Baffle Bay Concept

[boatgeek]

I have a couple of projects in the hopper where I'm stringing wire to the fin can (one stager, one lit up for night launch). In looking at the baffle threads, I had an idea to mount an AV bay in the fin can so I don't need a pull apart disconnect. At the same time, I was seeing a bunch of threads about baffles. Aha, said the overthinker!

My idea is to have an AV bay that blocks maybe 50%-75% of the free area of the body tube so that ejection charges can still go by. The parachute would be above the AV bay. I'd probably screw the AV bay into place so it doesn't get blown out with the laundry. Has anyone done something like this before? Are there rules of thumb for how much free area you should leave open to still get good ejection?

Thanks!

 

[Tyler P]

That sounds really cool. I envision solid bulkheads drilled out on the sides with an AV bay in a tube in the middle.

Is this what you're thinking?

 

[boatgeek]

That sounds really cool. I envision solid bulkheads drilled out on the sides with an AV bay in a tube in the middle.

Is this what you're thinking?

Depends on the rocket. On the small one (29mm), I'm carrying two batteries to run lights for a night launch. That's probably sort of figure-8 shaped with the batteries in the top and bottom loops. The other one is in a bigger airframe, carrying staging electronics (likely Eggtimer Proton),so it's more likely going to be a box that goes all the way across the airframe. Both of them would be 3D printed.

 

[Homer_S]

Any issue with shifting the CoM too far back?

Homer

 

[K'Tesh]

I was working on something similar not too long ago...

https://www.rocketryforum.com/threads/nosecone-av-bays-pros-cons.147380/#post-1806239

This is a modification of the Binder Design baffle used in the Velociraptor. The idea is that the AV bay would be sequestered from the baffle by a wall, and would fire the separation charge back towards the motor. Careful alignment thanks to notches and keys in the appropriate places would allow external access to the electronics.

 

[snrkl]

I was working on something similar not too long ago...

https://www.rocketryforum.com/threads/nosecone-av-bays-pros-cons.147380/#post-1806239

This is a modification of the Binder Design baffle used in the Velociraptor. The idea is that the AV bay would be sequestered from the baffle by a wall, and would fire the separation charge back towards the motor. Careful alignment thanks to notches and keys in the appropriate places would allow external access to the electronics.

I just find it hilarious (and just a wee bit freaking awesome!) that k’tesh’s OR kungfu is so strong, it stretches all the way to making an eye bolt out of what look like body tubes... [emoji12]

 

[K'Tesh]

I just find it hilarious (and just a wee bit freaking awesome!) that k’tesh’s OR kungfu is so strong, it stretches all the way to making an eye bolt out of what look like body tubes... [emoji12]

Funny that you should lock on to that... I suggest you try to recreate that baffle... There's a much harder (and bigger) trick hidden in that sim.

I'll add that other than removing the CG/CP marks, there's no other 3rd party graphical editor tricks involved in those images. Basically, what you see is what you'll get.

 

[snrkl]

Funny that you should lock on to that... I suggest you try to recreate that baffle... There's a much harder (and bigger) trick hidden in that sim.

I'll add that other than removing the CG/CP marks, there's no other 3rd party graphical editor tricks involved in those images. Basically, what you see is what you'll get.

Oh I’ve given up trying to keep up with your OpenRocket Kung-fu... when faced with the master, bow out gracefully and with what little honour you have left!! [emoji23]

 

[K'Tesh]

Oh I’ve given up trying to keep up with your OpenRocket Kung-fu... when faced with the master, bow out gracefully and with what little honour you have left!! [emoji23]

It's not a competition... It's a challenge to help you improve your skills, both with OR, and with observation.

 

[boatgeek]

Thanks for that link K'Tesh. For that one, it looks like Binder used 2x 1/2" PVC for baffle vents in a 4" rocket. That comes to roundabout 5% of the cross-section area of the rocket for the baffle openings. Your version with the single 29mm bay would have been 8%. Did your version fly, or is it still a majestic hack of OpenRocket?

Regardless, I'll shoot for 5%-10% open area. No offense to OpenRocket, but I think I'll do my 3-D work in Rhino.