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Best Way to Arm Altimeter

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edwardw

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Hey all,

I have been wondering how you all arm your altimeters? I have a 3" mailing tube rocket for my L1/L2 certs coming up in March. I have the e-bay built and in the past have used a roller switch that is NO when depressed. I put a piece of brass tubing to guide a dowel and then remove it before flight. I think the perfectflite site has something on this already.

Any other easier methods to arm an altimeter? What do you all prefer?

Edward
 

Ryan S.

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Twist the wires together. I would put a switch in my rockets but it gets complicated when you need to switch between rockets unless you put the switch in the board and reach through the vent hole.

I prefer just twisting the wires, it simple and easy
 

Johnnie

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Do you remember the old Gateway 2000 computers??? They had a key switch installed in the computer case for locking something out, lord only knew what it was...anyways, they are aerodynamic on an airframe, tough as nails (can't be turned off in the case of a hard recovery) contain only 2 wires, and can be turned on and off with a key. There is a vender that sells the switch that I am talking about, for like $5 a piece, but I can't for the life of me think who it is.

The twisting of the wires together is fast and simple (K.I.S.S.), just make sure to tape the wires to a non seperation point of the rocket, as you will want to be able to get at them to be able to dissarm in case of a miss-fire.

Johnnie
 

n3tjm

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The Keyswitch is the method I will use when I rebuild my Magnum's Payload section. Twisting the wires together has its problems... the wires will wear out, so you constantly have to replace them, and there may not be sufficient contact if the wires become corroded. Taping the wires to the outside of the rocket will prevent them from getting untwisited in the slipstream.
 

wyldbill

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Originally posted by n3tjm
Twisting the wires together has its problems... the wires will wear out, so you constantly have to replace them, and there may not be sufficient contact if the wires become corroded.
I twist and use a small wire nut to keep 'em together. I also design my setup so that these "switch wires" can be easily replaced.

FWIW,
-bill
 

edwardw

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Twisting wires does seem simple, but on my rocket the altimeter is stuffed about 10" down in the forward section of the rocket. I dont have small enough hands to arm it. I was also thinking a key switch mounted flush with my altimeter bay and a hole cut in the airframe. Turn the altimeter to the hole, arm it and then rotate it to line up with the vent holes. I think for now I might stick with my roller switch pull string method. Any ideas would be appreciated!

Edward
 

RocketboyG80

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I use a Single Pull Single Throw submini slide switch. I get them at Radio Shack. Attached is a drawing of my dual deployment configuration in my LOC/Legacy. I have it setup so I just reach a toothpick in the 1/4" vent hole to flip the switch on. The switch sits back enough to let air in but forward enough to allow me to see what I'm doing to arm the alt.Switch
 

edwardw

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Thats a good idea, I like it a lot.


ALSO

How do you all hold your batteries in? I have used every type holder and broken all of them. On my last rocket I used a screw down method to apply pressure to the battery and connector so they wouldn't move at all.

Edward
 

RocketboyG80

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I use one of those metal 9-V battery holders. Radio Shack
I flattened one of the flared edges so that I could epoxy it on flat to the altimeter sled. I put a loop of Kevlar around it that tightly fits over the battery and harness once it is slid into the holder. This keeps the battery from loosening itself out due to flight vibrations and ejections.
 

DavRedf

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Have a word with Sandman as he has aquired half of radioshack's stock.:D :D :D

I have no ties to the afore mentioned Mr Sandman, not even as a customer.










Will collect the $10 later ;)

David
 

wyldbill

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Originally posted by edwardw
How do you all hold your batteries in?
nylon zip ties through holes in the mounting plate. 2 radial, 1 axial per 9V.

-bill
 

edwardw

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Well, for this rocket I just armed the altimeter by means of a remove before flight pin. I will post pics of the finished e-bay once I take them.

Edward
 

daveyfire

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Originally posted by wyldbill
nylon zip ties through holes in the mounting plate. 2 radial, 1 axial per 9V.
I've gotten away in the past with 1 radial, 1 axial per 9v, even on 40g+ flights (J570W in a 54mm rocket and M2400 in 75mm rocket to name a few :D ) I then just solder wires directly to the contacts to avoid having the little 9v connector deelys short out. Have yet to have one fail!
 

AZ_Ron

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Agree with the screw switches... I've NEVER seen Kevin or Marty's rockets NOT fire... I was twisting wires for years, because I was unhappy with every switch I'd tried, but Kevin showed me the screw switches, and they are what I have in my 2-stage, and that's what'll be installed in my 8" Red Max...

Ron
 
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