FXC12000 plastic bag activation trick?

[councilman24 37]

It's been a while since I maintained any rigs with an FXC12000, and when I did I used a vacuum chamber to test them. But I seem to recall some folks using a plastic baggie around the sensor to fire them. I never knew how to do it because I didn't need to but I do now. Not for use in a rig but to use the FXC12000 for some other testing.

Can anybody help me out with how to fire it without a putting it in a vacuum chamber?

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[NovaTTT 2]

PPM 9.5.2

"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

[councilman24 37]

Not in mine.

Oh, you didn't say VOLUME II!

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[councilman24 37]

Okay, so have you ever got it to work?

Fires in a vacuum chamber but I can't blow hard/fast enough to get it to fire with the sensor in a bag.

Yes, I know that was a set up but this isn't bonfire.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[NovaTTT 2]

PPM II! My bad!

I've not tried it, Terry, but if I were going to, I'd try it with a hair dryer on no-heat setting.

I wonder if a latex balloon would work better, using the squeezing method.

Cheers!

ETA: Perhaps it's not your method of blowing but too much air escaping? Just wondering if you have a good seal and are using a small tube for blowing?

"Even in a world where perfection is unattainable, there's still a difference between excellence and mediocrity." Gary73

[peek 21]

Quote

[FXC1200] Fires in a vacuum chamber but I can't blow hard/fast enough to get it to fire with the sensor in a bag.

Put the bag around it, blow it up until it is full, twist/tape the opening of the bag really tight around the cable, and (this is the trick) smack the bag from both sides (between your hands) really hard. This creates a pressure increase quick enough to simulate a rapid descent. I have successfully activated one in the past like this.

[mark 107]

What Gary said, more or less.

Blow into the 1-quart heavy zip-loc plastic bag to expand it; no need to pressurize above ambient. Hold the mouth of the bag closed tight around the braided hose with one hand. Squeeze the bag briskly with the other hand.

Mark

[riggerrob 643]

The bag test is just the first step in chamber-testing FXC 12000 AADs.
Just wrap a plastic or paper bag around the control head and squeeze briskly.
You can accomplish the same test by closing two of the sintered brass vents - on the control head - with you fingers an blowing into the third vent.
Mind you this only proves that it fires at a rapid rate of descent.
Then you have to go back and repeat the process to determine it it fires slightly faster than the threshold and refuses to fire at slightly slower than the threshold.
You need an accurate rate-of-climb instrument to tell you how fast you are "diving" your AAD.

Oh!
And if you are building your own pressure chamber, there are two types of instruments: genuine aircraft instruments (calibrated recently) or JUNK!

[councilman24 37]

Rob,

You missed the back story. This isn't going in the air. It about the only think I can think of that might pull a bridle fast enough to recreate the bridle over the pin PC in tow we've been seeing lately. And I still can't get the think to fire out side my vacuum chamber.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[erdnarob 1]

You don't even have to use a plastic bag to test a FXC12000. You can just "envelop" the sensor in your two hand palms as much as possible and blow with your mouth suddenly thru the opening left between your thumbs or so. I used that trick quite often to show my students the way the FXC (removed from the container) works. But later on I was told not to do this since there is no resistance for the spring like pulling an actual pin, and that there was possibility of damaging the unit.

Learn from others mistakes, you will never live long enough to make them all.

[theonlyski 8]

Quote

Rob,

You missed the back story. This isn't going in the air. It about the only think I can think of that might pull a bridle fast enough to recreate the bridle over the pin PC in tow we've been seeing lately. And I still can't get the think to fire out side my vacuum chamber.

Got an air compressor?

Try the thing where you seal off the 2 brass nozzles and just hit the third with the air from an air compressor... sounds like it should work the same?

"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

[councilman24 37]

At some point they started putting in a bumper. And of course for testing you were supposed to use a spring or other load or bumper.

And I FINALLY got it to fire cover two ports and blowing into it!

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[riggerrob 643]

Only FXC 12000 Revision "M" comes standard with a black rubber bumper.
Teh bumper is similar to the black rubber bumper that you are supposed to slide onto Rev. "J" when you chamber test them.
You can also cheat by wrapping a thick rubber band around the cable - multiple times - just below the cable's end fitting.
The goal of all these rubber gadgets is to prevent the steel cable end from slamming against the Teflon lining of the "power" housing. Slam it too many times and the Teflon will fracture and jam the cable. Just ask the USAF Academy how they learned that lesson the hard way!
Hah!
Hah!