Airship Airlift

Thursday, February 23rd, 2012

The Gulf War of 1990–91 revealed a logistical gap between the US military’s small, overnight airlift capabilities and its immense, but far-from-overnight sealift capabilities. Those first combat troops to arrive had no way to sustain combat operations until supplies arrived weeks later, via “fast” surface ships. Fortunately, their Iraqi enemy gave them months to build up their forces, and 95 percent of American materiel eventually arrived via sealift.

This need for mid-term transport led Lieutenant Colonel Donald E. Ryan, Jr., of the USAF to consider the airship’s potential for airlift. In his estimation, a modern Hindenburg would be able to carry roughly as much as a cargo jet, would be able to reach anywhere on the globe within 10 days, and would cost just a fraction of what a jet costs.

Further, airships can land without an airstrip, they can carry “outsized” cargo, they’re almost invisible to radar, and they’re surprisingly robust:

For example, the only US airship lost in combat during World War II, the K-74, took three 88mm gun hits and 200 rounds of 20mm cannon fire from a submarine it was attacking before finally going down.

Posted in Technology, War | 3 Comments »

Comments

  1. Philip Ngai says:
    February 25, 2012 at 2:35 am

    If you read Ryan’s biography, it’s not clear he has any aerodynamics training, despite working for the Air Force.

    I skimmed his thesis and did not see any description of how lift would be controlled as the weight of the airship changes by a few hundred tons.

    For example, on page 30, an airship drops 200 tons of cargo, yet has to rev up his engines to take off.

    In real life, it would be like releasing a cork you held 3 feet underwater (assuming the airship was close to neutral buoyancy before dropping the cargo).

    If the engines were providing 200 tons of lift before the drop-off, what you really have is a helicopter and why bother with all the gas?

  2. Isegoria says:
    February 25, 2012 at 8:55 am

    Indeed, using irreplaceable helium as your lifting gas introduces operational considerations — namely, you can’t just vent off the gas:

    Operational considerations further decrease the useful payload of a helium-inflated airship. As an airship rises, its lifting gas expands; an airship that begins a flight with its gas cells fully inflated must therefore release gas as it climbs to keep the cells from bursting. Because hydrogen is easy to manufacture and inexpensive to buy, hydrogen airships often began flights fully inflated to maximize payload and released hydrogen as they climbed. But since helium has always been a rare and expensive gas, helium airships began their flights at only 90-95% inflation, thus reducing payload, to allow their gas cells to expand without releasing helium. In addition, hydrogen airships compensated for fuel burned during flight simply by releasing hydrogen; helium-inflated ships, on the other hand, required heavy water-recovery apparatus (to recover water ballast from engine exhaust), which further reduced the useful payload available for fuel, passengers, and freight.

    (Helium blimps do not need to vent helium to maintain equilibrium; they employ internal ballonets, or air sacs, which can be inflated or deflated to maintain the blimp’s shape and buoyancy.)

    Ryan also ignores any other alternatives between current jet transports and ships — he doesn’t consider slower, less-expensive airplanes or faster, more-expensive ships.

  3. Darrell Campbell says:
    February 25, 2012 at 8:49 pm

    I invite you to see more at militaryairships.blogspot.com or turtleairships.blogspot.com.

Leave a Reply