have i attached the shock cord correctly to my LOC IV

[Lt72884]

Ok, i have seen 3 different ways to attach this thing, and i had a thread about similar topic a few weeks ago.

Here is how i have done it:

loop hole tied to payload eyebolt
second loop hole at the far end is quick linked to the motor mount ring eyebolt
4feet down (from payload) i have tied the parachute to the shockcord

so when it pops open, its :

nosecone section-parachute-bottom section
will this work?

thanks
this is for my lvl 1, the rest of the team has done L2. Ill be L2 soon, just had to work the days of the launches since they are 4 hours from me and i travel 6 hours a day for school. I couldnt find a cover for work haha

 

[David Schwantz]

I assume it is NOT dual deploy from your pic. It is best to not tie in the chute at the halfway point of the shock cord. Tie it closer to the NC to avoid NC from slamming into fin can section.

 

[Hobie1dog]

what David said

 

[Lt72884]

I assume it is NOT dual deploy from your pic. It is best to not tie in the chute at the halfway point of the shock cord. Tie it closer to the NC to avoid NC from slamming into fin can section.

yeah, thats why i went with 3 to 4 feet down the cord. its hard to see that in the pic, but it is labeled with my bad hand writing haha

it is not dual deploy

 

[Lt72884]

what David said

yeah, its not tied half way, the pic is small but i have it labeled 3 to 4 feet from NC is where it is tied. if you click image, it will make it larger.

Next question, is tieing the chute ok, or should i use a quick link, but that can be harder for the ejection charge to push out i have heard??

thanks

 

[tfish]

i would tie it directly to the object (nose cone) that is pulling it out of the body tube.

if your deployment charges only ejects the nose cone a foot..your chute..could remain in the body tube..tied where you and others are talking about.

what harm does tying it to the nose cone create?

Tony

 

[Lt72884]

i would tie it directly to the object (nose cone) that is pulling it out of the body tube.

if your deployment charges only ejects the nose cone a foot..your chute..could remain in the body tube..tied where you and others are talking about.

what harm does tying it to the nose cone create?

Tony

ok, so tie it to the eybolt the shock cord is hooked too on the payload section?

i could actually use another quick link to attach it to the eybolt

 

[loopy]

You want the parachute as close to the top of the cord as possible. I usually attach directly to the piece being blown off or maybe a few inches.

 

[David Schwantz]

The more quick links you use, the heavier it gets.

 

[bobbyg23]

You are good the way you have it. 3ft down is perfect

 

[loopy]

What is the total length of your shock cord? You don't want your nose cone swinging around and bashing into your booster...

 

[Lt72884]

What is the total length of your shock cord? You don't want your nose cone swinging around and bashing into your booster...

15 feet

 

[loopy]

12 feet

Okay - with a 12 foot shock cord, you should be good a few feet from the nose for your attachment point. I tend to put it closer to the top, but that should be fine.

 

[Lt72884]

The more quick links you use, the heavier it gets.

that was my concern. I would only have 2 total quick links though.

 

[Lt72884]

Okay - with a 12 foot shock cord, you should be good a few feet from the nose for your attachment point. I tend to put it closer to the top, but that should be fine.

im just going to attach it to the payload eyebolt with the shockcord and call it good. Its going to be about 10*F outside during launch so the air is going to be THICK!! We are about 6400 feet as well

 

[David Schwantz]

do NOT attach the chute to the payload eyebolt. It will never come out of the payload section. Attach the shock cord to the payload eyebolt on one end. Then attach the shock cord to the NC attachment point, eyebolt, molded loop, bulkhead, whatever it is that you have. Then attach the chute to the shock cord a foot or two down from NC. All you need to do is tie a loop in shock cord and then thread the chute through that loop back on itself. No quick link needed.

 

[rharshberger]

do NOT attach the chute to the payload eyebolt. It will never come out of the payload section. Attach the shock cord to the payload eyebolt on one end. Then attach the shock cord to the NC attachment point, eyebolt, molded loop, bulkhead, whatever it is that you have. Then attach the chute to the shock cord a foot or two down from NC. All you need to do is tie a loop in shock cord and then thread the chute through that loop back on itself. No quick link needed.

+1, and to add to what David said, chutes do not get "blown out" (unless a piston ejection system is used), they are either pulled out by the nosecone, a pilot chute (deployment bag setup) or slide/fall out during descent.

 

[Lt72884]

do NOT attach the chute to the payload eyebolt. It will never come out of the payload section. Attach the shock cord to the payload eyebolt on one end. Then attach the shock cord to the NC attachment point, eyebolt, molded loop, bulkhead, whatever it is that you have. Then attach the chute to the shock cord a foot or two down from NC. All you need to do is tie a loop in shock cord and then thread the chute through that loop back on itself. No quick link needed.

ok, i will do it that way then. thanks for that info.
is a slip knot secure enough for the loop i attach the chute to? or is a square knot better?

