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On Electric Aircraft



 
 
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  #1  
Old February 10th 20, 04:43 PM posted to rec.aviation.soaring
Dan Marotta
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Posts: 4,326
Default On Electric Aircraft

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_mediu m=email&utm_content=Bryant+Crash+Prelim%2C+Drone+C ertification+NPRM&utm_campaign=Bryant+Crash+Prelim %2C+Drone+Certification+NPRM-Monday+February+10%2C+2020.

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

Ads
  #2  
Old February 10th 20, 04:59 PM posted to rec.aviation.soaring
kinsell
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Posts: 445
Default On Electric Aircraft

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_mediu m=email&utm_content=Bryant+Crash+Prelim%2C+Drone+C ertification+NPRM&utm_campaign=Bryant+Crash+Prelim %2C+Drone+Certification+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/...zQBJD3aCPb93FA
  #3  
Old February 10th 20, 11:28 PM posted to rec.aviation.soaring
Eric Greenwell[_4_]
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Posts: 1,627
Default On Electric Aircraft

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_mediu m=email&utm_content=Bryant+Crash+Prelim%2C+Drone+C ertification+NPRM&utm_campaign=Bryant+Crash+Prelim %2C+Drone+Certification+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/...zQBJD3aCPb93FA

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/motorg...ad-the-guide-1

  #4  
Old February 10th 20, 11:38 PM posted to rec.aviation.soaring
Steve Bralla
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Posts: 38
Default On Electric Aircraft

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
  #5  
Old February 11th 20, 02:52 AM posted to rec.aviation.soaring
Martin Gregorie[_6_]
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Posts: 561
Default On Electric Aircraft

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

A couple of very good perspectives HERE
https://www.avweb.com/features/reade...-and-comments-

february-7-2020/?
MailingID=280&utm_source=ActiveCampaign&utm_medium =email&utm_content=Bryant+Crash+Prelim%2C+Drone+Ce rtification+NPRM&utm_campaign=Bryant+Crash+Prelim% 2C+Drone+Certification+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

  #6  
Old February 11th 20, 04:12 AM posted to rec.aviation.soaring
Eric Greenwell[_4_]
external usenet poster
 
Posts: 1,627
Default On Electric Aircraft

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/motorg...ad-the-guide-1
  #7  
Old February 11th 20, 06:03 AM posted to rec.aviation.soaring
kinsell
external usenet poster
 
Posts: 445
Default On Electric Aircraft

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 mo

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.
  #8  
Old February 11th 20, 01:33 PM posted to rec.aviation.soaring
Martin Gregorie[_6_]
external usenet poster
 
Posts: 561
Default On Electric Aircraft

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

  #9  
Old February 11th 20, 02:09 PM posted to rec.aviation.soaring
Tim Newport-Peace[_6_]
external usenet poster
 
Posts: 65
Default On Electric Aircraft

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 ;¬))


  #10  
Old February 11th 20, 05:10 PM posted to rec.aviation.soaring
Eric Greenwell[_4_]
external usenet poster
 
Posts: 1,627
Default On Electric Aircraft

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/motorg...ad-the-guide-1
 




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