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PMag Cooling Shroud

dtw_rv6

Well Known Member
Someone in another thread mentioned printing a cooling shroud for Pmags. Here is what I installed on mine:

oPg.jpg


Printed from Nylon - wasn't one of my easiest print jobs, but it does work. I've been using mine for about 6 months now.

Don
 
Amazing what the printers can do.

Did you record board temperature before and after?
 
Someone in another thread mentioned printing a cooling shroud for Pmags. Here is what I installed on mine:

oPg.jpg


Printed from Nylon - wasn't one of my easiest print jobs, but it does work. I've been using mine for about 6 months now.

Don

Interested in selling those, Don? I would like to have a pair.

Ron B
 
That's a great idea!

Can you make it like these? That way you won't have to flex the plastic as much to snap them on.
It might be worth adding something that allows the ends to be held tight, possibly by safety wire
11goy1w.jpg
 
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I second Bill's request. Simple design!

Ron B

My metal ones feed from the center and seem to work.
The P-mags record a max temp but it is from the beginning of time. So if you have already hit max temp, it won't be overwritten. The max temp is typically set on a hot day, you shut down for fuel, and start-up without the engine cooling.

There is a current temp on the P-mags, which our EIC32 logs and writes to a .CSV file.
 
Yes please, I?ll take two. With a black cowling I?ll do anything to keep the temps down.

Please let us know how to get a pair. Thanks
 
I would also like a couple of these if they fit the current 114 mags, although I question how much good they?ll do without any data. It seems that the most temperature critical time for emags is after engine shut down, especially on warm days. The only thing I can think of to combat this inner cowl heat rise is to open the oil door after shut down. Keeping the cowl temps below 200* in flight shouldn?t be too difficult (although I would like to make sure with your shroud), but after shut down, when temps can elevate might be a challenge.
 
Bill - quick dumb question on P-Mag temp sensors (the color dot on the exterior of the case). I had my P-Mag removed today to complete the annual gear inspection - what a PITA to get to the clamp nuts, but ya gotta do what ya gotta do. I checked the temperature sticker and it's all white, even within the black circle of the temp sensor area. What I can't remember is whether "all white" is good, or whether the sensor spot changes temp to something other than white if it exceeds the indicated temperature.

Thanks for your helpful reply.

BTW, while it was a PITA to remove the P-Mag to inspect its drive gear, oh man is it ever easy to time the P-Mag. Of course I checked and reset the timing on my Slick mag as it had drifted a couple of degrees over the first hundred hours of service. It took me more than a few tries to get it "just right" at 25BTDC while it took no time at all to set the P-Mag at TDC.
 
Bill - quick dumb question on P-Mag temp sensors (the color dot on the exterior of the case). I had my P-Mag removed today to complete the annual gear inspection - what a PITA to get to the clamp nuts, but ya gotta do what ya gotta do. I checked the temperature sticker and it's all white, even within the black circle of the temp sensor area. What I can't remember is whether "all white" is good, or whether the sensor spot changes temp to something other than white if it exceeds the indicated temperature.

Thanks for your helpful reply.

BTW, while it was a PITA to remove the P-Mag to inspect its drive gear, oh man is it ever easy to time the P-Mag. Of course I checked and reset the timing on my Slick mag as it had drifted a couple of degrees over the first hundred hours of service. It took me more than a few tries to get it "just right" at 25BTDC while it took no time at all to set the P-Mag at TDC.

I agree the inspection is a pain, especially on the left side; however, it is well worth the time! Our EICommander has found worn gears and bad bearings, without the EICommander, removal is the only way to know if you have an issue.

Regarding your question, the dot turns black when overheated.
Here is a link. (Scroll down )
 
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I would also like a couple of these if they fit the current 114 mags, although I question how much good they’ll do without any data.

Not much excuse for lack of temperature data. An ordinary LM34AH temperature sensor can be placed almost anywhere...hanging free, glued directly to a surface with thermally conductive epoxy, or clamped with a blob of thermally conducting silicone paste.

