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SoLong Solar-Electric UAV 48 hour flight



 
 
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  #1  
Old October 19th 05, 07:01 PM
Larry Dighera
external usenet poster
 
Posts: n/a
Default SoLong Solar-Electric UAV 48 hour flight


The era of silent, zero emission flight is upon us. Never run out of
fuel again.


http://www.acpropulsion.com/whats_new.htm
AC Propulsion SoLong UAV Flies for 48 Hours on Sunlight
Two Nights Aloft Opens New Era of Sustainable Flight

Desert Center, California
Friday, June 3, 2005

An airplane that never needs to land might sound impossible, but it is
closer to reality now that AC Propulsion’s SoLong has completed a
two-day flight fueled only by energy from the sun. SoLong took off at
4:08 PM, Wednesday, June 1 from the sun-baked runway at Desert Center
Airport just east of Eagle Mountain in California’s Colorado desert.
It remained aloft until Friday when it skidded to a stop at 4:24 PM
after 48 hours and 16 minutes in the air. During that time it
had fully recharged its batteries during the day and then flown
through the night on battery power. Twice. Nothing, save the flagging
energy of its pilots on the ground, kept the SoLong from flying for
another two days, or ten, or a whole month.

The SoLong is an electric-powered UAV (unmanned aerial vehicle) that
collects solar energy from photo-voltaic arrays laminated into its
wings. It uses energy so efficiently that it can gather enough energy
during the day to keep flying all night. Remaining aloft for two
nights is the milestone for sustainable flight. One night is possible
just by discharging the batteries, but two or more nights means that
the plane has to fully recoup and store the energy used at night while
flying in the sunlight the following day. Once that is achieved, the
cycle can repeat continually, and keep the plane airborne
indefinitely.

“We flew 24 hours in April”, said Alan Cocconi, SoLong’s creator and
chief pilot, “but we split the night in two, flying midnight to
midnight. That was a warm up for this flight. It showed us that we
were getting enough solar energy during the day but we didn’t have
quite enough battery to takes us through the night. Just last week I
got new Sanyo high-capacity Li Ion cells. That made the difference”
Cocconi is founder, Chairman, and Chief Engineer of AC Propulsion,
Inc., a San Dimas, CA-based R&D shop that specializes in
high-efficiency electric propulsion.

Efficiency is the key to SoLong’s success. The power system includes a
high efficiency electric motor driven by a patented split-phase power
controller developed by AC Propulsion. The controller gives high power
for takeoff and maintains high efficiency even at the low power levels
used in steady flight. A variable pitch propeller allows tuning for
maximum propulsion efficiency under varying flight conditions. Solar
cells that convert solar energy to electricity with an efficiency of
20% are controlled by proprietary peak power tracking software that
makes best use of the photovoltaic energy. Much of that energy goes to
charge the Li-ion battery pack that powers the motor and a separate
pack for the controls and communications. With a charge discharge
cycle efficiency over 95%, the Li-ion batteries do not squander the
bounty from the solar cells, and at 220 Wh/kg, the Sanyo cells pack a
lot of energy without much weight. Still, the battery makes up 44% of
the aircraft’s total weight because the air frame uses efficient
structure and composite materials so it is light but still strong
enough to withstand 30 mph winds. The 6 servos that move the control
surfaces use special electronics that were developed for this mission
by AC Propulsion to reduce power consumption and to extend durability.
“Every system and part on the SoLong was designed to minimize weight
and drag, and maximize efficiency” Cocconi stated. He continued, “of
course that is true of just about every airplane, but with the SoLong
the entire mission depends on efficiency. We had to push everything to
the limit.”

That included the pilots who flew SoLong from the 5 ft x 8 ft trailer
that serves as SoLong’s ground station. Led by Cocconi, the team of
crack radio-control and hang glider pilots took turns monitoring
flight conditions from the twenty three channels of telemetry plus GPS
navigation and video downlink data available in the ground station.
The pilot’s job is to find updrafts, avoid downdrafts, and make
judicious use of the battery power to maintain altitude and find “good
air” that will lift the plane. The energy budget requires riding
thermals with the motor off as much as possible during the day. With
the motor off, the entire output from the solar wings goes into the
battery. The energy margins are so thin, and the weather so dauntingly
capricious that the pilot must focus intently, always trying to bank
energy, either as battery charge or altitude, that can be drawn upon
to get the plane out of trouble when the air turns bad.

After 46 hours, with the critical achievement of two nights flown
already in the bag, the air did turn bad. In bright clear skies,
SoLong flew into an invisible but huge mass of down rushing air that
seemed inescapable no matter which direction she flew. Sinking at 5
meters per second even full power was not sufficient to check the
descent, SoLong’s altitude reserve diminished rapidly. An abortive
early landing seemed a possibility until Cocconi, drawing on 30 years
of piloting experience, determination borne of exhaustion, and perhaps
some good luck too, found less treacherous air at low altitude. The
atmospheric disturbance lasted a total of 20 minutes, and the SoLong
was restored on a course of energy equilibrium.

The first mission of any flight is to land the plane safely. This is
no less true because the SoLong’s pilots remain on the ground. SoLong
represents 4 years of work by Alan Cocconi to develop light, strong,
and efficient aircraft, control, and propulsion systems. SoLong
herself took him the more than a year to build and test. The funding
was his own. The consequences of pilot error or system failure would
be devastating. But still there is no margin to make the plane
stronger than it has to be, or easier to fly, or to add a few extra
batteries. The balance points between strength and weight, between
stability and drag, between energy and power make a very fine line. On
one side of that line are airplanes that cannot fly through the night.
On the other side are airplanes that fall from the sky. Many efforts,
some extremely well-funded, have tried to find the balance that will
keep a solar-powered airplane plane in the air for two consecutive
nights. Until today, not one had found it.

