My Velocity 20B has
a radiator in the cowl, a second radiator in the wing root, and an oil cooler
in the wing root on the other side. Without going into detail (covered here
before) the airflow through the in-cowl rad is very effective, and that through
the wing root coolers is not very effective.
In-cowl rad: 176 sq in area, 440 cube in volume
Wing rad: 132 “ “ “ , 363 “
“ “
Oil cooler: 114 “ “ “ , 382 “
“ “
The coolant plumbing in and out of the engine is 1 ½”
dia; which divides into 1 ¼” lines to each of the rads.
That cooling of the coolant is entirely adequate; on a 70F
day maybe max of 195 -200 on extended climb; about 160-165 cruise. Oil temp
gets up to 225F on climb, drops to about 185-190 cruise. Above 70F OAT the 220
limit on oil temp limits climb rate. I am about to take some action to improve
oil cooling, probably adding an oil to coolant exchanger and possible other
changes.
Based on temp measurements, because of poor air flow the
wing root rad is dissipating roughly 20-25 of the coolant heat load; so my “effective”
volume is about 560 cu. in.; or about 2.1 cu in per ‘rated’ sea
level HP; but more like 3 – 3.5 cu in per actual cruise HP.
The oil cooler is about 1.4 cu in per rated hp and about
2.5 cu in per cruise hp. The cooler could/should dissipate 30-40% more heat
load with fully effective ram scoop.
Probably more than you ever wanted to know about my setupJ
Al
Subject: [FlyRotary]
Re: Cooling the 20B
How thick (Dimensions) is your
radiator, and what size hoses are you running? Thinking of surface mounting the
feed and return lines, and the best way to do that.
----- Original Message -----
Sent: Saturday, March
01, 2008 9:55 AM
Subject: [FlyRotary]
Re: Cooling the 20B
I meant to
attach this photo of the fan installation to the previous post.
Al
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