On 6 May 2015, at 9:31 am, David Leonard <flyrotary@lancaironline.net> wrote:

I agree with Bobby, this may (hopefully) be the cause, but if so it just means that you didn't design in an adequate way to fill the coolant without trapping air.  You would hate to have to do a coolant-prep flight every time you wanted to drain and refill the coolant. (but not the end of the world).

I originally designed my system like Ed's.  Minimal drag (just the 2 stock RV-6 inlets) but cooling was like you and Ed describe...  OK, but you always have to keep and eye on it and often reduce power or AOA in order to keep coolant temps in check.  Then I made a major change to provide TONS of air to an adequately sized radiator.  Since,  I never even think about cooling.  Yes, I do probably burn a little more fuel but it is well worth it to never worry about cooling again.  Its not rocket science.  Adequate air to an adequate radiator equals adequate cooling.  Change adequate to plenty in that sentence and now your are rocking!

Dave Leonard

On Mon, May 4, 2015 at 12:37 PM, Bobby J. Hughes <flyrotary@lancaironline.net> wrote:

Jeff,

 

Congratulations on getting back in the air. That ½ quart of coolant may have been trapped air that purged during flight.

 

Bobby Hughes

N416AS-

RV10  223 hrs

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Monday, May 04, 2015 7:53 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Return to Flight

 

Yesterday 3-May, my bird got airborne once again on its maiden flight after 2+ years rebuilding.  I had a friend test-pilot fly it while I was flight engineer watching the gauges.  Flight controls and rigging were reported to be good and the engine performed flawlessly.  The oil temperature was stable around 160F (Mazda oil cooler in series with a Fluidyne) but again the water temperature was high reaching 210F by circuit height so we backed off the throttle, did a touch and go with a 500’ circuit and parked it.  One unusual result was the cooling system pressure was only at 5-6 psi; with the high temperature it should have been 15-16 psi.  Removed the cowlings and found no leaks of either oil or glycol.  I checked the coolant level and it was down, requiring 1/2 quart to top it up. I also looked at my pinched duct and think it needs more pinching, so am already starting to modify that – hope to get another test flight in before the weekend.

 

Jeff

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