Cooling System

[Murray Parr]

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I placed the oil cooler in between the engine mount tubes and also had room to attach the oil canister.

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The 3" scat is almost direct to the cooler, I will most likely build a NACA duct for this in the future

[Murray Parr]

Same deal with the radiator, not really much room anywhere else

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I built a fresh air duct attached to the cowl, attached piano hinged air deflectors sealed up against the cowl and radiator

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This arrangement was a blend of 2 other peoples designs and they might chime in here, Brett and Gary B they both told me it is sufficient in the air but don't dawdle too long taxiing around. I haven't flight tested it yet but it does seem to get hot rather quickly on the ground stationary while doing full power tests. Interestingly, it cools great without the cowl on and not so great with either full cowl or just the bottom cowl. This tells me that the fresh air duct is a bit too close to the center of the prop so I might add a naca duct inside the fresh air duct and scat tube it directly at the radiator.

[Murray Parr]

Just to add to my above posts, I am not a fan of placing coolers in series or ducting the hot cowl air through them. Contrary to common belief, these systems are air cooled, a lot of folks believe the coolant is doing the cooling but it is the air flowing through the cooling fins that removes the heat from the coolant or oil.

[Skippydiesel]

Here is another install that has similarities with the Sonex cowl/engine;

http://www.stoneylake.org/pipcom/912cooling.htm

[Skippydiesel]

Just to field something more to mull over:

When Edge tested out his original EFI setup, it was done on his Sonex Legacy (#037). This engine had a turbo, an aftercoolder, and a CS prop. See pic below (never mind the non standard windshield and canopy). Incidentally, this airplane originally had a VW Aeroconversions engine under its universal Sonex cowling, so this was the starting point for the conversion.

The fairly large coolant radiator that the 912 requires, was a bother to position under the existing original cowling- there was just not enough space with all that other hardware. The bright idea then came up to have two identical radiators manufactured, with a total grid identical to that of the standard radiator. It would then be fairly easy two find space for these two rads behind the existing cooling air intakes. Incidentally, these rads were then hooked up in series and installed with selv made brackets on the front of the gear housing, just behind the prop flange. The pic should give some idea of the setup.

The intake side of the cowling had to be slightly doctored, but this work was minor. To the best of my knowledge, there have been no cooling issues.

Hi Kai,

Yeah! this is very similar to the Europa installation. The twin radiators lend themselves to a small cowl frontal area. The down side is a small increase in weight and a large increase in connections/failure points. I could still adopt this concept.

There is/was a Sonex, on the Airmaster web site, that has the twin coolant radiator concept (Owner Thomas Hauklien of Edge Performance) https://www.propellor.com/

Cant quite make out for sure where they have placed the oil cooler - can you enlighten me?

[Skippydiesel]

This arrangement was a blend of 2 other peoples designs and they might chime in here, Brett and Gary B they both told me it is sufficient in the air but don't dawdle too long taxiing around. I haven't flight tested it yet but it does seem to get hot rather quickly on the ground stationary while doing full power tests. Interestingly, it cools great without the cowl on and not so great with either full cowl or just the bottom cowl. This tells me that the fresh air duct is a bit too close to the center of the prop so I might add a naca duct inside the fresh air duct and scat tube it directly at the radiator.[/quote]

Hi Murray,

Great work!
Ref your oil cooler; It looks to be regular LyCon style, quite diffrent from the Rotax offering.
The one I have in the Sonex is probably 1/2 as big again, as the one I had in my Zephyr. The Zephyr one, located on the firewall, down near the air exit, without ducting/shroud of any kind, overcooled in winter, just about right in summer (95C in cruise) - My Sonex one is struggling to keep cruise temperatures below 110C and it has a dedicated air in/out circuit - something is wrong!

[Murray Parr]

Hi Murray,

Great work!
Ref your oil cooler; It looks to be regular LyCon style, quite diffrent from the Rotax offering.
The one I have in the Sonex is probably 1/2 as big again, as the one I had in my Zephyr. The Zephyr one, located on the firewall, down near the air exit, without ducting/shroud of any kind, overcooled in winter, just about right in summer (95C in cruise) - My Sonex one is struggling to keep cruise temperatures below 110C and it has a dedicated air in/out circuit - something is wrong![/quote]

My oil cooler came with a VW engine I used to have, maybe it will be too small but so far it cools well on the ground, probably needs longer run times to get the oil temp high though.

For your cooler, maybe confirm the temp quage is accurate first. I wouldn't be too worried about 110c though

[Skippydiesel]

Hi Murray,

The 110C can only be maintained with constant care/attention and in cool air - I had to return to base the other day when encountering 30C at 4500 ft - oil temp went up to 120C before I reduced power and slowly descended back for a landing.

My oil/coolant/head cruise temperature goal, is to have consistent sub 100C (Australian summer, although a rarely fly above 30C ambient) . In climb, I am comfortable with temps up to/not above 120C.

I would very much prefer to have an over cooling situation in winter, that needs to be managed by temporarily reducing heat exchanger/air flow efficiency, than a system that wont allow worry free summer operations.

[Kai]

Hi Kai,

Yeah! this is very similar to the Europa installation. The twin radiators lend themselves to a small cowl frontal area. The down side is a small increase in weight and a large increase in connections/failure points. I could still adopt this concept.

There is/was a Sonex, on the Airmaster web site, that has the twin coolant radiator concept (Owner Thomas Hauklien of Edge Performance) https://www.propellor.com/

Cant quite make out for sure where they have placed the oil cooler - can you enlighten me?

Consider yourself enlightened: look closely at the oil tank in the picture- next to it you see a vertical squarish object. That is the cooling air collector/hood for the automotive oil cooler, fed with 2 in scat hoses (not in the pic). Also in view are the (capped) blue AN type elbow connectors for the lubeoil in and out of the cooler. Personally I am not in favour of using automotive style coolers in aircraft installations: their cooling grids are often too dense for the much higer airspeed encountered here. However, I must admit, that very often they seem to work quite well.

[Skippydiesel]

So does anyone know of a reputable supplier ???????