7.5” Diameter AvBay

[Steven88]

Hello. I have a 5 1/2 inch Loc AvBay that I use on my Big Nuke rocket. When I built it I was not thinking of using it on future models of larger diameters. I have been interested in building a 7 1/2 inch Loc kit and wondering if there is are some good suggestions on how I can mount my sled in a larger AV Bay? I will send some pictures of my sled. I had as much time it seemed putting this together as building the entire rocket. Unfortunately, I didn’t make it to where the sled is easily removable without cutting some wires and putting in some connectors or figuring out a way to detach the main side. I always figure more connectors is worse as it can lead to more failures. Is this something flyers often do is interchange electronics on different size rockets? It sure would save a lot of build time if you are short on it

 

[Joe Rocket 97]

drill the holes in the 7 1/2 inch av bulk plates the way they are in the 5 1/2 inch bulk plates

 

[Steven88]

Ya was just hoping to not have to take the wires out of the altimeter every time and reinsert them on the main side to switch sizes every time, but maybe that’s really not a big deal. Also, the antenna wire has to be taken apart

 

[mtnmanak]

Ya was just hoping to not have to take the wires out of the altimeter every time and reinsert them on the main side to switch sizes every time, but maybe that’s really not a big deal. Also, the antenna wire has to be taken apart

It may be difficult to get this Ebay into a 7.5" ebay without some modification. I would drill a 5" hole in one of the 7.5" bulkheads (or large enough that the sled fits through, but smaller than your current 5.5" bulkhead). Build the other 7.5" bulkhead out just like your current 5.5" removeable bulkhead and use that as your removeable bulkhead in the 7.5" rocket. Secure the sled through the large hole you made in the fixed 7.5" BH. You may need to put a couple screws on the 7.5" BH to keep the 5.5" BH from sliding around.

Instead, you may just want to call this one a learning experience and build a new modular Ebay. I personally think 54mm is about the optimal size for a modular Ebay because you can then cut holes in 4" bulkheads and larger to secure it in place. Something similar to how the Kate 3 is formatted to fit in a 54mm hole in a bulkhead:
https://www.multitronix.com/kate-3-transmitter.html
I have tried for years to figure out the best way to build a modular ebay, but, since Eggtimer hardware is so cheap and is relatively easy to build out, I have found trying to shoehorn modular ebays into my rockets seriously degraded my already fragile sanity rather than just building out a new ebay each time. I am sure other people have had far better success than I.

 

[KenECoyote]

I don't know if this helps in your case, but when I was trying to finish a rocket for a club drag race and ran out of time to make new AV bay, I used another one and had to extend the rods using couplers.

I used red/strong/permanent thread lock since I didn't want it loosening at all so after I was done I had to actually remove the entire rods to switch back since I couldn't undo them!

Alternatively, can't you drill holes 6" apart in the 7.5 bay caps, use threaded rod through and secure the bay inside somehow?

 

[pathtouch]

I use the same sled and electronics in my 4” and 7.5” rockets. Wire external wires up with JST connectors! These are the same ones most smaller lipo batteries use too so good to have on hand.

 

[jd2cylman]

Or ditch the terminal blocks and wire your ejection lighters directly to your altimeters. Just plug the holes where the wires pass through. That’s how all of mine are set up. Or JST connectors as was suggested.

 

[Steven88]

I was wondering how you guys suggest keeping your terminal blocks and deployment wires from corroding from the ejection charge gases? I have used my AvBay shown in the above pictures on three flights and the terminal blocks are already pretty dirty. I suppose it would be a good idea to stick a piece of tape over them at minimum? Can the wires/terminal blocks ever get so corroded that there will not be good continuity? I guess one good thing about most altimeters is they will tell you if you don’t have continuity to the charges

 

[OverTheTop]

I cover the terminal blocks with tape.

 

[Tim51]

I cover the terminal blocks with tape.

This.