Mr. Dennis Roberts Numerous TetheredFlight Technology Projects Discussed February 10, 2012
Director of Airspace Services
Docket Operations, M-30
U.S. Department of Transportation
1200 New Jersey Avenue SE, Room W12-140
West Building Ground Floor
Washington, DC 20590
Re: Docket Number 2011-1279, Notice of Policy and Request for Information on Airborne Wind
Energy Systems
Mr. Roberts,
My name is Wayne German. This is late for your info request, but I have tried three times before.
Please acknowledge this. I have emailed three times previously without receiving acknowledgment.
________________________________________________________________________________
While it is no doubt true that the Aircraft Owners and Pilots Association (AOPA)
represents more than 400,000 members nationwide, but when, not if, the technology
discussed in this paper is developed everyone in America and most everyone worldwide
would be passengers that could fly in their autonomous vehicles without gasoline, pilots,
or crew. And anything and everything would now be transported by air – using one
wing at low altitude tethered to one that is high. Simply assigning different altitudes and
using out-moded radar technology will not cut it – but fortunately a far simpler solution
exists that would cost far less and be virtually fully automated and would provide precise
coverage everywhere – and it would virtually eliminate the collision of small aircraft –
such as the one that literally crashed on my street a couple months ago.
________________________________________________________________________________
I was honored at the First International High Altitude Wind Power Generating Conference in Chico
California as the Father of Tethered Flight Technology. I have included my single page resume and a
primer that discusses the projects that I conceived at the Flight Research Institute (FRI) that I chose
to release into the public domain that it might interest other people into pursuing these endeavors
also. As you can see, just the KiteEnergy projects (no space for easy searching) whose concepts
have been released to the public in this primer have capabilities far beyond those that are commonly
discussed. They also have significantly greater requirements. All of these matters I have been
pursuing in virtually my own time for 22 years now because they lead to the prospect of everyone
flying without fuel by tacking in the air alone – airSailing -- in cars that might cost a half or a third of
what cars cost now because they would have almost no parts in comparison – aside from a lighterthan-air neutrally buoyant wing at high altitude tethered to another at low altitude – so by the
difference of the velocities of the wings at these two altitudes these craft could tack in the three
dimensions of air using the same basic aeronautical principles that enable sailboats to tack over
water. Obviously, this would require different methods to monitor and control aircraft. But such would
be required in short term anyway.
But let’s make things a bit more interesting, shall we? I once was offered a trillion dollars to take a
new financial service that I had developed across America alone – not to mention all the other
countries in which such a financial service would not only prove desirable, it would be guaranteed to
generate over 90% interest if my organization were to act as a fully automated loan broker on the
internet. Unfortunately, just before I went to launch the service our financial partners around the
world colluded and required significant usury rather than reasonable interest as we had agreed. I
always saw this as a means to enable flying without fuel worldwide, but only now have I realized how
to do it in a way that investors worldwide would not be able to prevent it from helping low income
Americans that our government has done much to cause them financial loss. So I suggest that your
organization arrange through the government to allow us to borrow money from the Fed that we can
show will be guaranteed to be repaid. And then we will establish a global TetheredFlight center in
Coos Bay Oregon since it would be on the best underdeveloped bay in America – to shallow for most
commercial vessels – but great for all craft (water based or air based) that can be made with this
technology. Not only that, but low level jets that have five times as much power as at the top of the
largest wind turbines pass along the Oregon-California coast and right over Coos Bay which is well
away from most all commercial air traffic. America could then develop an industry to extract power
from winds to generate electricity and hydrogen safely (Japan pays three times as much for power
from hydrogen during peak consumption times to they do not die from smog). And it could be used to
develop prototypes of devices to pull ships or canoes or kayaks. And it could be used to develop the
means to airSail so that people, cargo, and/or freight could travel between any open areas fully
automatically without pilots or crew to be required. Everything could be done fully automatically.
All this can happen and should happen and I will lead and guide and provide all money but I require
the government then to be amenable to promoting and acquiring a moratorium in the United Nations
preventing the use of this technology to be used for any military purpose whatsoever – even flying
military personnel – just like there is a moratorium on parking nuclear weapons in space. Our need
for a moratorium is identical. This technology could be used to park military weapons over countries
and they could do so over us. This is one weapons race we should see coming even before it starts
and not allow it to be used to build up military stockpiles because then all craft that might use this
technology would likely be shot down when others would think the craft might be camouflaged to look
peaceful where in fact it would really be a military craft and therefore shoot it down.
I have been trying to discuss these matters with people I have met and discussed other matters at
NASA. I have even suggested that they might buy a few computers that anyone and everyone
worldwide – even our high school youth could use to develop craft using TetheredFlight Technology
using something like SolidWorks CAD and then simulate everything and compare with others using
software such as Hanley Innovations simulation software so that anyone and everyone could then
design and test aircraft or TetheredFlight craft or projects by using their computers remotely.
Although one of these people at NASA has said that “I am very visionary and an inspiration to him”
they no longer respond to my emails because all NASA apparently wants to discuss is the
development and deployment of military hardware – and not promote peaceful technology or even
discuss doing so. Therefore, I am convinced the NASA and the military are now being very
obstructionist in refusing to do what is reasonable and rational to promote peace and prosperity
worldwide. In other words, if America could invest even 1% of the money it now invests in military
solutions to promote ever greater pre-eminence, America could show that it is a friend to the world.
Not even fanatics kill their best friends. Why do we not ever really try to see what might be the effect
of exporting benevolence rather than malevolence worldwide. The Global Tethered Flight Center
could be where we help other nations around the world work with us and us with them to meet their
needs and desires as well and not just use the opportunity to establish ever greater pre-eminence –
which only makes them want to oppose us more – it does not buy us any more security – just more
determined opposition.
There is vastly more that I could and should say that I am certain no one else would think to say. So I
think that it would make most sense that I tell you much more that could be done and should be done
– among which would make freeways on the ground obsolete because cableways in the skies could
transport people hundreds of miles an hour at vastly less cost over-all. There are many other
opportunities as well. I would appreciate being paid as a contractor because I have donated almost
all of my spare time in researching these options. Again, please see my single page resume below
and the primer regarding many of the more obvious TetheredFlight products and crafts that should be
developed along with design considerations for each. Thanks.
Wayne German, Director, Soaren Aviation, 1000 Wilsonville Rd. #108, Newberg Oregon 97132
WayneLGerman@Yahoo.Com, Cell: 503-929-9949, Answering Machine: 503-538-4132
How to Monitor and Control KiteEnergy and Autonomous Flight Products with Aircraft in Airspace
Dear Sirs,
February 09, 2012
My name is Wayne German. I was honored as being the Father of TetheredFlight Technology at the
First International Conference of High Altitude Wind Power Generators held in Chico California. This
was due in large part to the fact that twenty years ago I was invited by the Flight Research Institute
(FRI) which was a non-profit offshoot of Boeing to become a project leader. They had seen a
compilation that I had started of the different ways that TetheredFlight Technology could make use of
the power of the winds at higher altitude. The retired chief of product development at Boeing and his
right hand man, a retired supervisor of aeronautical development at Boeing both volunteered to join
my group – so I provided the concepts and the two of them turned those concepts into sound
aeronautical principals in the hope that we might make prototypes. We applied to about a hundred
different foundations but were turned down every time – and almost always for the same reason:
because we had no track record. It didn’t matter that we had a couple of the most outstanding
aeronautical minds of all time on our team, we had not established a track record doing such things
previously!!! But I did compile a subset of the applications that we had agreed showed merit and
released it into the public domain as a primer that our concepts might do much to motivate many
others to pursue these goals for everyone’s common good worldwide. This primer is attached below
and should be offered prominently that it might motivate many others as it has many if not most of
those who now pursue TetheredFlight Technology. The following are recommendations that should
be adopted to pursue these goals and promote ways that air traffic can be monitored and controlled
at far less cost using far simpler methodology in ways that would readily accommodate KiteEnergy
and Autonomous Aircraft and they are recommendations regarding the development of these fields of
endeavor in general.
1. We should drop the name Airborne Wind Energy Systems. First of all, those of us who have
grown up in aeronautics usually think of the word Airborne as meaning being carried in an aircraft,
like the “Airborne Rangers”. The Rangers obviously do not fly themselves. They are carried aloft in a
plane. Also there is already a device that is an Airborne Wind Energy System. It is a small wind
turbine on airplanes that provides power to the basic controls in the event that the main power fails.
Also having such a long name encourages people to reduce it down to the AWES snappy acronym
that no newbie has any idea is good or bad or worth learning more about on the internet. And only if
they dive round about through the internet until they find a definition for it can they decide if it is
anything even worth pursuing. This name came about because Dave Santos coined in one day
shooting from the hip and Joe Faust was the one who gave it is snappy acronym. (Don’t get me
wrong, Dave and Joe are amazing guys and have promoted anything and everything in this field and
have been cataloging, storing, and informing everyone regarding anything tether related for years
now at no pay.) But now even Dave and Joe agree that KiteEnergy says a lot more in half as many
words – primarily because Airborne Wind Energy Systems does not even imply that these systems all
have one component in common: a tether. But now it will take some agency like the government to
enforce logic and reason regarding this name, because right now it is like when Christopher
Columbus first called Native Americans Indians. We all know it is wrong but it is a very bad habit that
is very hard to break and never will break without a lot of concerted effort. That is why we should
start using KiteEnergy now rather than using Airborne Wind Energy Systems or the dozens of other
names that have popped up less often. For example, if you want to talk about a car another name or
two like automobile might make sense. But not dozens.
