To use a switch or twist and tape?

Has anybody consider using twist and tape with a modification. Consider this- twist the wires, whip out the Weller Butane powered soldering iron, solder the wires together, and tape to the rocket. Am I the only one who's brain is, no pun intended, wired this way?

I never tried it, but it is a thought.

markkoelsch said:

Has anybody consider using twist and tape with a modification. Consider this- twist the wires, whip out the Weller Butane powered soldering iron, solder the wires together, and tape to the rocket. Am I the only one who's brain is, no pun intended, wired this way?

I never tried it, but it is a thought.

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My only concern with that process: How can I, or someone else in an emergency etc., quickly disarm the electronics ???

Frederocket said:

My only concern with that process: How can I quickly disarm the electronics in case of an emergency, etc., or someone else for that matter, if the flyer is not present???

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Not to mention the amount of solder that ultimately gets used vs. the cost of just buying a switch. And then there's the time element...

Frederocket said:

My only concern with that process: How can I quickly disarm the electronics in case of an emergency, etc., or someone else for that matter, if the flyer is not present???

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One has'ta do what someone who has had their jaw wired shut for a jaw fracture. They have to carry a wire cutters in their back pocket! (To be able to cut the wires in case they gotta puke.)

If mishap = something already fired, what is there to disarm?

If a catastrophic mishap, there is nothing left to disarm?

If rocket is lost and performed nominally, there is nothing left to disarm.

If rocket lost for long time, battery is dead. What is left to disarm?

The only major nuisance I can foresee if an igniter falls or for some reason one wants to take the rocket off the pad before launch. That might be a problem. It would not be recommended for a MAD unit only rocket!

Boy, I can remember reading tons of posts dissing twist and tape (or stuff) in the past. Interesting to see how folks have been able to get the method to work over the years. I am FURTHER heartened by the people who
promote direct wiring of ematches to the altimeters. I remember a time when it was stipulated in the "rules" of a particular group that "each" ematch had to have a "safety interlock switch" on it!! Talk about
redundant points of failure!! I'm glad that was tossed into the dustbin of the past! Kurt

Frederocket said:

My only concern with that process: How can I, or someone else in an emergency etc., quickly disarm the electronics ???

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This!
Its is a basic problem will all switches, except the most simple mounted externally. Magnetic switches? New radio controlled switches? Screw switches or pushbutton switches accessed through a vent hole? Forget about it - there is no way in these VERY common switch arrangements for a non-owner to know how to disarm electronics. A few use the externally mounted Schurter or other type switches that could be turned off by a outsider (if well marked and they have a screwdriver!). Twist and tape can be a bit more obvious, soldered wires could be cut - though I wonder if spurious contacts in these cases could with the right (wrong?) altimeter cause deployment. Really, the most reliably safe way to disarm is for the owner to do it. If its an emergency, just dont touch the rocket.

ksaves2 said:

One has'ta do what someone who has had their jaw wired shut for a jaw fracture. They have to carry a wire cutters in their back pocket! (To be able to cut the wires in case they gotta puke.)

If mishap = something already fired, what is there to disarm?

If a catastrophic mishap, there is nothing left to disarm?

If rocket is lost and performed nominally, there is nothing left to disarm.

If rocket lost for long time, battery is dead. What is left to disarm?

The only major nuisance I can foresee if an igniter falls or for some reason one wants to take the rocket off the pad before launch. That might be a problem. It would not be recommended for a MAD unit only rocket!

Kurt

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Why add an additional step that slows the disarming process? The logic escapes me... I see Solder and tape as a safety issue and, while as a TAP for L-3 cert flight, I would allow a twist and tape---soldering and tape not so much... Also, if I was the launch duty RSO and was certain a flyer intended to solder and tape I would caution; "that is a no-no",:no: if I'm signing their flight card...No one I know at our launches would even think to consider overriding my decision in either case...Your mileage may vary, depending on your launch venue...

AndyC said:

This!
Its is a basic problem will all switches, except the most simple mounted externally. Magnetic switches? New radio controlled switches? Screw switches or pushbutton switches accessed through a vent hole? Forget about it - there is no way in these VERY common switch arrangements for a non-owner to know how to disarm electronics. A few use the externally mounted Schurter or other type switches that could be turned off by a outsider (if well marked and they have a screwdriver!). Twist and tape can be a bit more obvious, soldered wires could be cut - though I wonder if spurious contacts in these cases could with the right (wrong?) altimeter cause deployment. Really, the most reliably safe way to disarm is for the owner to do it. If its an emergency, just dont touch the rocket.

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Your points are well taken and I agree...However, still doesn't change my concern or position on the issue...

If it was Fred or Andy's rocket and I had to disarm it; I would either

• Use a shaped charge
• Back over it with Fred's truck

Seriously, I have used both methods, though twist and tape is usually the result of a broken switch and an available vent hole. I have a slightly different approach that I have been working on. I basically bring a terminal strip to the outside of the air frame, loop a wire around the two screws then tighten them down.