By three o’clock with good air and full batteries, the 48th hour
became a formality to make a numerical milestone – two full days in
the air. The network film crew arrived to record SoLong’s historic
landing and the jubilation, showing through the fatigue, on the
pilots’ faces. Steve Bellknap, Jerry Bridgeman, David Fee, “RCDave”
Freund, Chuck Grim and Steve Neu had all ably assisted Alan Cocconi in
piloting the SoLong over its record setting flight. They had helped
accomplish something never done before, and in doing it the first
time, they made it easier to do the next time and then again, and
again. Now, it is within the realm of reality that airplanes flying
sustainably on rays from the sun may become commonplace, may become
useful tools in the service of humans and their environment.

SoLong Specifications
Wingspan 4.75m
Wing area 1.50 m2
Mass 12.6 kg
Power sources 120 Sanyo 18650 Li-Ion cells
76 Sunpower A300 solar cells
Solar panel nom. power 225 W
Battery mass 5.50 kg
Max motor power 800W
Min electrical power for level flight 95W
Stored energy 1200Wh
Speed range 27 to 50 mph
Max. climb rate 2.5 m/s
Control and telemetry range 8,000 m


Contact:
Ads
  #2  
Old October 20th 05, 02:47 AM
Ash Wyllie
external usenet poster
 
Posts: n/a
Default SoLong Solar-Electric UAV 48 hour flight

Larry Dighera opined

I ran across this flight earlier. there is less here than meets the eye. During
the day the pilots, all of whom are experienced RC glider pilots, used thermals
so all the solar power collected could be used to charge the batteries for the
night time.

If the aircraft had had to circle over the same spot, the flight would have
been much shorter.

Solar cell efficiency and battery storage density need to at least double before
true stay aloft forever is going to happen.

The era of silent, zero emission flight is upon us. Never run out of
fuel again.



http://www.acpropulsion.com/whats_new.htm
AC Propulsion SoLong UAV Flies for 48 Hours on Sunlight
Two Nights Aloft Opens New Era of Sustainable Flight


Desert Center, California
Friday, June 3, 2005


An airplane that never needs to land might sound impossible, but it is
closer to reality now that AC Propulsion’s SoLong has completed a
two-day flight fueled only by energy from the sun. SoLong took off at
4:08 PM, Wednesday, June 1 from the sun-baked runway at Desert Center
Airport just east of Eagle Mountain in California’s Colorado desert.
It remained aloft until Friday when it skidded to a stop at 4:24 PM
after 48 hours and 16 minutes in the air. During that time it
had fully recharged its batteries during the day and then flown
through the night on battery power. Twice. Nothing, save the flagging
energy of its pilots on the ground, kept the SoLong from flying for
another two days, or ten, or a whole month.


The SoLong is an electric-powered UAV (unmanned aerial vehicle) that
collects solar energy from photo-voltaic arrays laminated into its
wings. It uses energy so efficiently that it can gather enough energy
during the day to keep flying all night. Remaining aloft for two
nights is the milestone for sustainable flight. One night is possible
just by discharging the batteries, but two or more nights means that
the plane has to fully recoup and store the energy used at night while
flying in the sunlight the following day. Once that is achieved, the
cycle can repeat continually, and keep the plane airborne
indefinitely.


“We flew 24 hours in April”, said Alan Cocconi, SoLong’s creator and
chief pilot, “but we split the night in two, flying midnight to
midnight. That was a warm up for this flight. It showed us that we
were getting enough solar energy during the day but we didn’t have
quite enough battery to takes us through the night. Just last week I
got new Sanyo high-capacity Li Ion cells. That made the difference”
Cocconi is founder, Chairman, and Chief Engineer of AC Propulsion,
Inc., a San Dimas, CA-based R&D shop that specializes in
high-efficiency electric propulsion.


Efficiency is the key to SoLong’s success. The power system includes a
high efficiency electric motor driven by a patented split-phase power
controller developed by AC Propulsion. The controller gives high power
for takeoff and maintains high efficiency even at the low power levels
used in steady flight. A variable pitch propeller allows tuning for
maximum propulsion efficiency under varying flight conditions. Solar
cells that convert solar energy to electricity with an efficiency of
20% are controlled by proprietary peak power tracking software that
makes best use of the photovoltaic energy. Much of that energy goes to
charge the Li-ion battery pack that powers the motor and a separate
pack for the controls and communications. With a charge discharge
cycle efficiency over 95%, the Li-ion batteries do not squander the
bounty from the solar cells, and at 220 Wh/kg, the Sanyo cells pack a
lot of energy without much weight. Still, the battery makes up 44% of
the aircraft’s total weight because the air frame uses efficient
structure and composite materials so it is light but still strong
enough to withstand 30 mph winds. The 6 servos that move the control
surfaces use special electronics that were developed for this mission
by AC Propulsion to reduce power consumption and to extend durability.
“Every system and part on the SoLong was designed to minimize weight
and drag, and maximize efficiency” Cocconi stated. He continued, “of
course that is true of just about every airplane, but with the SoLong
the entire mission depends on efficiency. We had to push everything to
the limit.”


That included the pilots who flew SoLong from the 5 ft x 8 ft trailer
that serves as SoLong’s ground station. Led by Cocconi, the team of
crack radio-control and hang glider pilots took turns monitoring
flight conditions from the twenty three channels of telemetry plus GPS
navigation and video downlink data available in the ground station.
The pilot’s job is to find updrafts, avoid downdrafts, and make
judicious use of the battery power to maintain altitude and find “good
air” that will lift the plane. The energy budget requires riding
thermals with the motor off as much as possible during the day. With
the motor off, the entire output from the solar wings goes into the
battery. The energy margins are so thin, and the weather so dauntingly
capricious that the pilot must focus intently, always trying to bank
energy, either as battery charge or altitude, that can be drawn upon
to get the plane out of trouble when the air turns bad.


After 46 hours, with the critical achievement of two nights flown
already in the bag, the air did turn bad. In bright clear skies,
SoLong flew into an invisible but huge mass of down rushing air that
seemed inescapable no matter which direction she flew. Sinking at 5
meters per second even full power was not sufficient to check the
descent, SoLong’s altitude reserve diminished rapidly. An abortive
early landing seemed a possibility until Cocconi, drawing on 30 years
of piloting experience, determination borne of exhaustion, and perhaps
some good luck too, found less treacherous air at low altitude. The
atmospheric disturbance lasted a total of 20 minutes, and the SoLong
was restored on a course of energy equilibrium.