2. Air traffic control could be done vastly better at unimaginably less cost. A single laptop might be
able to monitor and control all aircraft around the world, believe it or not, every couple of minutes on
standby, if it had a wireless modem and the pilots all had Android cell phones connected to wireless
modems. Anytime aircraft might be close they could be told by the laptop who they were close to and
how they could communicate directly. Then the two craft that were getting somewhat close could
communicate via their satellite modems and they could play the electronic equivalent of a “rock,
paper, scissors” game until one would win and become the master and the other would become the
slave. Then the master would act as air traffic controller and direct both planes via their autopilots
how to deviate to increase their separation. This would work for all aircraft everywhere. Maybe even
just a single laptop could control all airplanes worldwide since the airplanes themselves would
negotiate how they should fly when close. No longer would aircraft have to be assigned their own
unique separate altitude anymore. This is particularly good because this system would accommodate
high altitude tethered devices easily – which would just look to such a system as an airplane that was
not making headway into a wind. But the fact that it would have a tether is information that it’s
Android cell phone could transmit to the ground based laptop or other aircrafts that would like to play
“rock, paper, scissors”. In such cases it would always become the master that would direct the slave
approaching aircraft. Of course, the main ground laptop could then be updated regarding all
communication between planes either in real time or non-real time to conserve bandwidth –
particularly if the objective is really nothing more than archiving all communication on the network with
the least possible overhead on the network possible.
Even if the vast majority of existing pilots or plane associations wanted to retain the ability to “fly
blind” by only seeing what people might be able to see, or might observe if they were paying
attention, or might not see at all – such as an approaching mountains at night – which happens a lot.
If they want to see visually it is likely they would know a lot more day or night just looking at their
Android cell phones that could show them day or night what it would look like during the day. This
could even eliminate the need for a wind shield and all mechanical gauges and substitute soft foam in
the event of accidents. What I am suggesting be considered is that there may only be need for a pad
with 16 buttons labeled with names. The buttons could be backlit also. Now if a pilot wants he could
just push the altimeter button which would use blutooth technology to alert his Android cell phone
anywhere in the plane to show what would look like the altimeter gauge on his Android cell phone.
Those that would have current or older technology could be able to do all these things and be far
more accurately protected and directed by simply buying one of these Android cell phones with the
App and a satellite modem. Likely, in time, this combination will come altogether for pilots and save a
lot of accidents or near accidents – like the collision of two small air craft that fell on my very street –
and which killed one of the pilots. Apparently, neither one saw the other until they crashed – and they
were too far away from an air traffic controller. But if they both had the modern solution that I am
recommending by each investing in just an Android cell phone and a very cheap satellite modem then
their laptops would have regularly sent their coordinates to a central laptop and the laptop could then
have told their cell phones when they started to get close to another aircraft and their cell phones
could then used canned speech that would be in the app what they should do – just like ladies’ voices
tell fighter pilots what they should do. And they could see the other air craft on their cell phones and
some arrows or other things to indicate which way to turn or what they should do. In other words,
even the oldest and least equipped of legacy aircraft could now have perfect voice directions and any
kind of visual representation from simulated 3d to topographical, etc. The fact of the matter is, that if
the FAA had updated their systems earlier, the two aircraft that crashed down the street most likely
would not have. They should each have been required to obtain the three hundred dollar cost that
the FAA should have required in the form of this cell phone and satellite modem that would then
make them able to see and know far more and also the FAA’s single fully automated laptop that could
see aircraft accurately anywhere without air traffic controllers – except in an emergency. The FAA’s
central laptop could simply have told each where to go before they got too close or to start negotiating
their own airspace on a distributed basis like birds everywhere.
3. Perhaps the main reason such a flexible system having centralized or distributed monitoring and
controlling is that in the future craft will be able to fly without fuel by tacking in air alone – airSailing –
having an inflated lighter-than-air neutrally buoyant wing at high altitude tethered to one at low
altitude. By the difference in the velocity of the wings at low and high altitude the craft would be able
to tack in any of the three dimensions of air like sailboats tack over water in two dimensions. Such
craft could take off and land from any open areas and fly fully automatically – even without pilots or
crews – and transport passengers, cargo, and/or freight anywhere fully automatically – and simply
hover in flight in flight if the wind dies or stops altogether – but always in the configuration that would
most readily promote tacking once the winds were to pick back up again. Unfortunately, the military
would be all over such a craft if it were available – which has kept it from becoming available for
decades – I do not want to have it on my head that I provided our Military the means to kill more and
more people when it is widely reported they have killed 500,000 innocent Iraqis as “collateral
damage” already. But such craft if developed would likely cost less than half as much as cars do now
since they would not require motors, tires, or all the many complexities that go into making cars.
America needs to have the United Nations promote a moratorium that when approved would prevent
militaries around the world from using TetheredFlight Technologies for military applications.
I have talked to NASA. They appear adamant that they do not and will not consider having a division
devoted to pursuing peaceful aeronautical applications. I have told them that all they would need to
do is have some laptops that others use remotely that have SolidWorks cad and something like
Hanley Innovations simulating software then everyone worldwide could use it remotely on a time
shared basis to develop any kind of tethered or untethered aeronautical project and use Hanley
Simulation’s simulator. Then they could design any kind of tethered project and compare it against
other people’s tethered projects in the same exact wind field to know which is best in what ways. The
designs could be sent to greatly automated manufacturing facilities in the United States. That way,
even high schools could get experience designing with cad and simulating software and show
considerable prowess even before they leave high school if they pursue such software rather than
their computer games.
All low level jets should be the primary domain of TetheredFlight technology. With one wing in and
one wing out of such jets craft could travel very fast without fuel. And the winds over the Great Plains
that extends to two thousand feel above ground could generate enormous amounts of power – up to
five times more than can be accesses by the tallest wind turbines normally. Also flying without fuel
would be possible and should be pursued. I can develop ground based GPS having military accuracy
that could not be taken out during a war. Such GPS could be used to very accurately direct wing
warping from below to make flying without fuel practical and even fully automatically between and two
open fields world wide, but the tether between the two wings would cut through a lot of air space
using mere radar and current air traffic controlling equipment – so again the solution that I have
recommended would work best to monitor and control Air Traffic Controlling.
WayneLGerman@Yahoo.Com, Director, Soaren.com, cell: 503-929-9949, answering machine: 503-538-4132
Soaren Financial
Developed a guaranteed financial service to give 75 million low income people worldwide
thousands of dollars of immediately and every four years. Global investors offered a trillion to
take the plan across America alone but before the launch they got greedy and required usury.
Intel’s Development Authority All programming and microprocessor issues worldwide were eventually escalated to me.
Intel’s Lead EFI Developer
Led six software engineers developing the Extensible Firmware Interface to replace BIOS.
Intel’s BIOS Tool Developer
Programmed Enhancements to Intel's BIOS testing tool – about 12000 pages of source code.
Intel’s Math Library Developer Developed efficient trigonometric & indefinite math libraries that were distributed worldwide.
Intel’s Car Software Expert
Intel's Technical Liaison to the Ford and Bausch Motor companies
Add-on Memory Eng. Manager Engineering Manager at world's largest add-on memory board manufacturer
Freightliner Truck Software
Senior Software Engineer – responsible for half of all embedded programming in Trucks.
Manufacturing and Vision
Developed negative and print cutter using machine vision then packaged them for stores.
Avionics and Vision
Tested redundancy in computers in “head up” displays so aircraft could land in bad visibility.
Aerospace Concept Architect Project Leader at Flight Research Institute. Conceived aircraft to tack in air alone without fuel.
Automating Aerospace
Developed Software to make Filament Winding Machines to make rocket chambers.
Divers and Submarines
Developed an artificial gill to extract oxygen from water for use by divers and submarines.
Satellite Communication
Architected Distress Beacon technology to be powered only when satellites are overhead.
Automated Wireless Paging
Developed software for pager call centers.
Telephony Technology
Developed telephone answering machines and designed half cost “touch tone” detection.
Data Acquisition/Controllers
Team leader developing data acquisition systems and controllers.
“True” CAD Splines
Developed "true" CAD splines to emulate the curves made with paper, wood, etc.).
s.
Extreme Sinusoid Processing Developed extremely fast novel algorithms to process sinusoidal signals for wireless encoding.
Artificial Hearts
Worked with Dr. Jarvik developing First Artificial heart and developed an artificial heart tester.
Theatrical Lighting
Architected the electronics and software for a lighting console for the largest live theaters.
Parent for Unwed Mothers
My wife and I were house parents for unwed mothers. We had 42 stay in a year and a half.
Foreman Carpenter
When I was 14 I worked 8 summers and 2 years and became a foreman carpenter.
Soaren Aviation -- to be funded by the profits from Soaren Financial above
Conceiving, architecting, designing, developing, and deploying state of the art TetheredFlight technology
Occasionally, new technologies are developed that meet global needs and generate considerable revenues in the
process. Widely recognized examples are the light bulb, transistor, radio, television, computer, automobile, and airplane.
Tethered wings could generate revenue that would greatly exceed all of these. The development, marketing, and
deployment of this technology could yield the cheapest and cleanest means of: 1) electrical power generation, 2)
communication (radio signal relaying), and 3) flying fully autonomously and automatically to and from any open area
worldwide without fuel, pilots, or crew to transport passengers, cargo, and/or air freight.
These new products in each of these standard categories could be revolutionized by the introduction of products
that incorporate Tethered wings. For the purpose of this paper, Tethered wings are aerodynamically efficient inflatable
kites in the shape of wings that have lift to drag ratios of ten to one or greater. Unless stated otherwise, they are
extremely light when inflated with air and lighter-than-air when inflated with helium, hydrogen, or steam. These airfoils
have on board power, processors, and autopilots for stable autonomously controlled flight and a satellite modem so the
craft could be remotely controlled by a laptop anywhere on earth that could monitor and control all functions and see the
craft’s environment as the craft would see it itself. Most importantly, they provide a means of harnessing wind power to
provide the mechanical power required to generate electricity, synthesize fuel, or propel ships or aircraft by tacking.
