WIG Hovertrain: Innovation Takes Time

In 2012, I wanted to share my idea for a form of rapid transportation that uses magnets for propulsion and the wing-in-ground-effect (WIG) for suspension above a track. Various “hovertrain” ideas using air suspension have been examined since before I was born, but are still being explored today as well. I have spent many years studying the variations others created before my own “eureka” moment, and many exceptional inventors have repeatedly tried to create a floating train system through the years. This is the story so far of my design in case it can help you with your own design as well. I often use this example to illustrate the design and conceptualization process during Inventing Merit Badge sessions for the Boy Scouts or in the STEM sessions on innovation at other events.

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Magnetically-levitated (MagLev) trains were first patented in the US in 1905 by a German inventor named Alfred Zehden with another in 1907 by F. S. Smith, but then World War I took the world’s attention. After the end of the war, a flurry of designs in the 1930s by other Germans like Hermann Kemper, again sought to bring a floating train to the world but World War II again caught the attention of the global powers. After the great war during the 1950’s, patents from designers like G. R. Polgreen and others in America, Canada, German and the United Kingdom again proposed magnetically levitated trains but the first functional MagLev wasn’t to appear until the 1984 MAGLEV at Birmingham Airport.

Birmingham Airport MAGLEVSince that time, other designs like the Railway Technical Research Institute (RTRI)’s MLX01, American California University of Pennsylvania (CUP)’s MagLev System (MagnePlane), and the magnificent German Transrapid system, conceived back in 1934 but not brought into public service in the 1990s. The MLX system runs within a box track using repulsive magnets, the MagnePlane was designed to operate within a track with a round profile using repulsive magnets, and the Transrapid system is lifted by attractive magnets towards the track’s elevated rail.

Another path towards floating trains did not require powerful magnets, but relied instead on aerodynamic support like that in hovercrafts (air cushion) or like birds use when flying above water (wing-in-ground-effect). An air-cushion design relies on pressurized air below a vehicle providing support and reducing drag, and works both while still and in motion, while the ground-effect design uses similar strategies to pressurize air under a moving vehicle’s wings for support. Very close to the ground, ground-effect designs take advantage of the interaction between their supportive air and the ground, sliding atop this layer with far less resistance to forward movement. The first patents of ground-effect vehicles were submitted by designers like the Austrian Dagobert Müller in 1915, and followed similar patterns as maglev designs around the two World Wars.

French Aerotrain from the early 1970's

In the early 1960’s, the American Tracked Air-Cushion Vehicle (TACV), and its later French counterpart, the Aérotrain, explored flying trains supported like a hovercraft running on a track. Another popular design was the DIY “Air Car,” made from a vaccum cleaner and used to scoot around the house. The Air Car was featured many times in Boy’s Life magazines and I recall it from my father’s collection of those from the 1940’4s or 1950’s.

Russian Ekranoplan

Recent hovercraft designs are used for vehicular transport over water in civilian or military configurations, while ground effect craft have left the track behind and operate close to the ground in WIG as well as flying out of ground-effect as airplanes do, relying on wind airfoil dynamic lift. These scale from small personal designs like the Flarecraft to massive heavy-lift military transports like the Russian Ekranoplan built during the Cold War era.

Japanese Aerotrain

Recent tracked ground-effect vehicle designs include the Japanese Aerotrain from 2011. This design uses an enclosed track with a box-shaped profile, along with horizontal lifting surfaces and vertical alignment surfaces to maintain its position within the track while in motion.

Elon Musk's HyperLoop

The latest idea for a high-speed rail transportation system using a tracked air-cushion design, is a design by Elon Musk, termed the Hyperloop. This design uses a leading intake to pressurize air below the vehicle’s plenum, exhausted to the rear, reducing forward air pressure and provide contact-free movement along the box-shaped track. Press coverage indicates this design is intended to operate in near-vacuum to reduce resistance from the vehicle’s passage through the atmosphere.

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Original idea in 1988

My original idea for a Pneumatic/Magnetic Levitant vehicle in 1988 borrowed from the Boy’s Life hovercraft design, but I considered it operating atop a rail track. I noted this design in my journal after reading about traffic congestion at the D/FW air terminal, during a summer class at Odessa College where our professor had asked us to offer a potential solution to problems caused by population growth in Texas.

