Construction in the developing world, where roads, bridges, tunnels and other infrastructure are not yet established, often calls for extreme access requirements. Special tools now are being developed or deployed to get construction staff, materials and supplies into such regions.
Take, for example, an Oregon-based contractor that is preparing to mobilize for the first application of precision heavy-lift helicopters in India to construct electricity transmission lines in inaccessible terrain. Meanwhile, last summer, an aerospace university major unveiled a hybrid airship to transport cargo and personnel to remote sites.
These are two very different aircraft designed and built for a similar purpose: One is a twin-engine helicopter; the other, a combination blimp and airfoil. But the mobility and precision-lifting capacity offered by the two may greatly reduce obstacles posed by geography and topography for remote construction projects. Officials of both companies see demand for them growing, especially in developing countries, where burgeoning demand for electricity, water, sanitation and other necessities is creating a market for equipment and services that can cost-effectively and safely overcome once-insuperable obstacles.
Erickson Inc., Portland, Ore., this month won a contract with Sterlite Grid, India’s largest private developer of independent power-transmission systems, to install nearly 160 double-circuit, lattice-steel transmission towers in the challenging terrain of the Pir Panjal mountain range, in northern India, using Erickson’s S64 Aircrane helicopter. Contract terms were not disclosed.
Erickson’s project encompasses one of the most challenging sections of Sterlite Grid’s $436-million Northern Region System Strengthening 29 project, a 400-kV transmission line to deliver 2,000MW of power from Punjab to energy-starved Jammu and Kashmir, deep in the Himalayas. Another American firm, Burns & McDonnell, is acting as owner’s engineer for a 54-kilometer section of the line. Erickson will assist Sterlite Grid by flying in materials and steel as well as using the Aircrane’s high-precision lift capability to erect the towers along the power line. The work will be performed at altitudes between 9,000 and 12,500 ft in a remote region of the Himalayas.
The company currently is planning to deploy just one Aircrane to the project, plus one smaller support ship, says Jeff Stein, transmission-line sales manager. The S64, a modified Sikorsky helicopter, has a maximum velocity of 115 knots and a range of two hours of operation, equivalent to 230 nautical miles.
“The S64 was purpose-built for precision heavy-lifting,” Stein says. “It was not designed as a high-speed transport aircraft.” Instead, it trades speed for the other characteristics. “There are times when it may be desirable to move material—gravel or rock or cement—but it’s generally within a 10- to 15-mile range, and the longer ranges reduce the payload capability,” he adds.
Additionally, the S64 Aircrane “is the only aircraft that was ever designed to do precision, external-load operations,” Stein says. Instead of the usual complement of two pilots, a third occupies an aft pilot station that offers an unobstructed view of the load when it’s being picked up and, together with a patented, anti-rotation rigging system, when in flight. Generally, taglines held by ground crews are not needed.
“The pilot can turn the load and has [the] full authority of the helicopter to move the load to within inches of where it needs to be,” Stein says. “We have developed a number of proprietary guide systems that help the steel align itself as we deliver it—that adds to the safety factor and the efficiency of the projects.”
At sea level, the Aircrane can lift about 20,000 lbs, but the thinner air at higher elevations reduces the payload capacity. At 10,000 ft, it can lift about 10,000 lbs, depending on temperature and other factors, Stein says.
“The elevation of this project does require us to build the towers in smaller pieces than we would at a lower elevation and erect them in smaller pieces,” Stein notes.
Erickson will provide all the pilots and mechanics to support the operation of the aircraft. “We will have a project manager, and we will have load masters, who will serve as radio men for hooking up and calling in the loads. All other personnel will be supplied by the local contractors,” Stein says. The company is scheduled, from July to October 2016, to set all towers in its scope.
Heavier Than Air
In operation, Lockheed Martin’s LMH-1 airship contrasts with the S64 Aircrane, but their missions are complementary. “It’s primarily a cargo aircraft, although you can also carry passengers,” says Bob Boyd, hybrid-airship program manager. “It’s very difficult to do a flying-crane mission. The atmosphere is highly variable, so the movement of the atmosphere makes it very difficult to hold position precisely enough to do a crane-type mission. We’re a lot more like a semitruck than we are a crane.”
The LMH-1 debuted for the commercial market at the Paris Air Show in June 2015. Developed over 20 years in Lockheed’s Skunk Works, the product is a helium-filled hull with a tri-lobed aerodynamic shape. Its immediate predecessor, the P-791 airship, was designed for a military competition, which Lockheed lost to Northrop Grumman. Lockheed redesigned the airship with a higher payload capacity for the commercial market. “It’s specifically designed to be a heavy-lift aircraft on remote construction sites,” Boyd says. “In our industry, the [words] ‘heavy lift’ means you’re carrying 10 tonnes or more.”
The LMH-1’s 20-tonne payload capacity means it can transport some small to medium-size construction equipment, such as a Cat D5K2 dozer or a John Deere 200C-LC excavator. Larger equipment has to be dismantled and later reassembled. The airship can carry 19 passengers. It requires 2,400 ft of open field but, with a reduced load, can execute a near-vertical takeoff in 500 ft. At its full speed of 60 knots, the LMH-1's range is 1,400 nautical miles, but, at lower speeds, the range greatly increases, says Boyd, adding, “At 50 knots, we can cross the Pacific.”
The LMH-1 might have difficulty operating on Sterlite Grid’s Himalayan transmission project. “Airships being blimps, they don’t like to go too high. The lift gets worse as you go higher, so we typically stay fairly low,” Boyd says. “We made a design decision to stay unpressurized, which keeps us at about 10,000 ft and below. Most of the time, you want to fly as low as you can because that gives you more lift and more efficiency.”
Four 300-horsepower diesel engines provide propulsion, fueled by standard jet fuel, Boyd says. The propeller blades will be 6 ft to 7 ft each, but the number of blades has not yet been decided. A heavier-than-air vehicle, the LMH-1 is called a hybrid because it relies on a combination of aerodynamics and buoyancy for flight.
“It is a wing, so, at max load, we carry about 80% of the lift from the blimp lift and 20% from the aerodynamic lift,” Boyd says. “It’s a lifting body. The body has a longer arc on the top than the bottom, so it’s a wing—a cambered airfoil. It does straight lift. Although it’s not a very good wing, it is, in fact, a wing.”
The air-cushion landing system consists of pads on the bottom that allow the ship to taxi on soft surfaces, including water. When the airship gets to the parking spot, it reverses the fans and, using suction, the pads grip the surface. This is possible because the airship is heavier than air. “You don’t want to have to build airport infrastructure at remote sites for these things to operate,” Boyd says.
The target market is cargo operators, such as cargo airlines that primarily serve mining companies and oil-and-gas producers. “They have the biggest need for lots of weight moving out in these remote areas—tens of thousands of tonnes,” says Body. The remote cargo operators would provide the service to the end users for a fee. Other specialty markets include wind-turbine blades, “but the bulk of the weight that keeps the aircraft flying will be supplies and products for the big resource extractors,” Boyd says. “We expect to make deliveries in late 2018 for commercial operations. Our listed price is about $40 million apiece.”
The LMH-1 is the latest entry in a series of airships whose goal is to serve heavy-lift needs at remote sites. Eight years ago, Boeing Co. and Calgary-based SkyHook International Inc. announced that they would partner to develop SkyHook’s JHL-40 heavy-lift airship, a 40-ton-capacity vehicle capable of 70 knots for a round trip of 200 miles (ENR 7/28/08 p. 18). SkyHook ran short of funds in 2010 and is now out of business. Boeing confirms that the project is no longer active.