While maritime transportation offers the lowest costs per container, a portion of the market seeks fast delivery of their containers. This market niche sends containers by rail between China and Europe, at higher transportation costs, and it is extending across the ocean where an evolving technology could carry containers much faster than ships and at much lower rates than heavy-lift freight aircraft.
A market for faster transportation of containers has been developing over several years. Across extended distances separated by ocean, wing-in-ground effect transportation technology shows possible promise. Russia built the Caspian Sea “Monster” also known as the “Ekranoplan” that was originally intended for military transportation. Boeing developed a concept ground-effect plane called the “Pelican” that was intended to fly with 300-feet wingspan. It was intended to travel a few feet above water across ocean and on approaching a coast, increase altitude to up and over 10,000 feet. Boeing suspended the Pelican project.
Present wing-in-ground effect vessel builders have so far developed small versions of the technology, several utilizing the triangular or reverse delta wing profile while a single German builder utilizes the tandem wing arrangement. Triangular wing builders are located in Singapore, South Korea, Germany and Australia. Russian designers combine the rectangular main wing with a high-mounted tail wing, a feature also common to the triangular wing variants. One Russian concept proposes to carry four lengthwise rows of containers, placed in six columns built into special compartments across the upper width of each “blended” wing that involves extreme chord length.
Heavy-lift Freight Aircraft
While several designs of heavy freight aircraft are able to carry standard shipping containers, these heavy-lift carriers operate mainly in military transportation service. Boeing has shown a simulation presentation of a concept civilian heavy-lift carrier of 28 standard shipping containers stacked in two levels of 14 containers carried width-wise, with rapid loading and unloading capability. The largest heavy-lift freight aircraft in the world is the Russian built Antonov-AN-225 with a take-off weight of 700 tons.
Many commercial companies engage in fast transportation of freight using modified commercial aircraft, but they have been reluctant to develop air transport of standard containers. Fuel consumption represents the single biggest cost factor in commercial freight aviation, and very few airports internationally can serve an aircraft of 700-ton weight and 289-foot (88-meter) wingspan.
The market for international fast transportation of standard shipping containers may require a trans-oceanic vehicle that is faster than ships and perhaps travels at the speed of a long-distance fast freight train, while consuming a fraction of the fuel of heavy-lift commercial aircraft. There may be an evolving market application for a large, heavy-lift wing-in-ground effect vehicle that lifts off from and touches down at seaplane runways.
Fuel consumption varies with engine power output that in turn varies with vehicle speed. Aerodynamic (hydrodynamic) drag varies with the square of vehicle speed while power required = drag x speed making power vary with the cube of the speed. Doubling vehicle speed increases power requirement by a factor of eight, in turn increasing energy consumption by a factor of eight. For equal weight and frontal cross sectional area, a ground effect vehicle traveling close to a ground or water surface will require a third of the power of the identical vehicle flying at 1,000 feet elevation using aeronautical wings.
Air density at ground level is 1470/347 = 4.25 times that at 35,000-feet, so converting a jet liner to a ground effect vehicle will increase power requirement and fuel consumption by a factor of 4.25/3 = 1.42 times. By slowing the plane from 500 mph to 250 mph, power requirement and fuel usage would drop to 1.42/8 = 0.18 or about 20 percent of the amount consumed at 35,000 feet at 500 mph. A type-A ground effect vehicle built up to 2,000 tons laden weight and carrying standard shipping containers, could touch down on and lift off from designated seaplane runways at protected bays and inlets.
Economy-of-scale would contribute to the economic case of large type-A ground effect vessels built to several times the laden weight of commercial freight aircraft and traveling at about a third the speed to reduce energy consumption. While carrying many times containers as freight aircraft, the transportation cost per container is intended to be a fraction of that of such aircraft. A percentage of the market may be willing to delay delivery of their containers by a few hours compared to air freight, to realize savings in transportation rates. Builders may need to collaborate to build such a vehicle.
U.S.-U.K.-Europe: Railway lines at the City of Bristol connect into the Western Europe via a tunnel built under the English Channel. Bristol is located on the Trent-Severn channel where a designated seaplane runway for ground effect vehicles may be possible. Along the American east coast, a designated seaplane runway may be possible at Long Island Sound with a container terminal being located near La Guardia Airport or near railway lines located on both sides of the sound. The ground effect vehicle would be able to accelerate to lift-off speed on calm water at both ends of the route.
