flyrotary@lancaironline.net Mailing List Archive

Tracy and All, Now that the 2.85 RD1C is looking good do you think we should address the question of water pump speeds. With the Racing Beat eccentric shaft pulley the pump is seeing approximately the same RPM as the engine. As I recall the stock pump begins to cavitate as it approaches 7000 RPM. Can you tell us what engine RPM you were running at the Sun 100? Kelly Troyer (Thrilled at the performance of the RD1C) -- Dyke Delta/13B/RD1C/EC2 (Eventually)

From:	Tracy Crook <lors01@msn.com>
Subject:	[FlyRotary] Re: water coolant percentages
Date:	Tue, 20 Apr 2004 01:49:44 +0000
To:	Rotary motors in aircraft <flyrotary@lancaironline.net>

----- Original Message -----

From: Bill Dube

Sent: Monday, April 19, 2004 4:47 PM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: water coolant percentages

If you dont need the high freeze protection, Id opt for corrosion inhibitors in a solution of maybe 25-30% e-g in water (for some increase in boiling point), and a pressure cap of 22-25 psig.

        As noted earlier, all airplanes need freeze protection. I was flying recently in Tampa at night and the temperature at 15,000 ft was something like -10 Celsius.

        Water will often freeze in the radiator if you do not have anti-freeze, even if the engine is warm. The freeze will start in a low flow (water) region and will then spread as the flow is further blocked, perhaps bursting radiator tubes as it progresses.


I suppose this might be possible at a low power setting and while using a thermostat. The problem can be completely avoided if you use a cowl flap for temperature control instead of thermostat. Restrict the airflow through the rad and the coolant stays hot. Reduced cooling drag is a bonus too.

Tracy