Quantcast

Zipper prevention...best methods ?

The Rocketry Forum

Help Support The Rocketry Forum:

Silverleaf

Well-Known Member
Joined
Feb 22, 2003
Messages
1,127
Reaction score
0
What are the best methods to curtail or to prevent zippering ?.

I ask because I'm nearing the point of worrying about a proper method to lower the odds of a zipper effect, but also know that no method is 100 % flawless. Any help would be appreciated. 8)

Cheers and happy New Year,
 

Ryan S.

Well-Known Member
Joined
Mar 24, 2003
Messages
3,553
Reaction score
0
there are lots of things, zipperless coupler (can still cause zippers though), fiberglass will toughen your airframe, a longer shock cord, and o yeah deployment at apogee always helps :D
 

rbeckey

Well-Known Member
Joined
Jul 19, 2012
Messages
1,520
Reaction score
1
I saw an add for a soft kevlar covered ball that attaches to the shock cord at the point where it would press against the BT end. It would probably be very hard to zipper that setup.
 

rocwizard

Well-Known Member
Joined
Jul 21, 2002
Messages
636
Reaction score
0
The kevlar covered ball that rbeckey describes is the Fireball from Giant Leap.

A method I like to use is adding a 1" strip of carbon fiber around the opening of the tube. typical glassing hten covers that. Gives amazing rigidity to the tube. I have never zippered a tube thus far.
 

Rocketmaniac

Well-Known Member
Joined
Jun 18, 2003
Messages
4,066
Reaction score
0
Originally posted by rocwizard
A method I like to use is adding a 1" strip of carbon fiber around the opening of the tube. typical glassing hten covers that. Gives amazing rigidity to the tube. I have never zippered a tube thus far.
Eric, do you put the carbon fiber on the inside or outside of the body tube? Or on the actual edge?
 

loopy

Well-Known Member
Joined
Dec 13, 2009
Messages
4,586
Reaction score
1
This question is really kind of open ended - the solutions you've seen posted are mostly for the high power end of things. If you're talking about low power models with a kevlar leader out the top of the tube, wrap it loosely with a thick layer of masking tape where the cord hits the top of the tube. You don't want it really tight - let it give a little. This should help on the low power end of things.

Loopy
 

rocwizard

Well-Known Member
Joined
Jul 21, 2002
Messages
636
Reaction score
0
Rocketmaniac, the carbon fiber strip is placed on the exterior of the tube up on the end. Fiberglassing then takes place as usual which sells down the carbon, not to mention that since carbon can't be sanded it must be covered in 'glass.

It might be a tad overkill for most rockets, but the rockets I ahve used this on are high performance. I will start a thread on one inparticular soon.


HTH;)
 

swimmer

Well-Known Member
Joined
Feb 20, 2009
Messages
670
Reaction score
0
Silverleaf,

Go to Rocketry Online's InfoCentral and look at the zipperless design article by Stu Barrett. I'm currently using the design to build my first zipperless rocket. This design allows the rocket to seperate somewhere along the midsection of the bodytube allowing for the parachute to be pulled out the back of the forward bodytube section. This design will work for LPR-MPR and HPR.
 

Silverleaf

Well-Known Member
Joined
Feb 22, 2003
Messages
1,127
Reaction score
0
Many thanbks for the comments and suggestions. I found the zipperless article, that should do the trick. 8)

Happy New Year
 

Super

top secret
TRF Supporter
Joined
Sep 28, 2018
Messages
18
Reaction score
2
Location
Chicago, Illinois
Anyone know a manufacturer of a carbon fiber or other suitable material that will fit over a LOC VII, 7.5 inch paper body tube? If it is necessary to cut the ring, are there any special techniques used for the putty in the gaps? Thanks for your help.


While frightening the confronting of the likes of the Ripper, much more is the terror of an "O" engine zipper. o_O
 

dhbarr

Amateur Professional
Joined
Jan 30, 2016
Messages
6,829
Reaction score
1,309
Anyone know a manufacturer of a carbon fiber or other suitable material that will fit over a LOC VII, 7.5 inch paper body tube? If it is necessary to cut the ring, are there any special techniques used for the putty in the gaps? Thanks for your help.


While frightening the confronting of the likes of the Ripper, much more is the terror of an "O" engine zipper. o_O
Soller Composites sells glass or carbon sleeving to epoxy on as a skin.
 

FredA

Well-Known Member
Joined
Jan 19, 2009
Messages
2,154
Reaction score
331
Want to avoid a zipper - don't deploy at speed.
Snarky reply, yes.........but accurate.

Your first efforts should be placed to make sure you nail the deployments which is the "root cause" of zippers.
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
6,486
Reaction score
3,171
Location
Butte, Montana
Anyone know a manufacturer of a carbon fiber or other suitable material that will fit over a LOC VII, 7.5 inch paper body tube? If it is necessary to cut the ring, are there any special techniques used for the putty in the gaps? Thanks for your help.