U.S.-Australia: There may be scope to designate seaplane runways at both the bay at San Francisco and at Botany Bay, Sydney Australia, where container terminals for ground effect vehicles may be located next door to the international airports. Railway access would be possible at both Sydney and San Francisco. Both locations would provide calm water for a ground effect vehicle to accelerate to lift-off speed.
Asian Locations: There may be scope to designate a seaplane runway for ground effect vehicles at Johor Strait near Singapore, where a container terminal may be located near Changi Airport. At Hong Kong, a designated seaplane runway may be possible right next to the international airport, where a container terminal may be located. At Osaka in Japan, a seaplane runway may be possible next to Kansai International Airport. At South Korea, a designated seaplane runway may be possible near Seoul and close to Incheon International Airport.
Brazil: The international airport at Rio de Janeiro is located at the inner bay where a container terminal for ground effect vehicles may be developed. Upon arriving at and departing from Rio, the central span of the bridge measures 300 meters (1,000 feet) while the spans of the immediate adjacent spans each measure 200 meters (660 feet). The bridge is of sufficient height to clear large ships and airborne ground effect vehicles guided by automated computer navigation control. Route connections to the eastern U.S. and Europe (via the U.K.) are possible.
Trans-Arctic route: Between late in April to early December, ground effect vehicles that fly at sufficient elevation could travel via the Arctic region, connecting east coast U.S. to eastern Asia, west coast U.S. terminal in U.K. and also a major western European terminal to major Asian terminals. Ground effect vehicles would still be capable of travel across the Arctic when early winter conditions prevent ships from sailing via the region.
Trans Ocean Requirements
A large ground effect vehicle may likely be built with catamaran twin hulls or even triple hulls to provide good stability in wave conditions during touch down and lift off. Designers may consider including retractable hydrofoils to increase speed during journey departure to assist with lift off. An airborne vehicle traveling at perhaps two meters elevation above “calm” deep seawater could manage waves where crests could be 1,000 meters or 1,600 feet apart and wave height of six meters (20 feet). The vehicle could also be designed to travel at higher elevation when storm conditions occur on the open ocean.
Russian designers claimed that the Ekranoplan could travel at 10 meters (33 feet) above the Caspian Sea. The South Korean built ground effect vehicle could apparently climb to an elevation equal to 40 percent of its wingspan, suggesting that a vehicle built to a 40-meter (132-foot) wingspan may be able to climb to 16 meters (52 feet) elevation. Type-B wing-vessels are designed to climb to 150 meters (500 feet) elevation, and some routes would require such performance capability. Ground effect vehicles intended for trans-ocean service across the open ocean would require sufficient elevation capability to travel across storm driven seas.
Vehicle Research Challenge
Courtesy of the presence of a local industry building ground effect craft, engineering researchers at National University of Singapore studied the dynamics of such technology. They discovered that changing the scale of the technology revealed changes in vehicle dynamics that were inconsistent with change of scale. Russian researchers who have built large-scale ground effect vehicles for military purposes have been reluctant to elaborate on vehicle dynamics inconsistencies related to change of scale. The large-scale Russian vessels built with rectangular main wings provide a basis to add a second wing in tandem configuration behind the main wing.
In Germany, research engineer Gunther Jorge built several tandem wing ground effect vehicles in Germany. The configuration offers future promise of an extended length mega-size type-A vehicle built with two-pairs of main wings (60-meter wingspan) in tandem configuration plus the high elevation tail wing for improved stability when carrying heavy payloads over rough seas. Such a configuration would require further research, as would a mega-size vehicle built with triangular or reverse-delta shaped wings of up to 60 meters wingspan. Researchers would need to focus on a possible 2,000-ton vehicle capable of extended-distance trans-oceanic service.
Partial Scaling Alternative
Several years ago, a researcher who discovered that some occurrences that involve either fluid dynamics or thermodynamics cannot be scaled, suggested an alternative that involves partial scaling. When applied to a rectangular wing profile, the partial scaling approach would involve building a section of wing, including a tandem wing configuration at full height and length, but only 0.3 meter or one foot in width. Fans would blow air at varying flow rates into the narrow and high inlet. A rectangular wing would involve building and testing multiple narrow sections of wing profile that represent different regions of wing.
The intended objective of partial scaling research would be to develop a wing capable of carrying a trans-oceanic ground-effect vessel of 2,000 tons at speeds of 25 to 35 percent that of commercial freight aircraft, at sufficient elevation to assure passage across storm driven ocean wave conditions. Each of the forward and rear wings of a tandem wing configuration would likely involve greatly extended wing chord length to carry such a weight objective involving a vessel of perhaps 60-meter wingspan and the overall length of a bridge span.
