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From: "Bryan" <bhcishere@comcast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-811640@logan.com>
Subject: Re: [FlyRotary] Re: FD coolant level sensor?
Date: Sat, 19 Mar 2005 11:36:04 -0800
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David,

Where and how did you install the air bleed at the high point of the cooling
system?

Bryan


> There are two kinds of cooling systems (kinds of "expansion tanks") as far
> as I know:  1) the one most people think of and talk about is a
> non-pressurized expansion tank that gets fluid when pressure "burps" past
> the radiator cap.  That is the kind where the fluid gets sucked back into
> radiator AFTER engine shutdown (IF there are no leaks anywhere to let AIR
> suck in - which would prevent sucking fluid from the expansion tank).
> 2) the 1998 or so Ford Contour system (and others) where "expansion
> tank"/"header tank" is pressurized (the pressure cap is on the tank, not
the
> radiator), and it has a tube going down out of the bottom of tank to a T
> fitting at bottom radiator hose; also there is a tiny "air bleed line" in
> the highest part of the engine (somewhere in the head at the top of the
> water passages) that slopes UP into the bottom of the "pressurized
expansion
> tank/header tank" - any air at top of engine would flow up into the tank
and
> would be replaced in the head by gravity flow of coolant into the system -
> coolant level in the expansion tank is slightly above the highest point in
> the head's coolant passages.
>
> This "Contour" system would be perfectly safe to have the "coolant level
> switch" in the tank.  There would be none of the dangers cited for systems
> that have the NON-pressurized exp tank.
>     -  Also, none of the "burping" several times after filling as there is
> with the "non-pressurized" tanks - in Contour system, you fill thru the
> "expansion tank" - fluid runs out bottom and fills entire radiator-engine
> block system from the bottom up, with (theoretically) NO air trapped in
any
> radiator or engine part as the fluid rises to top of head and then up into
> bottom of tank.  When fluid in the tank starts to rise, you know th engine
> and radiator system is full.  Of course, there could be "pockets"
somewhere
> or a hose that runs up and back down slightly where air could be trapped -
> so an engine run should move the air to top of system, where it would
bleed
> into the bottom of pressurized expansion tank, and "burping" would be
done.
>     -  This is what I'm designing for my RV-6/13B aircraft.
>
> David Carter
>