Mailing List flyrotary@lancaironline.net Message #11600
From: Steve Brooks <steve@tsisp.com>
Subject: RE: [FlyRotary] Re: Still high temperature
Date: Mon, 20 Sep 2004 06:14:38 -0400
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Al,
I am running the cores in series, and I agree that it appears to be insufficient cooling.  Since others are running the evaporator cores with no trouble.  I assume that the issue is air flow.  John Slade seems to have no trouble with his temperatures, and has the identical plane and scoop.  Actually I've added a front end to my scoop to get outside the boundary layer, but still have high temperatures.
 
I have a P-51 style scoop that I had put on earlier with the old cooling system.  I removed it when it didn't improve the cooling, but the old set up I think was beyond help.  Maybe I should try it with the new set up.
 
I was also wondering about any other factors causing excessive heat from the engine, like timing.  I haven't tried to retard the timing any, but I know that in piston engines, if you get the timing too advanced, it can result in allot of heat.
 
Steve Brooks
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Al Gietzen
Sent: Sunday, September 19, 2004 3:28 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Still high temperature

 

The high temps are indicating insufficient cooling capacity ( I guess that’s obvious); which means insufficient air flow or too little heat exchange area.  If others are getting adequate cooling at the same power with the same cores, then it is air flow.  As I recall, you are no longer running the coolers in series, but there still may be a pressure recovery issue with your scoop, or just too small an opening; more like the first.

 

After a few runs it seems that the air should be purged.  Do you have a means of checking (confirming your temps to be sure there isn’t some boiling going on?

 

Al

 

Subject: [FlyRotary] Still high temperature

 

I would appreciate input to a problem that I have.  I just overhauled the

engine, and reworked the cooling system.  I'm now using the A/C evaporator

cores for radiators.  The problem I'm having is, that when I take it up, I'm

seeing coolant and oil temperature of about 210 degrees.  That is climbing

to pattern, leveling off, and throttling back to low power.  The oil stays

pretty much where it is, and the coolant come down just a couple of degrees.

 

When throttle back to land, the coolant and oil both come down to about 180

at touchdown.  I taxi back to the hanger and shut down with oil and coolant

about 190-195, but after shut down, I get all sorts of gurgling noises from

the header tank, which is fed by the tap on the side of the thermostat

housing.  The gurgling noises go on for 5-6 minutes, which would seem like

the engine is overheated, but while hot, it doesn't seem overly hot. The

other end of the header tank feeds coolant to the turbo, so maybe the hot

water is coming from it ? Maybe my header tank should be fed differently ?

Also at this time, after a short flight, there is only a couple of cups of

additional coolant in the overflow tank.

 

I assume that the higher than desired coolant temperature, and the gurgling

noise are related.  I pulled the water pump off today to double check it,

and all seems OK.  The pump only has about 10 hours on it.  When I run it on

the ground, and feel the radiators after shutdown, they are uniformly hot.

I put a furnace blower pointed at the scoop, and I'm getting very even

airflow through the radiators.  The oil cooler, on the other hand, has about

75% of the air going through the middle of the cooler, so I'm going to have

to add some deflectors in the plenum to push more air to the outside.  That

seems to be a less significant issue at the present.

 

Any thoughts ?

 

Steve Brooks

Cozy MKIV

Turbo rotary

 

 

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