Yes, I too will be wary of the thermostat and if I had found one that was a little cooler, say 170F I likely would have selected it; however, there was only 180F or 190F to chose from.  Mindful of the "temperature over 160F hurts power" I can't say there was any detectable power reduction during my climb out.  Typically cruising at 180F on warm days was not unusual when operating without a thermostat.  The main difference between with or without is how the engine warms up: without a thermostat the engine, coolant and radiator all heat up gradually in uniform fashion; with a thermostat the engine heats up more rapidly and cools itself by burping hot coolant out through the thermostat and replacing it with cold/colder fluid from the radiator.  One thing I did not mention is that my heater core loop is plumbed through a larger oil cooler for extra cooling in the summer and for cabin heat in the winter.  Thus there is a larger volume of coolant being heated gradually than with just a radiator alone.

Anyway it sure is nice to be able to chop the power on a cold day and glide in for a landing without worrying about engine temps dropping back into the 110F range and having cabin while taxiing back to the hangar.

Jeff Whaley

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, January 29, 2018 11:19 PM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Thermostat for winter operations

When I built my Rotary, I cut the pump down and removed the thermostat. I replaced the thermostat with a restrictor orifice. I built a cowl flap to control airflow\water temp but I need to change the actuator for more mechanical advantage. In 20 degree air I am only getting up to 120 degree water temp.

Dave Williams
Wisconsin

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, January 29, 2018 7:15 PM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Thermostat for winter operations

Well, I am wary of thermostats, an old Volvo truck and a 2 year old Mercedes wagon have left on the side of the road with stuck shut thermostats, luckily both times within 10km walking distance of home. am I just unlucky?
If I do install one in the plane it will become part of the annual inspection to remove and check its operation in boiling water.


Andrew

On Tue, Jan 30, 2018 at 7:20 AM, Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net> wrote:
No doubt Lynn is correct. But while power is everything to a racer, it rarely is everything to the rest of us. Look at how temps in cars have been inching upward for decades. If metallurgy & lubricants would allow it, they'd be running 500 degree engines because it's more efficient (Lower delta-T; less energy lost to the coolant/outside world, where it's not doing any work).

On Mon, Jan 29, 2018 at 4:49 PM, Kelly Troyer keltro@gmail.com <flyrotary@lancaironline.net> wrote:
Guys,

   None other than our Rotary Guru Lynn Hanover has stated in the past that coolant temps over 160F hurt power........Perhaps
he will Chime in here again and enlighten us !!............<:)