course, empty fuel tanks are a lot lighter than full ones but a
>flat battery weighs the same as a fully charged one.
>
Not Quite True.
Since a charged battery contains a greater total amount of energy than a
dead battery, the earth's gravity will pull more strongly on it.
But you will have trouble measuring the difference ;¬))

[Eric Greenwell[_4_]]

Martin Gregorie wrote on 2/11/2020 4:33 AM:
> On Mon, 10 Feb 2020 19:12:42 -0800, Eric Greenwell wrote:
>
>> Your chart doesn't account for the efficiencies in converting energy to
>> propulsion. An electric motor will deliver about 95% of the electrical
>> energy to the propeller, but only about 40% of the gasoline energy will
>> be delivered to the propeller.
>>
>> Since it is propulsion we desire, not just stored energy, you should
>> reduce the lead acid and lithium battery sizes by 55% to account for
>> their greater energy to propulsion efficiency.
>>
> Fair point, but SLA still shows as a non-starter while SAFT cells are
> still six times the weight of hydrocarbon and occupy at least 25 times
> the volume.
>
> The one thing we both missed, though is that a good brushless motor plus
> its controller will be a lighter and smaller than the equivalent ICE
> piston engine driving a propeller. Has anybody got numbers for this? IOW,
> is motor+controller+prop+Li-ion battery still heavier than petrol+piston
> engine+prop? It will almost certainly be heavier than a Jet-A+turboprop
> engine+propeller.
>
> And, or course, empty fuel tanks are a lot lighter than full ones but a
> flat battery weighs the same as a fully charged one.

We are all agreed that short powered range favors electric power, while long range
favors fossil fuel power. The details, such as overall weight, become very
interesting in the design of a self-launching sailplane, because the desired power
range is much smaller than for an airplane.

Schleicher's ASH 26E and AS-34 are 18M span gliders with similar gliding and power
performance. That would be a good start for comparing propulsion systems. My
impression is the propulsion systems have similar weights. Note the fuel weight is
not significant for powered ranges less than 250 miles: the 26E holds 4 gallons,
only 25 pounds in a 1020 pound glider (including pilot).

High density altitude favors the electric systems, because the motor power does
not decrease with altitude, unlike the normally aspirated Wankel or two-stroke
engines.

The smaller, lighter, but powerful electric motors give electrics an advantage
unmatched by IC engines: they make the FES system practical.

For us, all this talk about electric powered seaplanes, passenger carrying
airplanes, and alleged fraud is irrelevant: electric powered gliders are available
from all the major manufacturers and some of the smaller ones. They will only get
better and more numerous.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Bob Kuykendall]

On Tuesday, February 11, 2020 at 5:15:04 AM UTC-8, Tim Newport-Peace wrote:

> Not Quite True.
> Since a charged battery contains a greater total amount of energy than a
> dead battery, the earth's gravity will pull more strongly on it.
> But you will have trouble measuring the difference ;¬))

But seriously, no. Energy in and of itself has no mass. A an old-time watch or windup toy has the same mass regardless of whether it is wound or unwound.

[Bob Kuykendall]

On Tuesday, February 11, 2020 at 4:33:26 AM UTC-8, Martin Gregorie wrote:

> ..The one thing we both missed, though is that a good brushless motor plus
> its controller will be a lighter and smaller than the equivalent ICE
> piston engine driving a propeller...

Not only that, but it delivers smoother power with less vibration, delivers it the moment it is started, requires less service infrastructure (starting, lubrication, cooling, exhaust, etc), and can easily be positioned for stowage. It runs cleaner and cooler and more predictably under a wider range of conditions, and is more easily monitored for performance and troubleshooting.

--Bob K.

[Martin Gregorie[_6_]]

On Tue, 11 Feb 2020 10:09:18 -0800, Bob Kuykendall wrote:

> On Tuesday, February 11, 2020 at 5:15:04 AM UTC-8, Tim Newport-Peace
> wrote:
>
>> Not Quite True.
>> Since a charged battery contains a greater total amount of energy than
>> a dead battery, the earth's gravity will pull more strongly on it.
>> But you will have trouble measuring the difference ;¬))
>
> But seriously, no. Energy in and of itself has no mass. A an old-time
> watch or windup toy has the same mass regardless of whether it is wound
> or unwound.