While frightening the confronting of the likes of the Ripper, much more is the terror of an "O" engine zipper. o_O
Super,
Many people over the years have taken a strip of Kevlar and made a zipper reinforcement ring at the mouth of the body tube.

Your question about “putty” makes me wonder: What exactly is your level of experience with composite construction and rocketry in general?
 

Mugs914

"A crummy commercial..!!??"
Joined
Oct 1, 2012
Messages
1,274
Reaction score
865
Location
Temple TEXAS
As mentioned, the first order of business is proper deployment timing. There is no substitute for proper planning. But since nothing is perfect (with the possible exception of some forms of human stupidity) it can be good to take precautions...

Cross-form chutes tend to have softer opening characteristics than conventional chutes so they can give everything a tad more time to get properly oriented before the big yank (Texans don't like big yanks...:p). Plus they look cool... I use that type anytime there is a question about deployment, like when using motor ejection and your rocket sims out right between two available delay times. In fact, I use them most of the time because, well, they look cool.

Top Flite has them down to 10" diameter, I think, and in thin-mil. They make fantastic drogues for DD.
 

T-Rex

Ordinary Average Guy
TRF Supporter
Joined
Jul 22, 2011
Messages
2,980
Reaction score
34
Just keep them x-chutes away from yer dog..... Mine no longer has shroud lines thanks to a puppy..... :(:p
 

Ted Cochran

Well-Known Member
Joined
Jan 22, 2009
Messages
515
Reaction score
174
FWIW, I’ve used as much pool noodle as will fit on the ends of the tubular nylon for large rockets. Nerf darts for smaller ones, and masking tape applied face to face for even smaller ones.
 

Super

top secret
TRF Supporter
Joined
Sep 28, 2018
Messages
18
Reaction score
2
Location
Chicago, Illinois
Super,
Many people over the years have taken a strip of Kevlar and made a zipper reinforcement ring at the mouth of the body tube.

Your question about “putty” makes me wonder: What exactly is your level of experience with composite construction and rocketry in general?
Dear President Shannon: I am uncertain what you mean by my "Level of Experience." Thank you for your input though. It was truly helpful. To explain, I assume that all Kevlar rings do not fit all body tubes appropriately. Some may need to be cut and tightened to fit? I use the term "putty" generically to mean a filler-type substance. I hope I did not promulgate any confusion. I simply wanted some help because i don't even know half of what is in NASA's library. I will be more cautious the next time I write the forum.

Sincerely,
Tom Long, PhD.
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
6,486
Reaction score
3,171
Location
Butte, Montana
Dear President Shannon: I am uncertain what you mean by my "Level of Experience." Thank you for your input though. It was truly helpful. To explain, I assume that all Kevlar rings do not fit all body tubes appropriately. Some may need to be cut and tightened to fit? I use the term "putty" generically to mean a filler-type substance. I hope I did not promulgate any confusion. I simply wanted some help because i don't even know half of what is in NASA's library. I will be more cautious the next time I write the forum.

Sincerely,
Tom Long, PhD.
Tom,
The Kevlar ring I mentioned is made by wrapping a strip of fabric around the mouth of the tube in an epoxy matrix, which is typical of composite construction. Because the ring is made from fabric it fits any size tube and there’s no gap which needs filling. That’s why I asked for your level of experience with composites, so you would receive answers that don’t talk above or below your knowledge level. Apparently you feel offended by my question; my intent was not to insult you. Your question didn’t seem to indicate prior experience with composites, so I asked.
In the same way as Kevlar, fiberglass or carbon fiber reinforcement rings can be added to the mouth of a body tube: Fabric embedded in an epoxy matrix.
When you do need fairing compound (putty), having experience mixing laminating epoxy with various amendments, such as fumed silica, carbon or glass pulp, or microballoons can be helpful.
 

Super

top secret
TRF Supporter
Joined
Sep 28, 2018
Messages
18
Reaction score
2
Location
Chicago, Illinois
Haaaaa, i like that reply. Hey, a Snarky? Is that a ballistic missle of the US? Many were painted red with a huge hawk on the side? I think the hawk's mouth surrounds the forward intake? Anyway, funny response. Thanks


QUOTE="FredA, post: 1869900, member: 279"]Want to avoid a zipper - don't deploy at speed.
Snarky reply, yes.........but accurate.

