Jim,

I’m not sure I’d be = real concerned about the cooling you’re getting on the ground. Your = normal operation will be at lower power settings on the ground and 90% of the = time will be for a much shorter duration. See what kind of cooling you = get at a slow taxi and idle. If you get stuck at OSH or somewhere else in a line for takeoff you will be sitting for long = stretches at idle. If your engine can handle that – then all you need to = worry about is climb and cruise cooling.

I think my setup responds about the = same as yours – except I have an electric fan that I can kick on to = help with the water cooling if I’m doing high RPM runs on the = ground.

Joe = Hull

Cozy Mk-IV (45 hrs - Rotary 13B = NA)

Redmond (Seattle), Washington

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of James Maher
Sent: Monday, July 10, = 2006 10:28 AM
To: Rotary motors in aircraft
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)