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Electroflight Team Aims To Fly 300 MPH On Batteries



 
 
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  #1  
Old September 7th 14, 11:32 PM posted to rec.aviation.piloting
Larry Dighera
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Posts: 3,892
Default Electroflight Team Aims To Fly 300 MPH On Batteries



http://www.avweb.com/avwebflash/news/Team-Aims-To-Fly-300-MPH-On-Batteries222710-1.html

Electroflight Team Aims To Fly 300 MPH On Batteries

By Mary Grady | September 1, 2014

Electroflight http://www.electro-flight.co.uk/aeroplane.html, a team of
British glider builders, recently announced it has teamed up with Williams
Advanced Engineering to build a single-seat airplane that will set a new speed
record for electric aircraft of 300 mph. Team Electroflight has built a mock-up
of its design, and said it will be powered by a "unique contra-rotating
electric propulsion system." Williams is affiliated with the Williams Martini
Formula One car-racing team, which is developing technology to compete in a new
fully electric car-racing series, called Formula E, that is set to debut this
month. "We are certain that the combined expertise of the teams will enable us
to achieve our goal and break the world speed record for electric aircraft,"
said Roger Targett, of Electroflight. The current speed record for electric
flight is 220 mph.

Electroflight exhibited its mock-up of the new design at the recent Red Bull
Air Races in Ascot, England. "There was a huge amount of interest and large
numbers of people, mainly children, queuing to sit in the cockpit of our space
allocation fuselage," said Targett. According to the Electroflight website:
"Our aircraft design combines advances in carbon composite materials and
construction methods with emerging electric motor, control system and
energy-storage technologies. Its twin propeller contra-rotating propulsion
offers unique maneuvering capabilities. Two fixed-pitch propellers have been
designed and engineered specifically to the rotational and torque
characteristics of the motors, together with thrust and acceleration bearing
assemblies that far exceed the loads presented during aggressive 10 G
aerobatics and air racing.

"The carbon composite airframe is fitted with a whole aircraft ballistic
parachute system and incorporates a separate pilot safety cell, similar to that
in F1 racing cars. The airframe has extremely low form drag and incorporates
purpose designed compartments to carry batteries, controllers and electronic
equipment. The result is a completely new type of race plane and technology
demonstrator that is light, fast and capable of maneuvers impossible for
single-propeller piston or gas-turbine-driven aircraft."

------------------
Propulsion System
The propulsion system is a wholly new generation of an electric contra-rotating
unit. The high torque of the electric motors allows the propeller shafts to be
directly driven without gearing or other speed reduction devices and achieves
simplicity unknown in non-electric forms of contra-rotating propeller
propulsion. Except for the shaft bearings, the motor rotors, propeller shafts
and propellers form the only two rotating assemblies in the system.

This allows for almost maintenance free operation for the life of the system. A
unique feature of electric propulsion is the ability to apply full power almost
instantly with no spool up or inertial lag time found in piston or turbine
types. The system's thrust to take-off weight ratio is greater than one and
allows the aircraft to accelerate vertically (vertical take-off) and to operate
at extreme altitudes far above oxygen dependant engines in unpiloted
conditions.

Two fixed pitch propellers have been designed and engineered specifically to
the rotational and torque characteristics of the motors, together with thrust
and acceleration bearing assemblies that far exceed the loads presented during
aggressive 10 G aerobatics and air racing.

The carbon composite airframe is fitted with a whole aircraft ballistic
parachute system and incorporates a separate pilot safety cell, similar to that
in F1 racing cars. The airframe has extremely low form drag and incorporates
purpose designed compartments to carry batteries, controllers and electronic
equipment. The result is a completely new type of race plane and technology
demonstrator that is light, fast and capable of manoeuvres impossible for
single propeller piston or gas turbine driven aircraft.

Facts
The single seat prototype aircraft is designed to demonstrate the advantages of
pure electric flight.

