Cooling System

[13brv3]

Has anyone hear from the factory Rotax testing recently? They can't still be snowed in :-) I'd hope they'll try to standardize an approach that works for the side by side planes. The Onex has it's own problems with space.

Tinkering with inlets and outlets is part of the fun for me. I've got another CHT temp probe that I keep mounted inside the cowl, and periodically I repurpose one of my CHT inputs to connect to that probe instead for cowl temps. I have manifold pressure as well, and I will at some point open that hose to the cowl to try to determine how much pressure is inside the cowl. From that, I can test inlets vs outlet sizes. All in good fun.

[Skippydiesel]

I am reworking the radiator intake to allow more airflow and will post some photos in about two weeks after i return from some travels. I will also post some photos of the exit air outlet. I am wondering in the Sonex B side outlets would be beneficial for the cooling?

Jake

I don't know if you have ever seen photos of Robin Austin's world record braking Sonerai SGS & now his new varient SRS http://worldrecordplane.com/. His cowling inlets are small - unfortunately I don't think there are any photos of the exit air treatment. My guess his cowling design is to give negative (to outside air)under cowl pressure so as to optimise the air flow through the radiator & oil cooler - he probably has some sort of movable cowl flap, to accommodate the cooling demands of ground and altitude ie he can vary the exit air aperture.

Of particular note is how few & small are his air inlets are and the internal size of the cowling - you might think he would have engine heating issues - apparently not

[SonexN76ET]

I seem to have my ground cooling under control now. In 95 degree temperatures here in Florida I was unable to get it to overheat in my ground testing after these modifications.

-Enlarged both the cooling inlets and outlets as shown in the photos.
-Oriented the radiator to allow airflow to be exactly in line with the cooling vanes.
-Placed radiator hose springs in the radiator hoses where there any any bends.
-Replaced 90 degree bends in radiator hoses with 45 degree bends.
-Sealed all inlet gaps leading to radiator.
-Put lips and seals on inlet channel to provide smooth airflow to radiator.

I am still in the process of cleaning up the modifications as I was doing lots of trial and error to get it right. I hope to get in the air to test it out in the next few days.

Jake

[Skippydiesel]

Good "stuff" Jake.

My Sonex is back in the workshop - I have removed the Radiator & Oil Cooler pending relocation of both.

Radiator will move from base of firewall to front of cowling - exact location & orientation still under consideration.

Oil Cooler- initial thoughts have the oil cooler moving from front of cowl to roughly same position as Radiator moved from. This is not as contradictory as you might think. Radiator relocation has resulted in Radiator sized exit air hole (previously restricted by Radiator). Previously the Radiator completely filled the exit air hole , the Cooler will be located in front of the hole (not in it). I have also acquired the Rotax Extra Large Oil Radiator (Cooler) which is about 3 coolant tubes larger than the current Large. Its hoped that the combination (larger cooler/exit air hole) will bring my summer operating temperatures down to the low 90C's (I live in hope).

[CaseyCooper]

Hey guys,
I don’t check this all that often to see updates, but I’m very much enjoying seeing everyone’s installations! Many great ideas and construction. I hope everyone is doing well, making progress and building hours! Currently I haven’t changed my system in a year and half (doesn’t seem like that long) and a few hundred hours with this set up. On the way to Oshkosh this year, I encountered 90 degrees, 10,500ft DA, and pressures of 30.39 on the ground in New Mexico. Over 100 degrees in other places. Overall I flew for 10 hours straight some days, straight through the heat of the day and conditions. At full gross, 5,300rpm-5,500rpm cruise, I never got over 225 cht and 220 oil temp no matter what I did. I was very happy. I am finally convinced I have nothing to do to my engine setup whatsoever. But I would like to finish my cool air intake. I did some more flight testing at home during the summer (on days over 100 degrees), I can’t get the engine above 180 cht and 140 oil temp sitting on the ground. In a full power climb, at about 80 mph (repeated about 3 times) for about 5 minutes, I got a maximum of 230 cht and 225 oil temp trying all I could to heat it up. The purpose is I’m thinking of producing my own firewall forward kits (while still ensuring people use the components made by Sonex), or just small component kits depending on what people need. However it’s restricted to conventional gear, Legacy models currently. I may do a B model, and a tri gear soon to try and iron those out also. But, I would like to get some better information on how it’s set up (pictures/video/commentary) and try my best to help the community. I have spoken to the guys at Sonex a little lately, and they may try some variation of how mine is set up. But more information will be coming soon!
Again, I truly adore seeing everyone’s hard work and innovation, and such a diverse community!

[Skippydiesel]

UPDATE!

First flight after cooling (& unrelated) mods a week ago.

Ambient 30+C on ground. 22C @ 6500ft.
60 minute flight
Oil - 72C on ground. 105C on Climb Out. 94 -97C in Cruise.
Coolant - 72C on ground. In Cruise 82C
DELIGHTED!!!!!

Brief Mod Description;

Coolant Radiator - Moved from rear of cowling/under lower firewall, fed/restricting ALL exit air from cowling. Relocated to forward, under gearbox/exhaust pipes, fed with ambient air through new scoop in cowling - no sealing/ducting.
Oil Cooler - Rotax Large Cooler, moved from under gearbox, fed ducted ambient, air exiting through duct (seperate air system to cowling). Installed Rotax Extra Large in cowling exit air - no sealing/ducting.

I now expect there to be overcooling in winter - my initial plan is to modify the cowl flap, so that it will provide a restriction when closed. The restrictor will be removed for summer sorties. The restrictor may help with drag by increasing exit air velocity.

[Murray Parr]

UPDATE!

First flight after cooling (& unrelated) mods a week ago.

Ambient 30+C on ground. 22C @ 6500ft.
60 minute flight
Oil - 72C on ground. 105C on Climb Out. 94 -97C in Cruise.
Coolant - 72C on ground. In Cruise 82C
DELIGHTED!!!!!

Brief Mod Description;

Coolant Radiator - Moved from rear of cowling/under lower firewall, fed/restricting ALL exit air from cowling. Relocated to forward, under gearbox/exhaust pipes, fed with ambient air through new scoop in cowling - no sealing/ducting.
Oil Cooler - Rotax Large Cooler, moved from under gearbox, fed ducted ambient, air exiting through duct (seperate air system to cowling). Installed Rotax Extra Large in cowling exit air - no sealing/ducting.

I now expect there to be overcooling in winter - my initial plan is to modify the cowl flap, so that it will provide a restriction when closed. The restrictor will be removed for summer sorties. The restrictor may help with drag by increasing exit air velocity.

Lots of pictures please, I am hoping to plagiarize any successful design...

[13brv3]

I missed this yesterday. Sounds like great progress. Congrats!
Rusty

[Skippydiesel]

UPDATE!

Lots of pictures please, I am hoping to plagiarize any successful design...

Would if I could - tried to send photos' when I first joined the Forum - never worked.

Can email you

[Skippydiesel]

UPDATE!

Can email you

Hope you were able to make sence of the photos'