Silent Flight: PV Powered Blimps

It's surprising there aren't more solar powered blimps for tours of
canyons. The forest service could use them to count big horn sheep and
other lildlife. If the weather was fair, wouldn't you like to take a
quiet ride in an airship? Maybe sneak up on a mule deer . . .

There's no question conventional PV would get a blimp going over 25
mph. Boeing's new 40% efficient PV would move an airship at 30 - 35
mph.

The first PV airship should be named the "Pronghorn."


Bret Cahill

In article .com,
"Bret Cahill" wrote:

It's surprising there aren't more solar powered blimps for tours of
canyons. The forest service could use them to count big horn sheep and
other lildlife. If the weather was fair, wouldn't you like to take a
quiet ride in an airship? Maybe sneak up on a mule deer . . .

There's no question conventional PV would get a blimp going over 25
mph. Boeing's new 40% efficient PV would move an airship at 30 - 35
mph.

The first PV airship should be named the "Pronghorn."


Bret Cahill

The solar cells to power it would consume a lot of its payload.

Orval Fairbairn wrote:
The solar cells to power it would consume a lot of its payload.

In the text "Airship Technology" Edited by Khoury and Gillett, Chapter 16,
"Solar Power" deals with design issues of solar powered airship proposals.

Using thin-film PV arrays and brushless DC motors, it states that:
"Potentially, the solar power system could weigh less than 10% of the gross
lift of the 22 tonne airship and would then be competitive in weight with
the conventional airship."

Jim Logajan wrote:
Orval Fairbairn wrote:
The solar cells to power it would consume a lot of its payload.

In the text "Airship Technology" Edited by Khoury and Gillett, Chapter 16,
"Solar Power" deals with design issues of solar powered airship proposals.

Using thin-film PV arrays and brushless DC motors, it states that:
"Potentially, the solar power system could weigh less than 10% of the gross
lift of the 22 tonne airship and would then be competitive in weight with
the conventional airship."

And if something other than silicon solar cells are used, the efficiency
can be much high. In 1981 I heard a talk by one John Fan who was
launching a company to make galium arsinide cells. I believe he could
get 10% conversion efficiency rather than 1 to 2% for Si .

On Sat, 13 Jan 2007 22:10:25 -0500, Stubby
wrote:

Jim Logajan wrote:
Orval Fairbairn wrote:
The solar cells to power it would consume a lot of its payload.

In the text "Airship Technology" Edited by Khoury and Gillett, Chapter 16,
"Solar Power" deals with design issues of solar powered airship proposals.

Using thin-film PV arrays and brushless DC motors, it states that:
"Potentially, the solar power system could weigh less than 10% of the gross
lift of the 22 tonne airship and would then be competitive in weight with
the conventional airship."

And if something other than silicon solar cells are used, the efficiency
can be much high. In 1981 I heard a talk by one John Fan who was
launching a company to make galium arsinide cells. I believe he could
get 10% conversion efficiency rather than 1 to 2% for Si .

We're up to about 18% for 3-bandgap Si, although SunPower's getting
21% with special wafers that have a long enough minority-carrier
lifetime to allow the collection grid to be placed on the backside of
the wafer. Amorphous panels produced using a web-printing process
seem to be getting around 15%, enough for one of the oil companies to
be using them to power one of their oilfields on the patch down by
Bakersfield.

Don

"Bret Cahill" wrote in message
oups.com...
It's surprising there aren't more solar powered blimps for tours of
canyons. The forest service could use them to count big horn sheep and
other lildlife. If the weather was fair, wouldn't you like to take a
quiet ride in an airship? Maybe sneak up on a mule deer . . .

There's no question conventional PV would get a blimp going over 25
mph.

There is considerable question (in my mind at least) that conventional PV
could get a blimp going at that speed, you are talking several hundred HP yes?
How many square yards of PV would that take? Remember that only a portion of
the cells would be receiving full sunlight, so multiply the PV area you need by
at least two. Remember that PV cells have significant weight, would the thing
fly?

Boeing's new 40% efficient PV would move an airship at 30 - 35
mph.

There is a little problem here, you would need to figure out how to place a
giant lense over your blimp. Those are concentrating solar cells. From the
article: "Using concentrated sunlight, Spectrolab demonstrated the ability of a
photovoltaic cell to convert 40.7 percent of the sun's energy into electricity."