The first mission of any flight is to land the plane safely. This is
no less true because the SoLong’s pilots remain on the ground. SoLong
represents 4 years of work by Alan Cocconi to develop light, strong,
and efficient aircraft, control, and propulsion systems. SoLong
herself took him the more than a year to build and test. The funding
was his own. The consequences of pilot error or system failure would
be devastating. But still there is no margin to make the plane
stronger than it has to be, or easier to fly, or to add a few extra
batteries. The balance points between strength and weight, between
stability and drag, between energy and power make a very fine line. On
one side of that line are airplanes that cannot fly through the night.
On the other side are airplanes that fall from the sky. Many efforts,
some extremely well-funded, have tried to find the balance that will
keep a solar-powered airplane plane in the air for two consecutive
nights. Until today, not one had found it.


By three o’clock with good air and full batteries, the 48th hour
became a formality to make a numerical milestone – two full days in
the air. The network film crew arrived to record SoLong’s historic
landing and the jubilation, showing through the fatigue, on the
pilots’ faces. Steve Bellknap, Jerry Bridgeman, David Fee, “RCDave”
Freund, Chuck Grim and Steve Neu had all ably assisted Alan Cocconi in
piloting the SoLong over its record setting flight. They had helped
accomplish something never done before, and in doing it the first
time, they made it easier to do the next time and then again, and
again. Now, it is within the realm of reality that airplanes flying
sustainably on rays from the sun may become commonplace, may become
useful tools in the service of humans and their environment.


SoLong Specifications
Wingspan 4.75m
Wing area 1.50 m2
Mass 12.6 kg
Power sources 120 Sanyo 18650 Li-Ion cells
76 Sunpower A300 solar cells
Solar panel nom. power 225 W
Battery mass 5.50 kg
Max motor power 800W
Min electrical power for level flight 95W
Stored energy 1200Wh
Speed range 27 to 50 mph
Max. climb rate 2.5 m/s
Control and telemetry range 8,000 m



Contact:



-ash
Cthulhu in 2005!
Why wait for nature?

  #3  
Old October 20th 05, 04:19 PM
Larry Dighera
external usenet poster
 
Posts: n/a
Default SoLong Solar-Electric UAV 48 hour flight

On 19 Oct 2005 20:47:6 -0500, "Ash Wyllie" wrote in
::

Larry Dighera opined

I ran across this flight earlier. there is less here than meets the eye. During
the day the pilots, all of whom are experienced RC glider pilots, used thermals
so all the solar power collected could be used to charge the batteries for the
night time.


Where did you get that bit of information?

If the aircraft had had to circle over the same spot, the flight would have
been much shorter.


Agreed, if atmospheric convective lift was indeed used to sustain the
aircraft during daylight hours. While it's still solar power, but not
photovoltaic, it would not be of practical use for sustaining the
aircraft indefinitely.

Solar cell efficiency and battery storage density need to at least double before
true stay aloft forever is going to happen.


How did you calculate that factor?

Triple-Junction Gallium Arsenide solar cells with efficiencies of
about 31% under terrestrial conditions are the most efficient of which
I am awa

http://www.boeing.com/news/releases/...r_030725s.html

HIGH-EFFICIENCY SOLAR CELLS
July 25, 2003
News Release
A Spectrolab, Inc. associate places wafers on platters for epitaxial
growth. The wafers are then fabricated into solar cells that will be
capable of an unprecedented 36.9 percent efficiency in converting
sunlight to energy when exposed to concentrated sunlight. Spectrolab,
a Boeing subsidiary, uses these state-of-the-art photovoltaic solar
cells in concentrator modules of various sizes and power-generating
capabilities. Several modules are already being tested throughout the
world by photovoltaic concentrator system manufacturers. These
Spectrolab products could be part of terrestrial systems that
dramatically reduce the cost of generating electricity from solar
energy.

Contact:
Spectrolab, Inc.
Public Relations Department
P.O. Box 92919 (S10/S323)
Los Angeles, CA 90009
Public Relations (310) 364-6363
www.boeing.com/satellite
http://www.spectrolab.com/

Triple-Junction with a minimum average efficiency of 26.5%) developed
and manufactured at Spectrolab. Ultra-Triple-Junction solar cells,
with a minimum average efficiency of 28.3%, are now in production

http://www.spectrolab.com/stores/
Spectrolab has a variety of solar cells in inventory and available in
limited quantities. Some of these solar cells are rejects from the
production line, others are surplus material from space programs. All
are limited to small batches and sold on a first-come first-serve
basis.

Improved Triple-Junction Gallium Arsenide with efficiencies of about
26.8% (AM0) or about 31% under terrestrial conditions.


Some of these solar cells are in excellent condition while others are
functionally limited to a certain type of application. Call Mike
Kalachian at (818) 898-7540 or send an e-mail to: Mike Kalachian to
inquire about what is currently available.


If you are ready to place an order, please download the appropriate
form, fill it out appropriately and fax it to Mr. Kalachian's
attention at: (818) 361-5102

The era of silent, zero emission flight is upon us. Never run out of
fuel again.



http://www.acpropulsion.com/whats_new.htm
AC Propulsion SoLong UAV Flies for 48 Hours on Sunlight
Two Nights Aloft Opens New Era of Sustainable Flight

[...]

  #4  
Old October 20th 05, 09:46 PM
Ash Wyllie
external usenet poster
 
Posts: n/a
Default SoLong Solar-Electric UAV 48 hour flight

Larry Dighera opined

On 19 Oct 2005 20:47:6 -0500, "Ash Wyllie" wrote in
::


Larry Dighera opined

I ran across this flight earlier. there is less here than meets the eye.
During the day the pilots, all of whom are experienced RC glider pilots,
used thermals so all the solar power collected could be used to charge the
batteries for the night time.


Where did you get that bit of information?


Aviation Wek and Space Technologies, IIRC. I probably didn't keep that issue.

If the aircraft had had to circle over the same spot, the flight would have
been much shorter.


