29mm Nose Cone Coupler Attachment

[Skyreaper11]

Hello to all,
I recently received and plan to begin building a Madcow Go Devil 29mm. I was planning to mount an eggtimer mini in the nose, using countersink machine screws and clench lock nuts on the cone/coupler junction. However I am not sure if this is the best method as the tube diameter is so small. Does anyone have any advice? Keeping in mind I would like to keep everything as streamlined as possible.

Thanks in advance

 

[GrouchoDuke]

How about a custom-designed 3d printed sled in the nose? I've done several like that with set screws on the coupler that holds the sled in place. An Eggfinder Mini fits in the coupler diameter just fine.

 

[Skyreaper11]

Do you have any pics of how you do the anchor points? I am interested to see more about what you are describing.

 

[GrouchoDuke]

Sorry, I don't have any good pics of a 29mm rocket done that way. On my Go Devil 29 & Vanish 29, I attached the coupler to the body tube and put the avionics bay in the coupler/body tube and the chute in the nosecone. The post linked below has a picture of the 3d printed piece I made to hold the Kevlar to the nosecone. That piece is just epoxied in place.

https://www.rocketryforum.com/threads/modified-go-devil-29-build-thread.138462/#post-1661409

Here's a shot of a sled I printed for a 38mm nosecone with 3 set screws holding it in place. On that one I think I used #8 x 3/8" set screws from Home Depot. I used much smaller screws on several 24mm rockets with similar designs. I'd guess that #6 or #8 set screws would be about right for a 29mm rocket.


Once I printed these pieces, I also 3d printed a drill guide to align the holes for the coupler. That shouldn't be required though. Depending on how you design your sled, you should be able to just eyeball where the set screws go. So, design & print your sled then put in in place to drill the holes for the set screws. Tap threads in the coupler & sled - that's it!

 

[David Schwantz]

Here is how I did mine. Counter sunk for wood screws that go into the NC bulkhead. Bulkhead holds eyebolt also. You could attach your sled to the bulkhead, this will make it removable. The coupler has held up well with the counter sinks in it.

 

[Skyreaper11]

Here is how I did mine. Counter sunk for wood screws that go into the NC bulkhead. Bulkhead holds eyebolt also. You could attach your sled to the bulkhead, this will make it removable. The coupler has held up well with the counter sinks in it.

Thanks David, This is kind of what I had in mind. What material did you use for the bulkhead inside the coupler and how thick is it?

 

[Skyreaper11]

Sorry, I don't have any good pics of a 29mm rocket done that way. On my Go Devil 29 & Vanish 29, I attached the coupler to the body tube and put the avionics bay in the coupler/body tube and the chute in the nosecone. The post linked below has a picture of the 3d printed piece I made to hold the Kevlar to the nosecone. That piece is just epoxied in place.

https://www.rocketryforum.com/threads/modified-go-devil-29-build-thread.138462/#post-1661409

Here's a shot of a sled I printed for a 38mm nosecone with 3 set screws holding it in place. On that one I think I used #8 x 3/8" set screws from Home Depot. I used much smaller screws on several 24mm rockets with similar designs. I'd guess that #6 or #8 set screws would be about right for a 29mm rocket.

View attachment 401562
Once I printed these pieces, I also 3d printed a drill guide to align the holes for the coupler. That shouldn't be required though. Depending on how you design your sled, you should be able to just eyeball where the set screws go. So, design & print your sled then put in in place to drill the holes for the set screws. Tap threads in the coupler & sled - that's it!

I would like to get one if you could make for me. How do we get in touch to discuss the details?
Thanks,

 

[David Schwantz]

Hi Sky, it is 3/4" ply.

 

[GrouchoDuke]

I would like to get one if you could make for me. How do we get in touch to discuss the details?
Thanks,

Sorry, no can do. I’m 4 months into an RV road trip and I don’t have my printer with me.

 

[David Schwantz]

Sky, there is no av bay in the NC. It is made to add and remove weight. Try checking out Labrat rocketry or SMT Designs. They make AV bays and sleds. Don't know if they make what you need but worth a shot.