[NRVR-Members] Meeting with NRVR

Tue Dec 8 23:50:20 CST 2015

Hey Fareez..
Here are those other button standoff photos:
http://theweeks.org/rockets/HONEST-JOHN/BUTTONS/

Tweeks

On Monday 07 December 2015 14:44:55 Thomas (Tweeks) Weeks wrote:
> [CCing the nrvr-members mail list so this will be archived]
> 
> 
> Wow.. if large autonomous roverer/rocket design is going to be at the
>  meeting, that would rock! (but also really suck bc I'm going to miss the
>  meeting. I'm a huge arduino geek and would LOVE to see an autonomous
>  arduino-rover pop out of a big bird! [😊]  ) Here's one of my little
>  arduino bots I was thinking about popping out of my next big rocket
>  (currently seeking a nice big fat rocket for this):
> 
> [cid:b4102d3e-05f8-4cd3-95a0-84bc6ea33326]
> 
> 
> 
> I'm eager to hear what Bob has to say about 1inch standoffs, but I've done
>  some 3/4" standoffs for rail buttons on one of my fat-nose rocket designs.
>  It can be done very robustly if you do it right.
> 
> 
> But you're rocket is going to be pretty heavy it sounds.. so before showing
>  how it should be done there's a common way you should probably AVOID doing
>  it.  Below is the common way to make rail-botton standoffs for
>  smaller/lighter large nose rockets (which you probably want to avoid):
> 
> [https://www.apogeerockets.com/images/apogee_products/Rail_Button_with-stan
> doff.gif]
> 
> It looks nice, but taking that design out to 1" would give you too much
>  button torque on a large heavy bird. Plus the screw/epoxy nipple inside
>  your BT (body tube) will create a snag point for any recovery gear/chutes.
>  But the torque from the 1inch of clearance is the real problem with a
>  rocket as heavy as yours.
> 
> Instead, here's a graphical view of how I did it (on this smaller 2.6"
>  rocket design) using streamlined basswood blocks and T-nuts creating a
>  much wider "hugging footprint" to the standoff (VERY solid):
> 
> [cid:6c8e1aa4-7eb2-49c6-b1d8-71e004b4c7de]
> 
> 
> http://theweeks.org/rockets/HONEST-JOHN/NOSECONE/dscf0107.jpg
> 
> 
> The block is sanded to fit the tube by simply putting the sandpaper (rough
>  side up) and sanding the button-block directly against the BT.. creating a
>  perfect fit to hug your BT and give you a solid anchor.
> 
> 
> This design yields MUCH more lateral rocking resistance (than a simple,
>  columnar plastic standoff).  If interested, I have some more pics of this
>  design at home I can put on my webserver tonight.. I did a longer 3inch
>  block standoff like this that will give you room for both outward and
>  inward facing T-nuts. Tricky getting it all screwed down without any
>  snag-points, but VERY solid, and you end up with nuts and bolts anchoring
>  the button base to the BT, (not just some epoxy or a 1inch plastic
>  cylinder).
> 
> 
> For an even more solid anchor, you could also go with a larger triangular
>  block base with three outward facing threads (t-nut style) with
>  flush-nut-head inside and screw bolts from the outside with an internal
>  re-inforcing ring (fiberglass or aluminum ring) that the internal
>  flush-nut mount the block to to give it a super solid mount point.  Email
>  me off list and I'll get you the other design photos.
> 
> Also..
> If this is your first HP rocket.. I would recommend comparing deisng notes
>  by the experienced experts in the nrvr.org mail list (CCd).  If you're not
>  a member, students can join for free here http://nrvr.org/membership/.
> 
> However, to beef up on HP rocket design best practices I recommend picking
>  up a copy of this excellent HP rocket design book that has decades of
>  big-rocket design wisdom: http://www.amazon.com//dp/1412058104
> 
> 
> Any of you other guys have feedback?
> 
> Bob? You done any heavy rocket button standoffs?
> 
> Tweeks
> p.s. Fareez.. with a rocket this big/heavy.. you ARE using the larger 1515
>  buttons right?
>  http://aeroconsystems.com/cart/launch-and-recovery-accessories/rail-button
> -8020-style-1515-pair/  (unless Bob recommends something beefier)
> 
> 
> ________________________________