Agreed, if atmospheric convective lift was indeed used to sustain the
aircraft during daylight hours. While it's still solar power, but not
photovoltaic, it would not be of practical use for sustaining the
aircraft indefinitely.


Solar cell efficiency and battery storage density need to at least double
before true stay aloft forever is going to happen.


How did you calculate that factor?


It was in the article.

Triple-Junction Gallium Arsenide solar cells with efficiencies of
about 31% under terrestrial conditions are the most efficient of which
I am awa


http://www.boeing.com/news/releases/...r_030725s.html


HIGH-EFFICIENCY SOLAR CELLS
July 25, 2003
News Release
A Spectrolab, Inc. associate places wafers on platters for epitaxial
growth. The wafers are then fabricated into solar cells that will be
capable of an unprecedented 36.9 percent efficiency in converting
sunlight to energy when exposed to concentrated sunlight. Spectrolab,
a Boeing subsidiary, uses these state-of-the-art photovoltaic solar
cells in concentrator modules of various sizes and power-generating
capabilities. Several modules are already being tested throughout the
world by photovoltaic concentrator system manufacturers. These
Spectrolab products could be part of terrestrial systems that
dramatically reduce the cost of generating electricity from solar
energy.


Contact:
Spectrolab, Inc.
Public Relations Department
P.O. Box 92919 (S10/S323)
Los Angeles, CA 90009
Public Relations (310) 364-6363
www.boeing.com/satellite
http://www.spectrolab.com/

Triple-Junction with a minimum average efficiency of 26.5%) developed
and manufactured at Spectrolab. Ultra-Triple-Junction solar cells,
with a minimum average efficiency of 28.3%, are now in production


http://www.spectrolab.com/stores/
Spectrolab has a variety of solar cells in inventory and available in
limited quantities. Some of these solar cells are rejects from the
production line, others are surplus material from space programs. All
are limited to small batches and sold on a first-come first-serve
basis.


Improved Triple-Junction Gallium Arsenide with efficiencies of about
26.8% (AM0) or about 31% under terrestrial conditions.



Some of these solar cells are in excellent condition while others are
functionally limited to a certain type of application. Call Mike
Kalachian at (818) 898-7540 or send an e-mail to: Mike Kalachian to
inquire about what is currently available.


If you are ready to place an order, please download the appropriate
form, fill it out appropriately and fax it to Mr. Kalachian's
attention at: (818) 361-5102


Weight and flexibility arealso important as well.

It's not that the goal is impossible, just a little bit off.

The era of silent, zero emission flight is upon us. Never run out of
fuel again.



http://www.acpropulsion.com/whats_new.htm
AC Propulsion SoLong UAV Flies for 48 Hours on Sunlight
Two Nights Aloft Opens New Era of Sustainable Flight

[...]



-ash
Cthulhu in 2005!
Why wait for nature?

  #5  
Old October 21st 05, 07:38 AM
Larry Dighera
external usenet poster
 
Posts: n/a
Default SoLong Solar-Electric UAV 48 hour flight

On 20 Oct 2005 15:46:26 -0500, "Ash Wyllie" wrote in
::


Larry Dighera opined

On 19 Oct 2005 20:47:6 -0500, "Ash Wyllie" wrote in
::


Larry Dighera opined

I ran across this flight earlier. there is less here than meets the eye.
During the day the pilots, all of whom are experienced RC glider pilots,
used thermals so all the solar power collected could be used to charge the
batteries for the night time.


Where did you get that bit of information?


Aviation Wek and Space Technologies, IIRC. I probably didn't keep that issue.


Thanks for the pointer. There is a lot more information in that
article:

http://www.aviationweek.com/avnow/se...2F06275p01.xml
SoLong Solar-Powered Drone Stays Aloft for 48 Hr.
By Michael A. Dornheim
06/26/2005 03:05:12 PM


PERPETUAL MOTION

People have long dreamed of perpetual flight, and the tipping point
was reached earlier this month when a solar-powered drone stayed aloft
for 48 hr.

It showed that enough energy could be stored during the day to fly the
aircraft at night, for at least several days. All that's needed are
small, near-term improvements in technology to tip this feat into
flights lasting reliably for months.

One application, albeit much harder, would be as a radio tower in the
sky, giving line-of-sight access across a city.

AC Propulsion, a small research company in San Dimas, Calif., made the
flight after several years of dedicated effort by its founder, Alan G.
Cocconi. Semi-perpetual flight has been sought after for years, most
notably by AeroVironment and its solar-powered Helios drone with fuel
cell storage (AW&ST Feb. 28, 2000, p. 58). More recently the company
has been working on a pure fuel cell week-long flier (see p. 52).

But AC Propulsion used lithium-ion laptop computer batteries for
storage instead of fuel cells, as well as an overall simpler approach,
to become the first to fly through two full nights under solar power
(AW&ST Sept. 15, 2003, p. 66). It's a friendly rivalry, as Cocconi has
been an important collaborator on several AeroVironment projects.

The aircraft is called SoLong and is a powered sailplane of Cocconi's
own design with solar cells built into the wing. It weighs 28.2 lb.,
has a 15.6-ft. span, and takes off with its own 1-hp. motor from a
wheeled dolly. The control system includes a sophisticated autopilot
with inertial, barometric and GPS references; a television camera
gives an over-the-nose pilot's-eye view. It's easy to dismiss the
project due to the small size of the aircraft and the 5 X 8-ft. ground
station, but the flight system is equal to those many times larger.

Still, Cocconi is quick to point out the limitations of the
achievement. There was no mission flexibility. The six skilled glider
pilots were focused only on soaring to keep the motor off most of the
day in order to put more solar power into the battery. No payload was
carried, though the TV camera is good for simple reconnaissance. A
mostly cloud-free sky on a long summer day and reasonable weather were
required.

But the flight probably could have lasted a third night, and perhaps a
fourth and a fifth. Cocconi landed after 48 hr. 16 min. because the
pilots were exhausted, not because the battery was low on juice. The
flight started at 4:08 p.m. PDT June 1 with a charged battery; two
days later at that time, the charge was down less than 5%. The landing
was made at 4:24 p.m. at the Desert Center airport operating base in
southeastern California.

