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Reply-To: "David Carter" <dcarter@datarecall.net>
From: "David Carter" <dcarter@datarecall.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-811691@logan.com>
Subject: Re: [FlyRotary] Re: FD coolant level sensor?
Date: Sat, 19 Mar 2005 14:17:48 -0600
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Gotcha - you thought I actually had a system!  It's all in my head (and a
huge bunch of e-mails I've saved in various folders)!

I should have said, "It is what I 'want' or 'plan' to implement.

I do have my two junk yard evap cores - looking for someone to weld on 1"
dia  tubing or fittings.

On a 13B (RX-7 or RX-8 - I'm planning to buy an RX-8 engine)  in my tail
dragger RV-6 with engine mounted so transmission end of engine is fwd with
Tracy's 2.85 PSRU, I'll want a hole in the "back housing" (up front in
airplane) at top of water jacket.  I have no idea if there is any hole there
in the production engine.  Tracy?
    -  I believe the coolant pressure should be higher at that point than at
the outlet of radiators/inlet to water pump - inlet to pump should be lowest
pressure in system (and this should be the pressure int the expansion/header
tank which is plumbed directly to that point), so I expect some coninuous
flow of coolant through the "high point bleed line into the tank and then
down into main hose going to inlet of pump.  Since this flow will be
bypassing the radiators, there needs to be a restrictor in the line, just
line there is a restrictor in a "mechanical oil pressure gage's line from
the engine to the gage" - to prevent much flow if line cracks.  In this
coolant case, the worry is not cracking, just the fact we know there is some
coolant bypassing the radiator - so flow must be low, just good enough to
pass air during filling - and steam during high power/too hot?

David

----- Original Message ----- 
From: "Bryan" <bhcishere@comcast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, March 19, 2005 1:36 PM
Subject: [FlyRotary] Re: FD coolant level sensor?


> 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
> >
>
>
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>
>