Honored as “Father of Modern Tethered Flight Technology” at International Conference on High Altitude Wind Power
“You are very visionary and inspiring to me” – Dave North, NASA Langley Research Center -- david.d.north@nasa.gov
Tethered Wings
By Wayne German, Director, Soaren Aviation, WayneLGerman@Yahoo.Com. Feb.10,2012
For Autonomous Flying (without fuel, pilots, or crew) to transport passengers and air freight, or for
Ship Propulsion, Low Altitude Hovering Serviceable Satellites, or Electricity or Hydrogen Generation
1. Overview
Occasionally, new technologies are developed that meet global needs and generate considerable revenues in the
process. Widely recognized examples are the light bulb, transistor, radio, television, computer, automobile, and airplane.
The intent of this paper is to introduce another technology, Tethered wings, whose potential to generate revenue exceeds
all of these. The development, marketing, and deployment of this technology could yield the cheapest and cleanest
means of: 1) electrical power generation, 2) shipping, 3) transportation, and 4) communication (radio signal relaying).
Each of these four areas could be revolutionized by the introduction of products that incorporate Tethered wings.
For the purpose of this paper, Tethered wings are aerodynamically efficient inflatable kites in the shape of wings that have
lift to drag ratios of ten to one or greater. Unless stated otherwise, they are extremely light when inflated with air and
lighter-than-air when inflated with helium or hydrogen. These airfoils have on board power and autopilots for stable,
remotely controllable flight. Most importantly, they provide a means of harnessing wind power to provide the mechanical
power required to generate electricity, synthesize fuel, or provide propulsion.
2. The Potentials of Tethered Flight Technology
The potential applications for tethered wing technology are numerous. Some of the applications that should be
possible are listed below. The applications that could most easily be developed are listed first followed by those that
would require more skill and experience.
2.1.
Wind power generators that use reciprocating airfoils to produce electricity on the ground.
2.2.
Water pumps that use reciprocating airfoils to pump water for irrigation.
2.3.
Sailing craft that have a tethered wing to tack into the wind or with the wind -- the airfoil
being held aloft by aerodynamic lift, or buoyancy (helium or hydrogen), or both.
2.4.
Recreational airships that fly over water without fuel by tacking in the air while being
attached by tether to submerged hydrofoils.
2.5.
Paraglider wings and ultralight aircraft that could use buoyant lift, and/or the methods of
manufacture that are discussed in a separate paper entitled, making tethered wings and air
tensioners, would greatly reduce cost.
2.6.
Passive self-regulation of altitude using highly pressurized lighter-than-air structures.
2.7.
Ship and vessel propulsion assistance with minor retrofitting.
2.8.
Energy conserving tugs that could deploy tethered wings to pull unmodified vessels across
oceans.
2.9.
Land Based High altitude wind power generators that use reciprocating tethered wings to
tap winds as high as the jet stream to produce electricity at a generator on the ground.
2.10.
Sea Based wind power generators (low or high altitude) to produce electricity at a boat or
barge.
2.11.
Synthesizing Hydrogen at Sea Using Tethered Wing Generators
2.12.
Flight without fuel over land or water by using an airfoil at lower altitude tethered to another
airfoil at a higher altitude to harness the power available in the differential velocities of the
two altitudes.
2.13.
Radio signal relaying by hovering indefinitely in the air while using excess wind to generate
electricity to relay radio signals.
3. Conceptual Descriptions of Products Incorporating Tethered Wing Technology
3.1.
Wind Power Generators
Wind power generating systems can be developed using reciprocating tethered wings. Using
two airfoils and a tether that passes from one airfoil through an electrical generator on the ground to
the other airfoil, power could be generated if one airfoil flew at a high angle of attack (nose up) while
the other flew at a low angle of attack (nose into the wind or slightly down). The airfoil flying at a
high angle of attack would have greater lift and drag, which would cause it to be blown downwind
and upward while pulling the other airfoil upwind and downward. Electricity would be generated as
the cable is pulled and the generator is forced to spin.
As the airfoil having the lower angle of attack approaches sufficiently close to the generator,
remote control could cause it to assume a high angle of attack and cause the airfoil further
downwind to assume a low angle of attack. This would cause the upwind airfoil to fly downwind and
the downwind airfoil to fly upwind. Periodically changing the angles of attack would, therefore,
cause the two airfoils to reciprocate in the sky producing power on the ground. Between strokes, as
the airfoils change their angles of attack, and as the cable changes its direction of travel, there
would be a brief time when no power would be generated. Therefore, in tethered wing wind farms
the flights of all the airfoils should be synchronized so that as few as possible would change
direction at the same time. This would ensure that the power generated at the farm would be as
even and continuous as possible.
Note that only the pitch, or angle of attack, would have to be controlled remotely -- not the yaw
and roll. This should make the design and development straightforward. Adjusting the tether bridle
position fore and aft should provide the level of control required for this application. The tethered
wing could be designed to passively correct for yaw and roll -- much the same way that single string
kites do today.
A single tethered wing could produce electricity if a flywheel or external electrical power is
used to winch the airfoil in on the upwind stroke. The airfoil would produce more power on the
downwind stroke flying in a high lift, high drag mode than would be required to winch it back in on
the upwind stroke.
The amount of power that a tethered wing could generate is not proportional to the size of the
airfoil. It is proportional to the area swept by the airfoil per unit time -- just as in wind turbines. A
small airfoil that quickly traverses a large area would generate more power. But Tethered wings
could generate far more power than wind turbines because they could sweep a greater area for an
equivalent cost since they would not have the cost of the tower, nor be limited to the sizes that
towers can accommodate.
Unlike standard wind turbines, Tethered wings would not require expensive towers, specially
designed low speed generators, and would not be subject to the strong vibrations that cause
premature failures. Most importantly, they could fly at higher altitudes to harness more powerful
winds. On average, over flat land, the wind is twice as powerful at every five-fold increase in
altitude. So a Tethered wing flying at only 500 feet would encounter twice the wind power as a wind
turbine 100 feet off the ground. At a half mile the Tethered wing would encounter more than four
times as much wind power. This effect can be greatly magnified by terrain that causes the air to be
funneled -- as is generally found at the best wind farm sites.
Obviously, Tethered wings that fly at high altitude would need to be assigned their own
airspace a safe distance away from commercial flight paths. They might obtain permission to fly in
the restricted airspace over wilderness areas because they do not pollute or make noise.
Alternatively, the vast areas that exist offshore would provide excellent sites for both low and high
altitude wind farming (as will be discussed) later. But initially, windy rural areas would provide good
lower altitude proving grounds.
Inflated with helium, these tethered wings would simply float up in exceptionally calm winds.
But in places, such as Minnesota, where the winds are constant and strong close to the ground it
may prove practical to develop tethered wing generators that rely exclusively on aerodynamic lift
rather than buoyant lift. Inflated only with air, they could be developed to automatically launch from
a stand when the winds blow sufficiently strong and be winched down quick enough to maintain
controllable flight when the winds are exceptionally calm.
While the jet stream offers the greatest potential power per unit area, it may be more practical
to fly larger Tethered wings at lower altitudes. This would reduce the cost and drag of the tethers,
but would require larger or more numerous airfoils to generate a like amount of power.
Even in typical installations, wind power used in conjunction with hydropower or fossil fuel
plants could reduce the long-term rates at which these plants use water or fuel. These plants on
the other hand, could provide backup power during periods of calm winds when these wind power
generators would produce little or no power.
3.2.
Water Pumps
Tethered wings can be used to pump water as well as to generate electricity. The specific
application of pumping water is mentioned here for three reasons. First, it would not require a
generator. Pulling the tether could drive the pump directly. Second, water pumps do not require a
consistent power source. If the winds cause short-term variations in the amount of water that is
pumped there is no problem provided that daily or weekly quotas are met. Third, many nations
require or could benefit by the use of good cheap water pumps.
Many underdeveloped nations need power to pump irrigation water. Studies conducted in Sri
Lanka, Kenya, Cape Verda, and the Sudan show that windmills can be cost effective compared with
diesel engines for pumping water. If windmills are considered cost effective, tethered wings should
prove superior because they can extract power from much stronger winds and sweep through a far
greater airspace. (As mentioned previously, the power that may be generated is proportional to the
area swept per unit time).
3.3.
Custom Sailing Craft
A lighter-than-air Tethered wing and a watercraft having a small wetted surface could be
tethered together to make a very fast and efficient sailing craft. Canoes and kayaks with
centerboards or catamaran hulls would make good choices. Tethered wings suitable for this
purpose would need to have remotely controllable pitch and roll so that they could fly "out to the
side" as well as downwind. These tethered wings would not require remotely controllable yaw.
These airfoils could be designed (perhaps with a delta wing shape) to ensure that the tethered
wings would always fly with nearly zero yaw with respect to the wind. (The purpose for flying "out to
the side" is to generate a force perpendicular to the direction of the wind just as sails do when
tacking into the wind.)
The tethered wings that have been discussed previously require pitch control only (nose up or
down) The purpose of this control is to: 1) generate varying tether tensions by adjusting the lift and
drag characteristics of these airfoils, or 2) to adjust the height of the tethered wings in the sky.
Tethered wings that could be used to provide propulsion into the wind (as well as with the wind)
require roll control as well. These airfoils must be able to fly out to the side as well as overhead and
downwind. The best Tethered wing for this purpose would be one that could be directed to assume
a relative position in the sky with respect to a hull -- in response to remote control -- and then hold
that position indefinitely without requiring power. It appears that such control may be possible (and
patentable).
