Switch on outside of switch band
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Assuming you mean drilling a hole and having just the 1/8” or so “lip” of the switch on the outside—that’s how just about everyone installs and uses those Schurter voltage selector switches. I use them on nearly all my HPR builds that way.
Space them at least a few inches apart if you’re using redundant electronics; it’s extremely rare, but in a worst-case situation, the two sections of a rocket could collide and shear the top of the switch off. (I wasn’t there, but heard that happened during a failed L3 attempt at one of the clubs I fly with.) Spacing them away from each other avoids that being an issue if you have a backup altimeter in use with the same switch type.
Space them at least a few inches apart if you’re using redundant electronics; it’s extremely rare, but in a worst-case situation, the two sections of a rocket could collide and shear the top of the switch off. (I wasn’t there, but heard that happened during a failed L3 attempt at one of the clubs I fly with.) Spacing them away from each other avoids that being an issue if you have a backup altimeter in use with the same switch type.
Some 3d printed electronics sleds have a bridge for attaching that same type of switch. From what I’ve seen the bridge is usually at one end of the sled, instead of over arching over the middle.
Unless you have a very long coupler I don’t think you could go thru a small hole in the switch band to access the switch mounted to that bridge
Unless you have a very long coupler I don’t think you could go thru a small hole in the switch band to access the switch mounted to that bridge
As said above, mounting them into the switch band is just about standard.
There have been reports of them failing since they are really intended to be set once and forgotten, not repeatedly used as a switch. Personally, I really like keyswitches like https://www.digikey.com/product-detail/en/e-switch/KO103C701/EG2623-ND/502087 for my rockets. I wish they weren't so deep behind the panel, though....
There have been reports of them failing since they are really intended to be set once and forgotten, not repeatedly used as a switch. Personally, I really like keyswitches like https://www.digikey.com/product-detail/en/e-switch/KO103C701/EG2623-ND/502087 for my rockets. I wish they weren't so deep behind the panel, though....
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I have used those switches for 20 years with zero issues. I have some that have been turned on and off more than 40 times. The biggest issue I find is people overheat them when soldering them.
user 30299
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Here's that same switch mounted on the outside. Been on this rocket for a few years - and numerous flights. No issues.
Just be sure the switch has a proper & tight fit, and clean wiring.
But it's not for every rocket. Most of my switches are inside the rocket.
I put them on the inside and stopped. The difference of light on the lake bed and the inside of the bay made it nearly impossible to see the switch. Even with a flash light. Now I put them on the outside. Have just started doing this so no experience.
I use them on builds at time also, always on the inside. I would never put a switch, of any kind, on the outside. Wind drags a rockets across field, dirt gets inside switch or gets damaged. You don't spot it until it does fail.
Tim51
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I have attached Schurter plastic switches to the outside of the switchband - in my experience they're pretty brittle and will fail after a while. The best switches for external mounting are Binder Design's screw switches, which are very robust and reliable. Just remember to take a Philips or Posi screwdriver with you when recovering your rocket!
Big fan of Lab Rat Rocketry switches. The pic is a double pull pin with Quantum and a Quark for back up from Eggtimer. Just bring your pin and replace it. 
I also use those almost exclusively now.
Tim51
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Glad to read this - I ordered some a while ago and I'm in the process of fitting out an Av-Bay with one for the first time.
Not to get away from the OP, but what is the purpose of the terminal blocks on the INSIDE of the av-bay? Confused....
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Not a fan of those Schurter switches... look at the specs on them. The are designed to be set once and left alone, they're rated for like 50 cycles LIFETIME. I have had them come apart on me... and that's when I quit using them (and created the WiFi Switch instead). If you want to use a mechanical switch, there are plenty of alternatives that can handle the G's and vibrations, and in most cases are a lot easier to mount... screw switches (Rail-Buttons.com, Missile Works, Featherweight) and pull-pin switches (LabRat) come to mind off-hand.
