Oil cooler placement

[kestrel]

Steve W, What do your cowling inlets look like?

If you guys would get real engines that put out some good horse power this wouldn't be an issue/question; the cooler would be bolted to the engine case...
Totally kidding by the way

I didn't know you were running above 260HP with that 360 of yours?!

[Battson]

This is the setup I finished up with:

The duct is too long for an engine with electronic ignition installed. It was fine with conventional magnetos. I fly around 90 to 95% of red line temp, but it takes an hour to get that hot and it does go any higher. So it is no problem. Prolonged flight at slow speeds leads to oil temps going to the red line, this is very rare though. A short power-off descent fixes this very quickly.

20140905_231005.jpg

[Steve W]

This was taken during mock up to see where it would be in relation to the inlet. I don’t have any sense I finished the baffle. I did this on other installs. The complete cooler and lines, which run on top of the engine, are in cooling air which really keeps the temps down. Sometimes too much requiring a plate to cover the front to get the temps back up in mid outside temps. This engine has piston coolers so I think I will need all the help I can get.

[svyolo]

I got the oil cooler where I want it, and made poor version of a shroud. I only finished the shroud to see if it would fit. It is a Positech oil cooler. I bought a 4 inch duct when I got my Van's tin kit, and a 3 inch from ACS. Most of the oil coolers and shrouds I have seen have 4 inch scat tubes. Is 3" enough? 4" is almost double the volume. I would rather leave that air for engine cooling.

[jaredyates]

The only way to know for sure is testing. Personally, I used 4" sceet and it's still nearly marginal. If at all possible, you want to put the curves in fiberglass and only run the duct in straight shots. It gets really wrinkly and turbulent when bent, especially scat single wall tubing.

[svyolo]

Thanks. I might make the duct face of both the oil cooler and engine tin easily changeable to 3 or 4 inch.
Lots of variables. As long as the oil is cool enough, I would rather give the air to the engine. 3 inch is 7 square inches, 4 inch is over 12. That is lots more air.

[jaredyates]

You can always block off some of the flow if necessary. Slower air through a bigger pipe is probably less drag, but more weight ans lost space.

[svyolo]

Yeah, I think I will go with that Jared. Thanks.

[Aero_tango]

Hello All, to resurrect this thread I would like to ask for a survey of sorts. Would those who have already found a successful arrangement for a -540 powered 4 place please post which make/model of oil cooler is installed and which method of installation you have used (I.E. installed on the baffle, engine mount, firewall, etc.)? I am curious if the answer I am looking at is also where most others have wound up, especially those with multiple iterations. Thank you much!

O-540 carb, Van’s diffuser mounted on fwall, Aero-Classic cooler model 8000215, 4’´ scat tube
Oil temp always been on the low side, even in summer, barely reaching 180F. I’ve installed a butterfly valve couple months ago, and i can now up the temp where it needs to be.

A4255B10-1A34-4693-8F12-C749A6A98EC6.png

322AEB3D-337C-4ECF-A346-7306C0245AE2.jpeg

Mike

[AKKen07]

Thanks Mike!

[svyolo]

I tried to figure out how to support the oil cooler off the baffle, but couldn't figure out how to support the inboard side of the baffle. The coolers are heavy. It seemed easier just to mount it to the engine mount (or firewall). I hung mine low to get it out of the way. It is not a preflight or normal service item. I can see and access the connections from above if needed. Remote oil filter above.

Someday I will get to see how it all works.

[Battson]

I got the oil cooler where I want it, and made poor version of a shroud. I only finished the shroud to see if it would fit. It is a Positech oil cooler. I bought a 4 inch duct when I got my Van's tin kit, and a 3 inch from ACS. Most of the oil coolers and shrouds I have seen have 4 inch scat tubes. Is 3" enough? 4" is almost double the volume. I would rather leave that air for engine cooling.

3" is acceptable for traditional ignition only, based on my experience. It would run warm in winter and hot in summer, our weather varies from about 32 degrees Celsius to -5 (20 to 90 Fahrenheit).

4" duct is definitely required for electronic ignition, especially in hot weather. Else it will overheat after an hour or two of flight.

Remember that longer ducts and ducts with bends will perform poorly compared to short straight ducts.

[Nev]

A4255B10-1A34-4693-8F12-C749A6A98EC6.png

I quite like aero_tango’s setup above where the oil cooler is firewall mounted and am considering this for my own installation. (Thanks for the helpful pics).

Has anyone tried using a NACA vent in the lower cowling to supply air to a firewall mounted oil cooler instead of a scat tube from the cylinder baffles ?

[svyolo]

Nev;
Several other BH's have the same mounting. I think it might be what comes with the Van's RV-10 kit. If I was going to do it again, that is what I would do. I know some EAB installations that use external air for the oil cooler. I am planning on using a NACA for cabin heat.

[Nev]

John, thanks. I’ve got the Vans firewall forward kit so it may include the firewall mount, not certain of this yet (all sitting in Marks warehouse currently).
I’m also considering something similar to your idea - a NACA duct for fresh air and cabin heat. I figure the ducts could be located very close to the air vents themselves, and the heat muffler inlet.

[zkelley2]

I was thinking about a naca duct as well for oil cooling. To provide more air for the cylinders instead of taking it from up there. Problem is I have yet to find a large naca duct to do it.

[Nev]

I was thinking about a naca duct as well for oil cooling. To provide more air for the cylinders instead of taking it from up there. Problem is I have yet to find a large naca duct to do it.

I was thinking of making the NACA ducts out of fibre-glass or carbon fibre. I’ll most likely do this, they’re small pieces and if it takes longer than I planned it’s not a show stopper.

Mike Patey shows how he does it on his Draco videos. He also shows a rather clever way of building them into a carbon fibre cowling. Mike also moulds the air filter compartment into the nose cowling. Same with his oil coolers.

While carbon fibre cowlings would be nice for a number of reasons, it’d increase the build time for me a lot so I’m planning original aluminum cowls.

[zkelley2]

Ya, making them would be a much larger project than I'm going to take on at the moment. I'd rather buy one and install it.
As far as making the cowl out of carbon, I'd advise against that if it took a single pound off the nose. Hell I'd consider making them from steel if I was to re-do it.

[Nev]

I agree, wouldn’t do it for weight savings. But the ability to mould various ducts and housings into the inside of the cowling is an appealing thought.

[svyolo]

The pictures of oil cooler NACA ducts that I saw they looked fairly big. I don't know if I have seen that big either.

[Nev]

https://www.competitionsupplies.com/aps-air-inlet-scoops-and-naca-ducts

The automotive racing suppliers have them. I’ve found 75mm - roughly 3 inches. I don’t know if this is suitable for an oil cooler. I’m guessing if it’s clean outside air instead of from via the engine intake it should be a few degrees cooler..

[svyolo]

I did find some 4" ones but they were spendy. So much so I would probably make my own. They were 250-300 USD.