A Tethered wing should be able to passively maintain a new relative position in the air in
response to a single radio control request to change the tether bridle position, flaps, wing warping,
or center of gravity. Using this technique changing the attitude of the airfoil would cause the airfoil
to select a different position in the sky. This, in turn, would cause the tether to be pulled in a
different direction -- causing a new tack to be taken. If the airfoil could maintain this new position
indefinitely after it had made these changes, it would be highly desirable, because power would
only be required when changing tacks -- not to maintain the course of a tack. Even more important,
is the fact that if it could passively self-correct it's own position it would be immune to brief system
power failures or shutdowns. It would still continue to fly just as well on the same tack.
Members of the Flight Research Institute have demonstrated the feasibility of water skiing
upwind or downwind with a Tethered wing at the Columbia River Gorge. They also won first place
in a speed sailing competition in England -- racing against craft having similar sail area. Even
though the airfoil and hydrofoil were inefficient off-the-shelf kites and skis, they won by the greatest
margin of the day.
While the principle of tacking into the wind with Tethered wings may sound unique, it has
actually been accomplished and documented as early as 1827 by G. Pocock. (The Samoans used
it even earlier.) It appears that as soon as Orville and Wilbur Wright showed that it was possible to
fly without a tether, virtually all scientific research into the applications of Tethered wing flight
ceased. Back then, the only way that an operator could remotely control a Tethered wing, was by
applying varying tensions on additional drag-inducing cables. The winds that kept the airfoil aloft
also acted upon these control cables. When a wind gust would cause an airfoil to start diving to
one side, different tensions would result in the control cables. Often, these different tensions would
cause the airfoil to dive even more. These airfoils often flew out of control and crashed. What is
surprising is that in 176 years nothing has changed.
To the best of my knowledge, no one has yet put an inexpensive autopilot and an
aerodynamically efficient Tethered wing together. I hope to work with others to be the first to
achieve this goal. With such equipment there is no reason why Tethered wings would not be every
bit as stable, controllable, reliable, and useful as standard aircraft.
Tethered wings could provide propulsion for small boats. Attached to the gunwales negligible
listing moment would be generated. In fact, traveling with the wind, the airfoil could help pull the
hull of smaller boats out of the water, thereby reducing drag. Motorboats, sailboats, hydrofoils,
canoes, kayaks, sailboarders, skiers (both water and snow) -- all could be accommodated with a
handful of different models. Unlike sails, Tethered wings need not be custom made for each boat
or application. No heavy masts, ballast, special ship design, or expensive retrofitting would be
required. Like sails on a sailboat, Tethered wings could provide power for all points of tack except
dead into the wind. They would be better than sails because they would have an aerodynamically
superior shape -- higher lift to drag ratios -- and therefore be able to tack much closer into the wind.
They would also have access to the stronger winds aloft. They would have one cable, requiring
one winch, and take up no deck space (mounted externally to a track on the gunwales).
Over land, the available wind power doubles with every five-fold increase in altitude. This
factor can be much greater over water when the wind causes the waves to crest and the waves
cause more pronounced boundary layer effects. So Tethered wings could tap much more powerful
winds than sails.
If a motorboat were outfitted with a Tethered wing that flew at 500 feet (where the winds at
sea are often three to four times as strong as at the top of most masts and towers) it could outrun
most sailboats -- without engine power. Naturally, If the winds became too strong the airfoil could
be tied down or deflated. For example, fishing fleets could race to their fishing grounds with their
airfoils at high altitude and troll with their airfoils slightly overhead.
Motorboats under power could use tethered wings to provide a component of thrust in the
direction they wished to travel. Suppose that a captain desired to travel east and decided to use an
airfoil to help reduce fuel consumption. Suppose further that the wind was blowing such that his
Tethered wing pulled strongest in a northeasterly direction. He could accomplish his goal by
directing the motors to cause an equally powerful thrust in a southeasterly direction. If the captain
wished to travel east at 20 knots, the motors would only need to propel the boat at 14 knots.
Depending on the ship and the sea conditions, this thirty percent reduction in motor propulsion
speed could result in a fifty percent reduction in fuel consumption -- yet he could travel just as fast
as if he had used motor power only.
It is typically reported that by assisting propulsion with standard sails, fuel consumption can be
reduced by a fourth. But since Tethered wings can harness winds having greater power, and since
they could be much larger, Tethered wings could save much more fuel. Since Tethered wings
could be attached at the gunwales they could never pull the boat over -- just along. So, unlike sails,
Tethered wings would never need to be furled to prevent capsizing. Tethered wings should always
be able to make use of the best winds -- at altitudes where there is over four times as much power
available.
The Tethered wings for sailing applications could be inflated with lighter-than-air gases such
as helium or hydrogen so that they would simply float up in exceptionally calm winds. Alternatively,
they could be inflated with air in which case they would need to launch and land as the winds would
permit. As the winds would become strong enough, or as a boat having a propulsion source would
pull, an air inflated Tethered wing could be launched by letting out the tether. To land the airfoil
when desired, or in the event of exceptionally calm winds, a winch could pull the Tether back in
again at a sufficient velocity to maintain stable flight.
Airfoils that are inflated with air would be advantageous because they could readily be
deflated and conveniently stored on board when not in use. Also, there is additional cost and
logistics involved in obtaining, storing, and transferring lighter-than-air gases. As elegant as it
would be to have lighter-than-air Tethered wings pull boats, in general it would probably be more
practical to use air inflated Tethered wings.
3.4.
Recreational Airships that Fly Over Water without Fuel
As soon as Tethered wings are developed that can pull hydrofoils reliably, passengers could
fly in gondolas attached to airfoils rather than sail in hulls over the water. The principles of
operation would be just the same. The only difference is that the hydrofoil would now be remotely
controlled rather than the airfoil. Such a craft should have a much smoother ride. The tether would
dampen Wave action before it was transmitted to the gondola. In the event that the wind stopped,
the gondola would simply float -- being held up by the buoyant lift of the lighter-than-air airfoil.
This configuration could render a truly efficient sailing craft because a lighter-than-air airfoil
could support the passengers, cargo, and all other components of the craft except for the hydrofoil
that would be required for tacking. In other words, the craft could be made very efficient by the
elimination of the hull and all unnecessary water drag. Having a high sail, very little drag, and
always being "up on the hydrofoils" such a craft could sail even in the lightest of winds. For truly
high speed, the airfoil could fly at high altitudes. For passenger comfort without cabin
pressurization, the gondola could be attached to the tether a reasonable distance above the ocean.
Nearly this same level of comfort and efficiency could be obtained by using Tethered wings
that are inflated with air. In this case, the Tethered wing and gondola would have to launch and
land as the winds would permit. But this would probably not be a very big penalty because they
would land when the winds would provide little or no propulsion and when the water would be calm.
The one disadvantage in using air rather a lighter-than-air gas to inflate the airfoil is that some of
the aerodynamic and hydrodynamic lift generated by the airfoil and hydrofoil would have to be used
to lift the gondola and wing. Normally, a relatively small percentage of the power would be required
to lift the gondola and wing. The vast majority of the power would still be available to provide
propulsion.
As the winds would start to pick up, this craft could be launched by releasing tether from a
spool in the hydrofoil. In many cases this would be sufficient to cause the gondola and wing to take
to the air. But if the winds at low altitude were insufficient, the gondola and the airfoil would float on
the water downwind from the hydrofoil. When the tether would be let out sufficiently, the tether
could be winched back in briefly and strongly to cause enough tension in the tether between the
hydrofoil and the airfoil to pull the airfoil into the sky. Once in the sky, under the influence of greater
wind power, the winch could stop pulling and gradually let out more tether so that the gondola and
airfoil could ascend to the altitudes that would allow tacking.
3.5.
Paraglider Wings and Ultralight Aircraft
Tethered wing construction techniques should enable the construction of high performance
inflatable paraglider wings and ultralight aircraft. Standard Paraglider wings are ram-air inflated.
This causes drag to be generated at the leading edge. Also during flight, standard paraglider wings
can easily be deformed into less efficient shapes. Tethered wings should be at least as light, but
they should form much more rigid and well-defined airfoil shapes. It should also be possible to use
these techniques to make inflatable ultralight aircraft.
3.6.
Passive Self-Regulation of Altitude
Using the proprietary construction methods that are discussed in the paper “Making Tethered
wings and Air Tensioners”, highly pressurized lighter-than-air airships (airfoils, aircraft, or balloons)
could be manufactured that could passively stabilize their altitudes in free flight without being
restrained by tethers. These construction methods could be used to make lighter-than-air airships
that would prevent the internal gases from expanding as they rise. These would be constant volume
airships. As a consequence, if they were free to ascend or descend they would come to rest at the
altitude that would have the same density as the over-all airship. If these balloons rose higher -perhaps due to momentary gusts -- they would be heavier than the surrounding air so they would
settle back down. Likewise, if they were lower, they would be lighter than the surrounding air so
they would rise. They would always passively return to the altitude whose density is equal to that of
the airship. In short, they would require no monitoring, control, or power to automatically selfregulate their own altitudes. If they were in no hurry they could float to destinations downwind
consuming no power. This might be a useful plan in hauling freight inexpensively.
This technique was used by NASA in the Ultra Long Duration Balloon that launched March 16,
2003, and which was designed to circumnavigate the globe for 100 days. Interestingly, this
technique has never been used to maintain the altitude of lighter-than-air man-lifting balloons or
airships.
To date, all lighter-than-air man-lifting balloons require continual monitoring and adjustments
of altitude. This is because the air in these balloons expand during ascent and compress during
decent. If they start upward, they continue upward at an accelerating rate, until helium is released
to cause them to descend again to the desired height. But once they start to descend they continue
to descend at an accelerating rate, until ballast is released to cause them to ascend again. These
balloons continually rise and fall requiring continual releases of helium and ballast to compensate.
