On Thursday, May 29, 2003, at 03:30 AM, Pierce Nichols wrote:
It shouldn't be that hard if you can clear all the propellant from the tanks before impact. IIRC, Indy Cars use special fuel tanks that impound the fuel during a crash to limit the possibility of fire and explosion. The tanks and airframe would have to be designed to fail gracefully, like the crush cone on John's vehicle. I don't see any reason it couldn't be done.
You'd also want to almost completely depressurize the tanks and allow for blowout ports so the tanks could act as airbags. It would require careful tank design, but I think it would be easier to ensure controlled deceleration in airbag mode rather than in purely crumple mode, at least for cylindrical tanks.
Some math: For impact velocity v, crushable length x, mean acceleration is a = v^2/(2*x) or more useful, v = sqrt(2*a*x)
for 5m crush length and mean acceleration of 20g, v = 44 m/s
Unfortunately peak acceleration is probably substantially more. Also mean acceleration scales with the square of impact velocity. The good news is that 44 m/s is already pretty fast, so it ought to be possible to get down into that range with reasonable aerodynamic decelerators. Still, it's likely to be <accent = Russian>"worst experience of entire life"</accent>.
......Andrew
-- Dr. Andrew Case, PhD. Institute for Research in Electronics and Applied Physics, University of Maryland, College Park "It is seldom that liberty of any kind is lost all at once." - David Hume
_______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