Your first efforts should be placed to make sure you nail the deployments which is the "root cause" of zippers.[/QUOTE]
 

Super

top secret
TRF Supporter
Joined
Sep 28, 2018
Messages
18
Reaction score
2
Location
Chicago, Illinois
steve
Tom,
The Kevlar ring I mentioned is made by wrapping a strip of fabric around the mouth of the tube in an epoxy matrix, which is typical of composite construction. Because the ring is made from fabric it fits any size tube and there’s no gap which needs filling. That’s why I asked for your level of experience with composites, so you would receive answers that don’t talk above or below your knowledge level. Apparently you feel offended by my question; my intent was not to insult you. Your question didn’t seem to indicate prior experience with composites, so I asked.
In the same way as Kevlar, fiberglass or carbon fiber reinforcement rings can be added to the mouth of a body tube: Fabric embedded in an epoxy matrix.
When you do need fairing compound (putty), having experience mixing laminating epoxy with various amendments, such as fumed silica, carbon or glass pulp, or microballoons can be helpful.

Steve, Thank you very much. Your information is extremely helpful. Your high level of expertise is evident and certainly stands you in great stead. I bet you are a great resource for many people similar to me.
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
6,486
Reaction score
3,171
Location
Butte, Montana
steve



Steve, Thank you very much. Your information is extremely helpful. Your high level of expertise is evident and certainly stands you in great stead. I bet you are a great resource for many people similar to me.
Thanks. This is a link to the West Systems Handbook, which is chock full of helpful information on composite construction:
https://www.westsystem.com/instruction-manuals/user-manual-product-guide/

There are also a lot of very interesting looking books available from Aircraft Spruce and Spar that get into more advanced techniques.
https://www.aircraftspruce.com/menus/cm/books.html
 

MetricRocketeer

Well-Known Member
TRF Supporter
Joined
Jun 1, 2018
Messages
150
Reaction score
15
Soller Composites sells glass or carbon sleeving to epoxy on as a skin.
Hi dhbarr,

I went to Soller Composites. Very useful. So many choices are available, however, I don't know which one to pick. Could you please advise.

Thank you.

Stanley
 

dhbarr

Amateur Professional
Joined
Jan 30, 2016
Messages
6,829
Reaction score
1,309

MetricRocketeer

Well-Known Member
TRF Supporter
Joined
Jun 1, 2018
Messages
150
Reaction score
15
Hi dhbarr,

Thank you for your response. So I have these followup questions for you, or for anyone, please:
  • Are people suggesting that fiberglass then be laid over the carbon sleeve? I don't understand the point of that, but perhaps I am misunderstanding.
  • Epoxying the carbon around the outside the air frame would add some thickness to the air frame, which could make the fit of the nosecone too tight, right? So why not epoxy the carbon sleeve to the inside of the air frame? Wouldn't that contribute the same amount of anti-zippering protection as epoxying the carbon sleeve to the exterior of the air frame?
Stanley
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
6,486
Reaction score
3,171
Location
Butte, Montana
Hi dhbarr,

Thank you for your response. So I have these followup questions for you, or for anyone, please:
  • Are people suggesting that fiberglass then be laid over the carbon sleeve? I don't understand the point of that, but perhaps I am misunderstanding.
  • Epoxying the carbon around the outside the air frame would add some thickness to the air frame, which could make the fit of the nosecone too tight, right? So why not epoxy the carbon sleeve to the inside of the air frame? Wouldn't that contribute the same amount of anti-zippering protection as epoxying the carbon sleeve to the exterior of the air frame?
Stanley
Stanley,
1. If you use a carbon sleeve there’s no need to add fiberglass to the outside.
2. Nosecones typically fit inside the body tube so composite reinforcement on the outside doesn’t affect the fit.
 

MetricRocketeer

Well-Known Member
TRF Supporter
Joined
Jun 1, 2018
Messages
150
Reaction score
15
Hi Steve,
  • Good on issue #1. So I would measure the correct length of the carbon sleeve to fit around the exterior circumference of the air frame and cut the sleeve to that length. Then I would put epoxy on the back of the carbon sleeve and stick it onto the air frame. Perhaps I would do a little sanding to help with the epoxy attaching.
  • On issue #2. Of course. How silly on my part. I need to attach the sleeve to the exterior of the air frame precisely so as to not cause a misfit.
Thank you.

I will definitely consider this technique. It couldn't hurt except for the added weight of the carbon sleeve and the epoxy, and that might not make a difference.

Stanley
 

BradMilkomeda

Well-Known Member
Joined
Feb 26, 2017
Messages
177
Reaction score
28
Wholly thread reserection Batman!

The original post was over 15 years ago.
 

MetricRocketeer

Well-Known Member
TRF Supporter
Joined
Jun 1, 2018
Messages
150
Reaction score
15
Hi everyone,

But then here's a problem. I went to the Soller Composites website, and I tried to do a rough calculation of the price of 3K (Light) Carbon Sleeves. If I am reading the information correctly, you have to buy so much material at a minimum that the project would cost several hundred dollars.

I would plan to do this on my Minie-Magg, whose diameter is 5.5 inches (slightly less than 14 cm). This yields a circumference of a bit more than 60 inches (slightly more than 153 cm). That's all I need. But customers have to buy a minimum amount of fabric that far exceeds this.

Stanley
 
Top