SoLong is reasonably tough. It has been flown in 30-mph. winds and
desert turbulence, and has landed at night with the aid of a pair of
1/2-watt LED "landing lights" in the wing and a set of $2 runway edge
lights. The aircraft has flown more than 250 hr. in 60+ flights
without being seriously damaged--not bad for a drone.

AC Propulsion's multiday flight effort was self-funded and hence less
ambitious than AeroVironment's, which was covered by
multimillion-dollar contracts from NASA. Helios performance was
challenging because it operated in the thin air at 50,000 ft., where
more power is needed to loiter because of the high true airspeeds. The
benefits of that altitude are that it is above the clouds and the
winds are fairly low. Cocconi has an easier job loitering near sea
level, though his drone has to be stronger to withstand the frequent
turbulence there. Helios could carry some payload, and SoLong hasn't.
Helios' regenerative fuel cells were a major headache, and
AeroVironment and its contractors were not able to make them work.
SoLong's battery has less energy per pound--but it works. Helios was
destroyed in a crash in June 2003 (AW&ST Sept. 27, 2004, p. 59).

Rather than trying to do everything at once, Cocconi decided to focus
on the simplest path to multi-day flight, then build from there. He
estimates he spent $20,000-30,000 developing SoLong during a two-year
period, the majority of it full-time.

Key parameters for endurance are the energy density of the batteries,
the efficiency of the solar cells, and other efficiencies such as
round-trip battery storage and motor economy at loiter thrust. These
are on top of the usual parameters like lift-to-drag ratio, structural
weight and propeller efficiency.

Technology is improving in two key areas--the solar cells and the
batteries. Cocconi made the first 24-hr. flight here with SoLong on
Apr. 21-22, comprising two half-nights (AW&ST May 2, p. 19). The
100-cell, 800 watt-hr. battery was not quite big enough for a full
night and could not absorb all the day's solar energy. It used LG Chem
18650-size lithium-ion laptop cells storing 185 watt-hr. per kilogram.
In late May, Cocconi received Sanyo 18650 cells that could hold 214
watt-hr./kg., a 15% improvement. That, and increasing the battery to
120 cells, tipped performance to the current edge of being barely
capable of multi-day flights. The pace of battery improvement has
indeed been rapid.

SoLong is now fitted with Sunpower A300 single-crystal silicon solar
cells about 20% efficient. Each wing has a series string of 38 cells
and they cover a total of about 13 sq. ft. producing a nominal 225
watts. They weigh about 2.3 lb. Bending the thin silicon cells to fit
the wing contour is tricky and Cocconi has devised techniques to avoid
breaking them. "It's like bending a 5-in. square of microscope slide
glass," he says.

Right now, 28% efficient space-grade cells are available, making 40%
more power, but cost about 100 times as much. Covering the wing with
them would cost about $150,000, Cocconi says. But that boost in power,
along with the next generation of laptop batteries, would make SoLong
a no-brainer multi-day airplane with no glider soaring required. Solar
cell prices can only go down, and the reality of this craft is close.

SoLong was recently modified to include a variable-pitch propeller,
and inflight tuning has gained about 10% propeller efficiency. A load
cell in the motor mounts, cannibalized from a postal scale, sends
real-time thrust readings back to the ground. Pitch is automatically
scheduled in flight but can be manually tweaked. The 23-in. prop folds
back when not in use.

An important factor is to maintain motor efficiency when operating at
low loiter power settings. Maximum input is 800 watts for 1-hp.
output, but minimum loiter is 95 watts. Cocconi built a special
nine-phase motor controller that is 88% efficient at loiter power,
including motor geartrain losses, instead of a typical 70-75%.

The hollow wings are ribless with stiff sandwich skins to hold the
airfoil shape. The solar cells are under the fiberglass outer skin.
The fuselage is made of Kevlar and carbon-fiber composites.

The lift-to-drag ratio is roughly 20, and the loiter speed is about 28
mph., or 2-3 mph. above stall speed. The autopilot can fly a constant
lift coefficient to ease operating on the edge of stall. The ground
station plots areas of rising and falling air from telemetry, giving a
map to assist the pilots. On the first day, they were aggressively
hand-flying to seek the best air; but when they tired on the second
day, they would usually tell the autopilot to orbit a GPS waypoint at
a defined radius in a good area. The second night was more turbulent
and difficult than the first.

An ingenious barometric roll sensor picks up static pressures near
both wingtips and calculates the bank angle by measuring the flow due
to differential pressure between the wingtips. Running the autopilot,
flight controls, strobe lights and 5-mi.-range, 23-channel telemetry
and TV transmitter takes only 7 watts.

Cocconi would like to build a larger aircraft that can fly higher, but
both those objectives would make the job more difficult and require
bigger improvements in solar cell efficiency, battery energy density
and lightweight structure. And that would make him face more of the
problems that were tackled by Helios.

Energy Budget Per Day

(June 1-3 at 33.75 deg. N. Lat.)

(estimated by Aviation Week & Space Technology)

BATTERY CHARGING
(approx. 9 a.m. to 7 p.m. 10 hr.)
Solar power in 1.55 kw.-hr.
used to charge battery 1.1-1.2 kw.-hr.
used for housekeeping(7 watts X 10 hr.) 0.07 kw.-hr.
used for motor (95 watts X ~4 hr.) 0.38 kw.-hr.

BATTERY DISCHARGING
(approx. 7 p.m. to 9 a.m. 14 hr.)
Available in battery 1.2 kw.-hr.
used for housekeeping (7 watts X 14 hr.) 0.1 kw.-hr.
used for motor (95 watts X ~9.5-11.0 hr.) 0.9-1.05 kw.-hr.


DIMENSIONS
Wingspan 15.6 ft.
Wing area 16.1 sq. ft.
WEIGHTS
Gross weight 28.2 lb.
Battery 12.3 lb.
Solar cells 2.3 lb.
COMPONENTS
Battery 120 Sanyo 18650
Li-Ion cells
Battery capacity 1,200 watt-hr.
Solar array 76 Sunpower A300
solar cells
Nominal solar power 225 watts
Powerplant Kontronik 800-watt
electric
PERFORMANCE
Speed range 28-50 mph.
Min. loiter power 95 watts
Max. climb rate 490 fpm.
(Battery power alone can climb
to approx. 50,000 ft.)
Control and telemetry range 5 mi.






