Thanks Mike! We’re frugal, too, so this is great advice, thank you! This is all
about teaching Max that we can build cool things that don’t arrive in a glossy
box from Denmark with step by step instructions… ;)
I doubt we’ll be fabricating our own parts (at least not the main ones) but
that’s something to consider for the next project.
From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx] On
Behalf Of Mike Riss
Sent: Friday, June 26, 2015 1:43 PM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Scratch build tips
Adrian and Max,
I'm "frugal". So, I decided that rather than buying a kit of a rocket I really
wanted (LOC Expediter), I would build one from scratch. I'd suggest the same
principle (using an existing design, not the frugal part) for your first
attempt.
- Pick a rocket you really like.
- Then, find a sim file for it. Most manufacturers provide them, and there are
some online sources as well (rocketreviews.com for example).
- Use the sim file to get a list of parts.
- Then, source the parts from either online vendors if you need it right away
(or it's the only source), or keep in mind another back-yard source -- the
vendors that attend our launches.
- Use the instructions from the kits you've assembled as a guide. Modify them
with the knowledge you've gleaned from your experience so far.
- One thing to consider is upsizing the motor mount, so the rocket stays active
in your fleet as you progress through the hobby -- you can always adapt down,
but it's harder to make the motor mount bigger once the rocket's built.
Also, there's scratch, and then there's "scratch", where you fabricate parts
yourself. For instance, with a big rocket, you might use "sonotube" or
something similar for the rocket body. However, it doesn't always match up in
size with available nose cones. So, you make the cone yourself. Bryce had an
interesting method for his L3 Squat :-) Using composites, you can even make
the tubes yourself, as well as make flat stock for fins, centering rings, etc.
You can also adapt "trash", like carpet tubes you find (for free!) in a
dumpster.
Check out some of the online resources like John Coker's site (jcrocket.com),
or The Rocketry Forum (rocketryforum.com), which has a section devoted to
scratch builds (but there's lots of scratch projects in the other sections too).
Take advantage of the Tripoli TAPs and NAR L3CCs. Most people think of them
only for certification, primarily L3, but they have a wealth of knowledge that
anyone can use. They can be especially helpful if for example you're trying to
upscale a model rocket design but aren't sure what material/size/thickness/etc.
is appropriate for your rocket and intended motors.
Most of all . . . have fun!!!
Mike
On Friday, June 26, 2015 12:00 PM, Adrian P. Bailey <adrian@xxxxxxxxxxxxxxx
<mailto:adrian@xxxxxxxxxxxxxxx> > wrote:
LOL, we’re new to rocketry but I have been using McMaster-Carr for decades. And
they are in our back yard… ;)
From: roc-chat-bounce@xxxxxxxxxxxxx <mailto:roc-chat-bounce@xxxxxxxxxxxxx>
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of Allen Farrington
Sent: Friday, June 26, 2015 11:51 AM
To: roc-chat@xxxxxxxxxxxxx <mailto:roc-chat@xxxxxxxxxxxxx>
Subject: [roc-chat] Re: Scratch build tips
Excellent! I get components from Public Missiles, Giant Leap, and Madcow,
depending on what I'm up to. I'm sure others have good sources as well. Oh, and
I use McMaster-Carr for hardware.
Allen
Terseness and mis-spelling courtesy of my iPhone
On Jun 26, 2015, at 11:38 AM, Adrian P. Bailey <adrian@xxxxxxxxxxxxxxx
<mailto:adrian@xxxxxxxxxxxxxxx> > wrote:
Thank you!
We modified our Mirage to take an I motor with some help from David Reese. For
the next project we want a big, fat, low and slow rocket.
Any suggestions on where to source the parts?
From: roc-chat-bounce@xxxxxxxxxxxxx <mailto:roc-chat-bounce@xxxxxxxxxxxxx>
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of Allen Farrington
Sent: Friday, June 26, 2015 11:32 AM
To: roc-chat@xxxxxxxxxxxxx <mailto:roc-chat@xxxxxxxxxxxxx>
Subject: [roc-chat] Re: Scratch build tips
My first experience was that I modified a few kits, then later went to
full-scratch. I converted a L1 rocket into a dual deploy by adding a payload
section and electronics bay. Next I modified a LOC Magnum to change the motor
mounts and add air-start wiring as well as an extended payload section. The
nice thing about modifying a kit is that you get most of what you need
component-wise, and then you can order other components, usually from the kit
manufacturer. One common thing to do is to purchase a kit with a 29mm motor
mount and then find and order the parts to upgrade the mount to 38mm. You’ll
have to modify the fins to do this so it’s a good way to start getting used to
doing the types of modifications required to do a full scratch build. I would
stay away from minimum diameter for your first scratch build as it adds a bit
of complexity to the fin attachments.
Before you know it, you’ll start getting familiar with the different sizes of
the different types of tubing. For example, 3” cardboard is not the same as 3”
phenolic or 3” fiberglass. Couplers and bulkheads and centering rings all have
to be ordered or modified if you change tubing and modifying kits is a safe way
to step into that world.
Good luck!
Allen
--------------------------------------------------------------------
Allen H. Farrington
http://www.allenfarrington.org <http://www.allenfarrington.org/>
818-653-2284
On Jun 26, 2015, at 11:14 AM, Adrian P. Bailey <adrian@xxxxxxxxxxxxxxx
<mailto:adrian@xxxxxxxxxxxxxxx> > wrote:
Max and I are exploring the options for a project for November’s ROCstock that
we will start working on together over his summer break. Any tips on how to get
started building from scratch? We have been playing with OpenRocket (thank you
Chis and Phil) and I see that Apogee Components has a lot of parts available.
