Altimeter tester

[patbunn]

I built this altimeter tester this afternoon. Seems to work fine. I installed a whole 38 mm EBAY with e matches installed.
12 Volts on the pump. A finger over the open end of the T and the altimeter stopped warbling. took it off and the drogue e match fired and soon after the main fired. The e matches stained the jar a little. I may not use e matches for all tests.

A needle valve at the open end of the T would allow a slow release of the jar vacuum.

The Jar and the sealed top came from Amazon. I picked up the Pump at Electric Goldmine for about $7.

I use Egg Timer Altimeters and being to test my solder work before launching is nice to know.

 

[kjhambrick]

patbunn --

LED's work great for testing deployment events.

HTH ...

-- kjh

 

[sriegel]

Also old incandescent Christmas tree lights.

 

[Handeman]

Also old incandescent Christmas tree lights.

Back when I started DD 16 years ago, I used them to set off the charges too.

 

[patbunn]

patbunn --

LED's work great for testing deployment events.

HTH ...

-- kjh

If they have a current limiting resistor. Otherwise they burn out. Best is a small incandescent bulb from old style Christmas tree bulbs. These are getting hard to find.

 

[Handeman]

If they have a current limiting resistor. Otherwise they burn out. Best is a small incandescent bulb from old style Christmas tree bulbs. These are getting hard to find.

I never throw anything away so I still have a box of a few hundred of the old xmas bulbs, but if you look for xmas tree lights in the dollar stores and bargain outlets, you can still find some of the old incandescent strings. You are right, they are getting hard to find and I'm not sure how much longer they will be around.

 

[TRWXXA]

I never through anything away so I still have a box of a few hundred of the old xmas bulbs, but if you look for xmas tree lights in the dollar stores and bargain outlets, you can still find some of the old incandescent strings. You are right, they are getting hard to find and I'm not sure how much longer they will be around.

Been away from the hobby for 20+ years. Back in the day, I used flashbulbs to activate ejection charges off the altimeters -- cheap and easy. Can I assume those are as extinct as the Dodo bird?

 

[RocketPro]

I use these for testing ematch drivers.

https://www.amazon.com/gp/product/B00RZ4YRS0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[fyrwrxz]

Been away from the hobby for 20+ years. Back in the day, I used flashbulbs to activate ejection charges off the altimeters -- cheap and easy. Can I assume those are as extinct as the Dodo bird?

Nope! Some of us og's still have boxes of 'em. Some day I'm going completely retro at a launch with Adepts and flash bulbs. Can't wait to see some young buck RSO's face when he reads the launch card.

 

[Kane]

I do a nearly identical setup, except I don't use a pump. I just have a big syringe connected to the end of the surgical tubing. The altimeter reads "apogee" once the syringe plunger gets to the end and whatever main deployment height by slowly pushing the plunger back in.

 

[TRWXXA]

I do a nearly identical setup, except I don't use a pump. I just have a big syringe connected to the end of the surgical tubing. The altimeter reads "apogee" once the syringe plunger gets to the end and whatever main deployment height by slowly pushing the plunger back in.

Back in the day, my altitude chamber was a giant, glass, Prego spaghetti sauce jar, and a hand operated vacuum pump from a brake bleeder kit. The guage on it probably wasn't very accurate, but I could roughly calculate simulated altitudes off of it.

Later, I got an old aircraft altimeter from a flea market, and plumbed that in. Then I was really, really feeling like a steely-eyed missile man.

 

[Philip Tiberius D.]

I built this altimeter tester this afternoon. Seems to work fine. I installed a whole 38 mm EBAY with e matches installed.
12 Volts on the pump. A finger over the open end of the T and the altimeter stopped warbling. took it off and the drogue e match fired and soon after the main fired. The e matches stained the jar a little. I may not use e matches for all tests.

A needle valve at the open end of the T would allow a slow release of the jar vacuum.

The Jar and the sealed top came from Amazon. I picked up the Pump at Electric Goldmine for about $7.

I use Egg Timer Altimeters and being to test my solder work before launching is nice to know.View attachment 579082

Did the jar have that type of lid ?

 

[kjhambrick]

If they have a current limiting resistor. Otherwise they burn out. Best is a small incandescent bulb from old style Christmas tree bulbs. These are getting hard to find.

Oops, Yes now that you mention it, Scott Bartel gave me a handful of LEDs when I was writing the AltAcc Firmware and I never gave it any thought.

Thanks patbunn !

-- kjh

 

[patbunn]

The pump was cheap. I ordered some DC speedometer bulbs - thanks for the link.

Lots of good ideas. I appreciate the info.

Pat

Did the jar have that type of lid ?

No , it came from Amazon. Search Food Saver Jar Lids. They have many types.

 

[pathtouch]

I do a nearly identical setup, except I don't use a pump. I just have a big syringe connected to the end of the surgical tubing. The altimeter reads "apogee" once the syringe plunger gets to the end and whatever main deployment height by slowly pushing the plunger back in.

Don’t forget hot glue or bubble gum for the seal haha. Same.

 

[OverTheTop]

LED's work great for testing deployment events.

Also old incandescent Christmas tree lights.

Also "grain of wheat" bulbs work well.