In standard airships or blimps, the lifting gas is free to expand or compress to come to
equilibrium with the surrounding air. So as the airship descends, the gases compress. This would
cause the airship envelope to become limp were it not for ballonets. Ballonets are special internal
air pressure compensating balloons that inflate during descents to maintain a small but uniform
positive pressure in the airship. Unfortunately, a ballonet requires a fan to maintain a slight positive
pressure. The fan in turn requires a power source. Present day airships do not regulate altitude by
alternately releasing helium and ballast like balloons. That would be too costly. Instead, they use
the aerodynamic forces of thrusters to maintain altitudes when the airship has a different density
than the surrounding air. These thrusters are used to provide an upward force when the airship is
heavier than the surrounding air and a downward force when the airship is lighter. This method
requires engines that continually consume fuel.
It would be better if airships were designed to withstand high internal pressures (such as up to
5 psi). To ascend, air could be released from an internal ballonet. The loss of this air, and the
expansion of the helium that would result in the adjacent chambers, would lower the overall density
of the airship, which would cause it to rise to the altitude having the same density -- and no higher.
To descend, a compressor would be required to draw air back into the ballonet. This additional air,
and the compression of the helium that would result, would cause the airship to descend to the
altitude that would have the same density -- and no lower.
Such an airship would never need to discard helium or ballast, or consume fuel to maintain a
specific altitude. It could also be smaller because it would not need the extra buoyancy required to
lift ballast or the additional fuel required to maintain altitude. In the course of adjusting altitude, this
airship would only need to consume power when using the compressor to draw in additional air to
descend. It would require no power to maintain a specific altitude or ascend. It could float
indefinitely downwind at a specific altitude without requiring any altitude monitoring or control.
3.7.
Ship and Vessel Propulsion Assistance
If freighters and ocean going vessels used even relatively simple and inefficient Tethered
wings they could realize dramatic reductions in the costs of fuel. When traveling the direction that
the jetstream blows (eastward in the Northern Hemisphere) the vessels could pull large Tethered
wings into the jetstream. Once in the jetstream, these airfoils could simply pull the vessels
downwind. A 50 percent reduction in the cost of fuel one direction on a large freighter would save
hundreds of thousands of dollars annually. Efficient Tethered wings might be able to save
significantly more because they could provide propulsion assistance on the return upwind trip as
well.
Some freighters have been designed to use metal sails to provide propulsion assistance with
the wind or into the wind. They are designed to save as much as 60 percent of the cost of the fuel.
Like all sails, these metal sails cause the vessels to list to one side when the winds blow. Listing
causes all decks and cargo bays to have sloping floors. To prevent capsizing, the metal sails are
"furled" by folding. They require special ship designs to accommodate the masts, ballasts, and the
forces that the sails generate.
Tethered wings in contrast could provide greater power from higher altitudes and yet cause
negligible listing. Little or no retrofitting would be required because Tethered wings could pull the
vessels at the same attachment points that tugs would use. Even if these Tethered wings were not
lighter-than-air they could be self-launched into the apparent wind generated by these ships at sail.
Between territorial waters there are no governmental bodies that regulate how high Tethered
wings would be allowed to fly. As low as a ten percent reduction in the worldwide consumption of
fuel by freighters would save billions of dollars annually -- not to mention the environmental benefit
of reduced pollution and less global warming.
3.8.
Energy Conserving Tugs
Special tugs could be designed for the express purpose of manipulating Tethered wings to
pull ships across oceans. This would have the advantage that the large vessels would not have to
manipulate the Tethered wings directly. All the tasks associated with providing propulsion
assistance could be handled by a tug specially designed to do the job. Tethered wings suitable for
this purpose would probably not have to be lighter-than-air. The tug could sail into the wind, pulling
even a heavier Tethered wing into the air. A heavier-than-air airfoil would have to fly exclusively by
aerodynamic lift, but it could still land safely even in calm winds by being pulled in fast enough to
ensure stable flight back down.
3.9.
Land Based High Altitude Wind Power Generators
Most appealing is the prospect of harnessing winds in the jetstream where the wind power is
often hundreds of times greater than at the top of masts and towers. Technical and political hurdles
would have to be overcome, but as Tethered wing technology matures and gains acceptance
jetstream wind farming may prove practical.
At each site, the local terrain and the proximity to the jetstream will determine whether it would
be best to fly more airfoils at lower altitude or fewer airfoils at higher altitude. Mountains or other
land formations that funnel wind may favor lower altitudes. One such mountain range exists in
Hawaii. This range runs perpendicular to the prevailing winds and funnels winds up and over.
(Hawaii also has expensive electricity and a state government that has recently invested millions in
wind energy development in a single year.)
Obviously, Tethered wings that fly at high altitude would need to be assigned their own
airspace. They could be assigned airspace far from the commercial flight paths. In rural Kansas,
for example, strong constant winds at ground level would assure that the Tethered wings could selflaunch and self-land inflated only with air. Alternatively, they might obtain permission to fly in the
restricted airspace over wilderness areas because they do not pollute or make noise.
Many Third World countries are crossed by the jet streams of the northern and southern
hemispheres. They might desire to relinquish airspace to produce inexpensive electrical power. If
the winds at ground level are insufficient to launch these Tethered wings, they could be filled with
helium or hydrogen so they would always be in flight even in calm winds.
(Ever since the Hindenburg blew up, people have been reluctant to use hydrogen in lighterthan-air aircraft, but it should be noted that the Hindenburg contained the hydrogen in "gold beater's
skin" -- the intestines of calves beaten thin -- nothing to be compared with today's multi-layered
plastic films.)
A number of articles have been written about the feasibility of developing wind power
generating systems that could tap the power of the jetstream. But the systems described in these
research papers consist of wind turbines mounted on large metal wings that are tethered with
special power conducting cables. The wings use the turbines as thrusters for launching and
landing. The complexity and manufacturing costs are staggering; yet the amortized costs of the
electrical power generation are considered favorable (in the 7.5 - 9.5 cent per kilowatt range nearly
twenty five years ago).
However, it would be much simpler and less expensive to design a system that would:
1) Have an ordinary land based generator,
2) Have inexpensive inflatable fabrics that can be quickly deflated and stored away
during periods of excessive wind,
4) Bounce rather than crash in an accident,
5) Contain virtually no costly and fragile high tech components,
6) Require no heavy turbines or metal cables to conduct lightning,
7) Never need to land during light winds,
8) Provide a much greater return on investment because the same costs could be used
to construct larger Tethered wings that could extract power from a greater area.
Over much of the United States the average potential power of the air that flows through one
square meter of the jet stream exceeds 10 kilowatts. Drag on the tether and airfoil(s) will, of course,
limit how much of this potential power can be converted into mechanical or electrical power.
Greater potential exists over Maine where during a winter month (when the need for power is
greatest) the average power available per square meter exceeds 30 kilowatts (or 40 horsepower).
The greatest wind power in the world is found near Tokyo Japan where the average power exceeds
60 kilowatts (or 80 horsepower) per square meter in the winter.
As stated before, the power generated would be proportional to the area swept by the airfoil
per unit time, so if a Tethered wing the size of a soccer goal (8’ x 24’) were to fly in the jet stream
near Tokyo, and if it quickly swept an area ten times as large and was 20 percent efficient over all, it
would generate 2.14 Megawatts of electricity. The efficiency is conservatively assumed to be very
low to account for the weight and the drag of the tether and the fact that wind turbines are only 60
percent efficient at best. But in practice, it is expected that the efficiencies and the power generated
could be significantly greater. Even so, at 10 cents per kilowatt-hour, very modest by Japanese
standards, and assuming an average power of 40 kilowatts per square meter, this single small
airfoil could generate a gross revenue of $1.25 million dollars annually.
Japan has expensive electricity and no indigenous fuel supply. It has few hydroelectric
facilities and little land to set aside for solar power generators or wind turbines. The people of
Japan fear nuclear power due to the bombing at Hiroshima and a near catastrophic accident at one
of their nuclear plants. So harvesting the power in the winds offshore and/or in the jet stream may
be the most desirable means of generating electricity for their nation.
3.10. Sea Based High Altitude Wind Power Generators
Studies have pointed out the potential of generating electrical power using wind turbines at
sea. A major expense outlined in these studies is the cost of installing and maintaining the
stationary platforms and towers required to hold the turbines in the air. Tethered wings do not
require tall towers or large platforms. Instead, small boats or barges could contain generators and
be able to automatically launch, coordinate the flights, and retrieve the airfoils. Since the winds at
sea are generally strong, these airfoils could fly totally by aerodynamic lift, so they would not require
lighter-than-air gases. Using the methods of manufacturing that are discussed in the paper “Making
Tethered wings and Air Tensioners”, these airfoils could momentarily bend and deform in the
heaviest winds -- rather than break and fracture.
Since these Tethered wings could fly as high as the jet stream, where the wind power is often
30 to 100 times as great, and since they would not require tall towers or large platforms, and since
they could be made with inexpensive fabrics and low tech components, the cost of the power that
the Tethered wings could produce should be much less. Within 200 miles of shore both ocean and
airspace would have to be reserved, but permission to reserve this space should not be difficult to
obtain because Tethered wings do not pollute or make noise and they could not easily damage
people or property at sea if they are assigned their own space. More than 200 miles offshore,
outside of territorial boundaries, they could fly without obtaining permission from anyone. In fact,
with limited taxation (or no taxation in the case of Liberian registry), and no property cost -- save for
a power cable right-of-way connecting the wind farm to the land, this might be the most cost
effective alternative. (Lights, radar, and automated radio warning systems could warn approaching
craft.)
