9 July, 2018
Photo: Boeing's container plane concept
A researcher connected with Boeing envisioned a commercial jet aircraft capable of carry high priority containers. except that most commercial airports restrict the landing weight and wingspan of large aircraft.
Advancing research into wing-in-ground effect vessels could develop a winged ship mobile airport capable of carrying heavy freight aircraft that would be banned from commercial airports.
While mega-size container ships offer the lowest transportation cost per container per ton-n.m. on extended length voyages, there is a segment of the international trade market that seeks faster delivery of containers even at elevated transportation costs. This market segment includes container trains that travel between China and Europe, including trains that travel through Russia and that utilize special ‘change-of-gauge’ technology built into the axles and suspension systems to provide passage on different railway gauges. These trains may carry a minuscule segment of the Europe – Asia container market, at premium costs.
The railway option is not possible across the North Atlantic and Pacific Oceans where there may be a demand for fast delivery of containers and an absence of suitable technology to provide the service. Environmental concerns about the well-being of ocean wildlife could restrict the operation of trans-oceanic hydrofoil vessels. Winged ships that travel just above the water surface would pose less of a hazard to many forms of oceanic wildlife. Such vessels guided by computer could carry medium priority container freight at competitive tariffs on extended length, trans-oceanic voyages at speeds of 150 to 300-miles/hour.
Winged Ship Energy
Winged ships consume less energy of aircraft of equivalent weight and speed flying at 10,000 feet altitude in 70 percent of sea level air density. If the winged boat traveled at 150 mi/hour or half the speed of the aircraft flying at 300-mi/hour, it would consume 1/3 x 1/8 = 1/24th to 1/16th the energy. Compared to a jet freight airplane laden with containers flying at 600 mi/hour at 35.000 feet altitude in 25 percent sea level air density, an autonomous winged ship carrying the equivalent load and traveling at 150 mi/hour would consume 25 percent of (1/2 x 1/64) = 1/32nd to 1/24th the amount of energy.
Winged ships traveling at 300 mi/hour and close to ocean surface would still offer significant savings over freight aircraft flying at 300 mi/hour at 10,000 feet as well as at 600 mi/hour at 35,000 feet. However, if a segment of the container market seeks trans-oceanic delivery aboard a vehicle that travels at 600 mi/hour, the low air density at the high altitude would provide the freight aircraft with a slight competitive advantage over winged ships traveling at the same speed. Modified tandem-wing winged-ships operating as mobile runways could carry extreme size and weight of container aircraft during lift-off and touch down operations.
The tandem wing concept developed in Germany could serve as the basis by which to develop a mobile and floating airport capable of carrying freight container aircraft that would be too heavy to operate between commercial airports. A winged ship with perhaps 10 miles of designated seaplane runway could accelerate with a container freight airplane secured on its deck, beginning by riding on its hulls before rising in the water to ride on its hydrofoils. Further acceleration combined with directing some of the engine jet stream under the wings would enable the vessel to ride above water.
The slightly airborne vessel would further accelerate to above the lift-off speed of the freight aircraft secured to its deck, to assist the aircraft to becoming airborne and with the ability to slowly climb to jet altitude and jet speed. A combination of autonomous control involving coordinated speed, vehicle positioning and communication between navigation computers would assist to guide an incoming container aircraft to gently touch down on the deck of the speeding winged ship that would subsequently reduce speed to allow hydrofoils to contact with water and further reduce speed for hulls to touch on water.
Upon arrival at a transfer terminal, the aircraft could travel over a ramp extending from a dock to the winged ship deck. It could carry all containers in its hold or leave all containers on the deck of the winged-ship, to be transferred off the winged ship by crane. While many winged ship transfer terminals would be built at oceanic coastal locations, others may be built on the shores of inland lakes and along the banks of wide rivers. Containers would be transferred to high priority trucks and trains for their trip to their final destinations.
Boeing’s concept container carrying plane is intended to reverse over a pre-arranged array of stacked containers, lower itself before attaching to the containers and then raise itself on to its wheels. It could undertake such a task on the deck of a specially designed winged ship in preparation for lift-off. A fast moving tandem wing or multi-wing winged boat would allow the container plane flying at the same speed, to touch down on its deck, with the option of the plane lifting off after unloading the full consignment of containers.
An airplane capable of carrying a larger compliment of containers than Boeing’s original concept plane could be viable on some routes with high density of container traffic. Over time, the earnings from carrying additional containers would need to cover the capital and operational costs of winged mobile airports on which the large container airplanes may touch down and from which they would become airborne. Commercial airports do change fees to carriers for airport services that include landing, take-off and terminal operations. A container carrier airplane minus its payload could fly to a commercial airport for maintenance.
A container carrier airplane built as a seaplane would require additional structural reinforcement that would add to its total weight that would include pontoons and hydrofoils. As well, it would require additional engine power to accelerate across a water surface to sufficiently high speed to launch itself into flight. When carried on the deck of a ground effect vessel, it would become airborne at much lower speed and the combined engine power or airplane and winged boat could accelerate the laden container airplane to well above its design take-off speed.
Boeing’s patented container carrying concept airplane is limited in its capacity by the landing weight at commercial airports. There may be scope to develop a winged boat capable of traveling at the touch down and take-off speeds of such an airplane and with potential to allow such a plane to be built to carry much heavier loads and fly either with great wingspan or with multiple wings to carry the weight. The ground-effect capability of the winged boat combined thrust of engines from both winged boat and airplane would allow for easier lift-off above water compared to seaplanes. It is a concept that may have future potential.