Fellow r.m.r's I am fishing for the wisdon of the group. I am finishing a stock Aerotech Mustang. I will be attaching the parachute to the shock cord with a quick link and swivel. My question; should the mounting point be closer to the rocket body or to the nose cone? Or midway between? Thanks in advance, Bill Bahus Novice Rocketeer
I put my about 2/3 way up the shock cord. Closest to the nose cone. Just wait until you launch it they are a great flier.
-- Tom Priest Rockethead Rockets snipped-for-privacy@rap.midco.net
You always want the attachment point closest to the part that helps pull it out of the tube. In this case, the nosecone.
Don't tie it in the middle, unless you like hearing the parts bang together on the way down.
Don't tie it to close to the body section, otherwise it may not be pulled from the tube.
Mike Fisher Binder Design
Closer to the nosecone is better.
J.A. Michel
I seem to be the oddball. I don't like attaching the chute to the shock cord. I attach a quicklink to the nose cone, then connect every thing to that point.
If you use the molded plastic eyelet on a nose cone, NEVER have more than one thing connected to it. i.e do not terminate both the shock cord and chute at the plastic eyelet. It will rip out. Instead, connect ONE metal ring or quicklink to the nose cone, then connect everything to the ring.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
The potential problem is with 2 seperate connections to the nose cone, chute deployment can tear out the plastic eyelet. If you insert a metal eyelet, this isn't a problem. But that's why I always use a quick link on the nose cone, with everything connected there.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
I do something of a variation on that... a quick-link joins shockcords attached to nosecone and main body, and the parachute gets attached to that point. Sometimes, I'll put the `chute at the end of a short length of cord, or sometimes not.
Like this...
Chute \/ NC--------O------------------------FC
Never had any problems... :-)
I do mine by just passing the shock cord thru the nosecone eyelet, not tied to it, with the chute attached to 4 or 5 inches of cord coming out the other end of the eyelet Like this:
chute w/ quick link / / / / /
NC-------------------------------------------------body tube
It works for me. J.A. Michel
The main thing to consider is that the placement of the NC/payload bay will not "bang into" the rest of the bird, possibly causing damage. Most seem to use the end, or 2/3 to the end as an attachment point, but this can be based on the length of the SC in relation to the lengths of the of AF sections.
The only plastic loop I've had rip out on a LOC or similar nose cone was earlier this year with an un-bonus delay. It ejected at semi-warp speed, and broke the loop on my Cyclotron. As long as you don't have 2 or more things pulling on the loop in different directions at the same time, you're probably OK.
And yes, the rocket recovered OK, and the payload section tumbled down.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
And a cert attempt, or so I've seen.
Joel. phx
I was curious about this same point a year or two ago so I did some ground testing using 5.5 and 7.5 inch tubes. Without the NC attached to the recovery system the exhaust gases would usually go "fooof" around the deployment bag (and no deployment). Tight or loose bags didn't seem to make a difference, although I guess if you got the bag tight enough it might.
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