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Message-ID: <20060710181037.2317.qmail@web30102.mail.mud.yahoo.com>
Date: Mon, 10 Jul 2006 11:10:37 -0700 (PDT)
From: Steve Brooks <prvt_pilot@yahoo.com>
Subject: Re: [FlyRotary] Re: Temperature control
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-1231125@logan.com>
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Ed,
While you're on the subject of cooling, I have a
question.

What are you temps on takeoff when you are starting
with a hot engine ?

This weekend, I flew and the OAT on takeoff was about
75 F.  Climbing up about 1500 AGL my coolant was at
200 and oil about 180.  Both stabilized at about 190
in level flight.

I landed to check thing out and temps on shut down
were about 160.  Cooled off some on decent.

After sitting for 20 minutes or so, start up showed
about 185 and taxing to the runway. coolant was about
200 when starting the takeoff roll.  Climb to about
1000 AGL had the coolant up to 220, and oil about 200.
 I reduced power and continued a slow cruise climb
(about 200 fpm).  The temps came down withing 2-3
minutes to below 200, and stabilized to about 190
after 5 minutes or so.

Does this seem reasonable, or are my temps running a
bit high ?  I have always seemed to have temperature
problems when starting out with a hot engine. 

Just wondering about what is normal.

Steve Brooks


--- Ed Anderson <eanderson@carolina.rr.com> wrote:

> 
>   ----- Original Message ----- 
>   From: James Maher 
>   To: Rotary motors in aircraft 
>   Sent: Monday, July 10, 2006 1:28 PM
>   Subject: [FlyRotary] Temperature control
> 
> 
>   The setup:
>   ·        Engine/Model/Year: 13B 6 port NA mixed 
>   ·        Source Condition: David Atkins Rebuilt
> for Aviation Application  
>   ·        Modifications: Ported intakes and cooling
> for 180HP 
>   ·        Intake: Atkins short manifold w/TWM 48mm
> Throttle body 
>   ·        Exhaust: 321 SS tangential muffler 
>   ·        Engine Control: RWS EC2 
>   ·        Fuel Control: 4 Mazda 460cc Injectors,
> pri. in block & sec in manifold
>   ·        Fuel Pumps: RWS 
>   ·        Cooling System: 2 - 9"x13"GM evaporator
> cores with 0.75" auto hose, stock water pump with
> 180F deg.-thermostat, 50/50 glycol\water mix.
>   ·        Oil System: stock 1986 oil cooler 
>   ·        Installation: conventional - self built
> mount
>   ·        PSRU/Re-Drive: Ross 2.85:1 
>   ·        Prop: IVO Magnum 74" 45-105"pitch
> in-flight adjustable
>   ·        Power: 180HP?  
> 
>   The issue:
>   On the ground, cooling stabilizes at 180-190F deg
> and oil is usually 10 degrees below the cooling with
> an OAT of 65-70F deg.
>   When running with higher OAT (75-85F deg) after
> about 0.5 hours of moderate taxi runs (up to
> 4300RPM) the cooling temps reach 212Fdeg with the
> oil about 200F deg.
>    
>   The question:
>   Can something be done to get lower operating
> temperatures without redesigning the system?
>   Would switching to pure water help and if so by
> how much?
>   Would removing the thermostat help and if so by
> how much?
>   How much change should I expect if I were to do
> both?
>   You guys down south should have a good idea of how
> best to enhance cooling.
>   What are your suggestions?
>   Thanks,
>   Jim Maher(Dyke Delta)
> 
> 
>   Hi James,
> 
>   Welcome to the club, cooling appears to always be
> the first item of business.   I can not quantify the
> differences those changes you propose would make.
> 
>   However, a 50/50 coolant mixture has a 40% lower
> specific heat than pure water alone.  Meaning it
> will not carry as much heat away at the same coolant
> temperature.  Would pure water give you 40% more
> cooling - I personally doubt it, would it help, I
> believe it certainly would.
> 
>   I fly without a thermostat and my normal (60-70 F
> OAT) temps are 160F for coolant and oil at cruise. 
> On a hot day, right after take off, I may hit 200F
> on the oil and 220F on the coolant for a short
> duration.  With  a thermostat, your coolant temps
> are going to go right up to the thermostat limits
> shortly after starting your engine - after all that
> is what a thermostat does.  But, still at moderate
> rpm of 4300 on a 60-70F day, I would like for the
> coolant and oil not to exceed 200F.
> 
>   I fly without a thermostat to remove any flow
> restriction as well as permitting my temps to stay
> below any thermostat limit if conditions permit. 
> Since I get acceptable temperatures when flying I am
> satisfied without a thermostat.  In winter, the
> temps do run a bit cool, but then I can tape off a
> bit of the core and get higher temps.
> 
>   Ed
> 
> 
>   That's my 0.02 worth
> 
>   Ed
> 
>