Datasheet: http://www.ti.com/lit/ds/symlink/lm34.pdf

You can buy them from Digikey (https://www.digikey.com/product-detail/en/texas-instruments/LM34AH-NOPB/LM34AH-NOPB-ND/182346) or just type "LM34AH" into the search box on Ebay.

Hookup is three wires: main bus power, aircraft ground, and signal. The signal wire goes to your trusty digital voltmeter. Run the negative lead of the voltmeter to the same aircraft ground as the sensor power. Output is 10 millivolts per degree F, so with the meter displaying volts, just move the decimal point two places to the right. For example, if the meter says 2.50V, the temperature is 250F.

I make probes using 3-wire shielded, just because the shield braid makes good armor for a cable run at random through an engine compartment for quick tests. I've stuck them inside breather tubes, hung them under cylinder cooling air outlets, placed them in cowl exits, and inside oil cooler ducts. Here's one hanging near a cowl exit door servo. The location shields it from radiant heating, but I wanted to check local air temperature. In the second photo the probe is measuring exit air temperature. It's behind a heat shield made from fiberglass, fiberfrax, and aluminum tape, so it won't pick up radiant heat from the adjacent exhaust.

Let's quit guessing.

2012-11-10_16-44-54_99.jpg


Shielded%20Exit%20Probe.jpg
 
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Thanks for confirming, Bill - much appreciated. Nice to know my P-Mag hasn't hit that high temp mark to turn the indicator black. I'm using a simple 1/2" blast tube on the base of the P-Mag. I like Dan's idea of installing a simple temp sensor to get baseline temp data. That might be on my to-do list when I install the new engine monitor.
 
Off the top of my head I can name about a half dozen ignition systems that don't need cooling shrouds, external monitoring devices, temperature sensors, or annual inspections of a drive gear, requiring removal.

What I learned from this thread.

Just sayin.
 
I am interested in a couple

Don,

Are you still making the P-Mag shrouds.? I just bought two of the 200 models for the 6 cyl. and looking at keeping them as cool as possible.

Email me at [email protected] for price and how to pay.

Thanks.

Brian
 
Temperature recording strips

Great devices to be sure.

Mine on my P-Mags tend to record in the 190s, almost 200s. I have small blast tubes affixed. The question is when are these temperatures recorded. Did those temperatures peak in operation or on shutdown when case temperatures creep outwards towards the previously cooled components?

That said, yes please!
 
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The temps definitely creep up on shutdown from heat soaking. I just make it a habit on super hot days to open the oil door.
 
Cooling Shroud

Someone in another thread mentioned printing a cooling shroud for Pmags. Here is what I installed on mine:

oPg.jpg


Printed from Nylon - wasn't one of my easiest print jobs, but it does work. I've been using mine for about 6 months now.

Don

Don,

Can you make two more shrouds for my new P-Mags?

I am about ready to install them, and would like to keep them as cool as possible.

Email me at [email protected] for the price and shipping info.

Thanks.

Brian
 
The temps definitely creep up on shutdown from heat soaking. I just make it a habit on super hot days to open the oil door.
I don't mean to derail but I'm wondering if it's been posted in the past; has anyone installed some kind of temp sensor under the cowl and collected data on how effective opening the oil door is at reducing temps after shutdown?
 
PMag shroud and temp displays

Well, I have not heard from Don, so looking at trying to design my own 3D shroud, and will be getting another new 3D printer to print it up in carbon.

Now, I also found a simple temp probe I can stick to the PMag, and I will be able to input and display the temps of my PMag on my SkyView displays.

When I get it all done, I will post all the info and programming needed.

It will be a few months to get the new printer setup, and the shroud designed and printed, so please be patient.

Brian
 
Well, I have not heard from Don, so looking at trying to design my own 3D shroud, and will be getting another new 3D printer to print it up in carbon.

Now, I also found a simple temp probe I can stick to the PMag, and I will be able to input and display the temps of my PMag on my SkyView displays.

When I get it all done, I will post all the info and programming needed.

It will be a few months to get the new printer setup, and the shroud designed and printed, so please be patient.

