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Posted (edited)

Could be a simple bi-metal type of thing like a thermostat, or it could even be something melts and releases a switch.

It could be almost anything I guess.

‘If possible you should find the data on it and have an IA fill out a complete the record 337 to legitimize it.

Did you get the CD from the FAA with all the 337’s? It might could be documented

On edit, remove the panel and look for a part number or something

Edited by A64Pilot
Posted
3 minutes ago, A64Pilot said:

Did you get the CD from the FAA with all the 337’s? It might could be documented

On edit, remove the panel and look for a part number or something

Got everything the FAA has -- as they say in Poker "no help".

Looking behind the panel is a good idea, but the light and push button look like discrete components.  That said, the only way to know for sure is do what you suggested and take a look.

Posted
8 minutes ago, carusoam said:

Rocket Engineering still answers the phone when they want to…

I did talk to Conrad a few months ago but, based on the experiences of others, that may have been an anomaly.  Worth a shot.  Thanks.

  • Like 1
Posted
5 minutes ago, N201MKTurbo said:

When they get hot enough the salt melts and current flows between the wires.

Do you know if that salt type of detector is a one way street?  Is the detector toast after the current flows?

Posted
10 minutes ago, Fly Boomer said:

Do you know if that salt type of detector is a one way street?  Is the detector toast after the current flows?

No, when they cool off they turn off.

Posted
6 minutes ago, N201MKTurbo said:

No, when they cool off they turn off.

If I can't chase down any documentation or determine who manufactured these, I'll get out my heat gun and see what happens.  I don't like having things on board that I can't understand.

EDIT:  Except for certain passengers.

  • Haha 1
Posted

If they're switches they'll be normally open and only close when sufficiently hot.    The test lamp should close the circuit at the end of the loop, which tests the lamp as well as continuity of the harness to all of the sensors.

They don't look like the thermocouple type, but if they are there may be continuity across the sensors.

This is what a thermocouple-style discrete detector looks like.   The thing poking through the wall in the first pic, and on the end of the wire harness in the 2nd.image.thumb.jpeg.9b9f84f173bd2881e6bc1fbb4737f7a5.jpeg

image.thumb.jpeg.b2aec4dcc59a2e9fa8dd5ce93c8b892a.jpeg

  • Like 1
Posted
25 minutes ago, N201MKTurbo said:

I  believe these sensor are filled with salt with two wires running through it. When they get hot enough the salt melts and current flows between the wires.

That's the continuous-loop type that works that way.  They run those in loops around cowls over the hot sections in jets and turbines.  These are discrete sensors, so probably a switch or a thermocouple.   I suspect it's a switch.    I recall we had one in A&P school and heated it with a torch until it switched.

Posted
Just now, Fly Boomer said:

Does that mean that my heat gun will be too wimpy?

Maybe, who knows.   I think they can be adjusted, which I think is what the screws on the end are for.   They're probably adjusted to switch at a particular temp, but without knowing that temp it'd just be an experiment.   It's just a bi-metal switch, like what trips a toaster.

Posted
2 minutes ago, EricJ said:

probably adjusted to switch at a particular temp

One of the Fenwal detectors (which physically look similar to mine) are available in "Six Fixed Settings from 140 to 325°F".  Is that high enough for this application?  Not sure what the temps are with the turbo nearby, but would not be surprised to learn that they are above 325 even with some airflow.

Posted (edited)

I don’t think it’s nearly as hot as you think, there is a metric butt load of air moving through a cowling.

But if you want to know it’s real easy, get a multimeter that accepts a K type thermocouple and measure it, my old Fluke won’t, I bought the accy module so I could but a better Fluke will measure direct, and you need a good multimeter, you may just not know it :)

K type Thermocouple wire is cheap $1 a foot on Amazon and of course it’s good forever

 

1DC86E77-EA2D-42DA-A648-1AD5AEFC89B2.jpeg

1A9B2B20-B7D6-4B79-BF56-EE084BD796CA.png

Edited by A64Pilot
Posted
On 4/11/2022 at 10:42 AM, Fly Boomer said:

 

Can any of our Rocketeers identify this?  It's pretty far forward and under the turbo:

image.thumb.jpeg.032f0f64db281bc9794823e5b35cb949.jpeg

 

And two more (similar/identical) down low, starboard side, on the firewall:

 

image.jpeg

 

Appreciate any help.

Thanks,
John

Those are fire detectors right out of a Cessna Twin.  To test them, get a good quality heat gun, aim it at them one by one, look for a fire indicator on the instrument panel.

Clarence

58608BA9-AB8C-404E-9C96-2287422EDFD0.jpeg

Posted

Based on all of the details above…

1) It’s a thermal switch…

2) Adjustable temperature setting…

3) Switch can be selected either to open or to close…

4) The switch can be used to power anything from a fire extinguisher… or a light bulb….

5) The common way TC’s fail in Mooneys (cutting torch style), this and a CO detector will have you alerted early on…

6) And here’s the link!

https://www.kidde-fenwal.com/Public/System_Details/Fenwal-Controls/DETECT-A-FIRE-Fire-and-Overheat-Detectors

:)

Go MS!

-a-

 

Posted
3 hours ago, M20Doc said:

Those are fire detectors right out of a Cessna Twin.

Thanks Clarence!  The middle one (at least) is exactly what I have.  Given that my engine and prop are straight from a 414, I guess it's not surprising that the detectors came along for the ride.  What I don't understand is why all Rockets don't have them.  I have spent quite a few hours on the Internet looking for these.  Did a search for "cessna Fenwal" and the first hit brings one up.  Paradoxically, you have to know exactly what you are looking for before you can search for it.

Posted
12 hours ago, carusoam said:

@Austintatious and @aviatoreb

Does your Rocket have a fire detection system like Boomer’s does? (See pics above)

Apparently, this system may have come from the Cessna airframe that donated the engine/prop organs….

Best regards,

-a-

WOW - no kidding.  That seems like a useful thing.

No - as far as I know - I don't have such a system.

  • Like 1
Posted
On 4/12/2022 at 11:11 PM, carusoam said:

@Austintatious and @aviatoreb

Does your Rocket have a fire detection system like Boomer’s does? (See pics above)

Apparently, this system may have come from the Cessna airframe that donated the engine/prop organs….

Best regards,

-a-

Nope, I dont got it.  Would be nice though... wonder how they fit it... most the space inside the cowl is spoken for LOL.

  • Thanks 1

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