1989 vehicle pressure waves within track

A year later, I was considering the design while taking a Music course, and realized that a vehicle travelling within a solid track would create a significant pressure wave and reflections during its passage. By tuning vehicle speed based on barometric pressure, altitude, and humidity, that pressure wave could improve energy efficiency of the vehicle by combining at the rear of the moving vehicle to “push” it ahead. Testing this premise involved a lot of driving close behind large vehicles with a hand-made wind tunnel strapped to my hood where local law enforcement asked me to stop “drafting” off big trucks regardless of the scientific merits of those experiments.

1990InvertedV

In 1990, after playing a fierce game of Air Hockey, which uses air pressure from a fan below the game surface to support a plastic game puck without resistance to movement, I attended a Physics course where we used a track with the same principle to test basic principles of motion. I realized this design could work well with a magnetic linear motor propulsion system and later drew that up in the Drafting course for a lab assignment. 1991 Intake manifold

In 1991, I developed the idea for a track-independent means of providing compressed air beneath the vehicle, instead of providing air from the track itself. By using a leading intake to compress air and release it below the plenum, I could reduce the total volume of air needed along an extended track. Testing the design using electromagnets in the track and permanent magnets in the vehicle’s extended wings, I was able to determine relative efficiency using different intake and compression systems.

1991 Compression Plenum

Preliminary testing using the same hand-built wind tunnel identified that laminar flow of air could be improved by adding turbulence producers to the rear third of the vehicle’s upper surface along with pressure relieve valves in the trailing edge of the vehicle.

1991 track flow

Still in 1991, I started considering the process by which a car could enter and depart the motive track, and used this in several simulations I turned in for Computer Science classes while I tested different types of track and wheel bogey configurations, looking for a system that could operate and enter/leave without very large switching systems, whose movement could eventually cause difficulties if they slowed due to damage or age.

1992WIGLevitant In 1992, I settled on a broad horizontal profile with angled extensions for the track. This allowed the extended wings to dynamically balance the vehicle in ground-effect, so that during a turn, the inward side would close on the track and be reflected more strongly by the compressed air under that side, while the outward side would move away from the track and lose a measure of its lift until it dropped back to designed spacing. High-frequency coils in the broad horizontal part of the track could provide inductive power to the cabin itself without affecting forward propulsion provided the frequency was at least 17 times that of the linear motor’s magnet transitions.

1993 Variable Wing AngleAfter visiting San Francisco to speak at a conference in 1993, I returned with ideas drawn from the street cars and pantograph power systems they use. I modified the prototype model to include a variable wing angle of attack, so that the same vehicle could travel on the ground-effect track and standard light rail systems with support from an onboard electric motor – either powered by on-board batteries or through an external catenary wire like the pantograph powered streetcars. This flexibility would allow the use of common light rail during the transition towards ground-effect track mobility for higher rates of travel during the build-out of its infrastructure. Because the system has no contact between moving parts, it is perfect for alternative energy sources such as solar photovoltaic panels covering the track along its route, perhaps assisted by flywheel energy storage overnight.

During tests of the prototype in 1993, the model was damaged by debris cast from a passing truck carrying gravel. Patching the wing surfaces created a vehicle that eliminated the leading-edge tendency to dip towards the track so I considered multiple intake scoops along the wing’s upper surface, which created new limitations to overall speed as the forward pressure wave extended rearwards at increased speed, tearing out some of the new patches in the wings and causing a catastrophic performance during the final test of that model.

1993 divided sponsons

Damage to the prototype model’s wings during wind-tunnel tests caused me to consider a replacement for each wing as a series of smaller winds connecting the vehicle’s main body with a sponson on each side, much like the stabilizers on a Hawai’ian sailboat design called a Proa. I discovered much greater lift at lower speeds but higher drag once the following low-pressure zone extended to just ahead of the next wing in series when operating at higher speeds. Greater angle of attack for each wing could be increased for lower take-off speeds, but this adds a greater opposition to air passage at higher speeds, creating vortices behind each wing and making the design more susceptible to cross-winds and local microbursts.