  #6  
Old September 25th 16, 03:54 PM posted to rec.aviation.piloting
external usenet poster
 
Posts: 1
Default SoLong Solar-Electric UAV 48 hour flight

HELLO SIR|GE i saw ur plane it seems to be very nice implementation but whether ur plane motor(800watt) produced enough thrust to encounter 12 kg weight.i hope best reply from u.
  #7  
Old September 25th 16, 08:01 PM posted to rec.aviation.piloting
Larry Dighera
external usenet poster
 
Posts: 3,741
Default SoLong Solar-Electric UAV 48 hour flight



http://www.acpropulsion.com/products-drivesystem.html

Drive Systems
Since 1992, AC Propulsion has been a leader in development of drive systems
which lead the industry in power density and efficiency. Products ranging from
80kW to over 200kW (268 hp) motor output have been built for spirited driving
while maximizing vehicle range. Our custom designed induction motors feature
high efficiency over a broad operating range, thus achieving drive cycle
efficiency comparable to the best PM machines. Smooth and comprehensive energy
recovery is provided through traction-controlled regenerative braking. ACP
technology includes drive systems that feature an Integrated "Reductive"
Charger that delivers up to 18kW of charge power for reduced charger cost,
reduced weight and reduced charge time.

AC Propulsion designs and engineers drives systems for OEM vehicle companies.
Our latest generation is designed to meet the stringent demands of customers
for performance, reliability, environmental ruggedness and cost. Our sister
company, eMotor Advance, located in Beijing, China, is prepared to provide
serial production units to customers worldwide.
drive system engine overview
Dynamometer Testing Gen 2 Motor

Gen 4 Motor with Integrated Inverter

Motor with Top Mount Integrated Inverter

================================================== =================



http://machinedesign.com/news/solar-...-days-straight

Solar-powered UAV flies two days straight
An electric-motor driven UAV (unmanned aerial vehicle) recently completed a
48-hr nonstop test flight using only solar energy.
Aug 18, 2005 Machine Design Staff | Machine Design
EMAIL
INSHARE



COMMENTS 0
The SoLong unmanned aerial vehicle from AC Propulsion recently flew over 48 hr
nonstop fueled only by solar energy. The plane sports a wingspan of 4.75 m and
weighs 12.6 kg.
The SoLong unmanned aerial vehicle from AC Propulsion recently flew over 48 hr
nonstop fueled only by solar energy. The plane sports a wingspan of 4.75 m and
weighs 12.6 kg.

The two-day test demonstrated the feasibility of sustainable flight using
solar-electric power.

The test flight of the SoLong solar-powered aircraft by AC Propulsion Inc., San
Dimas, Calif., was more a test of endurance for its seven ground-based pilots
than the craft. The fatigued team, lead by AC Propulsion's chief engineer and
SoLong's designer Alan Cocconi, brought the flight to a successful touchdown 48
hr and 11 min after takeoff. The 48-hr mark was mere formality as SoLong could
stay flying indefinitely.

Power from 76 SunPower Corp. (Sunnyvale, Calif.) solar cells supply the plane's
energy. Power distribution among the onboard systems is controlled by
management software developed by Cocconi. During daylight flight the nominal
225-W solar array powers all systems and recharges 120 Li-ion cells from Sanyo
Corp. The Li-ion cells fulfill the craft's energy demand at night. Propulsion
comes from a high-efficiency electric motor driven by a split-phase power
controller developed by AC Propulsion. A variable-pitch propeller fine-tunes
thrust for different rpm and power settings using a load cell for in-flight
thrust measurements.

An earlier 24-hr test flight showed the original battery reserve couldn't keep
the craft airborne. "We split the first test flight's night in two, flying
midnight to midnight," said Cocconi. "We were getting enough solar energy
during the day but we didn't have quite enough battery to take us through the
night." The Sanyo cells pack 220 W-hr/kg and have a charge-discharge efficiency
of over 95%. "That made the difference," Cocconi stated, allowing the SoLong to
pass the 48-hr mark.

Twelve PIC18 microcontrollers from Microchip Technology Inc., Chandler, Ariz.,
control and monitor all vehicle systems. Systems under control of the PICs
include the autopilot, motor drive, power tracker, six servomotors, the battery
monitor, and a tracking downlink antenna. For example, the autopilot controller
decodes 13 PWM control signals from the uplink receiver, inputs serial data
from the GPS module, and monitors 23 analog sensor channels.

Data from all systems and a live video feed from the "cockpit" telemeter to the
pilots on the ground. Two servo positioners driven by another PIC18
microcontroller keep the telemetry-link antenna pointed towards the same ground
position. The PIC18 computes servosettings using signals from the plane's
autopilot and GPS.

Efficiency is the key to SoLong's success. Even so, the energy budget required
riding thermals with the motor off as much as possible during the day. The
variable-pitch propeller folds flat against the fuselage during motor-off
flight to minimize drag. SoLong pilots must always try to bank energy, either
in the form of stored solar-electric power or aircraft altitude. Pilots draw
against either to keep the plane in the air when conditions turn sour.

MAKE CONTACT:
AC Propulsion Inc., (909) 592-5399, acpropulsion.com
Microchip Technology Inc., (480) 792-7200, microchip.com
Sanyo Corp., (619) 661-4888, sanyo.com
SunPower Corp., (408) 991-0900, sunpowercorp.com
-------------------------------------------------------------------------------

http://aviationweek.com/awin/solong-...ys-aloft-48-hr

SoLong Solar-Powered Drone Stays Aloft for 48 Hr.
SoLong airplane, with lithium-ion batteries to store energy, flies through two
nights on solar power. Better batteries are soon to come.
Jun 27, 2005 MICHAEL A. DORNHEIM | Aviation Week & Space Technology

People have long dreamed of perpetual flight, and the tipping point was reached
earlier this month when a solar-powered drone stayed aloft for 48 hr. It showed
that enough energy could be stored during the day to fly the aircraft at night,
for at least several days. All that's needed are small, near-term improvements
in technology to tip this feat into flights lasting reliably for months. One
application, albeit much harder, would be as a radio tower in the sky, giving
line-of-sight ...

