[SS-VehDev] NC & fusel. joint

Tue Nov 29 08:23:43 PST 2005

Rich:

I like the idea of a "capsule assembly."

Since your sketch does not illustrate the motor section, has it been
separated from the capsule? Hopefully the thermal analysis will illustrate
whether or not the interface between the motor case and capsule is going to
get hot enough to cause separation problems. The concern I have is that
differential thermal growth (whether it be from aerodynamic or motor-related
heating) could cause a well-fitted interface to become very "tight," thus
causing separation problems.

Another thought: I'd think we would need redundancy on things like
separation and deployment events - what kind of ideas are being kicked
around? Primary and secondary systems would be altimeter based, and tertiary
system would be ground-activated "explosive" of some sort? Just curious.

Regards-

Dave

   _____  

From: ss-vehdev-bounces at sugarshot.org
[mailto:ss-vehdev-bounces at sugarshot.org] On Behalf Of Rich Nakka
Sent: Monday, November 28, 2005 9:36 PM
To: Ing. Roman Lev; SugarShot Vehicle Development Team; Sugar Shot
Subject: Re: [SS-VehDev] NC & fusel. joint

Roman
I would suggest keeping the nosecone & fairing joined together during
descent from space (see attachment) as a single "capsule". This would serve
a number of useful purposes.

- It reduces the potential problem of separating a hot nosecone & related
thermal expansion of the joint

-If the CG & CP can be separated something like in the sketch, the capsule
should descend in a stable manner. The bottom can be a "heat shield" if the
thermal analysis shows a need.

- The drogue chute can be deployed much later, once the assembly has
naturally slowed down significantly (see graphs I posted yesterday). In the
mean time, the main and drogue would be safely stowed in the fairing. Due to
the relatively low ballistic coefficient, it may be possible to not deploy
the drogue until a short distance above ground ( 1 km?). This should greatly
reduce downrange drift.

Richard
--------

Ing. Roman Lev wrote:

 Good morning all,

I worked a bit on  design details for the NC and I'd like to disscuss type
of joint between the NC & fuselage. Everybody draws the classic one [
concetric tubes ]. Is it really the best option? Both  fuselage and the NC
will be hot  for several minutes when separates, joint could stick togehter.
Is there a real hazard of this? Do we have a konwledge in this area? Is
there anybody with skills& experience with design of hems, locking
mechanism's, exp.rivets etc? Perhaps Bill? Does it make any sence speculate
about this hi-tech kind of design, doesn't?

thanks

r+
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