Moving from elastic to nylon - Any issue with this setup?

[overklock]

I'm moving my new, re-built Mega Der Red Max from elastic to nylon, I have never used Nylon before, and just want to make sure there are no issues with this setup before launching.

Rocket is 40 inches in height. Shock cord is roughly 12 feet. I understand that some individuals use Kevlar for inside the rocket, then connect that to the nylon, I am not going this route and would prefer to just attach the nylon directly inside the rocket.

Uni Knot connecting quick link to nylon shock cord. This then gets mounted inside of the rocket on the eye bolt. (This knot will be taped with masking tape to protect it).


Nomex blanket connected near aft end of rocket. Quick link with nylon shock cord is now attached.


Uni knot connecting nylon shock cord to nose cone (may change to another quick link).



Everything folder up. Nylon shock cord braided to reduce size before loading.

 

[cls]

That will be perfect!!

 

[overklock]

That will be perfect!!

Thank you! So no issues with the knot types? No issue with attaching the nylon directly to the quick link/eyebolt?

 

[cls]

Looks great to me.

Personally, I use doubled figure 8 knots, but your knots are fine.

 

[DigBaddy]

You may want to move the nomex away from the body so it can't hit it when unfurled and flapping around.

Attaching the chute to the shock cord would be something else I'd suggest. That plastic loop is weak and now your cord has much less give than elastic.

 

[overklock]

You may want to move the nomex away from the body so it can't hit it when unfurled and flapping around.

Attaching the chute to the shock cord would be something else I'd suggest. That plastic loop is weak and now your cord has much less give than elastic.

What exactly would be the issue with the nomex blanket hitting the body tube? Just scratches on the paint?

Good point on the plastic nose cone being a weak point. Ill have to move the parachute into the shock cord.

 

[K'Tesh]

https://www.rocketryforum.com/threads/using-protection-yes-rubbers-for-your-rocket.158586/

 

[waltr]

That looks real good except the Chute attached to the nose.

 

[overklock]

That looks real good except the Chute attached to the nose.

My main concern is with how far down the nomex is either the shock cord getting tangled up in the chute (due to how much of the shock cord is above the parachute) OR the ejection charge not fully deploying the parachute. Does attaching the chute further down on the shock cord instead of the nose cone decrease the chances of a successful deployment?

 

[waltr]

I have chutes down a foot or two from the nose and never had a tangle in dozens of flights.
I think a good reason is the chute is in a tightly wrapped Nomex Burrito, therefore the nose is clear before the chute start to unfurl.
The other reason is that the ejection charge blows the nose away which then pulls the chute out of the rocket (not blowing out the chute). Then the nose has the cord to the chute tight so it is clear of the chute so doesn't tangle.

 

[overklock]

I have chutes down a foot or two from the nose and never had a tangle in dozens of flights.
I think a good reason is the chute is in a tightly wrapped Nomex Burrito, therefore the nose is clear before the chute start to unfurl.
The other reason is that the ejection charge blows the nose away which then pulls the chute out of the rocket (not blowing out the chute). Then the nose has the cord to the chute tight so it is clear of the chute so doesn't tangle.

What about the excess shock cord that's sitting on top of the nomex wrapped parachute, that doesn't get in the way?

I placed my chute down about a foot from the nose cone, let me know if this looks right.


Parachute is now on the shock cord rather than the nose cone


Burrito folded and excess cord crocheted


Chute with nomex goes in, excess shock cord goes on top, and finally the nose cone goes in

 

[waltr]

Looks perfect and how I have been doing it.
As I said, the ejection blows out the nose cone which then pulls out the chute. So the cord is being pulled away from the chute when the Nomex blanket opens.

 

[overklock]

Looks perfect and how I have been doing it.
As I said, the ejection blows out the nose cone which then pulls out the chute. So the cord is being pulled away from the chute when the Nomex blanket opens.

Thanks! Wish me luck

 

[waltr]

Good luck... Straight Launch and soft landing.

 

[MALBAR 70]

It looks great to me, I use the daisy chain method on my nylon shock cords too. The only thing I would suggest is a shock cord protector, it'll help the nylon cord last a bit longer.

 

[teepot]

Add a swivel to the chutes shroud lines. The chute will spin. Without a swivel the chute could spin itself closed. I put a loop in the shock cord, attach a quick link and the swivel on the chute to the quick link.

 

[waltr]

I have found that a swivel on the chute is not required. all of my larger rockets (1.6" and up) use this Chute directly to the cord attachment method. Never have a problem with the chute spinning.
What I have found to the fin can (booster) does the spinning and a swivel between the shock cord and fin can attachment keeps the cord from getting twisted.

 

[novahobbies]

Good call moving the Chute. Someone pointed that out to me before in a way that made a lot of sense. The nose cone will probably survive the fall if it breaks. And even if it doesn't, nose cones are cheap. All the work you put into the body is the part you REALLY want to save.

 

[rcktnut]

Good call moving the Chute. Someone pointed that out to me before in a way that made a lot of sense. The nose cone will probably survive the fall if it breaks. And even if it doesn't, nose cones are cheap. All the work you put into the body is the part you REALLY want to save.

I agree, and right now the nose cone attachment is the weakest link. I would drill another hole through the bottom of the nose cone, and thread the shock cord through the holes.

 

[overklock]

I agree, and right now the nose cone attachment is the weakest link. I would drill another hole through the bottom of the nose cone, and thread the shock cord through the holes.

Have any examples of this? I feel like the walls of the nose cone would be weaker than the link itself, no?

 

[bobbyg23]

Have any examples of this? I feel like the walls of the nose cone would be weaker than the link itself, no?

Nope. Makes it super strong. That link is terribly weak.

 

[bobbyg23]

Pics

 

[rcktnut]

Pics

I forgot about this thread. Thanks for showing an example. I have none myself, I use elastic on all of my rockets that are 2lbs. or less and do use the nose cone attachments. I never had one fail. Adding a nylon shock cord does make the attachments the weakest link especially with a less than nominal deployment. I buy high quality elastic and wider if not satisfied with what is included in the kit.