[roc-chat] Re: Tether setups

  • From: Gregory Lyzenga <lyzenga@xxxxxxxxx>
  • To: roc-chat@xxxxxxxxxxxxx
  • Date: Sat, 16 Jun 2012 18:34:16 -0700

On Jun 16, 2012, at 5:01 PM, Jeff Gortatowsky wrote:

> Greg, yes thats it. Thanks. 
> 
> Q's:
> 1) How did you thread the wires from the inside of the tube to the outside of 
> the rocket where the electronics were for each flight? 
> 2) Also do you have details of the shunts you used? I have heard ppl 
> recommend AGAINST shunts as something that under G load can open up. What do 
> you think? Or did you mitigate that?
> 
> ---------------------------------------
> Jeff Gortatowsky, Redondo Beach, CA | Twitter: JeffGortatowsky | Yahoo: 
> indanapt 
> "(Scientific) Skepticism is not a set of beliefs, it is a set of methods for 
> asking questions about reality." -- Doctor Steven Novella


Hi Jeff:
Question 1)  The wires for all of my charges went downwards first, through a 
main plywood bulkhead (the one you can see forming the floor of the recovery 
bays.  Then once below the bulkhead, the wires were fed out through the side of 
the airframe into the 4" diameter scale conduit running along the side.  With a 
12" airframe, there was plenty of room to crawl inside and arrange things; not 
a luxury that is generally available with smaller tubes!

Question 2) The shunts were only in place while on the pad, and were intended 
as a possible safety against premature firing.  Perhaps what you meant to ask 
about was the charge break switches.  Those were required by NAR L3 as a means 
of externally safeing the rocket, should it land in an indeterminate state.  
That indeed might be a concern with opening up under load...  For that reason, 
and with the suggestions of other wise folks, I used the Aerocon screw 
switches.  They work by literally mashing the head of a screw into two wires to 
make the connection.  The design is as simple and dumb as a sack of doorknobs, 
but it is bulletproof, as far as I can tell.

Hope this helps!

                 - Greg

-------------------------------------
Gregory A. Lyzenga  <lyzenga@xxxxxxx>           ***     (909) 621-8378
Dept. of Physics, Harvey Mudd College           *** cell(626) 808-5314
Claremont, CA 91711-5990                        *** fax (909) 621-8887
<http://tinyurl.com/LyzengaPhysics>




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