Doug,
Is there a reliable and affordable shop for impact testing, or did you do
it in house?
Ben
On Tuesday, October 18, 2016, Doug Jones <djones@xxxxxxxx> wrote:
XCOR's glass- fluorpolymer composite has zero ignition in impact test at
the maximum setting, 72 ft-lb energy.
Doug Jones, Chief Test Engineer
XCOR Aerospace
1325 Sabovich
Mojave CA 93501
(661) 824-4714 x117
cell 661 313-0584
On 10/14/2016 11:16 AM, Henry Spencer wrote:
On Fri, 14 Oct 2016, Paul Mueller wrote:
So apparently the helium bottles are COPVs. Putting non-LOX compatible
composites (I don't know of any composites that are LOX compatible) inside
a LOX tank seems to be asking for trouble.
Well, remember that there's almost no such thing as "LOX compatible" in
an absolute sense, i.e. a useful structural material that *cannot* ignite
in LOX. The aluminum alloy used in the original shuttle ET reportedly has
about a 30% chance of ignition in the standard LOX-compatibility impact
test! (They wrote themselves a waiver...) About the closest thing to a
carefree LOX material is stainless steel, but even it can and will burn in
LOX if provoked sufficiently. Apollo 13's LOX tank exploded because
*Teflon* ignited in LOX (albeit after being somewhat degraded by an earlier
episode of prolonged accidental baking).
The practical question is whether a particular material is LOX compatible
*enough* to be safe in practice. Such an assessment is always a little bit
vulnerable to unsuspected failure mechanisms.
Henry
