Là où le JSF se pose, l’herbe ne repousse plus

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Là où le JSF se pose, l’herbe ne repousse plus

Encore une amusante péripétie pour le JSF. Une fois de plus, elle vient de Bill Sweetman, sur son blog Ares, le 11 mars 2010. (Voir le lien.)

Sweetman signale certains détails jusqu’ici inédits d’un rapport de l’U.S. Navy de janvier dernier, qui analyse les énormes problèmes posés par le JSF dans sa version du Marine Corps à atterrissage vertical (le F-35B). Cette version est faite pour intervenir sur des pistes ou des surfaces rudimentaires, aménagées près des théâtres d’opération. Mais la poussée et la chaleur dégagées vers le sol par l’avion en train d’atterrir sont telles qu’elles détruiront les surface planes, feront fondre l’asphalte, feront éclater les pavés, creuseront des cratères, etc…! En gros, il faudrait plutôt songer à aménager des pistes classiques pour permettre à l’avion à atterrissage vertical de ne pas atterrir verticalement.

«The Marines say that the the AV-8B's replacement, the F-35B Joint Strike Fighter, will be able to do the same: “The flexibility that the STOVL variant of the F-35 will add to the contemporary Marine Air Ground Task Force is amazing,” Marine commandant Gen James Conway said when the first F-35B was rolled out, more than two years ago. “This generational leap in technology will enable us to operate a fleet of fighter/attack aircraft from the decks of ships, existing runways or from unimproved surfaces at austere bases.”

»But a Navy report issued in January says that the F-35B, in fact, won't be able to use such forward bases. Indeed, unless it ditches its short take-off, vertical landing capability and touches down like a conventional fighter, it won't be able to use land bases at all without some major construction efforts.

»The newly released document, hosted on a government building-design resource site, outlines what base-construction engineers need to do to ensure that the F-35B's exhaust does not turn the surface it lands on into an area-denial weapon. And it's not trivial. Vertical-landing “pads will be exposed to 1700 deg. F and high velocity (Mach 1) exhaust,” the report says. The exhaust will melt asphalt and “is likely to spall the surface of standard airfield concrete pavements on the first VL.” (The report leaves to the imagination what jagged chunks of spalled concrete will do in a supersonic blast field.)

»Not only does the VL pad have to be made of heat-resistant concrete, but currently known sealants can't stand the heat either, so the pad has to be one continuous piece of concrete, with continuous reinforcement in all directions so that cracks and joints remain closed. The reinforced pad has to be 100 feet by 100 feet, with a 50-foot paved area around it.

»By the way, any area where an F-35B may be stopped with the engine running – runway ends, hold-shorts on taxiways, and ramps – also has to be made of heat-resistant concrete to tolerate the exhaust from the Integrated Power Pack (IPP), which is acting as a small gas turbine whenever the aircraft is stopped…»



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