....but an electron does have mass, just not very much:
9.1093837015 × 10^-31 kg

Not that it matters, because as many electrons flow into a discharging
battery as flow out.


--
Martin | martin at
Gregorie | gregorie dot org

[Martin Gregorie[_6_]]

On Tue, 11 Feb 2020 10:16:45 -0800, Bob Kuykendall wrote:

> On Tuesday, February 11, 2020 at 4:33:26 AM UTC-8, Martin Gregorie
> wrote:
>
>> ..The one thing we both missed, though is that a good brushless motor
>> plus its controller will be a lighter and smaller than the equivalent
>> ICE piston engine driving a propeller...
>
> Not only that, but it delivers smoother power with less vibration,
> delivers it the moment it is started, requires less service
> infrastructure (starting, lubrication, cooling, exhaust, etc), and can
> easily be positioned for stowage. It runs cleaner and cooler and more
> predictably under a wider range of conditions, and is more easily
> monitored for performance and troubleshooting.
>
Another thing, but this probably doesn't affect us much: a brushless
motor, which all these units are, has its rpm set primarily by the rate
at which the controller switches power round its (static) field coils
and, when driving a propeller, isn't much affected by the load its
working against. Its one reason electric brushless motors are popular
with the RC and CL aerobatic crowd - the nearly constant RPM causes
airspeed on uplines and downlines to be more constant than it ever was
with IC engines.


--
Martin | martin at
Gregorie | gregorie dot org

[Dan Marotta]

And who outside of the media did not understand that?

On 2/10/2020 3:28 PM, Eric Greenwell wrote:
> kinsell wrote on 2/10/2020 7:59 AM:
>> On 2/10/20 8:43 AM, Dan Marotta wrote:
>>> A couple of very good perspectives HERE
>>> <https://www.avweb.com/features/reader-mail/top-letters-and-comments-february-7-2020/?MailingID=280&utm_source=ActiveCampaign&utm_medium=email&utm_content=Bryant+Crash+Prelim%2C+Drone+Certifica tion+NPRM&utm_campaign=Bryant+Crash+Prelim%2C+Drone+Certific ation+NPRM-Monday+February+10%2C+2020>.
>>>
>>>
>>> Let the flames begin...
>>> --
>>> Dan, 5J
>>
>> Yep.Â* Came across an article from COPA (Canadian Owners and Pilot's
>> Association) filling in some the the details of the Harbour Air
>> plane. It was so stuffed full of batteries there was hardly any
>> useful load left.Â* Which puts it more in the category of publicity
>> stunt than a serious attempt to develop an electric plane.Â* And of
>> course calling it the first all-electric commercial aircraft is
>> disingenuous in the extreme.
>>
>>
>> https://copanational.org/en/2019/12/12/harbour-airs-e-beaver/?utm_source=wysija&utm_medium=email&utm_campaign=COPA%20eFlight-20191212&fbclid=IwAR2Z79lsJpXKCXr5s5wW5naWosNSSiK7OAgzMDVKL-c09zQBJD3aCPb93FA
>>
> The article made clear it's _test_ plane, not prototype for the
> commercial version. That version will use a different chemistry Li
> battery that is significantly lighter.
>
> "The flight was not in a commercial aircraft in the sense that it was
> certified to carry passengers – it is a prototype used in the
> certification process. As such, the flight was made for ‘proof of
> concept’ purposes only."
>
>

--
Dan, 5J

[Dan Marotta]

What a wonderful way to spend a snowy morning, discussing the weight of
a full versus an empty battery!

What if we talked in terms of mass instead of weight? :-D

Seriously, I got a lot of entertainment after the thread went off topic
as is so normal with RASicrucians.Â* I especially liked the comparison
that Bob made of a wound versus unwound watch or toy. I've been banging
my head against the wall trying to see that in the context of the Laws
of Conservation of Matter and Energy.

