From: <daveleonard@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: One step forward and .9 steps back.
Date: Tue, 30 Mar 2004 22:54:25 -0500
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> =

> Keeping water level up to the pump and/or eliminating air up there:
> =

> I don't think there can be a problem with air in the rads or pump housi=
ng if
> the system is filled from the bottom - from a hose going down from the
> bottom of a "header" tank (pressurized expansion tank) that is at or ab=
ove
> the level of the top of the pump.
>     - The liquid will go in the bottom of the entire system and force a=
ir
> upward as liquid level rises 'from bottom', and assumng that there is a=

> bleed plug at highest spot in engine or pump (removed) or a peck cock v=
alve
> (opened) during filling.  (ideal would be to have a permanent bleed lin=
e
> from that high spot into an 'always-partially-filled header tank that a=
lways
> keeps the entire system full of liquid - air has to be expelled.
>     -  Given, there may be air traps somewhere in the system, but the l=
iquid
> will either bypass them - or purge them as it keeps rising until it com=
es
> out the "high point" (bleed plug hole or pet cock or bleed line connect=
ed
> there and going into the header/expansion tank).
> =

> If you don't have such a header tank, then there should be a way to plu=
mb in
> a "fill hose" that is fitted to the bottom of the system (such as a pet=
 cock
> with an appendage for putting on a piece of rubber tubing), with "fill =
hose"
> running up to be held above engine with funnel in it - or put top end o=
f
> fill hose on bottom of a siphon hose to siphon or pump out of your cout=
ainer
> of coolant.
>     -  Fill the system until liquid comes out top of system.  Close pet=
cock
> at bottom of system.  Remove fill hose and put it and your funnel and/o=
r
> siphon, or whatever away and then start engine runs to purge any remain=
ing
> air and keep topping off the liquid level as air is expelled.
> =

> Does this make sense?  I'm talking about NOT having what I consider the=

> ideal system (pressurized expansion tank with fill line going to lowest=
 spot
> in system and with air vents from highest point in system into expansio=
n
> tank below liquid level).  I'm only suggesting that whatever OTHER syst=
em
> you have, permanently install a fitting (valve or pet cock) at bottom s=
o you
> can temporarily install a removable fill line and, holding the top end =
of
> the fill line above the engine & pump, pour in coolant so it goes in at=
 the
> bottom until it comes out the high point.
> =

> David Carter

David,

Thanks for the input.  I agree that filling the system from the bottom sh=
ould remove most of the air.  I have a means of doing just that and used =
it most of the times I filled the system, including the time that there w=
as no coolant flow.  I also have a pressurized surge tank connected to th=
e high-point in the system.

I ran it about 5 times today for short periods trying to burp the system =
but there is still a sizeable pocket of air somewhere.  If I put 30 PSI o=
f pressure on the pressurized surge system it will push about a cup of co=
olant into the system, but only coolant comes back when the pressure is r=
elieved.  That=92s probably about 2 cups of air in there somewhere.  I=92=
ll just keep trying to burp the system.

Today I went and ran the system after removing the piece of stuck RTV.  C=
oolant flow still seems anemic because the sides of the rad barely get wa=
rm.  There was some flow, however.   Coolant temp (measured at the outlet=
) would be120 at low RPM and quickly drop to 90 at higher RPM (4000) and =
go back up shortly after reducing RPM again.  This says to me that the hi=
gher RPM was generating good coolant flow.

I still need another surge tank to catch all the overflow.  =


I also partially solved the problem of not running well on batteries.  I =
discovered today that turning off the alternator just makes the mixture a=
 little more lean (I don=92t know why yet).  But if I just turn up the mi=
xture about 90 deg it runs great off just the batteries.  Shouldn=92t be =
too hard to trouble-shoot now.

Thanks for all the help.

Dave Leonard