Frederocket said:

Why add an additional step that slows the disarming process? The logic escapes me... I see Solder and tape as a safety issue and, while as a TAP for L-3 cert flight, I would allow a twist and tape---soldering and tape not so much... Also, if I was the launch duty RSO and was certain a flyer intended to solder and tape I would caution; "that is a no-no",:no: if I'm signing their flight card...No one I know at our launches would even think to consider overriding my decision in either case...Your mileage may vary, depending on your launch venue...

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I'd certainly agree on soldering. I don't see an upside, and you've put your finger on a downside. I've flown twist and tape as well as internal switches - to make the tape method more obvious, I tend to use colored electrical tape.

JohnCoker said:

The Schurter voltage selector switches are currently the standard. I'm not sure how the community decided they were the best, but somehow we did. (It sounds like something begging to be tested.)

Schurter SWA1

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I'm not sure how these switches became so popular. Have you ever taken a look at the data sheet for these switches? They are only rated for 300 cycles. That doesn't seem very durable or robust to me.

AndyC said:

I'd certainly agree on soldering. I don't see an upside, and you've put your finger on a downside. I've flown twist and tape as well as internal switches - to make the tape method more obvious, I tend to use colored electrical tape.

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I always carry a multi tool with wire cutters. This is what I would recommend. I was just thinking that it would be fast way to secure the twisted wire- maybe 45-60 seconds to solder. Then quick tape it to the body. It was just a thought.

I have flown plenty of different rockets.
Not many lawn darts or failures due to careful prep and a lot of good luck.
When I started doing dual deploy, I took the word "dual" to the extreme.

Any 4" in diameter and bigger vehicle has 2 altimeters, 2 - 9v volt batteries, 2 switches and everything soldered.
It all fits in a 3" x 8" tube......0 ELECTRONIC failures.
The only failed deploy was my 1st L3 attempt when the AV bay over-pressurized (my fault, leaking enclosure) where the drogue deployed, not the main.

With 6" or bigger rockets, they get more FG parts, more work / paint, (more expensive) I am trying to ensure a proper recovery.
I have integrated the afore-mentioned universal AV bay for ALL rockets. (dual stuff inside)

The bigger rockets have:
1) an extra 38mm tube in the bottom of the payload section for a 3rd altimeter just for drogue backup
2) the nose gets a 4" tube inside for a Missleworks WRC2, for 2 charges to make sure the main / d-bag deploy
The remote control can be pricey but you can sub another type of altimeter or timer for backup.
At $49 for a Perfectflite Strato CF, it is just good money, well spent.

I can see the KISS method on wire twisting. I have no issue with it, as long as bouncing is not a problem.
I would hate some wires at the RSO table touch each other and get a nose cone shot at me.

Everything has a backup, I would never depend on 1 switch unless a min diameter does not have room for it.

I have a racing motorcycle with a ton of wiring, ALL of it was soldered then the ends shrink tubed, by me. 0 ELECTRONIC failures.
Well thought and careful assembly of deployment systems are a must.
If I spend $200-$500 on fiberglass parts I will have lots of backups built-in.

Personally, I like the cleanliness and positive engagement of a switch.

I see many rockets with just 1 pair of wires hanging out a sensing port.
Does that mean you are arming only 1 set of electronics?
You arming possibly two sets with 1 set of wires?
Just curious.

Dave A said:

I see many rockets with just 1 pair of wires hanging out a sensing port.
Does that mean you are arming only 1 set of electronics?
You arming possibly two sets with 1 set of wires?
Just curious.

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Ummmmm, likely one device. There is no law that says one HAS to use two altimeters with M motors or above. It is a requirement for the certification flight only (at least in TRA) Achieve/earn L3 and one could use a single altimeter thereafter. Many routinely use two for backup because they are protecting their investment and perhaps increasing the safety factor. Kurt

I got the rules ok. My point, why would I not buy another $50 altimeter and greatly increase my chances of sucess. If I spend more than $100 and lots of my precious time on a rocket, I will have a backup plan.

Dave A said:

I got the rules ok. My point, why would I not buy another $50 altimeter and greatly increase my chances of sucess. If I spend more than $100 and lots of my precious time on a rocket, I will have a backup plan.

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No one can find fault with that point. Some who may be going for a record attempt might feel otherwise concerning risk and want the absolute minimum if they are at the optimum throw weight. Kurt

I am pretty sure I am going with switches at this point.

Has anyone used the screw switches from Featherweight? Interesting size and configuration- any opinions on them.

markkoelsch said:

I am pretty sure I am going with switches at this point.

Has anyone used the screw switches from Featherweight? Interesting size and configuration- any opinions on them.

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I've used them a bunch. Behind a vent hole. They work great, and are very small. I did loose a screw once by over loosening the screw at a launch - very frustrating, luckily I had a backup. My only complaint is where the solder pads are - right in the middle where they can get in the way. It would be nicer if there were pads off one end of the switch. Missileworks has a similar product, but a bit bigger overall with pads off 1 end; I have a couple, but have not tried them yet, but they look nice too.