Mailing List flyrotary@lancaironline.net Message #66808
From: Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Oil Cooler sizing
Date: Thu, 13 May 2021 19:51:01 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
4x5"oval inlet, about 17 sq in. Close to ideal diffuser.
CX Racing 11" 25 row knockoff. 2" thick, 76" sq in area.

So far no oil temp problems, but then I don't think I've gotten close to my 190 HP target. Overpropped for climb. (76x88 prop)
Max engine RPM straight and level about 6,400 @ 5,000' and 65F OAT. 170mph TAS. Engine monitor showed14.7 GPH, but looks like that's 50% higher than actual. So more like 10 GPH and 120 HP. That produced 210F oil temp in and 225 oil pan oil temp.
RV-4 with no gear leg fairings nor wheel pants, so looks promising.
Note that I don't fully trust oil in temp; probe is mounted in alum bock mounted on engine close to coolant passages, so could be subject to some heating by engine block.

Finn

On 5/13/2021 5:00 PM, Matt Boiteau mattboiteau@gmail.com wrote:
I'm trying to tackle the oil cooling. Currently have a CX racing 11x9x2 (https://www.cxracing.com/oil-cooler-kit/OC-248-30-AN10)

On a 30C / 85F day in FL @ 2200rpm cruising
Coolant is 180 outlet / 170 inlet 
Oil is 225-230 pan / 200 inlet / 215 PSRU. 

I use Valvoline VR1 20W-50 standard oil, and have synthetic sitting on the shelf ready to go. Since we can't post much in pictures here, I put a video on youtube of the setup. The cowl inlet is 4" and the opening to the start of the wedge is 3". I added some turning vanes to help the wedge shape send more air to the front, but didn't change the temps too much.  

The only thing left to do is increase the opening on the wedge. I could probably get away with a 5" opening. If that doesn't work, then time to source out a bigger rad. What sizes are you guys running?

https://www.youtube.com/watch?v=ONO4bJvw5rc


- Matt Boiteau





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