3.11 Synthesizing Hydrogen at Sea
There is a method of generating electricity from the winds at sea that would not require power
cables to transmit the electricity to land. In this case, boats at anchor or sailing the seas could
deploy reciprocating Tethered wings. The electricity generated could be used to electrolyze
seawater to generate hydrogen that could be stored in onboard tanks. Later these tanks could be
transferred to power stations where fuel cells or conventional steam turbines could use the
hydrogen to generate electricity. Therefore, boats could ply the waters off countries such as Japan
to harvest wind power for the purpose of synthesizing hydrogen to sell: 1) to local power stations to
generate electricity, or 2) as an automobile fuel.
Not all of the electrical power that is used to synthesize hydrogen can be reclaimed when the
hydrogen is used to generate electricity again. These processes are not a hundred percent
efficient. Also, the storage and transportation of hydrogen presents other difficulties. So it will
always cost more to synthesize, store, and transport hydrogen than use wind generated electricity
directly. But hydrogen is the cleanest fuel of all. When hydrogen is used to generate electricity the
output "exhaust" is pure water. Utilities pay a premium for electricity that is generated without
producing pollutants. More importantly, electricity that is stored in the form of hydrogen can be
converted back to electricity at times of peak demand when electricity can sell for over three times
as much as it normally does. So, all of the costs associated with converting electricity to hydrogen
and back again can be more than offset by selling the electricity at times of peak demand.
Moreover, the conversion of wind power to hydrogen to electrical power could provide backup
power during periods of calm winds for other Tethered wings that provide more efficient direct
power.
Wildcat oil miners risk much every time they attempt to sink a new hole at sea. Each hole
could come up dry or cause much pollution. Sea based Tethered wing wind farmers would risk
much less and would have a resource that would never run out. The main risk in developing sea
based wind power generating systems is the risk incurred in developing the first one. After the
methods of manufacture and deployment are resolved, there is never a chance of finding a "dry
hole''. The patterns of the jetstream are well known. In the United States, the owners of Tethered
wing wind power generating systems have another benefit: power companies are obligated to buy
the power produced by private individuals or companies at fair market rates. Having an obligated
customer means that this enterprise should be recession or depression proof. Wildcat oil miners, in
contrast, have no such benefit.
3.12 Flight without Fuel
Actually, there is not any reason why anything must drag through the water or be attached to
the land in order to make a system that can tack using airfoils. Two airfoils attached to opposite
ends of the same tether can accomplish the same thing. If one airfoil is in faster moving air at a
higher altitude and the other airfoil is in slower moving air at a lower altitude, then the craft can tack.
The principle is the same as an airfoil attached to a hydrofoil. The only difference is that instead of
using a hydrofoil in the slow moving water, another airfoil could be used as in the slow moving air.
If a passenger-containing gondola were attached to the lower of the two airfoils, then the
upper airfoil could ascend into the jetstream for fast, silent flight. This aircraft would require a
sophisticated autopilot because it could tack vertically as well as horizontally. Fortunately, low cost
microprocessors and servomechanisms can be developed that can perform all flight operations with
little or no human intervention. As an example, autopilots could be pre-programmed to fly between
any two points on earth using sensors that receive information from the Global Positioning System
(GPS). Using these sensors (and others) the airfoils could continuously monitor their exact
positions above the earth (to within a few meters), their attitudes (pitch, yaw, and roll) and the wind
velocity and direction. With this information, the autopilots could cause the airfoils to automatically
launch (causing the mooring cable to become disconnected from the ground) fly to a preprogrammed destination using a pre-determined route, then dock at a destination (flying the
mooring cable such that the ground end is caught by a waiting receptacle).
In June of 1982, the Smithsonian magazine had an article that stated: "A kite flying across the
wind will fly faster than the speed of the wind. If the lift-to-drag ratio is ten to one, the kite
theoretically can go ten times as fast as the velocity of the wind.'' This article also stated: "The wind
blows hardest (more than 100 miles per hour) about 30,000 feet above the ground in the jet
stream.'' Taken together, these two facts would suggest that Tethered wing airships could fly faster
than 1000 miles per hour in the jet stream! This is impressive but not realistic. At these speeds the
long tether would have considerable drag. Furthermore, flying crosswind means that the craft
would be restricted to flying in specific directions. If the average practical speed (due to limitations
of tether length and drag) were only 20 percent of this theoretical maximum, if it were no greater
than 200 miles per hour, it would still be highly desirable because it would be flying without fuel.
Since these airships would consume no fuel, they could prove very competitive as haulers of
airfreight, low cost air transportation, pleasure craft, or sightseeing craft. They would not need
airports. Moored to the ground as aerodynamically shaped helium filled kite-balloons, and perhaps
using thrusters to help maintain position, they could load and unload people or cargo from open
areas or the flat roofs of large buildings. In the days of the old airships it was said that: "You can fly
in an airplane, or you can voyage in a Zeppelin''. Zeppelins of those days had ballrooms and
verandas in the sky. There is no reason why these newer airships could not be at least as
gracious.
Since there is generally a large differential in velocities between the winds in the jetstream and
those just below, if the cabin were pressurized, and the lower airfoil was below the jetstream, the
tether required for free flight could be made much shorter -- thereby reducing drag, increasing
speed, and freeing more airspace. A commercial version of this airship could have metalized
plastics for the retention of lighter-than-air gases and for good visual and radar tracking.
3.13 Radio Signal Relaying
When it becomes possible to fly indefinitely by tacking in the air (as was just described), it
should be even easier to tack in order to stay in the same general location. When this feat is
achieved it could lead to the cheapest means of communication. Small wind turbines could
generate on-board power that could be backed up by battery to provide a consistent power source
24 hours a day. This form of hovering would not require the same aerodynamic efficiency as a craft
designed to tack to locations upwind. Therefore, the on-board wind turbine should not restrict
operation. Such wind turbines would introduce drag. But if the objective were to maintain position
rather than to progress to locations upwind, some additional drag could be accommodated.
Already, nations have expressed concern that there may not be enough locations above the
equator at which to position all the geosynchronous communication satellites that the world may
shortly need. It should be far cheaper to make geosynchronous craft that can tack in the air without
fuel. They would not need to be positioned above the equator and they could launch and land
under their own power wheneve maintenance would be required. Just a few of these flying high in
the jet stream could provide a network that could provide continental coverage. They could provide
the cheapest means of mass communication.
Recently an aircraft named Helios demonstrated that it is possible to fly at high altitude by the
power harvested by solar cells alone. This is a very technically complex craft. By contrast a
Tethered wing craft could accomplish this feat with two simple inflated craft tethered together. It
would not be restricted by the availability of sunlight.
3.13 In-Flight Generation of Fuel
If it proves to be possible to tack in the air while generating power from on-board wind
turbines, commercial wind power generators could be developed using this concept. By tacking “in
place” in the jet stream they could generate electricity with which to produce hydrogen from water.
Afterward, these craft could fly to power generating stations that could use fuel cells to generate
electricity from the hydrogen, generating no pollution aside from water vapor. Alternatively, the
hydrogen could be sold as a non-polluting automobile fuel.
4. The Initial Objectives of Tethered Wing Research and Development
Currently, the support and endorsements for the development and commercialization of
Tethered wing Technology are fairly balanced between those who would want to see it initially used
to generate electricity and those who would want to see it initially used to propel efficient sailing and
flying craft. Each has their relative merits. Electrical generators would have to overcome more
political hurdles if they fly at high altitudes, but sailing and flying craft would present more technical
challenges. Electrical generators might provide a greater income long term, but sailing and flying
applications would probably find more immediate acceptance. In either case, the Tethered wings
that would be best suited to these tasks would be airfoils that could maintain their relative positions
in the sky with respect to their mooring sites – positions that could be specified, and could be
changeable, by remote control. In other words, the best Tethered wings for these applications
would be ones that could be programmed by remote control to fly to specific locations left, right, up,
or down in any wind. These airfoils should maintain nearly constant position until programmed to
move to another position. Lastly, they should consume as little power as possible to stay in a
programmed position.
Typical kites stay in position without consuming power, but they cannot maintain position to
the left or right of their mooring location. The goal here would be to develop Tethered wings that
could stay in any programmed position in the sky that kites could reasonably fly in. These airfoils
would require an autopilot, remote control electronics, and servomechanisms. These are areas that
I would feel confortable developing. What I need is help developing the best control theories and
mechanisms to maintain position at the lowest possible inflight power consumption. But the first
goal is to demonstrate a practical method of being able to manufacture these Tethered wings
quickly and economically. It is for this reason that the objective of this initial unsolicited proposal is
to obtain funds to plan the development of a system that could be used to manufacture Tethered
wings. The proposal, itself, is near the end of this paper.
6. Tethered wing Generators Compared to Other Power Generating Technologies
All of the current and proposed methods of energy generation or fuel synthesis have their
advantages and disadvantages. Below the costs of consuming oil are discussed. Afterward, the
advantages of Tethered wing Generators are discussed and compared against the current and
proposed methods of energy generation. The intent is to lay a foundation that will clearly establish
our need for a cleaner, safer, cheaper source of power other than that, which is currently available
or proposed.
6.1. The Hidden Costs in Oil Consumption
According to the US Geological Survey (the branch of the government that assesses oil
reserves) virtually all of the oil that is known to exist or is likely to be discovered in the United States
will be consumed within the next twenty five years. Currently, oil is cheap and abundant, yet the
purchase of foreign oil is the single biggest contributor to our spiraling trade deficit and global
indebtedness. When oil is no longer abundant it will no longer be cheap -- in which case our trade
deficit and indebtedness will likely soar.
Even in peacetime we spend considerable sums just to secure access to Mideast oil.
According to an article in the April 1991 issue of Scientific American, it is estimated that the
Pentagon has spent between 15 and 54 billion dollars annually to secure access to Mideast oil –
even before the fitrst war in Iraq. As long as we are dependent upon the consumption of foreign oil
we will continue to spend much money securing access to the oil and safeguarding the remaining
reserves.