 

[David Schwantz]

No slip knots in rocketry, it is in the safety code . I just tie an overhand knot to form a loop.

 

[Lt72884]

No slip knots in rocketry, it is in the safety code . I just tie an overhand knot to form a loop.

ok, great. i will use that method then.

 

[teepot]

I would agree with some of the other guys. Chute a foot or two down from the payload section/nose cone. Use a swivel at the end of the shroud lines or too the quick link our however you decide to attach the chute to the shock cord. Otherwise the chute will twist the shroud lines up and make it less effective. Also attach your blanket below the chute maybe a foot to 6". Good luck with your cert.

 

[Lt72884]

ok, here is what i have done. its a small quicklink with the chute attached and now im attaching said quicklink to the shockcord via overhand knot about 1 to 2 feet from NC

 

[Lt72884]

No slip knots in rocketry, it is in the safety code . I just tie an overhand knot to form a loop.

random question, but is it possible to find these safety codes so i can add them to my interim report that is due next week? they want a list of all the HPR codes. I have the NFS code somewhere

 

[David Schwantz]

Tripoli website has the safety code. But I wa kiddin about the slip knot thing. But they still are not a good idea.

 

[strider07928]

I’d suggest using an Alpine Butterfly to create the loop in your line, this way it isn’t impossible to untie if you ever want to move or remove the knot.

 

[Sooner Boomer]

Here's what I've done. It works for me. There are many ways to do this. I use a 3/8 kevlar shock cord, about 10 feet long. It has a loop on the "free" end (where the nose cone attaches). I attached a swivel about 18 inches from this end. Swivels in the recovery system are a really good idea. It keeps the shroud lines from twisting up. On my L2 I *didn't* use a swivel and the shroud lines twisted up all the way to the canopy. This reduces the size of the opening of the parachute and makes the rocket come down faster.

1) the swivel on the shock cord. It's held tightly in place, but can be easily loosened and removed or relocated on the shock cord.



2) parachute - I try to use quick links on all high power (and some mid-power) rockets. It just makes things easier. They only weigh half an ounce or so. Be sure to size them appropriately! I use nylon cord and tie a running half hitch for about a half an inch. I squish the knots together and dab on a bit of white glue to keep them from coming loose. When dry, I trim the ends. The section of knots should be tight, but loose enough to slide on the shroud lines, and it should not be glued *to* the shroud lines, and allows you to make the loops at the end bigger or smaller. This loop of cords can be removed and the shroud lines untangled if the need comes up. I generally leave a swivel on each parachute, but that's just me.

 

[Ronz Rocketz]

Tripoli website has the safety code. But I wa kiddin about the slip knot thing. But they still are not a good idea.

I was like, "wait, what?"

 

[Lt72884]

Tripoli website has the safety code. But I wa kiddin about the slip knot thing. But they still are not a good idea.

lol, i spent about an hour and a half googling for this specific rule HAHAHA. I agree its for sure not a good knot to use.

 

[Lt72884]

Here's what I've done. It works for me. There are many ways to do this. I use a 3/8 kevlar shock cord, about 10 feet long. It has a loop on the "free" end (where the nose cone attaches). I attached a swivel about 18 inches from this end. Swivels in the recovery system are a really good idea. It keeps the shroud lines from twisting up. On my L2 I *didn't* use a swivel and the shroud lines twisted up all the way to the canopy. This reduces the size of the opening of the parachute and makes the rocket come down faster.

1) the swivel on the shock cord. It's held tightly in place, but can be easily loosened and removed or relocated on the shock cord.
View attachment 546755
View attachment 546756

2) parachute - I try to use quick links on all high power (and some mid-power) rockets. It just makes things easier. They only weigh half an ounce or so. Be sure to size them appropriately! I use nylon cord and tie a running half hitch for about a half an inch. I squish the knots together and dab on a bit of white glue to keep them from coming loose. When dry, I trim the ends. The section of knots should be tight, but loose enough to slide on the shroud lines, and it should not be glued *to* the shroud lines, and allows you to make the loops at the end bigger or smaller. This loop of cords can be removed and the shroud lines untangled if the need comes up. I generally leave a swivel on each parachute, but that's just me.
View attachment 546757

thanks for this information. I did not have a swivle for todays launch but i used a quick link for the chute and it did not tangle, so the smaller link must have helped. I had my chute about 16 inches from the NC. It had a BEAUTIFUL slooow landing. I was supper happy.

 

[Ronz Rocketz]

For LPR and MRP, slip knots are awesome when tying to an eyelet or where an overhand loop is not feasible. I'm not sure about HPR.