All Up Weight (excluding pilot); 345 kgs.
Maximum Power (3400rpm): 225 kW
Thrust 500 Kgs
Maximum level Speed (sea level) 250 kts
Climb rate (vertical) 9,000 ft/min
Battery power (720 volts) 15 kW
Ads
  #2  
Old September 8th 14, 12:52 AM posted to rec.aviation.piloting
[email protected]
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Posts: 2,879
Default Electroflight Team Aims To Fly 300 MPH On Batteries

Larry Dighera wrote:


http://www.avweb.com/avwebflash/news/Team-Aims-To-Fly-300-MPH-On-Batteries222710-1.html

Electroflight Team Aims To Fly 300 MPH On Batteries


Whoopee.

Let me know when they can fly 4 hours at at least 120 knots.



--
Jim Pennino
  #3  
Old September 8th 14, 01:47 AM posted to rec.aviation.piloting
Orval Fairbairn
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Posts: 824
Default Electroflight Team Aims To Fly 300 MPH On Batteries

In article ,
wrote:

Larry Dighera wrote:


http://www.avweb.com/avwebflash/news...-On-Batteries2
22710-1.html

Electroflight Team Aims To Fly 300 MPH On Batteries


Whoopee.

Let me know when they can fly 4 hours at at least 120 knots.


I would think that they could reach 300 mph without going to all the
extra effort being described, since some current homebuilts do that on
conventional 400 hp Lycomings, carrying 2 people.

Take an SX-300, replace the Lycoming with electric motor and batteries,
and you should be able to do it for enough time to set the record.
  #5  
Old September 8th 14, 11:43 AM posted to rec.aviation.piloting
Larry Dighera
external usenet poster
 
Posts: 3,892
Default Electroflight Team Aims To Fly 300 MPH On Batteries

On Sun, 7 Sep 2014 23:52:34 -0000, wrote:

Larry Dighera wrote:


http://www.avweb.com/avwebflash/news/Team-Aims-To-Fly-300-MPH-On-Batteries222710-1.html

Electroflight Team Aims To Fly 300 MPH On Batteries


Whoopee.

Let me know when they can fly 4 hours at at least 120 knots.


Hello Jim,

I recall researching this with you some years back in this newsgroup.
Technology is advancing, and hydrogen powered fuel cell based electric power is
on the horizon.

At the 2014 Consumer Electronics Show I spoke with Toyota engineer Ms. Jackie
Birdsall about Toyota's FCV concept car on display there. Here's link to a
video: https://www.youtube.com/watch?v=2bluUNxVLhE. She told me that their
fuel cell was 60% efficient in producing electricity from oxygen in the air and
compressed hydrogen; this is in contrast to ~30% efficiency of internal
combustion engines. If true, that will enable this technology to surpass
current propulsion technology. She also said the hydrogen would be compressed
to ten bar, which would raise its energy density comparable to that of
gasoline. So, it would appear that your dream specifications could be
achievable soon.

Best regards,
Larry

  #6  
Old September 8th 14, 01:03 PM posted to rec.aviation.piloting
Vaughn
external usenet poster
 
Posts: 154
Default Fuel Cells, Was Electroflight Team Aims To Fly 300 MPH On Batteries

On 9/8/2014 6:43 AM, Larry Dighera wrote:
She told me that their
fuel cell was 60% efficient in producing electricity from oxygen in the air and
compressed hydrogen; this is in contrast to ~30% efficiency of internal
combustion engines. If true, that will enable this technology to surpass
current propulsion technology.


Fuel cells have been the ultimate "vaporware". Starting about in the
1990's and continuing thru the first decade of the 2000's, fuel cells
were always "next year's technology. Several companies actually
announced consumer products, only to see them never actually materialize
on the marketplace.

Now we seem to hear a lot less about them.

It turns out that fuel cells are delicate things that have trouble
lasting in the real world. Feed them tainted fuel just once, and they
are junk. There are major problems obtaining a huge supply of hydrogen
and making the infrastructure to distribute it. It seems that we have
lots of oil wells and lots of natural gas wells, but no hydrogen wells.
To produce hydrogen takes prodigious amounts of energy, so it will
never be cheap.

