[NRVR-Members] Need Helpers for March Launch, and Outreach events

Thomas Tweeks Weeks tweeks-junk2 at theweeks.org
Sat Mar 17 13:20:19 CDT 2018

[Good new member, cert-flight questions, so I'm answering to the list]

Welcome to the group David!
Inline answers below.

On Friday, March 16, 2018 12:44pm, "David Bloom" <dwskb at att.net> said:
> I just ordered the launch rail buttons from your email.  I have others for a 1"
> and 1 1/2' rail that can be epoxied if they don't arrive mid-week.  Also, it comes
> with 1/4 lugs.  Some answers/questions"

You typically don't want to just epoxy on buttons. They usually get screwed in. If not using a cool new well-nut (like in the link I sent you).. then with a screw going into a t-nut and small chunk of wood, or in to some other solid anchor object such as a metal nnut (expoxied to the inside of your BT (body tube).. or into one or both of the motor mount rings (with some reenforcing).. Here are a couple of photo examples of traditional button mounting:


Here's an example of a conformal ACME rail guides:

I really like these, although you have to buy them to fit the specifc BT diameter you're using.  So it's usually good to keep some more universal rail buttons on hand in your hope shop too.  Here's a good supplier of various types of rail (and rod) guide solutions:


> 3. I have a 38mm motor casing and a motor that I think is for about 1000 ft as do
> not want to loose it first flight!

That sounds great.. 
Have you used RockSim or OpenRocket to simulate your rocket?

> 4. What is the distance you recommend between launch lugs/rail buttons&

Placement isn't /super/ critical, as long as they're not too close together (to minimize torque shearing) or too far apart (giving you less rail time). As long as both guides are within the bottom half of your rocket, they'll be most effective at getting your rocket up to speed and stable before leaving the rail.  

That being said, most people stick to the general rule of thumb of your forward guide being slightly behind (or forward of) the CoG (center of gravity), and the aft guide being located more toward the aft/fin area of the rocket. 

BTW.. Questions like this have been posted & debated for decades here:

For my aft guide, I like to use the rear centering ring, when possible (when I'm not using a well nut).

Anyone else have input?

> 5. Instructions call for mounting centering rings 1/8" from end of motor tube.  I
> am thinking about using a motor retainer and will chang this accordingly.  Do you
> see any problems.

Yeah.. for first time HP builders.. I usually recommend following the directions to the letter (there's much wisdom and other people's mistakes wrapped up in instructions.. some time us old timers pay for assuming we know better ;).. but that being said, if you're planning on using a nice screw on motor retainer, then yeah.. you need a little extra room for that, and if you don't want the retailer hanging out the back, you will often want to push the centering rings forward of where the instructions say to put them. However.. BE CAREFUL. Dry fit everything first.. In High Power builds (where the fins often mount through the BT to the MMT (motor mount), you'll want to make sure you don't push your MMT centering rings up too far so that they block or interfere with your through-tube fin mounts (a very frustrating mistake if you notice the problem too late).

> 6. It comes with a 36" chute.  Does the size of the field dictate a smaller chute
> for faster decent.

It can.. but so does the hardness of the ground. :)  For 1,000 flight, you're probably fine.  But on bigger, higher flying rockets.. this is why you see people moving to more dual deploy with a small drogue (to bring it down fast), and then a main popped at 500-800ft.

> 7. I read Apogee article re keep it simple so I abandoned doing dual deployment
> using two of the Jolly Logic Chute releases. 

Tempting.. but I agree with KISS for cert flights. You have enough first time details distracting you. After you've got the cert flight out of the way... then play with the fun/redundant stuff.. Wow.. a dual JL Chute Release?  That's an expensive recovery option.. heh cool if you can swing it though. :)

> Apogee recommends not using even one
> JL chute release as something can go wrong.

Yup.. I had one NOT open for me in one of my previous flights.. and a couple other members have seen them not work too:

so they're not perfect.  (great concept though)

>  Again what does the size of the field
> dictate because I do not want to use the JL chute release just for the sake of
> doing it.  (I should have other smaller rockets E - G motors to use the JL).

More important for very small fields. You should be fine at Kentland (a medium sized field).

> Thanks and look forward to the launch and meeting other members and you

By all means! Welcome to the group!  Looking forward to seeing your rocket next Saturday!


