On Sun, 17 Nov 2002, Pierce Nichols wrote:
> >No. Download the text file; it really does show 5 g +/- 10 g. Drag
> >never gets above 2 g as long as we're subsonic.
>
> Then it's got to be spurious. The only thing that could make
> negative G during the ascent is drag.
It is physically conceivable for sufficiently violent mass movements
within the vehicle to produce transient negative G measured on the vehicle
structure... but no sensible man would bet any money on that being the
real problem.
More likely is a resonance in the sensor or its support structures. The
support structures for inertial sensors can be a serious issue; several
past rocket programs have had to make changes there to get rid of spurious
sensor outputs. (The first four Thor-Agena-A flights would all have been
lost due to a 5Hz yaw oscillation -- the result of too flexible a gyro
mount -- had it not been limited by the hydraulic system, which was
incapable of doing large-amplitude gimbaling that fast!)
NASA SP-8036, "Effects of structural flexibility on launch vehicle control
systems", makes interesting reading.
Henry Spencer
[EMAIL PROTECTED]
_______________________________________________
ERPS-list mailing list
[EMAIL PROTECTED]
http://lists.erps.org/mailman/listinfo/erps-list
