Summer temperatures and cooling

[Bryan Cotton]

As the calendar rolls around to summer in my first year of flying, I'm starting to have issues. Pattern work with 2 people above 80F isn't working out. Oil temps are getting to around 230F and I got CHTs approaching 400F for the first time. Plus it's so hot under the cowl that the burps on the ground are ugly.

I've just ordered a set of B model outlets and are going to add them to what I already have.

[GordonTurner]

Hi Brian

Looking forward to your cowling exhaust mods documentation. I’m planning to start with only these vents, hoping the lower pressure at the fuselage sides will lead to more airflow with less drag.

Gordon

[daleandee]

Hi Brian

Looking forward to your cowling exhaust mods documentation. I’m planning to start with only these vents, hoping the lower pressure at the fuselage sides will lead to more airflow with less drag.

Gordon

Hi Gordon,

Just a heads up with the Corvair in a Sonex airframe as they tend to cool very well. My summer CHTs (under the plugs) read about 225ºF. Oil temp (with stock GM 12 plate cooler) runs 200-210 in the summer months. I did get it close to 230ºF in a steady climb with two on board. I use Rotella 15W40 and have seen evidence that it is not harmed at those temps at all.

I asked Dan Weseman about the cool temps with my Cleanex and he asked what problem I was trying to solve. 8~) He reported his Cleanex was the same way with the cool CHTs.

[Rick524]

Hi Bryan, I made side vents for my 'A' Sonex on my cnc router. I can send you the Vcarve files if you are interested.

Rick
Sonex 524

[Bryan Cotton]

Hi Bryan, I made side vents for my 'A' Sonex on my cnc router. I can send you the Vcarve files if you are interested.

Rick
Sonex 524

Rick, sounds good thanks.

[Rick524]

i guess the best way to send the files would be via email, if you want to pm me your address.

Rick
Sonex 524

[Rick524]

Got it, should have checked the pm before I answered.....duh.

[AlexZ]

Above 80F the Aerovee powered Sonex is basically a one seater. Flying with 2 onboard is possible, but only with a shallow climb out. Don't do pattern work. Temps will built up and ruin your cylinder heads.
I designed side vents as sheet metal.

Side-vent-Sheetmetal-4.jpg (40.29 KiB) Viewed 12650 times

Side-vent-Sheetmetal-5.jpg (75.08 KiB) Viewed 12650 times

Can send drawings.

[Bryan Cotton]

Got the files, thanks Rick!

Alex, looks great, I'll pm you my email address.

[Bryan Cotton]

Had some email exchange with Mark Schiable. He did not recommend running both A and B model outlets together. I bought a set of B outlets from Sonex but am holding off.

One other thing, my oil pressures have always been high - like 90-100 psi at startup depending on temp. Cruise was 70 psi on my long Tennessee trip. The Aerovee manual says 40-50 in cruise. My understanding of the VW oil system is that low pressure allows oil to go through the cooler, and maybe I've not been getting that. So I took out and polished both plungers, then cut a half loop off the pressure regulation spring. That is the short one near the back of the engine, away from the oil pump. On the last flight I saw 60-65 psi and ~220F. I'm going to cut off another half loop.