Vaughn




The first PV airship should be named the "Pronghorn."


Bret Cahill

Seen this site?

http://www.lockheedmartin.com/wms/fi...p=fec&ci=14477

Don

Seen this site?

http://www.lockheedmartin.com/wms/fi...p=fec&ci=14477

Not until just now.

They need to apply that technology to something fun. It would be like
those hot air balloon rides except you could go to more places faster
more often and with greater safety.

You could have conventional power backup for emergencies or getting
across town but most of the time you'ld be very quiet.

This is the best way for most people to see charismatic wild animals.

Most animals scatter when a hiker is even a mile away.


Bret Cahill

"Bret Cahill" wrote in message
oups.com...
It's surprising there aren't more solar powered blimps for tours of
canyons.

The last time I checked, a canyon is about the worst place in the world for
a blimp. First, it is a confined space. Blimps are not particularly
maneuverable, and a confined space requires maneuverability. Second, canyons
have swirling winds. Blimps are pretty tough to control in those conditions.
Third, canyons have walls, which cast shadows. Shadows put a damper on solar
cells.

The forest service could use them to count big horn sheep and
other lildlife. If the weather was fair, wouldn't you like to take a
quiet ride in an airship? Maybe sneak up on a mule deer . . .

There's no question conventional PV would get a blimp going over 25
mph. Boeing's new 40% efficient PV would move an airship at 30 - 35
mph.

Right. Until a cloud blew over (or you flew into the shadow of a canyon
wall). Then you'd need a hell of a lot of battery capacity (and weight) to
power your blimp.


The first PV airship should be named the "Pronghorn."


Bret Cahill

Bret Cahill wrote:
There's no question conventional PV would get a blimp going over 25
mph.

Maybe. Per http://www.goodyearblimp.com/faqs/fa...struction.html :

"The GZ-20A size blimps (Spirit of Goodyear; Spirit of Innovation; Spirit
of America) are 192 feet long, 55 feet in diameter, and 59.5 feet high,
with 202,700 cubic feet of helium and a gross weight of 12,840 lbs."

"The GZ-20's carry two fuel injected Continental I0-360's, producing 210
horsepower each."

"The usual cruising speed is thirty-five miles per hour in a zero wind
condition; all-out top speed is fifty-three miles per hour on the
GZ20."

Jane's "Encyclopedia of Aviation" (ISBN 0-517-10316-8), p. 425, says
that the Goodyear "Mayflower" (built 1978) has a gross volume of
202,700 ft^2, so I am assuming it's the same size as the current blimps.
Jane's also says that the Mayflower has "an envelope surface area of
2,006 m^2 (21,600 sq ft)". Jane's also cites the twin 210 hp IO-360
engines.

So, 420 hp is 313 kw. If your motors are 90% efficient, you need to
deliver 345 kw to the motors. If you covered the entire surface of the
envelope with solar cells, you'd need to _average_ 0.172 kW / m^2 to get
that much power. If you assume that everything is great and you're
getting 1 kW / m^2 coming in, that's 17.2% efficiency. I would guess
that at most half of the solar cells would actually be illuminated, so
that means you need to average 0.344 kW / m^2 or 34.4% to get that much
power. As has been noted, the "40%" cells require a concentrator (lens)
in front of them to get that efficiency. Spectrolab claims their TASC
cells ( http://www.spectrolab.com/prd/terres/tasc-main.htm ), which
don't need a concentrator, are up to 30% efficient.

On the weight side... Googling around says that a Continental IO-360
weighs something like 300 lbs. I have no idea what the fuel burn is
like in a blimp, but for grins let's say there is at least enough fuel
for two hours at 10 gal/hr/engine, or 240 lbs. So dropping all of that
stuff gains you 840 lbs.

Spectrolab says one of their cells is 2.277 cm^2 and weighs 0.234 g.
To cover the entire skin of the blimp, you'd need about 8.8 million
of these cells, or about 2060 kg or 4050 lbs. So you're up about
3210 lbs (25% over gross) and you haven't even strapped on any
electric motors yet.

You might be able to make it work with a smaller blimp - you'd need less
power, but you'd also have less surface area for mounting the cells.

Matt Roberds