REFLECTOR: Oil Cooling Capacity

[Chuck Jensen]

Brett,

My own experience is 1) with two and the nose pseudo-NACA pushing air through front oil cooler, I don't think I ever saw 200F under any circumstances.  The downside was, there flow through the front oil cooler was so great, it's use as a heater was nil.  2) with the NACA eliminated and air pushed through the front oil cooler, and the air dumped overboard or into cabin for heat, 195F-210F is typical and can go higher during hot or long climbs.  3) with the blower turned off, oil temps run 215F-225F and can go as high as 240F during climb or cruise at altitude in warm weather. In short, I cannot run with one oil cooler (300hp).

I'll probably make one last change to my configuration.  I'll put a Van's air diverter valve in the fresh air hose that current provides panel eyeball cooling from the remaining nose NACA.  In hot weather, particularly during a climb, I'll direct much of the air from the NACA through the oil cooler with just enough directed to cabin to keep the occupants comfortable.  The overhead plenum is okay, it provides a lot of air, but it blows on your head, whereas the panel eyeball can be directed to the lower torso area---much more comfortable.

This will allow better oil cooling, when needed, yet retain the ability to use the bilge blower to circulate cabin air through the oil cooler for cabin heat.

Ken Mishler reshaped the front oil cooler outlet area.  When it is flush, it definitely is a high pressure area and the air wanted to back up through the oil cooler, or it was near neutral.  Ken shaped a ramped lip on the front of the opening and tapered it back.  It did a good job of creating a low pressure area because the air is definitely drawn overboard through the oil cooler, so the shape of the outlet is important--no speed difference noted.

Chuck Jensen



-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of Brett Ferrell
Sent: Monday, October 12, 2009 8:07 AM
To: reflector
Subject: Re: REFLECTOR: Oil Cooling Capacity


Chuck,

That's a great question (and one that I asked recently).  It seems that most folks are running two.  It also seems that 1 is probably sufficient for oil cooling.  VV#11 seems to indicate that bubba originally flew with just one and had acceptable temps (http://n44vf.velocityxl.com/articles/views/full/V11.pdf), and the Cozy 540 guys tell me the same, that they installed the second for cabin heating.  Klaus also mentioned seeing a failed oil pump in a long-tubing-run-to-the-nose installation, he felt was caused from the excessive friction.

So, since we had our little issue with the nose cooler, I'm going to *try* and run without the nose cooler and see if I can maintain good oil temps, and if I can seal the airplane sufficiently that the electric heat I can squeeze out of my alternators can keep Unit 2 (Elizabeth) adequately warmed....

Brett

> Curious. Is anyone running an IO-540, 260 or 300 hp, using a single oil cooler, or do all of these installations use two?
> 
> Chuck Jensen 
_______________________________________________
To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html