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Author: Larry DigheraLarry Dighera Date: Aug 5, 2007 09:52
Electrically Powered Ultralight Aircraft
Below is a report of an electrically powered ultralight aircraft.
Further down is information about Sonex's electrically powered
home-built aircraft, and below that is information about Royal
Aeronautical Society's 2007-8 design competition (submissions close
May 2, 2008).
Personally, I'd like to see an electrically powered parachute
( http://skyhighflying.com/homepage.html) design attempted. Surly the
lighter weight would require less power. It would seem that
lithium-ion polymer batteries are a potential enabling technology.
AVGAS? WHO NEEDS IT? TRIKE RUNS ON BATTERIES
( http://www.avweb.com/eletter/archives/avflash/925-full.html#195816)
While concerns over price, availability and environmental impact
have aviators...
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Author: PhilPhil Date: Aug 5, 2007 10:53
On Aug 5, 11:52 am, Larry Dighera att.net> wrote:> Electrically Powered Ultralight Aircraft
>
> Below is a report of an electrically powered ultralight aircraft.
> Further down is information about Sonex's electrically powered
> home-built aircraft, and below that is information about Royal
> Aeronautical Society's 2007-8 design competition (submissions close
> May 2, 2008).
>
> Personally, I'd like to see an electrically powered parachute
> ( http://skyhighflying.com/homepage.html) design attempted. Surly the
> lighter weight would require less power. It would seem that
> lithium-ion polymer batteries are a potential enabling technology.
>
> AVGAS? WHO NEEDS IT? TRIKE RUNS ON BATTERIES
> ( http://www.avweb.com/eletter/archives/avflash/925-full.html#195816)
> While concerns over price, availability and environmental impact
> have aviators worried about the future of fuel, one ultralight
> flyer in New Jersey has already solved that problem. Randall
> Fishman has been testing lithium-ion polymer battery packs to ...
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Author: Larry DigheraLarry Dighera Date: Aug 5, 2007 11:12
>Very interesting. It doesn't mention how long it takes to charge the
>batteries.
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Author: James SleemanJames Sleeman Date: Aug 6, 2007 00:14
On Aug 6, 4:52 am, Larry Dighera att.net> wrote:> Electrically Powered Ultralight Aircraft
It's a nice idea, but realisitically there are too many problems, not
the least of which is battery size, weight, cost and safety. I don't
really see batteries as a viable in the near future (I struggle to see
them as viable in the distant future either).
That said though, I recently saw an article somewhere about an
electric car with a stirling engine tucked away in the back (Deam
Kamen was in on it somewhere - he's the Segway and fancy wheelchair
guy).
On the face of it, that seems like not a bad idea for how an electric
aircraft could be realistic - take your stirling engine, hook it
through a smaller, cheaper, lighter battery system to your electric
motor. The battery would act as a buffer (capacitor) to allow for
stored energy to do rapid changes in power to the drive motor, the
stirling engine would tick away at a constant rate feeding it's
generated electricy into the battery.
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Date: Aug 6, 2007 05:39
On Aug 6, 1:14 am, James Sleeman gmail.com> wrote:> On Aug 6, 4:52 am, Larry Dighera att.net> wrote:
>>> Electrically Powered Ultralight Aircraft
>
> It's a nice idea, but realisitically there are too many problems, not
> the least of which is battery size, weight, cost and safety. I don't
> really see batteries as a viable in the near future (I struggle to see
> them as viable in the distant future either).
>
> That said though, I recently saw an article somewhere about an
> electric car with a stirling engine tucked away in the back (Deam
> Kamen was in on it somewhere - he's the Segway and fancy wheelchair
> guy).
>
> On the face of it, that seems like not a bad idea for how an electric
> aircraft could be realistic - take your stirling engine, hook it
> through a smaller, cheaper, lighter battery system to your electric
> motor. The battery would act as a buffer (capacitor) to allow for
> stored energy to do rapid changes in power to the drive motor, the ...
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Author: AirjunkieAirjunkie Date: Aug 6, 2007 06:33
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Date: Aug 6, 2007 08:18
> For a battery-powered car todays practical approach is to have a
> second engine for backup or as you suggest to generate electricity.
> When they start selling cars only powered by batteries I'm going to
> invest in a tow truck business. For aircraft the best use for
> batteries today is to start the engine. Lange has demonstrated what is
> possible with today's batteries/motors and while it provides an
> attractive self-launch the cost and range tradeoffs bring it back into
> perspective.
>
I think this is a little pessimistic. Critics of the pure electric seem to
focus on the "one-car does everything" strategy where it's easier to find
faults. The "electrics don't equal engine powered cars" isn't the whole
story.
Americans, at least, seem to have developed a another strategy for dealing
with fuel prices that spike every summer. They own an old, cheap econobox
they dust off when gas prices exceed $3. They drive their SUV's only when
they need the capacity.
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Author: Larry DigheraLarry Dighera Date: Aug 6, 2007 08:39
>On Aug 6, 4:52 am, Larry Dighera att.net> wrote:>> Electrically Powered Ultralight Aircraft
>
>It's a nice idea, but realisitically there are too many problems, not
>the least of which is battery size, weight, cost and safety. I don't
>really see batteries as a viable in the near future (I struggle to see
>them as viable in the distant future either).
There is a fundamental problem with attempting to power an aircraft
with batteries: The propulsion system must not only move the vehicle
forward as it would with an automobile, but it must also
simultaneously maintain the aircraft's altitude; unlike an automobile
that only requires a small amount of energy to overcome rolling and
wind resistance once in motion, an aircraft can't coast without losing
altitude, so energy demands for powering an aircraft are considerably
more demanding than those for an automobile.
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Author: Larry DigheraLarry Dighera Date: Aug 6, 2007 08:42
>When they start selling cars only powered by batteries I'm going to
>invest in a tow truck business.
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Author: Orval FairbairnOrval Fairbairn Date: Aug 6, 2007 08:53
> On Aug 6, 4:52 am, Larry Dighera att.net> wrote:>> Electrically Powered Ultralight Aircraft
>
> It's a nice idea, but realisitically there are too many problems, not
> the least of which is battery size, weight, cost and safety. I don't
> really see batteries as a viable in the near future (I struggle to see
> them as viable in the distant future either).
Look at the problem this way: In an all-electric machine, you carry ALL
of your energy supply with you: fuel and oxidizer -- to make electricity.
With any IC engine, you carry the fuel only -- the air is free (20%%
oxygen), so, at 15:1 air/fuel ratio, you would need 90 lb of air for
each gallon of fuel.
Therefore, for a nominal 50 gallon fuel capacity (300 lb), you would
have to carry an additional 7500 lb of air.
That is a lot of weight for a 3000 lb aircraft!
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