Help with avionics bay - re-drilling bulkheads

[SierraDrinker]

I need some help and advice. I'm building a Madcow 2.2" fiberglass Frenzy XL as my first dual deploy rocket. My threaded rods in the avionics bay are too narrow and I can't fit a 9v battery between them. I can't mount the battery horizontally (no room), nor vertically on the front (no room with my Eggtimer classic), so I need to mount it on the back side of the sled. My thought is to remove the threaded rods, epoxy the holes, and re-drill them slightly wider to allow space for the battery on the backside.

Any thoughts on this idea?

 

[Theory]

That could work. Any though into changing to a power source with a smaller / different footprint?

 

[SierraDrinker]

I've thought about it, but I'm not sure I have time to source a new battery, terminal, etc. I've already tested on a 9v and I'm confident everything will work. The other issue is that the mounting hardware is also butting up against the threaded rods making it next to impossible to get the sled on and off the rods.

 

[Bat-mite]

When you fill the existing holes in the bulkhead, put some painters tape on the inside first. Then, when the epoxy is fully cured, peel it off. Done.

Consider using zip ties to attach your sled, sort of like a hammock.

 

[SierraDrinker]

When you fill the existing holes in the bulkhead, put some painters tape on the inside first. Then, when the epoxy is fully cured, peel it off. Done.

Consider using zip ties to attach your sled, sort of like a hammock.

View attachment 386767

Thanks! I really the zip tie idea as it will put the sled in the center of bay giving a bit more clearance for the altimeter.

 

[blackjack2564]

When dealing with tight space you can position sled on just one tie rod, rather than centered between 2.

Like here..way more usable room.

 

[roytyson]

Here is what I did. I got airsoft gun batteries from Hobbyking, replaced the ends with JST. I know going Lipo has some cost and learning curve.
https://photos.app.goo.gl/DKq9baAK4LfjjRhPA

If you decide to go lipo, you can get twice the power, in half the size.

 

[Cory]

I am a big fan of using cable ties for multiple jobs on the electronics sled including actually holding the batteries. Just drill holes either side and secure.
[url=https://flic.kr/p/QhZJyF] [/url]

 

[David Schwantz]

You can fill the holes with epoxy as stated, but I have always found that the drill will drift into the first holes. you might try filling with a wooden dowel and then drilling. I have had better luck this way.

 

[Joe Rocket 97]

Put a slight bevel on top of the wholes you will be filling, so the repairs just don't eventually fall through

 

[SierraDrinker]

When you fill the existing holes in the bulkhead, put some painters tape on the inside first. Then, when the epoxy is fully cured, peel it off. Done.

Consider using zip ties to attach your sled, sort of like a hammock.

View attachment 386767

Thanks for the suggestion as it worked great.

 

[SierraDrinker]

When dealing with tight space you can position sled on just one tie rod, rather than centered between 2.

Like here..way more usable room.
View attachment 386782 View attachment 386783 View attachment 386784

Thanks for the suggestion. I tried this method, and it was so close to working, but I couldn't squeeze the 9v in horizontally and I didn't have room to mount it vertically.

Next time I'm going with a LiPo or a smaller battery.