Electrically Powered Ultralight Aircraft

"Larry Dighera" wrote in message
...

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.


They might be lightweight and strong, but I think they would be far too
inefficent. All the canopies I have been around have had a very poor L/D
when compared to something like a sailplane.

I always assumed they were so popular because they were so strong, portable
and quick to set-up. But I'm thinking their fuel mileage would be very poor.

On Mon, 6 Aug 2007 20:43:47 -0500, "Maxwell" wrote
in :


"Larry Dighera" wrote in message
.. .

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.


They might be lightweight and strong, but I think they would be far too
inefficent. All the canopies I have been around have had a very poor L/D
when compared to something like a sailplane.

The web site below mentions an L/D of four to one.

I always assumed they were so popular because they were so strong, portable
and quick to set-up. But I'm thinking their fuel mileage would be very poor.

I would be more interested in the specific horsepower required to
operate powered parachutes than their efficiency. This web site
mentions 50 HP to 65 HP:
http://www.all-about-powered-parachutes.com/faq.htm

There is a 14 HP Powered Paraglider (PPG) engine offered he
http://www.poweredparasports.com/Par...#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.

If a 14 HP electric propulsion system weighing 46 lbs could be
constructed, apparently it would permit the use of PPGs by pilots up
to 180 lbs.

Larry Dighera wrote:

There is a 14 HP Powered Paraglider (PPG) engine offered he
http://www.poweredparasports.com/Par...#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.

If a 14 HP electric propulsion system weighing 46 lbs could be
constructed, apparently it would permit the use of PPGs by pilots up
to 180 lbs.

Yeah sure, but its not practical for anything but an hour or two of
playing around on a Saturday afternoon. You can't carry anything or
go anywhere to accomplish anything except maybe brag about how little
energy you used goofing off for a few hours. Its like blasting around
on a jet ski... basically a total waste of energy without producing
any useful work or benefit to mankind.

Don't get me wrong, I love new technology and if you can afford to
spend money on extra curricular stuff like aimlessley cruising about
in solar powered paragliders or jet skis fine. But don't think you
are doing the world a big favor because you used something other
than gasoline to power it.

On Wed, 08 Aug 2007 01:05:16 GMT, kontiki
wrote in :

Yeah sure, but its not practical for anything but an hour or two of
playing around on a Saturday afternoon.

I'll bet you would have said something similar to the Wrights. :-)
Where's you vision, man?

Now here's an electrically powered aircraft that really is playing
around: http://www.nesail.com/videos/jazz.wmv

"kontiki" wrote

Yeah sure, but its not practical for anything but an hour or two of
playing around on a Saturday afternoon.

Flight training in the pattern is an obvious first application.

"Larry Dighera" wrote in message
...

I would be more interested in the specific horsepower required to
operate powered parachutes than their efficiency. This web site
mentions 50 HP to 65 HP:
http://www.all-about-powered-parachutes.com/faq.htm

That's what I have seen. We even have a tandem trike locally that uses a
Subaru.


There is a 14 HP Powered Paraglider (PPG) engine offered he
http://www.poweredparasports.com/Par...#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.

If a 14 HP electric propulsion system weighing 46 lbs could be
constructed, apparently it would permit the use of PPGs by pilots up
to 180 lbs.

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.

On Wed, 8 Aug 2007 01:12:26 -0500, "Maxwell" wrote
in :


"Larry Dighera" wrote in message
.. .

There is a 14 HP Powered Paraglider (PPG) engine offered he
http://www.poweredparasports.com/Par...#Jet%20Details
They also state that the weight of their engines ranges from 46 lbs.
to 68 lbs.

If a 14 HP electric propulsion system weighing 46 lbs could be
constructed, apparently it would permit the use of PPGs by pilots up
to 180 lbs.

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?

"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.

On Tue, 07 Aug 2007 14:58:07 GMT, Larry Dighera
wrote:

If a 14 HP electric propulsion system weighing 46 lbs could be
constructed, apparently it would permit the use of PPGs by pilots up
to 180 lbs.

A PPG is a LOT more efficient than a powered parachute (PPC), but
still far less efficient than a rigid wing. Still, several electric
PPG's have been flown. The primary goal here is noise and vibration
reduction, a worthy goal when the engine is strapped to the pilot's
back.

The major problem is the weight of the batteries, still far heavier
than gasoline. Also the lithium polymer batteries used are still
quite expensive (over $10,000 for enough for a half hour flight) and
somewhat dangerous (sort them out and they can explode!)

-Dana

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"Dana wrote
The major problem is the weight of the batteries, still far heavier
than gasoline. Also the lithium polymer batteries used are still
quite expensive (over $10,000 for enough for a half hour flight) and
somewhat dangerous (sort them out and they can explode!)

Damn straight! No way am I going to strap a bunch of lithium polymer
batteries to my butt.

Some of the newer Lithium iron cells, maybe, but they also cost a LOT more.

Still, electric flight, like many have said, still have a way to go.
--
Jim in NC