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cwbullet

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this thread is awesome
Subscribe and like the posts and we will continue.

Thanks for the posts so far. This is gonna help.
 

Bat-mite

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I just picked up some of these from Aerocon. 3/4" hole is not helpful on smaller birds with a 1" switch band.



  • Two keys, removable in one position only.
  • 3 terminals, select key removable in on position or key removable in off position by your choice of terminals used.
  • Rated 4 Amps @ 125 Vac.
  • Chrome plated metal bezel and metal/ plastic body.
  • Bezel diameter 0.875".
  • Approximately 0.75" behind-the-panel clearance.
  • 0.75" diameter threaded bushing with nut.
  • Solder-loop terminals.
  • UL, CSA approved.
  • Weight, 7 grams.
 

Chris_H

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This photo is from after a very hard 'lawn dart' landing, and a resulting battery fire with the LiPo batteries in the AV bay. Everything in the AV bay was completely destroyed, including all of the surface mount components on the altimeter boards being torn off

The switches still feel fine, have clear continuity, and work like new.

There are almost infinite varieties of switches. Except for specialty situations that I cannot think of right now, these are the best, based on reliability and durability.




 

cwbullet

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This photo is from after a very hard 'lawn dart' landing, and a resulting battery fire with the LiPo batteries in the AV bay. Everything in the AV bay was completely destroyed, including all of the surface mount components on the altimeter boards being torn off

The switches still feel fine, have clear continuity, and work like new.

There are almost infinite varieties of switches. Except for specialty situations that I cannot think of right now, these are the best, based on reliability and durability.





What kind of switch?
 

Steve Shannon

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For any commercial switch I won’t use it in a rocket unless the data sheet includes a rating for shock or vibration of 50 gees. Many of the switches shown above were never intended for use in highly dynamic applications.
I’m comfortable using nhk slide switches, Honeywell and Omicron micro switches in a remove before flight holder, and the various screw switches. I’m also comfortable using the WiFi switch from Eggtimer.
 

Rocketjunkie

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Using left over ematch wires, twist and tape down. New wires every flight. Good at least through mach, would rethink for very high performance rockets.
 

Steve Shannon

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Using left over ematch wires, twist and tape down. New wires every flight. Good at least through mach, would rethink for very high performance rockets.
I would never recommend this. The transients introduced to the avionics when you’re twisting and taping could result in the avionics being left in an unexpected state. There is a reason no commercial vehicles have their switches replaced by twisted wires.
A high quality switch is extremely reliable, and nearly immune from shock.
 

rharshberger

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This photo is from after a very hard 'lawn dart' landing, and a resulting battery fire with the LiPo batteries in the AV bay. Everything in the AV bay was completely destroyed, including all of the surface mount components on the altimeter boards being torn off

The switches still feel fine, have clear continuity, and work like new.

There are almost infinite varieties of switches. Except for specialty situations that I cannot think of right now, these are the best, based on reliability and durability.




Was that the MDRM?......if so that was a serious lawn dart...
 

Cl(VII)

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For any commercial switch I won’t use it in a rocket unless the data sheet includes a rating for shock or vibration of 50 gees. Many of the switches shown above were never intended for use in highly dynamic applications.
I’m comfortable using nhk slide switches, Honeywell and Omicron micro switches in a remove before flight holder, and the various screw switches. I’m also comfortable using the WiFi switch from Eggtimer.
I use the Omiron switches in the pull pin kits precisely because they have a well described datasheet.

For the record, I'm also a big fan of the magnetic switches because I build a lot of fully-removable bays (the kind that slide into the tube whole, and have no switch band) that aren't compatible with pull-pins. Right tool for the job.
 

Ben Martin

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2x screw switches for my dual Stratologgers. They do require soldering but pretty much every switch does. I tested them and they work perfectly, confident they will hold up to all the Gs.
20190420_214019.jpeg
 

cwbullet

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That is an awesome design. It is inspiring.
 

Chris_H

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Was that the MDRM?......if so that was a serious lawn dart...

Yes, that was the one.

The fins were basically unscathed. Yesterday I ground off the remains of the epoxy on the fin tabs, and prepped them to be used again. I am rebuilding them into a new version of that rocket right now. It has a 75mm motor mount, and is built around a 3 grain motor, so there is no need for any fancy and risky AV bay design stuff just to fit a bigger motor. You will see it sometime this Summer. Maybe for the Apollo 50th launch, or the Sod Buster.
 

FMarvinS

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Chuck-pictured below is the 3D PETG double snap switch enclosure I printed and use (picture 6). Picture 7 shows its placement between the layers of a 3D printed 75 mm altimeter sled with the "pull-pin" in place. I've also printed a 4 snap switch enclosure in which all 4 switches are activated by the same single pull-pin. I'll attempt to post that after the weekend.
Fred, L2
ICBM, Camden SC
KG4YGP

pictures 6

Picture 6: 3D printed double snap switch enclosure .



Picture 7: double snap switch enclosure between
the upper and lower sled layers with pull-pin in place
 

WoShuGui

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Magnetic switches are great space savers. If you launch from a steel tower, however, be sure to test that it does not turn off your switches as the rocket exits the tower. There was enough magnetic field at the end of this one to turn off both altimeters. Fortunately I figured that out before launching.
9D00B4A8-9199-4621-9B01-940EEB2AC611.jpeg

32142430-F7DB-49F5-9F08-85F9A92685B3.jpeg
 
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