Ed as you so deftly have pointed out, the procedure for getting the air out of an RV-3 (tail wheel) is a bit more involved than those with the training wheel up front (RV-6A).

Radiators become the highest point in the system with tail down.
This time I put the extra (original) holes in the raditors up and out, with 1/8" NPT plugs in them (with JB Weld as a bit too small). Haven't used those bleeds yet, though.

Finn

Ed Anderson wrote:

 

----- Original Message -----

From: <13brv3@bellsouth.net>

To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

Sent: Wednesday, March 03, 2004 10:48 AM

Subject: [FlyRotary] Re: Ideal Cooling System Plumbing (was Re: [FlyRotary] Re: overflow connections

> > Now I think I have a reasonable explanation:  He had air trapped somewhere
> > in the top of his rad/cores or hoses in that vicinity, which impaired his
> > cooling; then by reversing "in and out", he started moving the air or air
> > bubbles out with the flow.  Makes sense to me and solidifies my position
> > that my hot coolant from the engine will enter the BOTTOM of  both of my
> > cores via a Y or splitter in between them, and exit at the TOP of each, into
> > another Y.
>
> I have my inlets and outlets for both cores on the bottom, so the top would seem to have great potential for trapped air.  I was thinking of addind a bleed port on the top of the cores, but Ed talked me out of it (and will be in trouble if this doesn't work <g>).  His is set up the same way, and he has no problems with air being permanently trapped.  Since I'll have a coolant pressure gauge with the new setup (thanks to the EM-2), I should be able to tell if there is air in the system by how fast the pressure comes up with temp. 
>
> I have to admit that I'm still mighty tempted to add a couple small bleed ports while it's still easy to do. 
>
> Cheers,
> Rusty (any excuse to weld something)
>

 

Oh, yea of little faith.  You will need to burp the engine a couple/three times to get all the air out of the cores.  But, by all means if your welding skills with very thin wall and brazed (lower melting temp than aluminum) aluminum cores are up to the task then bleeds will eliminate the need to do the burping runs.  Good luck {:>).

 

Ed.