Brian

Looking forward to it Brian. Do you have the intent to sell these when you are finished or would be willing to share the print file? I too have thought about printing something myself, just don't know if it would be worth it as the blast tube seems to be working.
 
Yes please keep us up to date with your progress. I am also interested in what you come up with. :cool:
 
PMag shroud

Will do guys, but I will give you the first problem. The first one I am doing is for a 6 cyl version in my Rocket. If it works, and my son can make a small mod for a 4 cyl version, I will let you know.

We are planning on getting another, better 3D printer to do them in nylon, carbon, or another type filament that can handle the higher temps.

As for passing it along, that will not be a problem, either the G-code, or a printed model.

As for being able to display the temp on the SkyView, after I have it up and running, I will pass on where you can get the temp probes, (they are fairly cheap), the hook up to SkyView, and all the settings.

Do to my normal work schedule, it will be later in Dec, or Jan before I have it all done, but will keep you updated.

Brian
 
Off the top of my head I can name about a half dozen ignition systems that don't need cooling shrouds, external monitoring devices, temperature sensors, or annual inspections of a drive gear, requiring removal.

What I learned from this thread.

Just sayin.

Add "opening the oil door on hot days" to that list :D
 
Add "opening the oil door on hot days" to that list :D
I do that anyway to let the vapor out of the oil dipstick, but totally agree that if you are designing a product, you need to make sure it works in the target environment. Engines get hot. If you make something that bolts to the engine, make sure it can handle that temperature, plus some safety factor. Not saying this is easy, but that's why we pay the big bucks!
 
My dots turned black on my second flight with new Pmags couple months ago. I have blast tubes. I landed, pulled into the hanger, and opened my oil door. With my infrared heat sensor I watched the temp climb from 180 to 216 and the dots turned black at that point. They later turned grey when it cooled down. I have since put about 12 hrs on them without any problems but haven't monitored the heat and open the oil door after flying when I can remember!
 
Thought this would be a good place to park this...

Not obvious from the picture but the tube is split and encompasses the whole cooling section of the Pmag. No pirep yet but I did stick the Van's electrical conduit in a pot of boiling water and it did very well with no deformation or perceptible softening.

Think it'll melt?
 

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I use the typical Van’s corrugated tubing, one for each pMag. The end pointed at the pMag as discussed in the install instructions.

The photo shows highest temp after several hundred hours.

Carl
5-B897-D1-E-7-E61-4595-B5-FA-39-D201-FCA4-D3.jpg
 
A very nice looking solution. What’s the red thingy on the right side?

Silicone tape to seal the gap at the start of the split. It's probably not necessary/effective but that's what it is.

It's surprising how well the sliced conduit fits the Pmag.

I tried to point the exhaust end at the mechanical fuel pump but abandoned that for lack of room. Don't know if it would heat or cool the pump.
 

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Thought this would be a good place to park this...

Not obvious from the picture but the tube is split and encompasses the whole cooling section of the Pmag. No pirep yet but I did stick the Van's electrical conduit in a pot of boiling water and it did very well with no deformation or perceptible softening.

Think it'll melt?

With temperature and vibration, I suspect that the safety wire will soon slice through the plastic tube.
 
Seems like a good project/idea for anyone with 3D printing capabilities.

Just be very, very careful what material you use ... you could end up with a bad situation in flight if your shroud melts or breaks in flight ...

3D printing is awesome for a lot of things, but I would stay away from critical parts unless you're very skilled and really understand the materials and environment involved.

Since 3D printing happens in layers, those layers are subject to delimitation, which is very common.
 
Just be very, very careful what material you use ... you could end up with a bad situation in flight if your shroud melts or breaks in flight ...

3D printing is awesome for a lot of things, but I would stay away from critical parts unless you're very skilled and really understand the materials and environment involved.

Since 3D printing happens in layers, those layers are subject to delimitation, which is very common.

Don't mean to disregard the caution but PMAGs worse heat conditions are typically when the engine has just shut down on a hot day, The heat from the engine with no cooling air may melt it much sooner than in the air when it is being*constantly fed with a blast of cold air.I don't know what the temp for 3D material is but I would imagine it would need to stand at 250 degrees for a long term use.* My temp strips on three sets of plane with PMAG has not show any recorded temp above 190F*and my current plane has a probe for the inside cowl (near the battery box) and I don't see temp above 120-125 when in the air
 
So how has the OP's 3D printed solution held up 4 years on? Has it held up to the heat?



