Electrically Powered Ultralight Aircraft

Larry Dighera wrote:
On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

They obviously don't make a 100HP motor of the type you showed or
you would have quoted it's specs.


Take a look at the ~75 HP electric motor installed in the Sonex Waiex:
http://www.sonexaircraft.com/news/im...irventure07/e-
flight_5947.jpg

Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.

You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

Of course I don't. But they might as well be at this point becuse the
electric motor they have has never been off the ground.

I wish the Sonex guys well and will praise the hell out of them if they do
what they are trying to do. But, as I said in a earlier post, I just don't
see this big of a technological leap coming from a company whose last major
enginnering feat was converting a VW engine for aircraft.

If and when it happens it will be either a bunch of guys from MIT or Cal
Tech or as the offshoot of a much more profitable electric motor project.

Larry Dighera wrote:
On Wed, 08 Aug 2007 07:20:22 -0700, wrote in
.com:


I have not seen any significant flight duration claim on the Sonex,
which speaks well for the design team.

I really hate to burst your bubble but, from the Sonex link above.

"Initial top speeds will reach approximately 130 mph, and endurance
is expected to range between 25-45 minutes or longer, depending
upon power usage on each individual flight."- Hide quoted text -

- Show quoted text -

I also read that but "Expected to be" isn't a claim and 45 minutes is
not what I would call significant duration.

Would you characterize 12 seconds ad significant?

http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur's first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville's second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.


I would now but when the best previous powered flight it was ZERO in both
time and distance anything 0 was significant. And, unfortunately, for the
electric powered airplane folks they have to be compared at least to what I
can build in my garage and attach a 1960's vintage Corvair engine too.

Sonex's electric airplane especially has to be judged against that criteria
because they already make a plane that I can build in my garage and hang a
Corvair engine on.

On Wed, 8 Aug 2007 10:48:40 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

Larry Dighera wrote:
On Wed, 8 Aug 2007 08:12:37 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

They obviously don't make a 100HP motor of the type you showed or
you would have quoted it's specs.


Take a look at the ~75 HP electric motor installed in the Sonex Waiex:
http://www.sonexaircraft.com/news/im...irventure07/e-
flight_5947.jpg

Exclusive of the two black boxes, the Sonex motor sure doesn't appear
to weigh any where near the 1,118 lbs motor you found. My guess would
be under 100 lbs. It is custom built for/by Sonex, so I'm not able to
quote its specifications.

You don't really believe Sonex is using an electric motor that weighs
any where near 1,118 lbs, do you. The entire empty weight of the
Waiex is only ~620 lbs with a gross weight of 1150 lbs.

Of course I don't. But they might as well be at this point becuse the
electric motor they have has never been off the ground.

The motor was apparently designed by Bob Boucher. He also designed
the motors Dr. Paul MacCready used to fly across the English channel
solely under power from the sun, and other successful AeroVironment
electrically powered aircraft commissioned by NASA. If anyone can
design a proper electric motor for aviation, Mr. Boucher should be
able to; he has the past successes to prove it.

I wish the Sonex guys well and will praise the hell out of them if they do
what they are trying to do. But, as I said in a earlier post, I just don't
see this big of a technological leap coming from a company whose last major
enginnering feat was converting a VW engine for aircraft.

If and when it happens it will be either a bunch of guys from MIT or Cal
Tech or as the offshoot of a much more profitable electric motor project.


Perhaps.

On Wed, 8 Aug 2007 10:55:38 -0500, "Gig 601XL Builder"
wrDOTgiaconaATsuddenlink.net wrote in
:

Larry Dighera wrote:
On Wed, 08 Aug 2007 07:20:22 -0700, wrote in
.com:


I have not seen any significant flight duration claim on the Sonex,
which speaks well for the design team.

I really hate to burst your bubble but, from the Sonex link above.

"Initial top speeds will reach approximately 130 mph, and endurance
is expected to range between 25-45 minutes or longer, depending
upon power usage on each individual flight."- Hide quoted text -

- Show quoted text -

I also read that but "Expected to be" isn't a claim and 45 minutes is
not what I would call significant duration.

Would you characterize 12 seconds ad significant?

http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur's first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville's second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.


I would now but when the best previous powered flight it was ZERO in both
time and distance anything 0 was significant. And, unfortunately, for the
electric powered airplane folks they have to be compared at least to what I
can build in my garage and attach a 1960's vintage Corvair engine too.

Sonex's electric airplane especially has to be judged against that criteria
because they already make a plane that I can build in my garage and hang a
Corvair engine on.


Electrically powered flight is in its infancy just as powered flight
was in 1903.

Larry Dighera wrote:


Electrically powered flight is in its infancy just as powered flight
was in 1903.

That matters not. It still has to be compared to what it is supposed to
replace. Would you want an electric car that was the technological equal to
this? http://www.ausbcomp.com/~bbott/cars/cugnot.jpg.

The otherside of that is that we can expect to wait until 2110 for electric
flight to catch up to where we are now with gasoline powered flight.

Would you characterize 12 seconds ad significant?

http://www.thewrightbrothers.org/fivefirstflights.html
The First Flight, spanning some 120 feet in 12 seconds. The next
flight, Wilbur’s first flight on the 17th, extended to some 175
feet in 13 seconds and a landing was accomplished with no damage
to The Flyer. Orville’s second attempt that day, and his last one
in The Flyer, carried him just over 200 feet in 15 seconds and
ended with a safe landing. At noon, Wilbur took-off on the last
and the longest flight which The Flyer would ever make, and flew
for 852 feet, staying aloft for 59 seconds.

In 1903 it was but times change...

