1450 Btu/min seems high to me. That is
35HP. Where do these numbers come
from, do others agree with this number?
Alex Madsen
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Al Gietzen
Sent: Tuesday, December 21, 2004
10:32 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil
Coolers
Subject:
[FlyRotary] Oil Coolers
I have
found some really nice oil coolers for aircraft (and other) at
http://lytron.com/standard/he_aluminum.asp They are a little expensive but are
suppose to have great performance.
Does
anyone know how much what the average oil flow rate of the 13b is (Gal/hour)
and the required heat dissipation (W) or (BTU/hour)
Alex
Madsen
Alex;
Heat
dissipation to the oil is between 10 and 11 Btu/min per hp. My opinion is
to design for about 75-80% power, so for a NA 13B figure about 1450 Btu/min.
I’ve
seen different oil flow rate curves that don’t quite agree; but best
figure about 12 gpm at 5000 rpm, and fairly linear with RPM up to that point,
maybe hits 15-16 gpm at 6500. I’ve seen one dyno curve that maxed out
at about 11 gpm; who knows –different pump, different back pressure.
One
issue for us with rotarys is the flow rate 30% or so higher than the typical
piston engine; so its worth checking the flow – pressure drop data for
“stock” coolers designed for piston engine use.
Al