More coffee is in order...

On 2/11/2020 11:34 AM, Martin Gregorie wrote:
> On Tue, 11 Feb 2020 10:16:45 -0800, Bob Kuykendall wrote:
>
>> On Tuesday, February 11, 2020 at 4:33:26 AM UTC-8, Martin Gregorie
>> wrote:
>>
>>> ..The one thing we both missed, though is that a good brushless motor
>>> plus its controller will be a lighter and smaller than the equivalent
>>> ICE piston engine driving a propeller...
>> Not only that, but it delivers smoother power with less vibration,
>> delivers it the moment it is started, requires less service
>> infrastructure (starting, lubrication, cooling, exhaust, etc), and can
>> easily be positioned for stowage. It runs cleaner and cooler and more
>> predictably under a wider range of conditions, and is more easily
>> monitored for performance and troubleshooting.
>>
> Another thing, but this probably doesn't affect us much: a brushless
> motor, which all these units are, has its rpm set primarily by the rate
> at which the controller switches power round its (static) field coils
> and, when driving a propeller, isn't much affected by the load its
> working against. Its one reason electric brushless motors are popular
> with the RC and CL aerobatic crowd - the nearly constant RPM causes
> airspeed on uplines and downlines to be more constant than it ever was
> with IC engines.
>
>

--
Dan, 5J

[Tango Whisky]

You mean that a glider hs a higher mass after releasing from tow because you added potential energy??

[kinsell]

Ummm, the COPA article is not the message that Harbour Air and Magnix
have been putting out.

This is representative of the story they tell, indicating the prototype
is ready for certification:

https://www.flightglobal.com/airlines/harbour-air-flies-first-all-electric-commercial-aircraft-a-dhc-2-beaver/135711.article

And yes, there's lots of people not associated with aviation that are
being mislead by this.

-Dave





On 2/11/20 11:56 AM, Dan Marotta wrote:
> And who outside of the media did not understand that?
>
> On 2/10/2020 3:28 PM, Eric Greenwell wrote:
>> kinsell wrote on 2/10/2020 7:59 AM:
>>> On 2/10/20 8:43 AM, Dan Marotta wrote:
>>>> A couple of very good perspectives HERE
>>>> <https://www.avweb.com/features/reader-mail/top-letters-and-comments-february-7-2020/?MailingID=280&utm_source=ActiveCampaign&utm_medium=email&utm_content=Bryant+Crash+Prelim%2C+Drone+Certifica tion+NPRM&utm_campaign=Bryant+Crash+Prelim%2C+Drone+Certific ation+NPRM-Monday+February+10%2C+2020>.
>>>>
>>>>
>>>> Let the flames begin...
>>>> --
>>>> Dan, 5J
>>>
>>> Yep.Â* Came across an article from COPA (Canadian Owners and Pilot's
>>> Association) filling in some the the details of the Harbour Air
>>> plane. It was so stuffed full of batteries there was hardly any
>>> useful load left.Â* Which puts it more in the category of publicity
>>> stunt than a serious attempt to develop an electric plane.Â* And of
>>> course calling it the first all-electric commercial aircraft is
>>> disingenuous in the extreme.
>>>
>>>
>>> https://copanational.org/en/2019/12/12/harbour-airs-e-beaver/?utm_source=wysija&utm_medium=email&utm_campaign=COPA%20eFlight-20191212&fbclid=IwAR2Z79lsJpXKCXr5s5wW5naWosNSSiK7OAgzMDVKL-c09zQBJD3aCPb93FA
>>>
>> The article made clear it's _test_ plane, not prototype for the
>> commercial version. That version will use a different chemistry Li
>> battery that is significantly lighter.
>>
>> "The flight was not in a commercial aircraft in the sense that it was
>> certified to carry passengers – it is a prototype used in the
>> certification process. As such, the flight was made for ‘proof of
>> concept’ purposes only."
>>
>>
>