Wildman 5 inch punisher shock cord harness.

[Joey Draney]

Hey everyone I recently received a 5 inch wildman punisher I bought a couple weeks ago and it was a bit of a special order. They didn't have the stock 60 inch booster tube in stock so they offered to send a 18inch lower booster tube section (left in the photo) and a upper 42 inch section (right in the photo) with a coupler to bond them together. (Middle). The problem with this is that the top centering ring on the motor sits with only about a 3 inch gap between it and the middle centering ring. This meant that I only had about 3 inches of area to glue the shock cord harness to the motor tube. At the time it would have been smart just to bring the shock cord through the middle centering ring as well but for some reason that slipped my mind. Im doubting the strength of this attachment and was thinking about maybe putting a strip of fiberglass around the tube at that point to make the shock cord sort of one with the tube but haven't tried that yet. If anyone has any tips or anything that might help please leave a comment. I'll be posting more build photos and updates of this project. Thanks!
Joey

 

[Joey Draney]

Hey everyone I recently received a 5 inch wildman punisher I bought a couple weeks ago and it was a bit of a special order. They didn't have the stock 60 inch booster tube in stock so they offered to send a 18inch lower booster tube section (left in the photo) and a upper 42 inch section (right in the photo) with a coupler to bond them together. (Middle). The problem with this is that the top centering ring on the motor sits with only about a 3 inch gap between it and the middle centering ring. This meant that I only had about 3 inches of area to glue the shock cord harness to the motor tube. At the time it would have been smart just to bring the shock cord through the middle centering ring as well but for some reason that slipped my mind. Im doubting the strength of this attachment and was thinking about maybe putting a strip of fiberglass around the tube at that point to make the shock cord sort of one with the tube but haven't tried that yet. If anyone has any tips or anything that might help please leave a comment. I'll be posting more build photos and updates of this project. Thanks!
Joey

 

[StreuB1]

That would be a good idea.

Though on 5" and up rockets, I always stick an eyebolt in the top of the motor and run a kevlar leash (3/8" or 7/16" tubular kevlar with an overhand loop in each end) about 1' longer, to the shock cord attachment point as an Oh-Sh1t!! backup connection point.

The chute isn't going to pull the entire motor/aeropack/rear CR, etc all the way through the airframe and if it does, you have more things to be worried about.

 

[Joey Draney]

That would be a good idea.

Though on 5" and up rockets, I always stick an eyebolt in the top of the motor and run a kevlar leash (3/8" or 7/16" tubular kevlar with an overhand loop in each end) about 1' longer, to the shock cord attachment point as an Oh-Sh1t!! backup connection point.

The chute isn't going to pull the entire motor/aeropack/rear CR, etc all the way through the airframe and if it does, you have more things to be worried about.

Ahh yea i guess I can always do that as a fail safe. But yea that's a good point if it's got enough force to rip the centering ring out I've got other issues. Im just the kind of person who worries about these things. Thanks for the tip!

 

[UPscaler]

If you haven't glued it yet, tie a knot in the shock cord behind the ring. That way if the epoxy somehow lets go, the knot will stop it from getting past the ring.

If you do add glass, just make sure you don't put it anywhere the fins will need to attach to the tube!

Braden

 

[Joey Draney]

If you haven't glued it yet, tie a knot in the shock cord behind the ring. That way if the epoxy somehow lets go, the knot will stop it from getting past the ring.

If you do add glass, just make sure you don't put it anywhere the fins will need to attach to the tube!

Braden

Yea I always do but for some reason I'm always paranoid about it. Sometimes ive just gotta tell my self "it's fine I know its fine" and it usually always works out. Thanks for the tips!

 

[Onebadhawk]

Please read here..

https://www.rocketryforum.com/threa...ness-mount-in-the-fincan.171991/#post-2508772
Teddy

 

[Jmhepworth]

The closest I have to your 5” Punisher is a 6” Wildman. Although I have at least twice as much Y harness epoxied to the motor tube as you have, I still attach a length of tubular nylon to a bolt in the forward closure of the motor. That way, in the entirely improbable event that either the Kevlar broke (twice, because there are two legs to the harness, followed by a figure 8 knot) or the Kevlar broke free from the motor mount (again, twice), the shock cord would still be attached to the motor itself, and the parachute will exert much, much less force on the motor than the propellant did. All this is to say you’re worrying too much. Just back it up to the motor with an eye bolt in the forward closure and you’ll be fine. More than fine.

 

[Joey Draney]

Please read here..

https://www.rocketryforum.com/threa...ness-mount-in-the-fincan.171991/#post-2508772
Teddy

Thanks a ton Teddy this was really helpful.

 

[Joey Draney]

The closest I have to your 5” Punisher is a 6” Wildman. Although I have at least twice as much Y harness epoxied to the motor tube as you have, I still attach a length of tubular nylon to a bolt in the forward closure of the motor. That way, in the entirely improbable event that either the Kevlar broke (twice, because there are two legs to the harness, followed by a figure 8 knot) or the Kevlar broke free from the motor mount (again, twice), the shock cord would still be attached to the motor itself, and the parachute will exert much, much less force on the motor than the propellant did. All this is to say you’re worrying too much. Just back it up to the motor with an eye bolt in the forward closure and you’ll be fine. More than fine.

Yea that's exactly what I plan to do I did end up putting a layer of 8.9 oz glass over the shock cord there and it's definitely much stronger now and definetly not going anywhere but just as a fail safe I plan to do that. Thanks for the comment!

 

[Joey Draney]

Does anyone know of anybody who's flown this rocket or one similar on an n3300. I feel like this might be a dumb idea but I also feel that a well built fiberglass rocket could hold up to that with ease. Sims to about mach 2.6 and 30k..

 

[Joey Draney]

Does anyone know of anybody who's flown this rocket or one similar on an n3300. I feel like this might be a dumb idea but I also feel that a well built fiberglass rocket could hold up to that with ease. Sims to about mach 2.6 and 30k..

Also I would love to hear people's opinion on featherweight trackers above 20000 feet. I've flown them plenty of times above 10k but Im a little skeptical about going much over 20 just because of the things I've heard about gps