Someone in another thread mentioned printing a cooling shroud for Pmags. Here is what I installed on mine:

oPg.jpg


Printed from Nylon - wasn't one of my easiest print jobs, but it does work. I've been using mine for about 6 months now.

Don
 
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With temperature and vibration, I suspect that the safety wire will soon slice through the plastic tube.

I used Safety Wire on the tube to the alternator and the mags. Have not had any wear with them on my airplane. Tube replacement on my RV-6 has had nothing to do with the safety wire. The cost of the tube is so low, it would not be an issue if tube were replace every condition inspection or oil change.
 
Don't mean to disregard the caution but PMAGs worse heat conditions are typically when the engine has just shut down on a hot day, The heat from the engine with no cooling air may melt it much sooner than in the air when it is being*constantly fed with a blast of cold air.I don't know what the temp for 3D material is but I would imagine it would need to stand at 250 degrees for a long term use.* My temp strips on three sets of plane with PMAG has not show any recorded temp above 190F*and my current plane has a probe for the inside cowl (near the battery box) and I don't see temp above 120-125 when in the air

Yep ... we have a high tech custom cooling solution just for that in the summer ... we open the oil access hatch after each flight :p
 
we open the oil access hatch after each flight :p

Same here. I fly in Phoenix, year round including some insanely hot summer days. I've never had a problem with the PMags. I also open the oil door to let my EarthX battery cool down. Works like a champ! I post this only as a data point for other's to consider. I really like the 3D printed idea and some other ideas here. Maybe I will do that someday too when I get bored. But for any new owners, I'd say you're probably fine going with the "standard" installation and common sense measures like opening a door for cooling after landing. You don't need to feel bad if you're not "keeping up with the Jones's" who own 3D printers. Just $0.02 from a hot weather desert rat.
 
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Silicone tape to seal the gap at the start of the split. It's probably not necessary/effective but that's what it is.

It's surprising how well the sliced conduit fits the Pmag.

I tried to point the exhaust end at the mechanical fuel pump but abandoned that for lack of room. Don't know if it would heat or cool the pump.

That's clever. What size conduit is that?
 
We've had really good parts made from 3rd party services that have high-end printing machines and a wide selection of materials, both plastic and metal.

Perhaps someone on the forum here knows what the best material would be for this application?

https://www.shapeways.com/

https://www.xometry.com/capabilities/3d-printing-service/

I have access to some very high-end 3D printing equipment where I work. If someone has a dfx file for the shroud in the OP, I would gladly print a few. My CAD skills just aren't that good (yet!).
 
I have access to some very high-end 3D printing equipment where I work. If someone has a dfx file for the shroud in the OP, I would gladly print a few. My CAD skills just aren't that good (yet!).

If someone wants to get the dimensions of a PMAG, I can design a cooling shroud pretty easily and make the CAD file available.
 
I use the typical Van’s corrugated tubing, one for each pMag. The end pointed at the pMag as discussed in the install instructions.

The photo shows highest temp after several hundred hours.

Carl
5-B897-D1-E-7-E61-4595-B5-FA-39-D201-FCA4-D3.jpg


I show the same temp range with the simple recommended solution. Why risk changing what has proven to work well!
 
I show the same temp range with the simple recommended solution. Why risk changing what has proven to work well!
I would guess the 3D-printed shroud or corrugated-surround would provide more even cooling to the unit, so why not?
 
I would guess the 3D-printed shroud or corrugated-surround would provide more even cooling to the unit, so why not?

I agree and I don't see any harm in it, other than a few bucks out of our wallets but that one looks neat and I would be willing to buy a couple of them if reasonably priced. Knowing that I created a similar unit out of aluminum for the oil filter (covered the length of the oil filter) and ran a blast tube thru it thinking that it would have some effect on the oil temp. Zero, zilch nada.
 
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