The largest hydrofoil boats built involve a weight of 300 tons or less than 50 percent the take-off weight of the Antonov AN-225 aircraft. A catamaran hull vessel of 2,000 tons weight and built with ground effect wings would need to accelerate to between 100 km/hour and 150 km/hour to become airborne then lift to sufficient elevation to travel above waves at speeds of over 200 km/hour (125 miles/hour). Gas turbine engines with exhaust heat reclamation to improve efficiency would form the basis of propulsion, possibly driving propellers the diameter of helicopter rotors to maintain high propulsive efficiency.
One American proposal that eliminates the reduction gearbox uses an engine-driven turbo-compressor to pump air through a pipe and into air ducts housed inside a rotor-propeller built with jets at the blade tips. General Electric is apparently developing a compact closed-cycle gas turbine engine that generates electric power that could drive multiple propellers on a mega-scale ground effect vehicle. The turbine engine industry seems able to provide engines capable of accelerating a 2,000-ton ground effect vehicle to lift-off speed and maintaining a high trans-oceanic cruising speed, provided that researchers could design a potentially successful version of such a vehicle.
The leading edge of the wings of ground effect scoop air to generate the necessary air dynamics to lift the vehicle as it accelerates. To enhance the lifting dynamics, some Russian builders have installed propellers forward of the leading edges of the wings. The arrangement directs a portion of the rearward moving fast stream of air under the wings, to enhance lift. There may be merit to installing forward propellers ahead of the wings of large-scale ground effect vehicles to enhance vehicle lift upon acceleration to higher speed and while traveling, to increase vessel elevation to ride above waves.
There may be scope to install an electrical generator to the main turbine engine, to produce electric power to activate forward propellers. At some future time, compact size closed-cycle turbine engine that drive electrical generators would provide power to sustain operation of both forward mounted and rear mounted propellers.
There is much ongoing development internationally related to autonomous vehicle navigation. Such navigation has for decades assisted commercial airline pilots on long-haul flights. In this modern era, there would be scope to adapt an undated version of automatic pilot control to navigate mega-size ground effect vehicles traveling extended distances across ocean. Following departure from a terminal, a reel-out glider housed in the tail assembly would reel out to an elevation of up to 2,000 feet to scan ahead and feed information to the automatic pilot. It would reel in upon arrival at the destination terminal.
Upon departure and arrival, remote crews located at shore-based play stations would navigate the ground effect vehicles using restricted-frequency radio control. An alternative could involve a small aircraft being attached to the vessel upon departure, with crew providing navigation. Once away from shore, the small aircraft would detach and return to its base, with crew onboard. Prior to arrival at a terminal, crew piloting a small aircraft would touch down on the deck and assume pilot control, guiding the mega-vessel to a terminal.
While Boeing is recognized for building commercial and military aircraft, the company has also built hydrofoil ferry vessels. Researchers in the faculty of engineering at National University of Singapore have for several years investigated various aspects of wing-in-ground effect vehicles, courtesy of Singapore being home to a builder of a 12-passenger version of such a vehicle based on triangular or reverse delta wings. The Wing-ship group of South Korea has built a 50-passenger version of such a vessel. In Germany, the Flair-boat company has built several vehicles that use a tandem wing arrangement.
While a Russian builder has shown a design of a container-carrying ground effect vessel, an extended length tandem wing version of the vessel could likely increase container carrying capacity from 48 to 60 TEU. Perhaps there may be scope for Boeing to discuss future prospects of mega-scale ground effect technology carrying containers over extended distances across ocean, with Asian and German builders of the triangular wing and tandem wing versions of ground effect craft. There will need to be discussions with possible customers such as UPS and FEDEX or even ship transportation companies.
Railway transportation along the East Asia – Western Europe container transportation link has revealed a market niche for fast movement of containers at premium tariffs.
Based on the Asia – Europe train, as yet untapped market niches that involve faster trans-oceanic container transportation than ship at much lower tariff than air freight would likely include several international links that is beyond the development of railway service could.
Potentially viable market niches may exist on links between East Asia and Western U.S., also between the northeastern U.S. and Western Europe.
The business case of a viable container-carrying ground effect vehicle built to many times the weight of the largest heavy-lift commercial aircraft, would be to carry many times the number of shipping containers at much lower per-container transportation that its high-altitude competitor.
Autonomous navigation would reduce crew requirements on long-haul voyages.