Compressed air as fuel?

On Jun 26, 7:23 pm, Orval Fairbairn wrote:
In article .com,
Dancing Fingers wrote:

Hi Guys,
I remember years ago Kitplanes did a series on the potential for
batterry-powered aircraft. Recently, I watCHED Future Cars on the
Discovery channel and this guy had developed a car that ran on
compressed air. This seems like a more viable fuel for aircraft then
batteries. Has anybody looked into it?
just curious.
Chris

You ned either:
1. a very long hose attached to a compressor or

2. a filament-wound balonium/unobtanium air tank filled with air
compressed to 100,000,000 psi.

Otherwise, you just can't carry enough compressed air around to make a
practical vehicle.

The "Future Car" ranks right there along with Moller's "Skycar," in that
it is all vaporware.

Ah yes the "Skycar" Seems he has given up trying to scam people with
that. He is now touting it as a Ground Effect vehicle and still
showing it in operation on the tether only. A long thread is
currently running in rec.aviation.homebuilt.

Harry K

On Jul 12, 7:48 pm, Harry K wrote:
On Jun 26, 7:23 pm, Orval Fairbairn wrote:





In article .com,
Dancing Fingers wrote:

Hi Guys,
I remember years ago Kitplanes did a series on the potential for
batterry-powered aircraft. Recently, I watCHED Future Cars on the
Discovery channel and this guy had developed a car that ran on
compressed air. This seems like a more viable fuel for aircraft then
batteries. Has anybody looked into it?
just curious.
Chris

You ned either:
1. a very long hose attached to a compressor or

2. a filament-wound balonium/unobtanium air tank filled with air
compressed to 100,000,000 psi.

Otherwise, you just can't carry enough compressed air around to make a
practical vehicle.

The "Future Car" ranks right there along with Moller's "Skycar," in that
it is all vaporware.

Ah yes the "Skycar" Seems he has given up trying to scam people with
that. He is now touting it as a Ground Effect vehicle and still
showing it in operation on the tether only. A long thread is
currently running in rec.aviation.homebuilt.

Harry K- Hide quoted text -

- Show quoted text -

Ooops. I thought I was still over in alt.home.repair

Harry K

"Harry K" wrote in message
s.com...
The heat problem is not in getting rid of it. The problem is that
that heat was produced while compressing the air and is then thrown
away. Right there should be a clue as one of the major reasons why
and "air engine" is not an economicaly viable design. That heat costs
money and represents energy that cannot be recovered.

This was already explained to the OP, and seems to have made no impression.

Vaughn

Dancing Fingers wrote:

I certainly don't think that compressed air would power a airliner but
it might be viable for small commutter flights. It seems like the
heat issue would only be an issue on the ground, during refueling,
although cabin heat would be a challenge. I was really wondering if
anyone had ever calculated the energy per cubic foot compressed air
can hold, relative to gasoline, diesel and hydrogen. There's a new
engine being developed, the Quasiturbine, that would be perfect for
this application.
For what it's worth.
Chris


Not only is the energy density of the compressed air ridiculously low
and nearly impossible to utilize efficiently, but nearly all of the
alternative energy schemes require that the entire set of propellant be
carried. With traditional fuels, the oxidizer is collected as it is
used. Between 12 and 17 pounds of air is ingested for each pound of
fuel carried.

Harry K wrote:
snip

It is an extremely complicated design for a rotary engine
with little or no improvement over the original Mazda (IIRC) rotary
engine.

Wankel?

Dan, U.S. Air Force, retired

On Tue, 26 Jun 2007 14:28:14 -0700, Dancing Fingers
wrote:

Hi Guys,
I remember years ago Kitplanes did a series on the potential for
batterry-powered aircraft. Recently, I watCHED Future Cars on the
Discovery channel and this guy had developed a car that ran on
compressed air. This seems like a more viable fuel for aircraft then
batteries. Has anybody looked into it?

No matter how you describe it compressed air is not a fuel although it
can be used as a source of stored energy which is quite different. The
amount of energy you could store in compressed air is a tiny fraction
of what you can get from conventional, or even bio fuels. I doubt you
could build a 4 passenger plane capable of making it around the
pattern on compressed air let alone any thing larger. It takes a lot
of energy to compress the air and then you only get a portion of that
back. It's probably one of the most inefficient and energy hungry
systems tried.

Battery technology is making some tremendous strides in current
density, but they are heavy, dangerous, (The higher the current
density the more dangerous) and a problem when it comes time to
dispose of them. Even at their best they have only worked on very
light experimental aircraft and although they carry much more energy
than compressed air is capable of doing, they are still far inferior
to conventional fuel.


just curious.
Chris