Tony

On Tue, 07 Aug 2007 17:51:27 GMT, "Neil Gould"
wrote in
:

Recently, Larry Dighera posted:
[...]
I'm thinking there would be necessity for some means of conducting the
heat from the engine to a remote heat exchanger, and the resulting
complexity and weight increase would negatively impact the potential
advantages of a Stirling aviation engine. In any event, in addition
to the Stirling engine and its fuel, a heat exchanger of some type
needs to factored into the weight, cost, performance, and efficiency
equations.

Of course, but I don't see a lot of reason why that couldn't be
incorporated into the overall design. My point is that heat exchangers
need not be heavy, and could probably double as structural and/or
aerodynamic components, further reducing (and possibly enhancing) their
impact.

How would you get the heat from the Stirling engine to the heat sink?
If you use liquid coolant, it would be heavy and prone to leaks.

There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if
the weight of the lead shielding were not too great. Imagine an
aircraft that effectively never runs out of fuel! There'd be no
more fuel exhaustion mishaps.

One downside would be the hazardous materials that could be
dispersed in a crash.

There are a lot of down sides to atomic power, but NASA uses it to
power Stirling engines in space.

Understandable, but their expectation is that catastrophic destruction
would disperse the nuclear material harmlessly. That can't be presumed for
light aircraft.

If the rocket detonated in the atmosphere, it might not be so
harmless. I would guess the reactor is jacketed with sufficient
strength to preclude its destruction. Presumably, that could be done
for a Stirling aircraft engine also.

Recently, Larry Dighera posted:

On Tue, 07 Aug 2007 17:51:27 GMT, "Neil Gould"
wrote in
:

Recently, Larry Dighera posted:
[...]
I'm thinking there would be necessity for some means of conducting
the heat from the engine to a remote heat exchanger, and the
resulting complexity and weight increase would negatively impact
the potential advantages of a Stirling aviation engine. In any
event, in addition to the Stirling engine and its fuel, a heat
exchanger of some type needs to factored into the weight, cost,
performance, and efficiency equations.

Of course, but I don't see a lot of reason why that couldn't be
incorporated into the overall design. My point is that heat
exchangers need not be heavy, and could probably double as
structural and/or aerodynamic components, further reducing (and
possibly enhancing) their impact.

How would you get the heat from the Stirling engine to the heat sink?
If you use liquid coolant, it would be heavy and prone to leaks.

I'm not a Stirling engine designer, so I can't answer that factually. I
have been reading up on it a bit since the article was referenced in this
thread, but I haven't seen such things as the required rate of dissipation
for the engine to work efficiently. If the heat sink needs to be large and
close to the engine, perhaps a design where the engine is mounted on or
even incorporated into the wing is a way to go.

There might be one advantage to using Sterling external combustion
engines for aviation: the use of atomic energy as a fuel source if
the weight of the lead shielding were not too great. Imagine an
aircraft that effectively never runs out of fuel! There'd be no
more fuel exhaustion mishaps.

One downside would be the hazardous materials that could be
dispersed in a crash.

There are a lot of down sides to atomic power, but NASA uses it to
power Stirling engines in space.

Understandable, but their expectation is that catastrophic
destruction would disperse the nuclear material harmlessly. That
can't be presumed for light aircraft.

If the rocket detonated in the atmosphere, it might not be so
harmless.

I don't see why it would be nearly as bad as a "dirty bomb" would be, as
the material would be dispersed over a pretty large area.

I would guess the reactor is jacketed with sufficient
strength to preclude its destruction.

My guess is that NASA et al are just hoping for good fortune. Having a
reactor land from orbit intact in the middle of a city wouldn't be all
that desirable. ;-) So, my bet is on there being no good plan for
dealing with such a catastrophe *other* than wide dispersal of the nuclear
material or the luck of landing in the ocean. Not that *that* outcome is
desirable either...

Neil

"Larry Dighera" wrote in message
...

I would think that would be close to the bare minimum. I flew a fixed wing
hang glider on 10 HP for a while back in the 70s. A Manta Fledgling, and
it
was very underpowered. Maybe 100 fpm climb or so.


I would guess the rigid wing would have a higher L/D than a powered
parachute's 4:1, so it might require less power. Does that sound
correct in your experience?

Indeed, quite a bit less from my experience. I think my Fledge was supposed
to be around 10:1.

A technology I have not seen even mentioned in this
lengthy (but very good) thread is that of carbon nonotube
enhanced ultracapacitors, which have the promise of
the energy density of the latest lithium polymers,
but almost infinite discharge cycles and can be recharged
in seconds. What would make a whole heap of sense (to
me at least), would to develop an electric tow plane
based around this technology. Quiet, efficient, hardly
affected by density altitude, quick as refueling with
avgas when charges are needed, etc. This would get
our fleet of non-powered aircraft off the ground just
fine, without angering the encroaching land developments
and such. An efficient/viable electric towplane, that's
what we need. I'm sure other developments would stem
from it too of course.
Hats off to all people/groups considering alternatives
at this point, and down with the naysayers!
Paul Hanson


At 23:24 09 August 2007, Maxwell wrote:

'Larry Dighera' wrote in message
.. .

I would think that would be close to the bare minimum.
I flew a fixed wing
hang glider on 10 HP for a while back in the 70s. A
Manta Fledgling, and
it
was very underpowered. Maybe 100 fpm climb or so.


I would guess the rigid wing would have a higher L/D
than a powered
parachute's 4:1, so it might require less power.
Does that sound
correct in your experience?

Indeed, quite a bit less from my experience. I think
my Fledge was supposed
to be around 10:1.



"Do the usual, unusually well"--Len Niemi