From what I've seen so far, cooling results on the ground have almost no relationship to cooling in-flight. I would not make any decision on the thermostat based on what you have observed so far.
My engine would be at redline in 15 minutes of medium throttle ground running. On a hot day (95 - 105 deg ), my engine will stabilize at about 224 deg F (water & oil) during a long taxi (like after landing at Oshkosh). This has always been the case. In the early days (10 years ago), if I had tried to take off at this temperature, the engine would have boiled over. I have improved in-flight cooling to the point where it will now cool off from this temperature during climb-out (but I still don't like to take off at those temperatures). At home it only takes about 5 seconds to taxi for takeoff so I have a 4 min wait for engine temps to reach minimum. I use 130 deg oil temp for min. takeoff temp.
----- Original Message -----
From: John Slade
Sent: Wednesday, March 31, 2004 8:34 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Requesting more thoughts on cooling
Guys,
I'm signed off and ready to fly, but I'm a little concerned about cooling issues. I don't want to melt anything in the first go around the pattern.
I'm finding that the engine gets REALLY hot after about 10 - 15 minutes ground running, and I'm wondering if that's to be expected, or if I have a cooling problem. Maybe I should just taxi gently to the runway and launch to get airflow as soon as possible.
For example, today I ran it up and down the taxiway for a few minutes at fairly low speeds and around 2500 - 3000rpm. Then I did some static runups (maybe 3800 - 4000 rpm - all the brakes will hold) and some EC2 tuning. Then I did some mode 1 programing at various rpm. During this run I watched the water temp gradually go up until it was over 200 and I shut her down. The oil was still down around 140 - 160. I took the cowl off and found that everything in the engine compartment was HOT. Radiator, oil coolers, hoses, intake, the cowl itself. Apart from giving my cowl a REAL GOOD post cure I dont think I've done any damage, but this doesnt give me a lot of confidence about whether I'll make it around the pattern.
The thermostat is now in place, and I get the feeling that I'd be much better without it. Once the engine gets a little hot the water temps seem to "run away" if I'm producing any kind of power. So... to remove the thermostat [3rd gen rew engine] I have to remove the water pump and have the by-pass hole welded shut - right?
Do you 13B drivers tend to just taxi out at low rpm then launch? Would your engine overheat if you did a 15 minute medium power runup? I'd appreciate any general thoughts, or comments on how much ground running I should expect to get away with before the temps get too high. Anything else I should check?
Regards,
John Slade