THIS CONTENT REQUIRES SUBSCRIPTION ACCESS

================================================== ===============================

https://xpda.com/junkmail/junk173/AC...2005-06-05.pdf

AC Propulsion’s Solar Electric Powered SoLong UAV
June 5, 2005
Alan Cocconi with SoLong at El Mirage Dry Lake in California

Steve Neu
SoLong landing at the end of its 48 hour flight at Desert Center
441 Borrego Court San Dimas, CA 91773 909 592 5399 www.acpropulsion.com
AC Propulsion SoLong UAV June 5, 2005
Background
AC Propulsion is a small R&D and manufacturing company specializing in high
performance electric drives and vehicles. Since 1991 most of the projects have
been automotive, and AC Propulsion has established itself as an industry leader
in the field of high performance AC drives and integrated battery-charging
systems. The self funded SoLong UAV project builds on this electric propulsion
expertise and has produced a small, inexpensive and rugged UAV that has
demonstrated multi-day solar powered flight on June 1-3, 2005.

Applications
The long endurance electric powered SoLong is a unique platform that can be
adapted to a variety of remote sensing applications. Its moderate size, the
quiet and clean electric propulsion and GPS navigation make it a practical
alternative to other available UAVs.

The airframe and propulsion system can be easily scaled up or down to
accommodate various missions and the R&D effort is continuing towards a fully
autonomous UAV data gathering “appliance” with automated launch and recovery.
AC Propulsion is eager to find partners and or customers for non-military
applications.

SoLong specifications
Wingspan 4.75m
Wing area 1.50 m2
Mass 12.8 kg
Power sources 120 Sanyo 18650 LI-Ion cells and 76 Sunpower A300 solar
cells
Solar panel nom. power 225 W
Battery mass 5.6 kg
Max motor power 800W
Min electrical power for level flight 95W
Stored energy 1200Wh
Speed range 27 to 50 mph
Max. climb rate 2.5 m/s
Control and telemetry range 8,000 m
2
AC Propulsion SoLong UAV June 5, 2005
SoLong takes off from a simple wheeled dolly, lands on its belly skid
Avionics (above) and propulsion battery (below) fit within 15 cm diameter
fuselage.
Propeller folds during non-powered flight
3
AC Propulsion SoLong UAV June 5, 2005
Construction
Fuselage Kevlar epoxy monocoque with carbon boom.
Wings Carbon, Kevlar and glass epoxy composite sandwich with molded in place
solar cells
using CNC machined aluminum molds.
Propeller Molded carbon epoxy with an in-flight adjustable pitch hub and a load
cell for inflight
thrust measurement.
225 W solar array is molded into the wing surface
CNC-machined wing molds provide accurate profile
For construction of wing and bonding of solar cells
4
AC Propulsion SoLong UAV June 5, 2005

Avionics
2.4 GHz video and data downlink with 23 channels of telemetry plus GPS nav.
data (position, velocity, waypoints etc.)

AC Propulsion developed autopilot with differential pressure for wing leveling,
3 axis gyros, accelerometers, and barometric pressure for stability
augmentation and pitot pressure for airspeed hold.

Ublox OEM GPS module for position information

Microchip 8 bit processor running assembly language code for all control and
navigation processing.

High efficiency AC Propulsion developed digital amplifiers for the 6 control
surface servos

Propulsion
AC Propulsion 9 phase motor drive with 88% minimum DC to motor shaft efficiency
over the 60 to 800W range.

Kontronik Tango 45-06 3 phase brushless ironless motor with 4.2:1 planetary
gear reduction turning a 23 inch folding, variable pitch propeller.

30 volt Li-Ion battery pack of 120 Sanyo 18650 cells 76 Sunpower A300 solar
cells.

AC Propulsion 300W 4 phase peak power tracker weighing 100g and operating at
98% efficiency.
5

AC Propulsion SoLong UAV June 5, 2005
Ground Station
A 5ft by 8ft utility trailer with GPS aimed tracking downlink antenna and 3
computer screens display live video feed and flight instruments, GPS waypoints
and altitude coded flight path overlaid on a moving topo map or satellite
imagery, and the third is multi function backup. The UAV flight and navigation
is controlled using a modified RC model transmitter. The flight and
landing is controlled from inside the trailer.

Navigation waypoints can be downloaded before flight or set and moved while
airborne.

Telemetry allows display and monitoring of solar power capture, energy use,
battery state of charge and real-time propulsion efficiency.
Ground station trailer with 2 axis tracking antenna
6

AC Propulsion SoLong UAV June 5, 2005
Flight screen with live video feed, instrumentation and telemetry
Navigation screen displays waypoints and flight path.
Trace color indicates rate of climb.
7
AC Propulsion SoLong UAV June 5, 2005
Flight Tests
The present prototype has had over 60 flights and 250 hours since July 2004 and
is the latest of a series of UAVs designed and flown since 1983 by Alan
Cocconi, chairman of AC Propulsion.

The SoLong has been operated safely in winds of up to 30 mph and has been flown
for many hours at night and has landed in full darkness with only runway marker
lights.

SoLong flew continuously for 48 hours and 11 minutes on June 1-3, 2005,
demonstrating sustainable solar electric flight.
48 hour flight pilots.

From left to right:, David Fee, Jerry Bridgeman, Alan Cocconi, Chuck Grim,
“RCDave”
Freund and Steve Neu
Contact Information
AC Propulsion
441 Borrego Ct
San Dimas CA
91773
Tel: (909) 592 5399
Email:
Website: acpropulsion.com
8
================================================== ===========

http://www.alternative-energy-news.i...lane-concepts/

THE 10 BEST SOLAR AIRPLANE CONCEPTS

Posted in Solar Power | Transportation

Solar Airplane Concepts Recently we posted an article announcing the production
of a portable solar charger for airplane avionics. At the end of that article
we asked if you thought airplanes could one day be powered by solar. Since then
we discovered a whole slew of existing solar airplane concepts and projects
that we thought we’d share with you. Click through the following links to visit
the related websites. At the bottom of this article you’ll find another
opportunity to vote your opinion and leave your comments about the feasibility
of solar powered flight.