In times of war we spend much more. In the heart of an oil glut we fought the first war in Iraq
to secure access to oil. A quarter of a million Iraqis died and over 60 billion dollars was spent by
the allied forces alone. Shouldn't we expect that when global oil supplies diminish such wars would
become more common and widespread? Already, Middle Eastern nations such as Iran are arming
themselves to exert regional authority and to prepare for such conflicts -- this time with nuclear
weapons. The point is simple: our need for foreign oil compels us to spend considerable sums to
ensure our access to oil in peace time and to fight wars when that access is threatened.
Perhaps most importantly, the consumption of oil or other fossil fuels degrades the
environment through smog, acid rain, the green house effect, and inevitable wide spread accidents
such as oil tanker spills. Millions suffer and many die from respiratory illnesses, entire forests are
being decimated, and vast stretches of ocean are being laid waste. According to the article in
Scientific American, it is estimated that at the current rate of oil consumption the environmental
degradation, increased health care, lost employment, and other factors cost the United States
between 100 to 300 billion dollars annually -- not to mention the 15 to 54 billion dollars that the
pentagon spends in peace time to secure access to Mideast oil -- nor the costs of fighting wars to
secure access to oil such as in Iraq. These "hidden" costs are in addition to the prices paid at gas
pumps. World wide these incidental costs may exceed one trillion dollars annually. The world pays
an enormous price to consume oil -- politically, economically, and environmentally.
6.2. Comparing Tethered wing Electricity Generation and the Solar Power
Solar power has long been promoted as an energy source that is likely to be used to meet much of the future
demand for power. Advocates of solar power point out that it is clean, dependable, and uses a renewable energy source.
While true, all of these claims can be made for Tethered wings Wind Power Generators as well.
Compared to solar energy sources, Tethered wing Generators:
6.2.1. do not require expensive and inefficient energy storage and retrieval systems to convert daytime
power into nighttime electricity,
6.2.2. do not require much sun-favored land since they can share land with agriculture (or go offshore to
avoid the use of land altogether),
6.2.3. can efficiently generate power at far more sites throughout the world (such as anywhere under the
jet streams of the northern and southern hemispheres or over the oceans where the installation of
solar cell arrays would be impractical, if not impossible),
6.2.4. can extract energy from a source that is hundreds of times more powerful per unit area (10 kilowatts
per square meter is often the average power available in winds in the jet stream versus 100 watts of
solar power per square meter), and
6.2.5. are more efficient at extracting power (even windmills are generally more than four times as efficient
as solar cells in extracting power)
6.2.6. could offer a greater return on investment by generating more power at less cost.
In short, Tethered wings hold greater promise for economical and ecological power generation than solar cells.
6.3. The Wind Turbine Alternative
Currently wind turbines offer the most practical and cost effective means of generating electricity from a
renewable energy source, but Tethered wing Wind Power Generators promise to offer a much more cost effective
solution. Wind Turbines will probably always be more efficient, but tethered wing Generators should be much less
expensive to install and maintain when generating equal power.
Unlike standard wind turbines, Tethered wing Generators would not require:
6.3.1. towers,
6.3.2. stationary platforms,
6.3.3. rigid, fragile blades,
6.3.4. airfoil sizes to be limited to the strengths of the towers,
6.3.5. expensive custom low speed generators,
6.3.6. operation in the slow and variable winds close to the earth, or
6.3.7. land.
Tethered wing Generators could use standard generators. Since they would have no rotating blades they would
not be subject to the strong vibrations and torsional forces that have caused many wind turbines to fail. They would be
constructed of inflatable fabrics rather than rigid materials so they would bend and deform in excessive winds rather than
fracture and break. Most importantly, they could fly at higher altitudes where the winds are stronger and more constant.
Generally over level terrain the velocity of the wind varies in relation to the elevation above ground by the "one
seventh power law":
velocity_high / velocity_low = (elevation_high / elevation_low) ^ (1 / 7)
The power available in the wind is proportional to the cube of the velocity, so over level terrain the power in the
wind varies in relation to the elevation above ground by the "three sevenths power law":
power_high / power_low = (elevation_high / elevation_low) ^ (3 / 7)
From this equation comes the simple relationship that winds that are 5 times higher are very nearly twice as
powerful. Similarly, winds that are 25 times higher are 4 times more powerful. Thus, if Tethered wings were to fly just a
half mile in the air above standard level terrain they should encounter winds that would be over 4 times more powerful
than the winds encountered by turbines that were 30 meters (nearly 100 feet) above ground -- and over 6.5 times more
powerful than turbines at 10 meters (nearly 33 feet). These comparisons are for winds above level terrain -- the general
case. Near mountain ridges, and other places where the terrain funnels the air, the power available can increase far more
with changes in height. Likewise, at sea, when strong breezes blow, the power available in the winds varies more
markedly with changes in altitude. This is because strong breezes make waves that effectively slow the winds closer to
the earth even more -- which causes a greater change in velocity with height.
The purpose of these discussions is to show that Tethered wings could tap into winds that are much stronger than
those accessible by commercial wind turbines -- even if the Tethered wings were to fly relatively low. But as the
technology progresses, and as it becomes practical to fly as high as the jet stream, then Tethered wings could tap into
winds that can be hundreds of times more powerful.
Besides being able to tap into much stronger winds, Tethered wings could also be more practically constructed
and deployed in larger sizes. This would allow them to extract power from a greater area. Compared to wind turbines,
Tethered wings would be more practical to scale up to larger sizes for two reasons: 1) Within reasonable limits, key
materials are more economically manufactured, more readily available, and easier to manipulate in larger sizes, and 2)
Tethered wings would not have to be limited to the sizes that towers can accommodate.
If wind turbine towers were made twice as tall then the blades could be twice as long, and the turbine could
extract power from an area four times as great. But the tower could require 16 times as much material
(and cost) to accommodate the greater load at the increased height. This simple example shows the strict size limitations
that towers impose on wind turbines. Tethered wings, on the other hand, have no tower and would channel all the force
that they would generate directly to a generator located on the ground.
7. The Advantages of Constructing Tethered Wings of Larger Size
For nearly all of these applications, the economies of scale should favor Tethered wings of larger size. If the
linear dimensions (length, width, and height) of a Tethered wing were all to double, then the volume and buoyant lifting
forces would increase by a factor of eight. Such an airfoil could support eight times as much payload during periods of
calm wind -- without requiring the use of a stronger tether. The payload or ballast of this airfoil could be adjusted to offset
the increases in buoyancy, so the tether would not have to increase in strength to support the greater buoyant forces.
If the linear dimensions of a Tethered wing doubled, then the surface area, aerodynamic lifting forces, and tether
tensions would increase by a factor of four. This would necessitate the use of a tether that is four times stronger, has a
diameter twice as large, and a drag about 2.5 times greater. (Tether drag increases faster than the diameter and less
than the cross-sectional area.) Therefore, when the tether is the predominant source of drag and when buoyant lift is
small compared to aerodynamic lift (as should normally be the case), each time the linear dimensions are doubled, the
overall lift-to-drag increases by a factor of 1.6. In other words, if a Tethered wing had an overall lift-to-drag ratio of 5.0,
then doubling it's linear dimensions would yield a lift-to-drag ratio of 8.0. The point is, that larger Tethered wings are more
efficient. This means that craft that use larger Tethered wings could travel faster and closer into the wind. Likewise,
Tethered wing Wind Power Generators that use larger Tethered wings could fly higher, tapping into winds that are more
powerful, or they could fly at the same altitudes with a shorter tether since the tether could be more vertical. In these
applications, the increased buoyancy would best be used to provide additional lift so that the airfoil could fly still higher
using even less tether. (It is assumed that the aerodynamic lift would still be much larger than the buoyant lift so a
stronger tether would not be required to support the additional tension due to bouyancy.)
Perhaps, the greatest advantage in increasing Tethered wing size is that the materials that are proposed for
Tethered wing manufacture are more readily available and economically produced in larger sizes. Using proprietary
construction techniques, larger airfoils would be easier to manufacture (within limits) and more aerodynamically refined
and efficient -- again leading to higher lift-to-drag ratios, faster speeds, and higher altitudes with less tether.
8. Technical Endorsements
Many of the ideas that are disclosed in this paper have been reviewed by some of the most widely recognized
authorities on aerodynamics and hydrodynamics:
8.1. Bernard Smith, the Retired Technical Director of the Naval Weapons Laboratory, has been a pioneer
in the integration of airfoils with hydrofoils to make efficient sailing craft. When he reviewed an early
draft of these concepts he pointed out a few inaccuracies and yet wrote:
"Your paper has enough good ideas in it to be worth the effort required to perfect it".
8.2. Later, a revised paper that describes these ideas was sent to the Flight Research Institute (FRI) for
their evaluation. (The FRI was a non-profit experimental offshoot of Boeing Commercial Aircraft.)
After reading the paper, Jack Wimpress, the Retired Chief of Product Development at Boeing, and
Harry Higgins, a Retired Engineering Supervisor, thought that the potential to generate electricity with
reciprocating Tethered wings appeared promising. They invited me to pursue this technology as an
Associate Project Leader under the auspices of the Flight Research Institute (FRI) and offered their
assistance and guidance (which is gratefully acknowledged!).
They wrote a letter of endorsement concerning Tethered wing Wind Power Generators that
says:
"As a result of our studies of your invention we have concluded that your concept is
fundamentally sound and we believe that your goals can be achieved by step-by-step
demonstrations and that each step can be accomplished within a reasonable effort."
Later they reconfirmed their willingness to provide assistance:
"We plan to continue our support of the Project in the areas of technical guidance
and account monitoring as we are able and as long as such efforts will help you attain
our goals. Be advised that we are able to call on professional support from both the
University of Washington and the Boeing Company in support of this work."
