[SS-VehDev] Re: casing

[william colburn]

Matt,

We can propose a mandrel diameter. We won't know the
actual wall thickness we will ultimately require until
be do more testing.

The nozzle is being made with an OD of 9.873 +.005
-.005 inches. 9.881 would be the OD of the mandrel
assuming a minimum clearance of .003 inch for "O" ring
and a slip fit. With a tolerance stack-up we could end
up with a diametral clearence of .013.

At a level of 41KSI, the tubing fabricator (who has
not yet quoted!) is using a wall thickness of .188.
The materials are E-glass and epoxy.

Even with hand-layup, we should be able to match that
tensile yield number. This means that our wall
thickness will be in the same ball-park as .188.

If so, we are in-like-Flynn. If not, then no-go as the
casing weight will be too great for making our mass
ratio.

So with a relatively simple experiment, we will know
if we can hand-layup our own casing. 

If we are successful in hydro, this sample or one like
it could be used for the short-stack test.

BC

--- Lakestake Rocketry <lakestake at gmail.com> wrote:

> Hi Bill,
> 
> I was getting ready to acquire the mandrel, I wanted
> to get your
> feedback/requirements soon so I could move forward
> on it. If the SS2S
> project does not have a hard size requirement I can
> make the other
> project to spec. If that won't work for us I can
> work on changing the
> other spec to match SS2S. I just need to know which
> way to jump.
> 
> The current M-100B design calls for a 250mm O.D.
> 
> I understand and can follow your approach below, but
> I don't want
> to change the other project to adhere to SS2S
> requirements unless
> it has been determined that this is the way SS2S
> will be going. It
> does not make sense to purchase one mandrel for
> testing, then
> another for the final project.
> 
> I see Richard has posted a follow up, more comments
> once I have
> read that.
> 
> Matt C
> 
> On 10/1/05, william colburn
> <space1space at sbcglobal.net> wrote:
> >
> > So the mandrel is 250 mm? Or is the finished part
> 250
> > mm OD?
> >
> > Here is a plan:
> >
> > Use your existing mandrel to make a short stack
> casing
> > to best procedure using carbon fiber, kevlar,
> glass
> > where appropriate.
> >
> > We will develop end closures and hydrotest the
> sample.
> >
> > From there we will make a decision to go forward
> or
> > move to another casing source.
> >
> > We can talk about the exact procedure when you are
> > ready to go. It would likely involve an initial
> room
> > temperature cure with shrink wrap, removal of the
> > shrink wrap followed by a two stage cure at
> increasing
> > temperatures.
> >
> > No gel coat, it adds weight and no increase in
> > strength. No sanding, weakens the outer layre
> which
> > them becomes dead weight also.
> >
> > BC
> >
> > --- Lakestake Rocketry <lakestake at gmail.com>
> wrote:
> >
> > > Hi Bill,
> > >
> > > The M-100B has a 250mm airframe. It doesn't
> really
> > > *need* to
> > > be 100% scale, but it would be nice. I can fudge
> > > either project to
> > > match the other as needed. I would need to know
> soon
> > > though...
> > >
> > > Matt
> > >
> > > On 9/30/05, william colburn
> > > <space1space at sbcglobal.net> wrote:
> > > >
> > > > Plug=mandrel over which you are applying the
> > > composite
> > > > material. The ultimate ID of the part.
> > > >
> > > > BC
> > > >
> > > > --- Lakestake Rocketry <lakestake at gmail.com>
> > > wrote:
> > > >
> > > > > Good evening Bill,
> > > > >
> > > > > To which plug do you refer below?
> > > > >
> > > > > The makeup of the composite should be
> discussed.
> > > I
> > > > > agree that
> > > > > should be several layers running both at 45'
> and
> > > > > 90'. We should
> > > > > probably use Aramid layers for toughness as
> well
> > > as
> > > > > the CF
> > > > > for strength. CF alone may be too brittle
> for
> > > this
> > > > > application.
> > > > >
> > > > > Once we have a design I, or someone else,
> can
> > > easily
> > > > > lay up
> > > > > a 1' square section that can be run through
> the
> > > > > ringer as needed
> > > > > to verify the design empirically.
> > > > >
> > > > > Those with Composites experience toss out
> ideas!
> > > > >
> > > > > Matt C
> > > > >
> > > > > On 9/29/05, william colburn
> > > > > <space1space at sbcglobal.net> wrote:
> > > > > >
> > > > > > Excellent guys. Remember to do the fiber
> > > > > orientation
> > > > > > to get 2 x hoop as longitudinal count.
> When
> > > Scaled
> > > > > > Composite did their motor for SpaceShip
> One,
> > > they
> > > > > also
> > > > > > did 45 degree wraps too. We ultimately
> need
> > > two 10
> > > > > > foot pieces and a 42 inch piece for the
> short
> > > > > stack
> > > > > > motor. We will hydrotest them all also to
> > > 10-15%
> > > > > over
> > > > > > MEOP. What is the OD of your plug?
> > > > > >
> > > > > > BC
> > > > > >
> > > > > > --- Lakestake Rocketry
> <lakestake at gmail.com>
> > > > > wrote:
> > > > > >
> > > > > > > Hi Roman,
> > > > > > >
> > > > > > > Do you want to take up this challenge
> with
> > > me? I
> > > > > > > think we can
> > > > > > > make better tube for less.
> > > > > > >
> > > > > > > Matt C
> > > > > > >
> > > > > > > P.S. I am making a bunch of 10" CF tube
> now
> > > for
> > > > > a
> > > > > > > scale M100
> > > > > > > (russian sounding rocket of course!) As
> I am
> > > > > tooling
> > > > > > > up I can run
> > > > > > > out a few dozen feet of SS2S tube while
> I am
> > > at
> > > > > it.
> > > > > > >
> > > > > > > I am looking for your confirmation that
> this
> > > is
> > > > > > > practical as I have
> > > > > > > not finalized my plans for the M100. I
> would
> > > > > also
> > > > > > > enjoy you
> > > > > > > as a collaborator on the team building
> the
> > > > > airframe.
> > > > > > > Let me
> > > > > > > know what you think.
> > > > > > >
> > > > > > > Are you visiting LA any time soon?
> > > > > > >
> > > > > > > On 9/29/05, Lakestake Rocketry
> > > > > <lakestake at gmail.com>
> 
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