PMag Cooling Shroud
 

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



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?

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

I second Bill's request. Simple design!

Ron B

I chose to feed the cooling air from the end because I think the air will mainly flow through only one branch if it is centered, and I wouldn’t know for certain if air was going both ways (with apologies to Schroedenger :) )

Certainly it’s easy to model and print a centerfeed version.

As for testing, I haven’t done any since it was recommended by the manufacturer. I believe the onboard logging in the PMag can record temperatures, but I’m not aware of how. Plane is down until spring, but I’d certainly report back if it’s simple to access.

Email me if you’re interested in a pair of these...
rv6wallet
GML
dotcom

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.

Don,

Check your PM's.

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.

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 )

I?d be interested in a pair of shrouds.

Bevan

Based on the mails and messages, there is a moderate interest in the shroud. It will take a bit of time to get all of them made, but I'll get back with everyone privately to confirm.

I do have a snag at this time however. My printer is acting up, and I'm having trouble diagnosing the problem at the moment. I spent the better part of Sunday just trying to determine if it's faulty hardware, the controller, or software with no luck. Hopefully I'll be able to get it resolved in the next day or two and I can start printing.

Thanks!
Don

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-deta...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.

Non printed version
 

This looks pretty easy:

https://www.enginebridge.com/3-cooling-shroud/

It's on my new year's list........

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.

Anybody want to do the data collection? Again - my plane is down for several weeks for a lot of reasons.... when I get far enough down on my squawk list I can take the measurements, but it won't be anytime soon.

Until then, the only claim I'll make is a gain in airspeed of 2 knots :rolleyes:

Don

share the file?
 

Don,
Are you willing to share the file with us? Thanks and Happy New Year.
T.Bear

I don't have any issue with sharing my design ideas, but currently I don't plan to share the actual models that I create. The image file along with the actual PMag is enough for anyone with 3d modelling experience to recreate my work, and there are online services that will print your creations (on much nicer hardware than I have). I've invested time in the printer and design effort that has some value that I want the option of recuperating. I consider this the same as someone posting photos of a fiberglass part that they've made, versus supplying molds and actual parts.

Don