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Insulated Cowling Cover

Posted: Sun Sep 11, 2022 1:55 pm
by norcal64d
Any recommendations for an insulated cowl cover for my MX-7-180? I see Bruce’s Custom Covers sells one for $520 for an M-7-235, I would imagine that’s probably close enough? Any other manufactures to check out?

Re: Insulated Cowling Cover

Posted: Sun Sep 11, 2022 3:47 pm
by Andy Young
I bet that would work just fine. I’m using one from a PA-12 on my M-6-235; while it’s far from a perfect fit, it gets the job done just fine, even in Alaska winter conditions.

Re: Insulated Cowling Cover

Posted: Sun Sep 11, 2022 4:27 pm
by gdflys
There's a reason they call them custom covers. They will make it exactly how you want it.

By the way I've been using one for a PA-28 and it works great too.

Re: Insulated Cowling Cover

Posted: Sun Sep 11, 2022 8:02 pm
by Dkuber

Re: Insulated Cowling Cover

Posted: Mon Sep 12, 2022 8:44 am
by andy
Bruces Custom Covers is your best bet. I have insulated Kennon engine, prop and spinner covers that I bought many years ago for my MX-7-180. They work great but Kennon no longer manufactures them. I don't know anything about Alaska Wing Covers but their website indicates that you have to measure the cowling in detail. There's also more shipping cost from Alaska but they offer military and cash discounts.

Re: Insulated Cowling Cover

Posted: Tue Sep 13, 2022 7:51 am
by andy
Ironically, the photo on the Bruce's Custom Covers website for the MAU 101 engine cover is of a MX-7-180 even though the description says INSULATED ENGINE COVER, M-5-235 & M-7 models.

Re: Insulated Cowling Cover

Posted: Tue Sep 13, 2022 3:04 pm
by Dkuber
When I ordered mine she already had the measurements. She just asked a few questions.

Re: Insulated Cowling Cover

Posted: Sat Sep 17, 2022 8:35 pm
by crbnunit
Alaska Wing covers;

https://alaskawingcovers.com/

Owned and operated by Kurt, Yellowmaule. Good stuff. Flys an M4

Re: Insulated Cowling Cover

Posted: Tue Nov 22, 2022 5:17 am
by norcal64d
I went with someone somewhat local, even though their website doesn't say it they can do pretty much any aircraft. Overall, pretty happy with the set up, time will tell how it holds up, especially if my plane gets parked outside more. I don't have an exact weight but its pretty heavy, at least 10-15 lbs maybe. There wasn't really an option to request an oil panel opening, but as soon as I put it on the plane, I wished I had one for my electric heater plug. Not a deal breaker, just a nice to have for me I'd say. For $300 delivered, I am satisfied. Mac's Airplane Covers. Best to call and leave a voicemail, they aren't good about replying to emails.


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Re: Insulated Cowling Cover

Posted: Tue Nov 22, 2022 11:41 am
by andy
How do you pre-heat the engine without flaps on the cover that open in the front of the cowling to allow air flow from the bottom of the cowling and around the cylinders?

Re: Insulated Cowling Cover

Posted: Tue Nov 22, 2022 12:22 pm
by Andy Young
andy wrote:
Tue Nov 22, 2022 11:41 am
How do you pre-heat the engine without flaps on the cover that open in the front of the cowling to allow air flow from the bottom of the cowling and around the cylinders?
I don’t understand this question. Air FLOW isn’t what you want. You want trapped air, so it can get as warm as possible under the cover. If you have flow, you’re releasing heat out from under the cover. Heat rises, so if warm air is introduced from below (like with a camp stove, induction heater, or Red Dragon-like heater) it will rapidly warm the air above, thence the whole engine. Likewise with an electric on-engine heater.

I’m open to different ideas; just saying I’ve never seen anyone in Alaska open a vent at the front to allow air to flow out. I always wrap it as tightly closed as I can, as do others I know. We do it the same way with our work planes.

Re: Insulated Cowling Cover

Posted: Wed Nov 23, 2022 1:49 pm
by norcal64d
I use an electric heater so I definitely don't want the cowl open at all to let my warmth out. Now I could see having a problem if I was using a preheater that just blew air in the top of the cowling but I haven't used one like that.

Re: Insulated Cowling Cover

Posted: Thu Nov 24, 2022 6:47 am
by andy
In the hangar I use an AeroTherm electric heater which has an inlet SCAT tube that goes in one cowl opening through a flap in the insulated Kennon cover and an outlet SCAT tube that goes in the other cowl opening through a flap in the Kennon cover. I take the Kennon cover with me in the Maule and use a Northern Companion AVGAS powered heater outside the hangar for overnight trips. The Northern Companion's SCAT tube wedges into the bottom cowl. While I can leave the two front flaps closed on the Kennon cover, it works better when I open them since there is better warm air flow up around the oil pan and cylinders. Any forced air heater pumping warm air into the bottom cowling will work better when there is less back pressure opposing the flow of air out of the heater. The same is true for a camp stove that relies on warm air rising and pulling more warm air behind it. Closing the front flaps in the cover creates higher air pressure in the engine compartment that slows down the pull of warm air from the stove so you get less heat in the engine compartment. Once I shut off the Northern Companion, then I close the front flaps on the cover to keep the heat in. Attached is a screen shot from a guy based in Denali who uses the same technique.

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Re: Insulated Cowling Cover

Posted: Sat Nov 26, 2022 7:25 am
by Andy Young
Interesting. I’ve seen people stick the hose from a forced-air heater into a cowl inlet, but that was always in the lower 48, usually without a cover, and typically done by an FBO just trying to get someone transient going in the morning (just trying to get it to start). I always wondered why they didn’t do it from underneath to the heat rise. I haven’t seen that done when heating from beneath, with a camp stove or catalytic heater. I can see how when using a forced-air heater (something with a fan) allowing the air to flow through might end up working something like a convection oven, where the air flow helps break up the boundary layer of cool air that tends to stubbornly remain right next to the metal surfaces.

In my case (and the case of the original poster), using electric heaters mounted on the engine, it seems to me that this logic would not apply, as the heat is being applied via conduction directly to the metal surfaces, vs convection from the air around it. The heat then radiates outward to the rest of the metal, as well as to the air surrounding it, meaning the engine is constantly LOSING heat to the air. Therefore, any air movement across the engine would increase this heat loss, slowing the warming of the engine.

So perhaps this is just a case where methodology depends on how you are applying heat. I do sometimes use hot-air heating, when away from a power source. Maybe next time I do that I’ll experiment with opening the front of my engine cover a bit.

Fun stuff to think about; made me use my brain a bit this morning.

Re: Insulated Cowling Cover

Posted: Sun Nov 27, 2022 4:51 pm
by gdflys
I use a small forced air torpedo heater (lowest setting) with the 4’ tube inserted into the cowl exit area. I typically pull the inlet plugs and throw the insulated cowl blanket over it to prevent heat loss. There’s plenty of air leaks even with no flaps, around the inlets, starter bendix, and carb intake areas to allow the air to migrate up and out. Cylinder head temps come up first and oil temp lags well behind but quickly increase once there some flow of the warmed sump oil on start up.