Boeing and SkyHook’s Zeppelin-Copter Faces Safety Challenges
OK, so this isn’t technically a Seattle story. But how can we resist a bizarre new flying machine being built by Boeing to travel to the farthest reaches of the Earth? This week, Boeing announced it is teaming up with Calgary, Alberta-based SkyHook to develop a “heavy-lift rotorcraft” that can carry a 40-ton load up to 200 miles without refueling. The JHL-40 (couldn’t they come up with a catchier name?) is designed to support drilling and mining operations in the Canadian Arctic and Alaska.
It certainly looks cool. It’s an airship, the length of a football field, with four helicopter rotors spinning alongside it. The ship will be filled with helium to make it neutrally buoyant—that keeps the vehicle and its fuel in the air—while the rotors provide lift and thrust to support whatever it’s transporting. The 40-ton capacity would be twice that of the world’s most powerful vertical lift aircraft, Russia’s MI-26 transport helicopter. Boeing is under contract from SkyHook to build two prototypes at its Rotorcraft Systems facility in Pennsylvania. Once built and tested, the craft will need to be certified by Transport Canada and the U.S. Federal Aviation Administration.
But there are some major safety and technical issues involved, which most news outlets aren’t talking about yet. Remember the Hindenburg? In 1977, my family spent a year in Germany, and I recall seeing the newsreel footage of the fiery disaster—it was the 40th anniversary of the German airship’s demise (the exact cause is still a mystery). Those images have always stuck with me, and with a lot of people, which is a big part of why zeppelins went out of style. Of course, today’s blimps don’t use flammable hydrogen for buoyancy, which was the Hindenburg’s fatal flaw. There are, however, other issues to consider—some of which helped to sink German company Cargolifter AG, which tried to build an airship capable of lifting 160 tons but went bust in 2002 after its prototype was destroyed in a storm.
To get the inside scoop on modern rotorcraft design, I went to Robert Breidenthal, a professor of aeronautics and astronautics at the University of Washington who has done consulting work for Boeing. Breidenthal points to three main challenges of the JHL-40’s design, which will need to be worked out before it can become a viable transport ship.
1. Vulnerability to turbulence
This is a “classic problem with neutrally buoyant vehicles,” says Breidenthal. “It might be necessary to limit operations to relatively tranquil atmospheric conditions, securing it during turbulence,” he says, adding that this might not be a problem in the Arctic, which has long periods of calm weather. But if a storm is coming, look out.
2. Aerodynamic control
Because the spinning rotors are close to the hull, they will affect the airflow and pressure along the side of the craft. That could lead to “substantial side forces,” says Breidenthal, which would need to be managed in flight. “It would be fun to work all the fluid mechanics of that out,” he says.
3. Price of helium
Because it’s so light, helium eventually escapes from the atmosphere into space, and is hard to find in the first place (only in natural gas wells). It is a “strategic resource with unique and valuable characteristics” so it’s under high demand, Breidenthal says. Helium prices have already, umm, ballooned by about 50 percent in 2008, and could keep going up.