Still, when Honda actually introduced a few fuel cell cars starting in
the early 2000's, I thought that fuel cells were finally on the way.
History seems to be proving otherwise. The Honda fuel cell cars
remained a pilot program, producing only a few hundred units over a
decade or so. Not one unit was actually sold. Honda leased them to
carefully vetted customers. Now the word is that they will end
production with the 2015 model.

Over all this time, battery technology has continued to improve and has
actually led to real products in the consumer market. We now have a
choice of several practical battery cars that are on the mass market,
although most of us choose not to buy them for solid economic and
practical reasons.

Now we are seeing the beginnings of the same thing happening in
aviation. There will be eventually be a few practical battery airplanes
available. They will be around, but few of us will actually buy them.

Fuel cells? Don't hold your breath! But if we ever get them, they will
be expensive to operate because hydrogen will never be cheap.
  #7  
Old September 8th 14, 05:29 PM posted to rec.aviation.piloting
[email protected]
external usenet poster
 
Posts: 2,879
Default Electroflight Team Aims To Fly 300 MPH On Batteries

Larry Dighera wrote:
On Sun, 7 Sep 2014 23:52:34 -0000, wrote:

Larry Dighera wrote:


http://www.avweb.com/avwebflash/news/Team-Aims-To-Fly-300-MPH-On-Batteries222710-1.html

Electroflight Team Aims To Fly 300 MPH On Batteries


Whoopee.

Let me know when they can fly 4 hours at at least 120 knots.


Hello Jim,

I recall researching this with you some years back in this newsgroup.
Technology is advancing, and hydrogen powered fuel cell based electric power is
on the horizon.


Yep, right around the corner along with cheap fusion power, true artificial
intelligence, a cure for the common cold and peace in the Middle East.

At the 2014 Consumer Electronics Show I spoke with Toyota engineer Ms. Jackie
Birdsall about Toyota's FCV concept car on display there. Here's link to a
video: https://www.youtube.com/watch?v=2bluUNxVLhE. She told me that their
fuel cell was 60% efficient in producing electricity from oxygen in the air and
compressed hydrogen; this is in contrast to ~30% efficiency of internal
combustion engines. If true, that will enable this technology to surpass


Efficiency has never been a particular issue, it has alway been energy
density, and for airplanes, that is both by weight and volume.

And to have an apples to apples comparison you have to include all the
support pieces like tanks and delivery equipment.

current propulsion technology. She also said the hydrogen would be compressed
to ten bar, which would raise its energy density comparable to that of
gasoline. So, it would appear that your dream specifications could be
achievable soon.


That's OK for a car, but a 145 psi hydrogen tank after the FAA gets done
with the requirements is not going to be particularly light.

There is also the issue of tank life. Tanks for compressed gas of any kind
are typically subject to periodic static testing and/or replacement.

I just can't see how all that is going to be practical in an aircraft
wing.

Best regards,
Larry


I'm not going to be holding my breath...



--
Jim Pennino
  #8  
Old September 8th 14, 05:41 PM posted to rec.aviation.piloting
[email protected]
external usenet poster
 
Posts: 2,879
Default Fuel Cells, Was Electroflight Team Aims To Fly 300 MPH On Batteries

Vaughn wrote:
On 9/8/2014 6:43 AM, Larry Dighera wrote:
She told me that their
fuel cell was 60% efficient in producing electricity from oxygen in the air and
compressed hydrogen; this is in contrast to ~30% efficiency of internal
combustion engines. If true, that will enable this technology to surpass
current propulsion technology.


Fuel cells have been the ultimate "vaporware". Starting about in the
1990's and continuing thru the first decade of the 2000's, fuel cells
were always "next year's technology. Several companies actually
announced consumer products, only to see them never actually materialize
on the marketplace.

Now we seem to hear a lot less about them.

It turns out that fuel cells are delicate things that have trouble
lasting in the real world. Feed them tainted fuel just once, and they
are junk. There are major problems obtaining a huge supply of hydrogen
and making the infrastructure to distribute it. It seems that we have
lots of oil wells and lots of natural gas wells, but no hydrogen wells.
To produce hydrogen takes prodigious amounts of energy, so it will
never be cheap.


