holes for switches in AV bays

I have built 4 AV bays with single altimeters, and I have always used the 120/220 switch mounted in a switch band.

I want to build a dual altimeter setup for safety on higher flights with bigger rockets using bigger motors. Two of those switches could get unsightly, and start to cause space issues with the back of the switches protruding into the bayI see some people stick a screwdriver through holes in the airframe to turn on altimeters. For those of you who do this, are these vent holes which are doubling as access for switches?

Thanks for any guidance on this.

They are for me, I've used screw switches as well as some horizontally mounted push-on, push-off switches in larger bays. The hole is the vent, or in some cases, there's two holes, one that aligns with the switch and one that doesn't.

N

I have experience with both the Schurter switches, and the PCB screw switches. Honestly, using the screw switches through a hole in the airframe can be a pain, and I don't do it anymore. If I don't have enough space for the Schurter 120/220 switch, I'll go with the Featherweight magnetic switch.


Here's a link for the screw switch:
https://aeroconsystems.com/cart/switches/featherweight-pcb-screw-switch/


And a link for the magnetic switch:
https://aeroconsystems.com/cart/switches/magnetic-switch-with-led-indicator/

The arming and vent hole are the same for my rockets, and until you get to larger av-bay volumes nothing more is really necessary.

(shameless plug)
If you want a really easy way to mount your altimeters and switches, you should check out my altimeter sleds.
They hold the 120/220 switches right near the surface of the airframe, so it is really easy to find the switch. www.additiveaerospace.com

I come from the robotic combat hobby and really like these switches:

https://mobile.robotmarketplace.com/0-FT-MINI-SWITCH.html

The little Featherweight screw switches are cheap, and work very well. One thing you can do with them is to mount them on a little pedestal so that they are closer to the coupler, they're a lot easier to reach that way.

I use homemade PCB screw switches that are mounted to the av-bay wall. The mounting seals the switch from the inside so the hole for the screw doesn't act as a vent. This has worked great for several years. I have proper sized and spaced vent holes in addition to the screw switch holes.

Don't use two switches; instead, run the positive wires from each battery to their respective electronics and run the negatives to your switch and then back to each altimeter.

hball55 said:

Don't use two switches; instead, run the positive wires from each battery to their respective electronics and run the negatives to your switch and then back to each altimeter.

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Does that defeat the dual redundancy?

Ravenex said:

I come from the robotic combat hobby and really like these switches:

https://mobile.robotmarketplace.com/0-FT-MINI-SWITCH.html

Click to expand...

Nice, might have to order one of these. Thanks for broadening my horizons.

grouch said:

Nice, might have to order one of these. Thanks for broadening my horizons.

Click to expand...

They're meant to go in small robots that get the snot beat out of them, so they take a beating and won't have any issues with g loads or vibration. I guarantee you that the robots I've seen these in surpass even the g loads of a v-max flying case.

I switched to the featherweight magnetic switches...no pun intended, just to keep things clean and seperate from the sampling/switch holes scenario.

I used to mount switches in the outer band, then I had 2 switches fail. Not easy removing the switch when it is installed in the band. Now I do the pedestal on the sled mount.

I have used the Aerocon screw switches lined up behind the vent holes and have worked well.
I used 2 120/240 switches in the switchband of a 6 inch dia av bay to run the dual altimeters. Yes you need to be careful how far they protrude into the av bay. I am rewiring it now and have bent the solder tabs on those switches 90 degrees for more clearance and less chance of interference. If not for those 2 big holes in my switchband I would have opted for one of Landru's sleds. I have two new builds to start & am interested in knowing more about the Featherweight magnetic switches. Can they (2 switches) be used for a dual altimeter setup? is the switch mounted on the av bay sled?

accpool said:

Does that defeat the dual redundancy?

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Not at all. It simply ties the two negative leads together. It would remove redundant switches, but that could be acceptable in some cases.

accpool said:

Does that defeat the dual redundancy?

Click to expand...

Yes it does.

Ravenex said:

I come from the robotic combat hobby and really like these switches:

https://mobile.robotmarketplace.com/0-FT-MINI-SWITCH.html

Click to expand...

Where have you been all my life?

I have been using these lately.
https://www.mcmaster.com/#7400k61/=v8h5yc

This is my solution. These are two Eggtimers with two 9v and two 120/220 switches. All are mounted to a single sled. I use the access holes as vents. Never had a problem. This fits nicely in 2.65" bays and I have adapted it to fit 3 and 4" bays and inside nose cones as well.
Space is a problem when mounting switches to the tubes. I've used pcb style screw switches and prefer this method. The distance required to reach the switch on a 4" tube (like this nosecone) can be a pain on the pad, but it really works for me.