Helios The Helios Prototype solar-electric flying wing was one of several
remotely piloted aircraft, also known as uninhabited aerial vehicles or UAVs,
that were developed as technology demonstrators under the now-concluded
Environmental Research Aircraft and Sensor Technology (ERAST) project. Prior to
its loss in an in-flight mishap in June 2003, the Helios Prototype set a world
altitude record for propeller-driven aircraft of almost 97,000 feet.

Pathfinder Pathfinder was first developed for a now-cancelled classified
government program in the early 1980’s to develop a high-altitude,
long-endurance aircraft for surveillance purposes. Known as the HALSOL (for
High-Altitude SOLar) aircraft, its eight electric motors — later reduced to six
— were first powered by batteries. After that project was cancelled, the
aircraft was placed in storage for 10 years before being resurrected for a
brief program under the auspices of the Ballistic Missile Defense Organization
(BMDO) in 1993. With the addition of small solar arrays, five low-altitude
checkout flights were flown under the BMDO program at NASA Dryden in the fall
of 1993 and early 1994 on a combination of solar and battery power.

Centurion The Centurion is a lightweight, solar-powered, remotely piloted
flying wing aircraft that is demonstrating the technology of applying solar
power for long-duration, high-altitude flight. It is considered to be a
prototype technology demonstrator for a future fleet of solar-powered aircraft
that could stay airborne for weeks or months on scientific sampling and imaging
missions or while serving as telecommunications relay platforms. Although it
shares many of the design concepts of the Pathfinder, the Centurion has a
wingspan of 206 feet, more than twice the 98-foot span of the original
Pathfinder and 70-percent longer than the Pathfinder-Plus’ 121-foot span.

Hy-Bird The “Hy-Bird” project plans to fly around the world with a 100% clean
electric airplane powered only by renewable energies: solar energy and
hydrogen. The goal is to design an airplane, which will use only renewable
energies with no greenhouse gas emission, and, to decrease dramatically noise
pollution, which airplanes do normally engender.Indeed, photovoltaic cells
affixed on the wing and on the horizontal tail will supply sufficient energy
for the take off and for on-board power supply. Besides, a fuel cell will fuel
the aircraft for cruise flight. An electric engine (more silent than heat
engines) will propel Hy-Bird. Inhabitat Article

Solar Impulse After four years of research, studies, calculations and
simulations, the Solar Impulse project has entered a concrete phase with the
construction of an initial prototype with a 61-metre wingspan, referred to by
its registration number “HB-SIA”. Its mission is to verify the working
hypotheses in practice and to validate the selected construction technologies
and procedures. If the results are conclusive, it could make a 36-hour flight –
the equivalent of a complete day-night-day cycle – in 2009 without any fuel.
EcoGeek Article

Solar Challenger Eric Raymond’s dream of a solar powered airplane began in
1979, when Larry Mauro demonstrated his solar powered ultralight glider, named
SOLAR RISER. Eric began construction of his design in late 1986. Progress was
slow until 1988, when support was found in Japan. With the help of Sanyo and
several other corporations the SUNSEEKER was test flown at the end on 1989 as a
glider. The motor and prop mechanism were not satisfactory, so an A.C.
brushless motor and a folding prop were installed. After many long test
flights, a series of flights were initiated across the country. During August
of 1990, The SUNSEEKER crossed the country in 21 flights, with 121 hours in the
air.

Sky Sailor The Sky-Sailor would be carried to Mars in a small aeroshell that
would be attached to a carrier spacecraft. Upon reaching the red planet, the
aeroshell would be released for direct entry into the Martian atmosphere. From
this point, the operations could be decomposed in different phases. It can
cover a distance of ~1700 km during a 12-hour period. This allows the airplane
to reach many different areas of interest. The exploration mission will end
when the airplane crashes normally due to the batteries life cycle and dust
deposition on solar panels.

Solong Solar UAV The SoLong is an electric-powered UAV (unmanned aerial
vehicle) that collects solar energy from photo-voltaic arrays laminated into
its wings. It uses energy so efficiently that it can fly all night on energy it
gathers from the sun during the day. Remaining aloft for two nights is the
milestone for sustainable flight. One night is possible just by discharging the
batteries, but two or more nights means that the plane has to fully recoup and
store the energy used at night while flying in the sunlight the following day.
Once that is achieved, the cycle can repeat continually, and keep the plane
airborne indefinitely.

Solar Powered Plane Called the Zephyr, it’s an aircraft that can fly
continuously using nothing but solar power and “low drag aerodynamics”. The
combination of solar panels on the upper wing surface and rechargeable
batteries allows Zephyr to be flown for many weeks and even months. The first
flight trial of the Zephyr were conducted recently by QinetiQ in White Sands
Missile Range, New Mexico. Two aircraft were flown for four and a half and six
hours respectively, the maximum flight times permitted under range
restrictions.

Venus Explorer Concept A Venus exploration aircraft, sized to fit in a small
aeroshell for a “Discovery” class scientific mission, has been designed and
analyzed at the NASA Glenn Research Center. For an exploratory aircraft to
remain continually illuminated by sunlight, it would have to be capable of
sustained flight at or above the wind speed, about 95 m/sec at the cloud-top
level. The analysis concluded that, at typical flight altitudes above the cloud
layer (65 to 75 km above the surface), a small aircraft powered by solar energy
could fly continuously in the atmosphere of Venus. At this altitude, the
atmospheric pressure is similar to pressure at terrestrial flight altitudes.



On Sun, 25 Sep 2016 07:54:42 -0700 (PDT), wrote:

HELLO SIR|GE i saw ur plane it seems to be very nice implementation but whether ur plane motor(800watt) produced enough thrust to encounter 12 kg weight.i hope best reply from u.

 




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