On Tue, 19 Nov 2002 12:08:09 -0500 (EST), Andrew Case <[EMAIL PROTECTED]> wrote:
>> The vacuum only needs to be drawn down a little bit -- our >> vehicles simply don't go that high. We have the pump, and the chamber just >> doesn't need to be that tight. > >Low pressure is only important if the compressibility and/or viscosity of >air has a significant impact on the system response to vibration. If >you're that close to the edge, you're too close :-) In practice all that >variations in air pressure should do is move resonances around by a tiny >bit, and possibly affect coupling of vibrations between components to a >minor degree. The effects should be in the noise, especially when you >consider the things you will not be able to simulate, such as variations >in pressure on (and in) the airframe due to fluid dynamic effects >in actual flight. Last night at the KISS III redux BBQ, we rejected the idea of testing devices made for HPR use, since they're black boxes. Still, I have apparently failed to make myself clear on the above point... The objective of the test under discussion is to test the baro altimeter under flight conditions without flying it. Since a critical function of the baro altimeter is the barometric detection of apogee, any such test must take place in an altitude chamber drawing down to simulate upward flight. -R -- [EMAIL PROTECTED] "The only time an aircraft has too much fuel on board is when it is on fire." -Sir Charles Kingsford Smith _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
