4" Fiberglass "outer" coupler

Hello all,

I've had a problem repairing airframe damage to my 4" Warthog upscale, and it's such a problem, that I think I'm going to scratch the repair and just rebuild the stupid rocket. In short, the BlueTube just will not cooperate with the epoxied 3/16" strakes that run the length of the airframe. When applying primer or paint, the BlueTube expands significantly, but the epoxied strakes won't allow the airframe to expand, so I end up with buldges of the airframe (outward) between the strakes. So...............

I'm looking at fiberglass for the rebuild. I know I can get plenty of G10 stock for the fins, get them cut (or do them myself), make the AV Bay, etc, but my issue is finding a fiberglass "outer" coupler so that I can make the upper and lower details of the original kit true to the model.

Any ideas where I might find such an item? I'd like the coupler material to be roughly the same wall thickness as the airframe...

Layup fiberglass over the blue tube.

I'm not really interested in doing any fiberglassing any longer as a rule - just don't like the dust and time it takes to get it right. More interested in buying a pre-made, pre-cut airframe and coupler to assemble. I've put my time in on this scratch built rocket and about the same amount on the repair, so I'm kinda over the build part at this point...

SammyD said:

I'm not really interested in doing any fiberglassing any longer as a rule - just don't like the dust and time it takes to get it right. More interested in buying a pre-made, pre-cut airframe and coupler to assemble. I've put my time in on this scratch built rocket and about the same amount on the repair, so I'm kinda over the build part at this point...

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Give Wildman a call he will have the parts you need in stock ready to ship.

Do you think he'll have an "outer" coupler??

SammyD said:

Do you think he'll have an "outer" coupler??

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He may have. What is the outer coupler for?

I doubt he will have a tube that has a larger ID than the body tube and would fit it as an "outer coupler". You could make your own from a section of tubing:
jcrocket.com/make-a-coupler.shtml
Of course, there will be a slot where the coupler had to be expanded, but that should be easy to fill.

Or, since this part is cosmetic, consider 3D printing.

As long as the rocket isn’t minimum diameter use a full length coupler as the airframe and then use short pieces of body tube as the outside coupler. The only problem will be the nosecone.

https://www.madcowrocketry.com/4-5-g12-coupler/
Another possibility, but will need to be split and sized to fit.

crossfire said:

He may have. What is the outer coupler for?

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Sorry for the delay - every other thing seems to be taking my time right now RATHER than rocketry. The "outer" coupler is for a cosmetic feature of the Warthog model. The top 3" or so of the airframe (just below the nosecone) has an outer band on it. The strakes start just below this band. On the sustainer/booster, there is another band where the strakes end and the fins begin. I'll see if I can't locate a detail photo of the design, but you might be able to see these bands in my account/avatar photo here. They are a light green (celery) color in that photo.

Gary Dow said:

https://www.madcowrocketry.com/4-5-g12-coupler/
Another possibility, but will need to be split and sized to fit.

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Not a bad idea there...!

SammyD said:

Not a bad idea there...!

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Assuming the 4.5" coupler would work, how log of a piece is needed? Are multiple pieces needed?