> --------------------------------------------
> On Wed, 3/7/18, Thomas Tweeks Weeks <tom at theweeks.org> wrote:
>  Subject: Re: [NRVR-Members] Need Helpers for March Launch, and Outreach events
>  To: "David Bloom" <dwskb at att.net>
>  Cc: nrvr-members at nrvr.org
>  Date: Wednesday, March 7, 2018, 2:07 AM
>  Welcome
>  to the list David!  You're our 101st member!... and an
>  old school Born Again Rocketeer! Welcome back to the sport
>  sir!
>  The
>  LOC IV is a good, classic mid/high power rocket with a nice
>  bigg 4" BT (body tube).. Great choice! Have any
>  pictures of your build you want to share?
>  Did
>  you have a 38mm motor or casing for it yet?  Did you have a
>  certified/HP mentor?  Please feel free to ask questions
>  here and we'll answer what we can.  I know that Bob,
>  Pete, Carlos, Steve myself or others would be glad to help
>  with any design/build, or cert questions you might have.
>  As
>  for your lugs.. We have all the common rod, rail and
>  unistrut sizes out there.  That rocket could fly on either
>  a set of 1/4" lugs, or the more common/modern 10/10
>  rail buttons or conformal railguides.  Most of our guys
>  seems to prefer the new, easy to use well-nut style rail
>  buttons like these:
>  http://aeroconsystems.com/cart/launch-recovery/rail-button-black-sky-style-pair/
>  They're
>  a little more expensive, but a real dream to use.. not like
>  the old days we used to mess with blocks of wood, T-nuts and
>  epoxy. :)
>  If
>  you don't have any, please don't hesitate to
>  ask!
>  Tweeks
>  On
>  Tuesday, March 6, 2018 8:17am, "David Bloom"
>  <dwskb at att.net> said:
>  >
>  Tom, I want to go for my Level 1 so interested if somebody
>  will be there to
>  > certify if we
>  launch.  I will bring a Loc 1V for an H engine and a couple
>  of
>  > others that fly with the Apogee F10
>  which are neat with about an 8 sec burn
>  >
>  time. 
>  >
>  > What type
>  of launcher do you use as I need to know what to install in
>  lug and/or
>  > rail button sizes.
>  >
>  > I have been in and
>  out of rocketry on several occasions since 1958 right
>  after
>  > Sputnik. I started up again this
>  past Dec. I am 78 yrs old this year and this
>  > will be my first launch since late 60s so
>  not of much help now but will assist in
>  >
>  the future.
>  >
>  --------------------------------------------
>  > On Tue, 3/6/18, Thomas Tweeks Weeks
>  <tom at theweeks.org> wrote:
>  >
>  > Subject: [NRVR-Members] Need Helpers for
>  March Launch, and Outreach events
>  > To:
>  nrvr-members at nrvr.org
>  > Date: Tuesday,
>  March 6, 2018, 12:11 AM
>  >
>  > Hey
>  > all!
>  >  
>  > Launch on March
>  > 24th! (need launch helpers):
>  >  We
>  > have our first
>  full launch of the year at Kentland,
>  >
>  scheduled for March 24th! Are you excited!
>  > http://nrvr.org/
>  >
>  > What
>  > are you
>  building and flying?!?
>  > Reply
>  > all here and tell us!.. or post it on
>  facebook:
>  >
>  https://www.facebook.com/groups/NRV.Rocketry/
>  >
>  >  
>  >  
>  > But
>  > for our first spring launch, we need
>  launch
>  > volunteers to pull it off
>  safely! We need folks to step up
>  > and
>  fill roles for:
>  >
>  > a
>  launch director  - someone to
>  > oversee
>  the launch, call in the waiver, open & close the
>  > launch
>  > RSO/LCO
>  coverage  - multiple
>  > people to fill
>  provide setup/breakdown and
>  >
>  > All
>  > roles are
>  detailed here if you want to drill down:
>  > https://tinyurl.com/nrvr-duties 
>  >  
>  > Please reply-all
>  here if
>  > you can pitch in (we'll
>  skip the formality of a
>  > doodle form and
>  see if we get minimum coverage like
>  >
>  this).  If you see no replies here.. it means the
>  > launch is at risk of not having adequate
>  coverage to pull
>  > off safely and could
>  get called off.  I know we all
>  > value
>  the club, so please pitch in if you can. ;)
>  >  
>  >  
>  > March Outreach
>  > Event
>  (need couple people):
>  > We
>  > called off the Salem Elementary outreach
>  event, as we had
>  > schedule conflicts.
>  But another, cooler (and maybe
>  >
>  closer/easier) outreach opportunity has popped up.. and
>  it
>  > may even involve a free movie for
>  those involved! :)
>  >  
>  > Virginia
>  > Tech has
>  asked
>  > up to come set up a rocket booth
>  at their girls-STEM
>  > "Hidden
>  Figures" movie event on March 20th from
>  > 3-7pm.  It sounds like a long time, but
>  we would
>  > only be running the table for
>  like 45min before the movie,
>  > and 45min
>  after the movie. If you've never helped with
>  > our static display tables, it's a lot
>  fun!
>  >
>  >  
>  > VT
>  > would like to host
>  our booth to attract more girls into
>  >
>  engineering and Aerospace.. Plus we'll also be
>  getting
>  > the word out about our club,
>  and attracting science-minded
>  > parents.
>  Just the kind of folks we need to grow the
>  > club.  Right now it's just me and my
>  ugly rockets
>  > and Bob's showing up
>  later.. But WE NEED SOME BIG and
>  > COOL
>  LOOKING rockets to show off! and if we play our cards
>  > right, we might even get a tour of the VT
>  Aerospace wind
>  > tunnel (the kind used in
>  the Hidden Figures Movie!).
>  >  
>  > Reply
>  > to me if you
>  can help out.  Right now.. it's
>  >
>  looking pretty sparse.. and we could use a couple more
>  > helpers (with cool rockets in tow!)
>  >  
>  > Let
>  > me know ASAP so I can let VT know!
>  >  
>  > Tweeks
>  >  
>  >
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