I like the terminal blocks inside the e bay so no carbon gets on them. After many flights they are like new. I use a 4 conductor disconnect to remove the one end of the e bay for easy loading. has worked well. A good place for electronics is allelectrics in Van Nuys CA.
Not to start an argument but the Schurtner rotary switches I have are rated for 300 cycles. On launch, recover off = 2 cycles so that would be 150 flights before you reach the manufacturers conservative limit, I’m guessing that there’s not a whole lot of birdies out there with that many flights on them.
300 cycles is under ideal conditions. Ground testing, dirt and mach, test the durability of that switch.
Any interruption in continuity will rest the electronics. 3000 + cycles switch at least. I use the same e bay on more than one rocket.
Any interruption in continuity will rest the electronics. 3000 + cycles switch at least. I use the same e bay on more than one rocket.
Point was 50 cycles was not correct, manufacturer states 300 cycles.
There are literally hundreds of different switches out there that could be used to arm your electronics, all have pluses and minuses, whatever you like and works for you is the the one to use. I actually have a few twist and tucks still that have no switches.
why not just recess them in flush with the switch band? Wouldn't that work?
firemanup
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I’ve never had one of the incredibly brittle Schurter switches fail. Used many of them.
Because of the way they take up room in the bay I don’t tend to use them in diameters smaller than 5” but that’s just personal preference…
Because of the way they take up room in the bay I don’t tend to use them in diameters smaller than 5” but that’s just personal preference…
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So, what's the best glue for a Schurter switch?
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You could do that. I have seen it done on many L1 certification rockets from university teams.
The holes are always ugly looking. You wish they would learn how to properly drill a hole in
cardboard tubes. lol
I opted to surface mount the switch. It has a fairly durable lip (shoulder) and a threaded body,
so the nut nicely snugs the switch to the body tube.
A little drop of Loctite keeps the nut from backing off.
It's a very clean installation, and looks good too. I have not had any issues.
You do need to be attentive to the length of the switch's barrel and the wire contacts.
They extend a good bit into the rocket and could interfere with electronics on the sled.
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I guess if you just sit around all night and flick your switch, then a Schurtner might not be for you. Being that they are plastic, I would recommend Testors or Duco Cement for glue if you’re a closet flicker
AHansom
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I used those switches on my level III. After that, most of the time I went with twist and tuck.
I went back to my first DD rocket, my L1 cert rocket, when I did my L3 and went with pull pin switches. I've now added screw switches in series with the pull pins so I can turn everything off without having the pins getting in the way while I prep matches and charges. I've gone that route with every DD rocket I've built since. It's just easier to pull the pins at the pad to power things up, especially while standing on the trailer launcher when the av-bay is 9 ft above the ground.
These key switches look really cool.
Do they fit into the Additive Aerospace or Missileworks 3-D printed sleds? It looks like they might but I’m not sure of the length and how those tabs stick out the wires get soldered to compared to the Schurter switches.
Do those keys give enough length so you can reach through a hole in the body of the rocket and turn the switch on and off if you are using the switch internally mounted? Or do you need to just mount them on the outside of the rocket instead of to the “bridge” of the sled?
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I purchased my first 3d printed sled from a popular source and to your point the switch band is all the way to one end of the sled.
Based on the installed depth of a rotary switch and possible conflict with mounted electronics I can understand why but based on my coupler length leaves it unusable if I want to use the switchband.
Perhaps cutting the switch bridge off and reattaching it one side mid-sled?
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Thanks for the reply to my question. The more I look into this, I can see that the switch doesn't really need to be centered over the switchband. Al long as you have holes lined up on the body and AV bay coupler prior to launch you can reach thru with a screwdriver and turn the switch, even if it is towards one end of the coupler..
My last question was on the key type switches. They look good, but I'm not sure if those are useable so easily with the 3-D printed sleds from Missileworks or Additive Aerospace??
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I'm new and trying to understand, would there be an ejection gas issue if the access is on the side of the coupler?
Not usually.
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