> From: Fareez Chowdhury <fareez.chowdhury at gmail.com>
> Sent: Monday, December 7, 2015 1:17 PM
> To: Bob Schoner
> Cc: Kevin Shinpaugh; james desposito; Jim Farley; Jordan Truesdell; Carlos
>  Zapata; officers at nrvr.org Officers; Pat Artis; Brad Smith; Eric Plevy;
>  Magda Moses; Johnny Jaffee; Ishan Arora Subject: Re: Meeting with NRVR
> 
> Mr. Schoner,
> 
> Any and all advice would be appreciated. I've CC'd the remainder of the
>  team so they can be in on this. In case anyone is curious, I am also
>  attaching the PDR we've submitted to the competition organizers and for
>  which we'll present on Wednesday morning, as well as the OpenRocket file
>  we've got going on right now.
> 
> An additional question would probably be: how would you recommend going
>  about building a 1" standoff for railbuttons? If you'll see from our
>  rocket file (and alluded to in one of the other questions), our rocket has
>  two diameters, and the lower stage is of smaller diameter than the upper.
>  Since it is not possible to mount the rail buttons on the upper section
>  due to payload reasons, we need to build standoffs for our railbuttons so
>  the buttons (attached to the smaller diameter tube) can reach past the
>  larger diameter upper stage and connect to the rails. What kind of
>  shape/material/size would those stand-offs be, etc.?
> 
> On Mon, Dec 7, 2015 at 9:16 AM, Bob Schoner
>  <bob.schoner at gmail.com<mailto:bob.schoner at gmail.com>> wrote: Kevin,
> 
> Lets's put this on our calendar and move forward with it.  I will update
>  the calendar on our webpage.
> 
> Officers,
> 
> We still have interested VT students that we can help out.  These are some
>  great questions and are always preferred over assumptions when folks are
>  getting into high power rocketry.  I don't mind addressing one or two of
>  these, but would like more people to help out and add their perspective
>  too.
> 
> I feel like I can offer something on any of these and will volunteer to
>  speak on #2.
> 
> Officers and NRVR members, please reply all to:
>  - indicate if you can make this meeting for 12/9 at 6:00 p.m.
>  - indicate which topic you want to address or research
> 
> We can certainly invite all our members as this may be of interest to them.
>   I know December is busy and we are not giving them too much notice.  Any
>  objections to open this up to the whole NRVR community?
> 
> I'm inviting the L1 and L22 people that I can remember.  Think back to some
>  of the assumptions you made when you first started and see if you have
>  some advice on any of these topics.
> 
> Since Time is short, please reply no later than 11:00 pm of 12/7.
> 
> Thanks
> 
> Bob
> 
> On Sun, Dec 6, 2015 at 4:03 PM, Kevin Shinpaugh
>  <kashin at vbi.vt.edu<mailto:kashin at vbi.vt.edu>> wrote: I think we can get an
>  NRVR meeting with you all for after 6pm on Thursday. Space at VT will be a
>  good meeting location.
> 
> 
> 
> On Dec 6, 2015, at 3:16 PM, Fareez Chowdhury
>  <fareez.chowdhury at gmail.com<mailto:fareez.chowdhury at gmail.com>> wrote:
> 
> Dr. Shinpaugh,
> 
> At the last meeting, you wanted us to remind you to ask NRVR if we can
>  schedule a meeting at Space at VT on Thursday (12/10) at 5:00 PM, to discuss
>  some rocket concepts and verify some things you guys are doing. We also
>  have a preliminary list of questions we wanted to ask:
> 
>   1.  Advice for cutting accurate fin slots
>   2.  Filleting fins to body tube at root
>   3.  How to prevent parachute tangling at apogee (booster main chute and
>  capsule drogue chute) 4.  Adding a shoulder to a modified LOC PNC 7.51 in
>  nosecone to convert it into a 7.51 in to 5.51 in transition piece 5. 
>  Advice on parachute deployment bag selection for capsule main chute 6. 
>  Amount of black powder and Pyrodex required for recovery
> 
> Please let us know as soon as possible. Thanks!
> --
> Fareez Chowdhury
> Mechanical Engineering
> Virginia Tech, Class of 2017
> 
> 
> 
> 
> 
> --
> Fareez Chowdhury
> Mechanical Engineering
> Virginia Tech, Class of 2017
> 