Bill Sweet­man Tech­ni­cally Speak­ing

Air & Space Smithsonian - - Front Page - Bill Sweet­man

Sonic Cruiser, loser

OVER THE DECADES, aero­space in­dus­try gi­ants, star­tups, armed forces, and ship­ping com­pa­nies have all floated (so to speak) dozens of ideas for air­ship de­signs. Why have none met with suc­cess?

Any prac­ti­cal ap­pli­ca­tion of the large air­ship poses for­mi­da­ble chal­lenges. The first is find­ing a use for it. In the 1990s, the Ger­man Car­go­lifter project was spon­sored by com­pa­nies in the busi­ness of mov­ing equip­ment weigh­ing up to 160 tons. The idea was to go from fac­tory to cus­tomer site in one op­er­a­tion, with­out ships or heavy road con­voys. The com­pany built a gi­ant hangar near Ber­lin, then failed.

One project that did reach the mockup stage was the U.S. Navy’s YEZ-2A, an ex­per­i­men­tal air­borne-early-warn­ing craft. An air­ship’s en­ve­lope of­fers pro­tec­tion from wind, so it is a good place to put a very large radar an­tenna. And a large an­tenna is a sim­ple, ro­bust way to de­tect stealthy tar­gets such as cruise mis­siles.

West­ing­house (now part of Northrop Grum­man) was part­nered on the YEZ-2A with the U.K.’S Air­ship In­dus­tries—one of a num­ber of com­pa­nies started by the late Roger Munk, the great­est apos­tle of the mod­ern air­ship. Ul­ti­mately, the project fell vic­tim to a fire that de­stroyed a sub-scale prototype and the mockup for the full-size ship’s gon­dola. (The Pen­tagon also de­cided that cruise mis­sile de­fense was not the Navy’s job, but the Army’s.)

Munk went on to found the Air­ship Tech­nolo­gies Group, which by the late 1990s had de­signed Sky­cat, a hy­brid air­ship with an air­foil-shaped hull de­signed to con­trib­ute lift to the buoy­ancy of its he­lium-filled en­ve­lope. It also had an air-cush­ion land­ing sys­tem. Munk knew the curse of the large-pay­load air­ship was its be­hav­ior on the ground. The slight­est breeze makes the ship move, so once its pay­load is re­moved, the ship has to be se­cured and its buoy­ancy ad­justed. Sky­cat could re­verse the air­flow through its air-cush­ion sys­tem and lit­er­ally suck it­self down while un­load­ing.

In the early 2000s, the Sky­cat and Lock­heed Martin stud­ies in­spired the De­fense Ad­vanced Re­search Projects Agency to launch a project called Wal­rus, an im­mense air­ship with a 500-ton pay­load ca­pac­ity. The U.S. Army was fas­ci­nated by the idea of a ve­hi­cle that could pick up a large mil­i­tary force and de­liver it

“from fort to fight.” But as Lock­heed Martin Skunk Works boss Frank Cap­puc­cio put it, Wal­rus “couldn’t pass the gig­gle test.” Munk didn’t live to see his hy­brid design fly—and so far it has done so only once, in the form of the Army-funded Northrop Grum­man Long En­durance Multi-in­tel­li­gence Ve­hi­cle. But the LEM-V project was poorly man­aged: The ve­hi­cle was over­weight, and the Army cut off funds af­ter one flight. ATG’S suc­ces­sor com­pany, Hy­brid Air Ve­hi­cles, bought the prototype cheap and wants it to fly again.

The Pen­tagon has helped fund Aero­scraft, an air­ship con­cept led by Rus­sian-born Igor Paster­nak. It’s based on a sys­tem that con­trols buoy­ancy by pump­ing he­lium into tanks un­der high pres­sure.

Even Northrop Grum­man’s Los An­ge­les-based Aero­space Sys­tems Di­vi­sion—a sep­a­rate en­tity from the radar out­fit on the other side of the U.s.—took a long look at air­ships a few years back. It ap­par­ently was in­ter­ested in mov­ing high-de­mand, fash­ion­able goods di­rectly from Asian fac­to­ries to Western dis­tri­bu­tion hubs. The project has since gone quiet. Why have so many air­ships failed? Two themes re­cur. One is grandios­ity: De­sign­ers aim for 500 tons straight out of the box; why not try to build an air­ship with a C-130’s 20-ton pay­load in­stead? The other is cock­i­ness. In­ven­tors treat air­ships as if they’re proven tech­nolo­gies rather than ex­per­i­men­tal ve­hi­cles. That mis­ap­pre­hen­sion stymied the Bri­tish at­tempt at a flight to In­dia, circa 1929, in the then-new R101, as surely as it af­flicted the U.S. Army, which wanted the LEM-V to be fly­ing in Afghanistan mere months af­ter its first suc­cess­ful demon­stra­tion. A truly rev­o­lu­tion­ary idea in air­ship design would be to aim for mod­est goals on a re­al­is­tic sched­ule. Be­cause hardly any­one has tried that yet.

Why have so many air­ships failed? Grandios­ity. De­sign­ers aim for 500 tons straight out of the box.

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