To summarize then, the Flight Research Institute offered to assist the Tethered wing Development
Project three ways: 1) by providing free technical consultations and monitoring of project finances by
some of the most widely respected aeronautical design engineers and managers of aeronautical
development, 2) by providing free access to the best aeronautical design and development
computers at Boeing, and 3) by providing tax deductions for money invested in development.
8.3. Reiner Descher, a professor of aeronautics at the University of Washington liked the concept of using
lighter-than-air airfoils in conjunction with hydrofoils to make efficient sailing craft -- and perhaps also
to pull freighters. He said he would like to supervise at least one graduate student who would spend
a year technically and thoroughly evaluating these proposals. We hope to find the funding required to
support this work.
Not too surprisingly, these three evaluators and endorsers have differing opinions regarding which
implementations of this technology should prove to be most practical and profitable, and which should be pursued first.
Smith, for example, believes that Tethered wings could be used as a means to pull freighters. Wimpress and Higgins are
more skeptical about this application and would rather not offer their support to pursue this objective initially. Descher, on
the other hand, believes that it might be possible to design around the technical limitations that Wimpress and Higgins
foresee. Also, Wimpress, and Higgins see more potential in the development of Tethered wing Wind Power Generators
than Smith.
9. Articles or Books Relating to Tethered Wing Development
9.1. Articles Regarding Low altitude airfoil, hydrofoil, and/or tether systems:
9.1.1.
9.1.2.
9.1.3.
9.1.4.
9.1.5.
9.1.6.
9.1.7.
9.1.8.
9.1.9.
9.1.10.
9.1.11.
9.1.12.
9.1.13.
9.1.14.
9.1.15.
9.1.16.
9.1.17.
9.1.18.
9.1.19.
9.1.20.
9.1.21.
Smith, Bernard (Retired Technical Director of the Naval Weapons Laboratory) "New
Approaches to Sailing'', Astronautics and Aeronautics, March 1980, pp.36 - 47.
Smith, Bernard, "The 40-Knot Sailboat'', Grosset & Dunlap, New York, 1963.
Smith, Bernard, "Sailloons and Fliptackers'', American Institute of Aeronautics and
Astronautics, Washington D.C., 1989, p. 76.
C. L. Stong, "The Ultimate in Sailing is a Rig Without a Hull'', Scientific American, (Date
was not noted) pp.118 - 123.
Schmidt, Theodor, "Unusual Sailing Systems for Kites'', (Periodical name was not
noted) February 1984, pp. E75 - E76.
Jalbert, Domina C., "New Uses for Toy that Grows up in the Space Age'', Product
Engineering, Oct. 10, 1966 pp. 38 - 39.
Bradfield, W.S. "Sam'', "A New-Fangled Foiler'', Sail, Nov. 1987, pp. 62 - 66.
Kindley, Mark, "For eye-in-the-sky inventors, kites can be much more than toys'',
Smithsonian, June 1982, pp. 55 - 65.
Loyd, Miles L., "Crosswind Kite Power'', Journal of Energy, May - June 1980, Vol. 4 No.
3 pp. 106 - 111.
Goela, Jitendra Singh, "How does a kite fly'', Science Today, January 1982, pp. 44 - 50.
Goela, J. S., "Effect of Wind Loading on the Design of a Kite Tether'', Journal of Energy,
Oct. 1982, Vol 6 No. 3, pp. 342 - 343.
Goela, J. S., "Performance Characteristics of a Kite Powered Pump'', Transactions of
the ASME, June 1986, Vol. 108, pp. 188 - 193.
"Soviets experiment with linear generator'', Electrical World, June 1987, p. 86.
"Lighter-Than-Air Systems'', Astronautics and Aeronautics, Dec. 1983, pp. 78 - 79.
Goela, Jitendra Singh, "In Search of a Much Higher Source of Energy'', Yankee, Mar.
1979, pp. 69 - 116.
Goela, J. S. "Wind Power Through Kites'', Mechanical Engineering, June 1979, pp. 42 43.
Smith, Bernard, "More Uses of the Airship'', Astronautics and Aeronautics, Oct. 1973,
pp. 5, 77, and 78.
"When Kite Meets Water Meets Skis'', American Kite, Fall 1988, pp. 9 & 10.
Correspondence with Roeseler,Wm. G. "Billy''.
Correspondence with Culp, Dave.
Correspondence with Smith, Bernard.
9.2 Articles Regarding High Altitude Tethered Wing Power Generating Platforms
9.2.1.
9.2.2.
9.2.3.
9.2.4.
Fletcher, C. A. J. et. al, "Aerodynamic Platform Comparison for Jet-Stream Electricity
Generation'', Journal of Energy, Jan. - Feb. 1983, Vol 7 No. 1, pp. 17 - 23.
Riegler, G. et. al, "Transformation of Wind Energy by a High-Altitude Power Plant'',
Journal of Energy, Jan. - Feb. 1983, Vol 7 No. 1, pp. 92 - 94.
Fletcher, A. J., "On the Rotary Wing Concept for Jet Stream Electricity Generation'',
Journal of Energy, Jan. - Feb. 1983, Vol. 7 No. 1, pp. 90 - 92.
AIAA 2nd Terrestrial Energy Systems Conference, "The Transformation of Wind Energy
by a High Altitude Power Plant'', AIAA Paper No. 81-2568.
9.3 Articles Regarding Early Traction Kites.
9.3.1.
9.3.2.
9.3.3.
Laurie, Nick, "Riding the Wind'', New Scientist, Sept. 28, 1978, pp. 922 - 924.
Pelham, David, "The Penguin Book of Kites'', pp. 25 - 29, 55, 56, and 86. Hazel Watson
& Viney Ltd. Aylesbury, Bucks, 1979.
Thomas, Bill, "The Complete World of Kites'', pp. 42 - 45, J. B. Lippicott Company,
Philadelphia & N.Y. 1977.
9.3.4.
Pocock, G., "The Aeropleustic Art'', London, 1827.
9.4 Articles Regarding Windmills
9.4.1.
9.4.2.
9.4.3.
9.4.4.
9.4.5.
9.4.6.
9.4.7.
9.4.8.
Kiler, L. A. (Westinghouse Electric Corp. East Pittsburg, PA.) "Design Study and
Economic Assessment of Multi-Unit Offshore Wind Energy Conversion Systems
Application'', June 14, 1979, Vol 3., 192p and Vol 4., 344p. WASH-2330-78/4
AIAA/SERI Wind Energy Conference, "Offshore Wind Energy Conversion Systems'',
AIAA Paper No. 80-619
Baker, R. W. and Hewson, E. W., "Network Wind Power Over the Pacific Northwest'',
Oct. 1979 - Sept. 1980, 122p., DOE/BP-60 DE81 029291
"Coastal Zone Wind Energy'', Mar. 1980, 192p DOE/ET/20274-7
Bhatia, Ramash, "Socioeconomic Aspects of Renewable Energy Technologies'',
particularly ch. 5, "Windmills for irrigation: Sri Lanka, Kenya, Cape Verde, and the
Sudan'', Praeger 1988.
Piepers, Gijsbrecht G., "Wind Energy in China'', Alternative Sources of Energy, pp. 40 &
41, 1981.
Putnam, Palmer Cosslett, "Power From the Wind'', 1948, Von Nostrand Reinhold
Company, New York.
Considine, Douglas M., et. al, "Energy Technology Handbook'', 1977, Mc Graw Hill.
9.5. Articles Regarding Wind Propulsion.
9.5.1.
9.5.2.
9.5.3.
9.5.4.
9.5.5.
Lawrence, Patricia A., "Wind Propulsion For Commercial Vessels'', Apr. 1986, 16p.,
PB83-202580.
Gerritsma, J., "Wind Propulsion of Merchant Ships'', Mar. 1983, 36p., PB83-175489.
Bergeson, Lloyd, et. al, "Wind Propulsion for Ships of the American Merchant Marine'',
Mar. 1981, 276p. PB81-162455
Shortall, John W., "Sail Assisted Commercial Marine Vehicles Bibliography and
Abstracts'', Mar. 1983, 111p. PB83-192286
Graham and Schlageter, Inc., "Economic Feasibility of Sail Power Devices on Great
Lakes Bulk Carriers'', Sept. 1982, 78p. DOE/R5/10288-2 DE83 001119
9.6. Articles Regarding Airships
9.6.1.
9.6.2.
9.6.3.
9.6.4.
9.6.5.
Vaeth, J. Gordon, "The Airship Can Meet The Energy Challenge'', Astronautics and
Aeronautics, Feb. 1974, pp. 25 - 27.
Hecks, Karl, "Pressure airships: a review'', Aeronautical Journal, Nov. 1972, pp. 647 656.
Hunt, Jack R, et. al., "The Many Uses of the Dirigible'', Astronautics and Aeronautics,
Oct. 1973, pp. 58 - 64.
Morse, Francis, et. al., "Dirigibles: Aerospace Opportunities for the 70's and 80's'',
Astronautics and Aeronautics, Nov. 1972, pp. 32 - 40.
Sonstegaard, Miles H., "Transporting Gas by Airship'', Mechanical Engineering, June
1973, pp. 19 - 25.
9.7. Articles Regarding Environmental Factors
9.7.1.
Solar Energy Research Inst., "Application of US Upper Wind Data in One Design of
Tethered Wind Energy Systems'', Feb. 1982, 133p. SERI/TR-211-1400 DE82 01 2880
9.7.2.
Daniels, G.E. (NASA) "Terrestrial Environment (Climatic) Criteria Guidelines For Use in
Aerospace Vehicle Development'', July 1973, 472p. NASA-TM-X-64757 N74-16292 thru
N74-16311