Project build plaque for retiring USMC SSGT.

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civicsr2cool
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Project build plaque for retiring USMC SSGT.

Post by civicsr2cool »

Been a while since i came around these parts of the woods and i need some help/advice.

I am stationed in NC right now and am currently a Test Cell Operator for a few helicopter engines(LOVE my job). My SSGT has been working here for over 17 years and is retiring in 3 months. He is a fuckin awesome guy and I volunteered to make a bad ass plaque for him which will include two RPM gauges and a TEMP gauge mounted in the center of the plaque..

I plan on having the gauges wired up and blinking engine operating limits and to have the dial either jump back and forth or redlining. The gauges have 7-segment led displays on the bottom to give the limit you are at and the needle is just there pretty much for a quick glance reference. I have one gauge that I experimented on and have the display set to 999.9 with 3v-5v(3v being the voltage i think would be easier to power the plaque with and 5v where the display is brightest)

The power source is still undecided. With 3v i can easily mount 2 aaa's behind the gauges concealing them. Another option is to use a dc converter and just plug it into the wall. Everyone i work with agrees that would be the best but i think mobility of the plaque is important let alone if he loses the wall plugin he would not figure out the correct amperage to replace it with. At least with aaa's its consistent.

The needles have what looks like a 180 sized can motor attached. got a positive lead and a negative lead. With 3v the needles moves very slowly, just the speed id like it to do a full gauge swipe from 0-120. At 5v the needle moves more in the speed if it were jumping quick to redline.

That is as far in this project I have gotten. I am coming to the pimps first for advice cause I have been out of the loop for a long while.

I dont know what to do as far as AC power or some relay(?) to make the motor switch polarity and for the display to blink. My first thoughts were to go to radioshack and see if they had an ac adapter and throw ac to it to make the motor switch polarity and to turn on and off the display. They had none and i dont know how fast the current would change even if they did. Second thought was relay or something. i really dont know how a relay even works so im kinda stuck on where to go with this project.

I was tasked with the gauges being completed in 3 weeks starting last friday. If I cannot get them to move electronically they will be mounted at a permanent limit.

I am hoping there are still some electronic gurus around like code.. havent heard from him in ages now though.

I will post pictures of the gauges later this afternoon since photobucket and such places are blocked on government computers, thank god BitPimps isnt!!

thakns for the help Pimps
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sidewinder
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Post by sidewinder »

I can't help you on all of the electronic technical stuff, but I do have an idea for power; why not use batteries but provide rechargeables' with the plaque? that way he doesn't have to replace the batteries and has the mobility you were looking for. Plus if he ever ends up in a place with different power levels like Europe, he can just swap to a different charger.

Also, I have no idea of what you're planning for the actual plaque design itself but I imagine aircraft use a lot of stainless steel...if you need an easy way to make a section stainless you might want to consider this: http://www.liquidstainlesssteel.com/Def ... roductName A buddy used it to redo his stove and it looks great (they have a hobby size so you don't have to buy a ton of the stuff).

Good luck on the build, sounds like a good project, and if you guys care enough for this SSGT then he must be a great guy. :-o
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Post by frizzen »

Since he's in the powerplant end, Stainless or Titanium would be good like Sidewinder said.

I'm more involved with the Airframe end of things, so I was thinking aluminum. Either bright polished, engine-turned, or alodined.

What kind of signals do your N1, N2 tachs need? I know it's "whatever the tach generator outputs" but is that voltage, phase angle, pulses...

Temp I assume runs off a thermocouple or a pyrometer? If so they should be easy to make run hacked or read OAT.

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crazydave
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Post by crazydave »

Regarding the power, couldn't you run it off batteries, and install a jack so a wall wart could be optional?
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civicsr2cool
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Re: Project build plaque for retiring USMC SSGT.

Post by civicsr2cool »

Sorry there hasn't been any pictures like I said there would. Forums were down for a while.. I was scared.. lol

Il start with pics first:

This one shows all three of them. The one on the left is an older style and I am going to have to dig through a few of our others to match up the display to the other rpm one.
Image

This tach is going to be replaced to match the first one. Its our experimental one and is pretty beaten up..
Image

Ass end of it. I have the display all hooked up to read out 999.9 I should have gotten a depth shot of it since these things aren't thin..
Image

One of the little led displays. not much to see but a visual none the less.
Image

pin outs.
Image

I was thinking about rechargeable but all of this is coming out of my pocket since i volunteered.. So i figured i can just get him alot of the free ones that our local hazmat provides us. They work fairly decent, they are industrial energizers

As far as the plaque layout and materiel. That is being handled by someone else and they have a BAD ASS layout planned. We have made over 7 of these in the last year or so to the various people going to recruiting billets and to Drill Instructor school so we have a format that is THE Test Cell plaque. But when i leave I do want one with that Stainless Steel on it :)

No idea on the signal they needed.. I tore them open! but yes the temp is off of thermocouples and the rpm is i believe pulses from the tach generator.


@Crazy-- how could i do the batteries and wall charger at the same time? If the batts are in at the same time it will blow them up right?

hopefully the pics help get at what my goal is, i need to figure out how to get the motors and displays to switch current at a somewhat steady pace.. Beyond me how to do that :-)


EDIT: just found a pic of the ka-bar/throttle display that will be on it :-o

Image
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frizzen
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Re: Project build plaque for retiring USMC SSGT.

Post by frizzen »

Most Battery with removable Wallwart setups have a leg in female jack that disconnects batteries when jack plugged in.

Uh, do you have any information about who made the Tachs to find out what signal they like being fed? Once you know what they need, we can hook you up with some circuits. (You better know how to build off a schematic, otherwise you're in over your head)

If Temp is thermocouple, you should be able to feed it a voltage dropped through some resistors, looking for MILLIvolt range here. You could throw in a switch and a thermocouple so it can run off real data too.

K-bar Throttle is cool, but why are both handles oriented Right? Up or Down would seem to be a nicer look.
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