1993August7

Repairing windows shutters later that summer offered a solution to lift variations between slow and fast travel above the ground-effect track, using variable yaw alignment of the new independent smaller wings at lower speeds that could close their spacing and reduce the angle of attack at higher speeds. At low speeds, each airfoil can provide dynamic lift for the vehicle as it accelerates, then the spacing can be closed to form a barrier for the plenum high-pressure support zone at higher speeds. By allowing the wings to be opened in response to angular displacement from side-winds, the vehicle could be kept safely closer to the track at a slight cost to forward velocity and energy efficiency overall. 1993 Track Mock-up

In the last testing series, I constructed a segment of track to support the modified prototype model. Under test, this prototype proved the system was capable of function although the vehicle’s aerodynamic properties needed additional refinement to stabilize certain issues with resonance during the transition from low-speed to high-speed travel and the converse when slowing down. A temporary overhead large pair or trailing ailerons provided measurable lift and stability in this configuration. Roadway pools of water splashed up by passing vehicles during the final test that year doused both track and vehicle, resulting in the eventual destruction of both as the cardboard and paper were partly returned to their original pulp at high speeds.

In 1994, I tried to attract interest in building a functional prototype as a proof of concept, talking to venture capitalists and the Bass family (Dallas-based billionaires involved with Disney at the time), but was told that existing air travel would cover the need for high-speed transportation past the end of the century at least.

In 1995, I received a formal notice threatening legal action by Southwest Airlines for polling people visiting the local Permian Basin airport, trying to determine what areas of air travel they found most unpleasant. Southwest’s contract at that time with airports it served disallowed any advertising or polls that cast negative attention on airlines.

In 1996, I moved to Texas A&M University, where I entered a dual-major degree plan for Mechanical Engineering (MEEN) and Electrical Engineering (ELEN), but the Vice President for Research (VPR) and the Texas Transportation Institute (TTI) both informed me that the time for passenger rail had long past and air travel was the current focus for long-distance, while ground independent vehicles were the obvious future for short- to mid-range travel.

In the mid 1990’s, the Intermodal Transportation Consortium awarded me an honorary membership for “Advances in the field of high-speed rail transportation” after I shared a copy of the deigns story with them.

This information was posted to an early web hosting service called Geocities in the late 1990s, and during the new “spare time” following Y2K preparations, I transferred it to my own website in 2000 as 2000MaglevFull with a shorter version 2000MaglevBrief for quick review.

In 2006, I submitted the design to Popular Science for one of their “Top New Designs” contests as 2006PopSciFlyingCarpet, but was told that some of my alternative energy production designs might have made the final cut if I had done the same amount of work on those instead.

In 2008, a German designer contacted me asking for more details on the variable-plenum design, but I have not heard back from him since. I hope he is still working on this in some way. Others have contacted me over the past several years, including the designer of the Air Sledd from YouTube, and many of my old friends after Elon Musk’s release of his new Hyperloop design since they wondered if it was my shared design once more.

To the best of my knowledge, that is not due to my own designs, as Mr. Musk is obviously a creative genius in his own right, and the design is fairly obvious once you think about Air Hockey and trains. I have posted several comments on Mr. Musk’s blog and through his contact forms at both Tesla and SpaceX, noting a few things to consider in his designs since he released the Hyperloop concept, but have never heard back if any helped him.

Since my first public posts would count as “prior art” in patent terms, I have long-since tried only to share the designs with other developers in the hopes that they may someday sponsor creative ideas that can help our world and its people.

Color rendering of the PML design

These days, I teach InfoSec courses at several universities and STEM workshops (http://STEMulate.org) for pre-collegiate students, leveraging my long experience with many different technologies in the inspiration and instruction of your next generation of Makers. I also write many technical novels, including the latest “3D Printing for Dummies” I developed around the SOLID Learning (http://SOLIDlearning.org) program, focused on developing 3D printed materials and tools for educational settings.

I have been teaching a series of 3D printing workshops this summer as part of the Aggie STEM Camp, but not on electric trains, flying or not.

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Please do let me know if you have a new idea for a design like mine, and if you are not going to develop it commercially – consider sharing the idea under Creative Commons license or as open-source so that others can use it to inspire their own creativity! After almost twenty-five years, I am still seeing new designs that are variations of my earlier-stage designs, and always try to share my own process with their creators. There are excellent results from turning many different minds towards the same fundamental tasks, and the failing of one alternative could be the prime benefits of another.

Always remember that creativity is not an all-at-once thing, it takes time, but it is nice to see a design realized in full form. Make sure to support your students, children and other when they bring you a new innovative idea!

[ CREATIVE COMMONS – ATTRIBUTION ]

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