The vast majority of commercial hydrogen is produced by steam reforming
of natural gas.

A fuel cell that runs directly on natural gas would make a lot more
sense for many reasons, but primarily because you can skip the reforming
stage and natural gas is a LOT easier and safer to store in a tank.

Still, when Honda actually introduced a few fuel cell cars starting in
the early 2000's, I thought that fuel cells were finally on the way.
History seems to be proving otherwise. The Honda fuel cell cars
remained a pilot program, producing only a few hundred units over a
decade or so. Not one unit was actually sold. Honda leased them to
carefully vetted customers. Now the word is that they will end
production with the 2015 model.

Over all this time, battery technology has continued to improve and has
actually led to real products in the consumer market. We now have a
choice of several practical battery cars that are on the mass market,
although most of us choose not to buy them for solid economic and
practical reasons.


Like the 2 to 3 times greater cost for an electric car versus a gas
car and the fact that batteries have a limited life span and are not
cheap to replace.

Another issue that is significant for aviation is the self discharge
rate of those high-tech batteries.

If you let them sit without charging for a month or two they go dead
and won't recharge.

Now we are seeing the beginnings of the same thing happening in
aviation. There will be eventually be a few practical battery airplanes
available. They will be around, but few of us will actually buy them.


Unless you fly a motor glider which is the only aviation application
where electric power is practical and likely to be for a very long
time.

Fuel cells? Don't hold your breath! But if we ever get them, they will
be expensive to operate because hydrogen will never be cheap.


Again, only natural gas fuel cells make any sense.


--
Jim Pennino
  #9  
Old September 9th 14, 08:59 AM posted to rec.aviation.piloting
Skywise
external usenet poster
 
Posts: 140
Default Electroflight Team Aims To Fly 300 MPH On Batteries

Larry Dighera wrote in
:

She also said the hydrogen would be compressed to ten bar,
which would raise its energy density comparable to that of
gasoline.


I'm not so sure about that.

An article I found many many years ago, published in 2002,
discusses such things. If the information in the article is
correct, it is extremely difficult to beat gasoline for
energy density.

It lists gasoline as having an energy density of 9000Wh/l
(watt-hours per liter).

150 bar H2 is only 405 Wh/l.

Liquid H2 is 2600 Wh/l.

Lithium batteries are listed as 250 Wh/l, but mind you
this was published 12 years ago. Battery technology has
made large leaps since then. Even if they've only
doubled in energy density since then, that would still
beat 150 bar H2.

http://www.tinaja.com/glib/energfun.pdf

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?
  #10  
Old September 9th 14, 03:58 PM posted to rec.aviation.piloting
Orval Fairbairn
external usenet poster
 
Posts: 824
Default Electroflight Team Aims To Fly 300 MPH On Batteries

In article ,
Skywise wrote:

Larry Dighera wrote in
:

She also said the hydrogen would be compressed to ten bar,
which would raise its energy density comparable to that of
gasoline.


I'm not so sure about that.

An article I found many many years ago, published in 2002,
discusses such things. If the information in the article is
correct, it is extremely difficult to beat gasoline for
energy density.

It lists gasoline as having an energy density of 9000Wh/l
(watt-hours per liter).

150 bar H2 is only 405 Wh/l.

Liquid H2 is 2600 Wh/l.

Lithium batteries are listed as 250 Wh/l, but mind you
this was published 12 years ago. Battery technology has
made large leaps since then. Even if they've only
doubled in energy density since then, that would still
beat 150 bar H2.

http://www.tinaja.com/glib/energfun.pdf

Brian


Battery technology hasn't (and probably never will) reached a
competitive level with hydrocarbons for energy density.

Just think, for back-of-the-envelope calculation, that the energy stored
in a battery represents the entire mass of all the fuel (and air) that a
combustion engine uses for power. The fuel represents only 1/15 the
total mass, which means that, for every gallon of gasoline (6 lb) 90 lb
of air must pass through the motor. So, for a 50-gallon fuel tank (300
lb), one must also carry 4500 lb of air.
 




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