[SS-VehDev] Re: casing
Rich Nakka
richnakka at rogers.com
Mon Oct 3 19:47:43 PDT 2005
Gents
I partly agree with Bill, but.... I feel communication is critically
important to keep all project members interested and so that they feel
they are a part of the project. Often, feeling as part of a project
simply means reading postings on various topics. Being informed of
"what's happening". Personally, I like reading about dipole antennas
even if I would not know one from a fishing pole. If one is not
interested, thats what the delete key is for.
I truly feel there is key value added in discussing topics "at large" on
the ss-main list .
Well, guys? Let's have other project members give their own opinions. Is
there value-added in discussing topics at large on the ss-main list (I
may be out to lunch here ,after all ;-)
Richard
william colburn wrote:
>Generally; but I think that Rich should bring motor
>discussions to the group directly and as a co-leader
>should bring whatever he feels important to discuss to
>the group at large. I will bring items of interest to
>the vehicle design group specifically and also to the
>group at large when it is of general interest.
>
>I was involved in the grit of the case composite
>question. It could have been brought up with the
>larger group earlier or later as I see it, so long as
>it was shared at some point. That actually is the
>purpose of having separate groups so the mailing list
>does not get bogged down with rehashing of already
>determined or decided design features or directions.
>(already happening, incidently)And the reporting of
>the groups to the list is that communication we all
>desire. For instance, I don't want to be involved in
>the slightest in choosing a patch, helix, dipole,
>dielectric slot or any other antenna for the vehicle.
>I prefer not to be in those discussions. I do want to
>hear the report after the decision has been made,
>however.
>
>Where I or others have special expertise, we would be
>missing the point of the group effort not to
>contribute in those specific areas.
>
>I apologize for the length of my reply. It clears some
>of the points I wanted to make.
>
>BC
>
>--- Lakestake Rocketry <lakestake at gmail.com> wrote:
>
>
>
>>Richard,
>>
>>I think Bill is the right person, as head of the
>>VehDev group, to open
>>this discussion up to the group when he feels that
>>either:
>>a) we have reached a proposed design ready for group
>>presentation
>>b) we have reached a point where we need more group
>>input
>>
>>Bill, do you concur with these two statements?
>>Richard, does this fit with your understanding of
>>'group procedure'?
>>
>>Richard, my suggestion is that you put together a
>>'topic starter' email
>>letter including your take on what specific
>>questions we should open
>>up for group comment and forward that to Bill for
>>revision and posting
>>as he sees fit.
>>
>>Bill, I agree with Richard, we could gain a lot from
>>the experience
>>the group brings to the table. As with everything on
>>the Internet we
>>will have to separate the wheat from the chaff...
>>
>>Matt C
>>
>>On 10/3/05, Richard Nakka
>><richard.nakka at aero.bombardier.com> wrote:
>>
>>
>>>Gents,
>>>Why don't we discuss this side-study on the
>>>
>>>
>>ss-main list?
>>
>>
>>>It'd be a good way to help re-establish interest &
>>>
>>>
>>communication in the
>>
>>
>>>SStS Project?! We've been sadly failing in this
>>>
>>>
>>regard, in my opinion.
>>
>>
>>>Richard
>>>-------
>>>
>>>
>>>william colburn wrote:
>>>
>>>
>>>>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...
>>>>>>>
>>>>>>>
>>>>>>>
>=== message truncated ===
>
>_______________________________________________
>SS-VehDev mailing list
>SS-VehDev at sugarshot.org
>http://www.exrocketry.net/mailman/listinfo/ss-vehdev
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.exrocketry.net/pipermail/ss-vehdev/attachments/20051003/1a5d014c/attachment.htm
More information about the SS-VehDev
mailing list