flyrotary@lancaironline.net Mailing List Archive

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)