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Post Info TOPIC: flippin' crew seats again !
10kBq jaro

Date:
flippin' crew seats again !


hey Ty -- here's those flippin' crew seats again ! (remember we discussed those in connection with an SSTO that would have the landing gear ports on the *top* side of the aerodynamic shape, relative to the reentry heat shield ?)


http://www.transformspace.com/index.cfm?fuseaction=projects.view&workid=CCD3097A-96B6-175C-97F15F270F2B83AA

Crew Transfer Vehicle (CXV)


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Rapid prototyping of innovative seats


The CXV launches nose first and reenters nose first, unlike all previous capsule designs that have reentered base-first. This means the crew seats must turn 180 degrees to orient the crew for the most comfortable position to undergo reentry decelleration. ("Eyes in" rather than "eyes out" in terms of which way the g forces are pushing.)


Col. Jim Voss (USA, Ret.) led a rapid-prototyping effort in early 2005 during his tenure as associate dean of aerospace engineering at Auburn University, based in part on his experience flying on both the U.S. Space Shuttle and the Russian Soyuz. His team created an innovative light weight crew seat for the CXV that is very low mass, weighing less than 10% of the weight of a current Space Shuttle crew seat and it incorporates support straps sewn to attenuate loads when the design limit of 8 g is exceeded.


But the most innovative feature is the ability to quickly rotate the seat 180 degrees for entry or in the case of an abort. In the case of an abort, this must occur rapidly, without egressing the seat, and without the need for electrical power. A pull of the rotation handle releases the seat latch and a torsion spring rotates the seat 180 degrees where it is locked in place, allowing the crew to better withstand the deceleration forces associated with entry. The crew seat has been installed in the t/Space CXV mock-up.


The project was developed under an academic grant to the Auburn University College of Engineering. Applying the t/Space rapid prototyping philosophy, a research team moved from concept to fully functional prototype in three months.


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Water landing of the capsule uses proven systems from the Apollo program and allows the aeroshell to remain unpenetrated by landing gear, airbag doors, or hatches. As 70 percent of the Earth's surface is ocean, water landing is important to enable safe abort under all circumstances.


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.....incidentally, the rest of the article is an absolute "must read" !!  ....bet you that Griffin will go for Rutan's CXV, leaving the launch of the unmanned CEV lunar shuttle to the big guys (Boeing/LockMart). The only remaining piece of the puzzle is whether the CEV will be a Borowski-style nuke lunar shuttle, or something less fancy.



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GoogleNaut

Date:

Well, I'll be darned. Thanks, Jaro!

It makes me think that sometimes I really do know what I'm talking about (it's not all hot air! )

It sounds like they may be on the right track. I'd be interested to know how they dissipate landing forces where deceleration lloads can actually exceed 25 g's. Even for a water landing the transient decelerations of a splashdown are substandtial (a landfall landing would be several times higher still, I'd imagine.) I'd be interested to know how the seats would perform under these dynamic loadings. If they're 10% as heavy as shuttle seats, it makes me a tad bit skeptical of their strength. Even composite graphite reinforced structures have been known to break. Some kind of internal compressable aluminum waffle--like that used in the landing struts of the Apollo-LEM---is a possibility. Apollo actually hung the seats from the forward end of the capsule. The struts were integral shock absorbers--a pretty efficient design. But the Apollo seats were fixxed--they didn't rotate at all.

These seats look almost like a semi rigid hammock. Should be a fairly efficient design.


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