Steve,
If all your exchangers dump into the cowl then the increased flow / pressure through the coolant exchangers may be limiting air flow through the oil cooler.
Bobby
-----Original Message-----
Sent: Sunday, November 03, 2019 3:42 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Update on Glasair Cooling in Phase #1
Sorry Matt, I just realised I hadn’t mentioned the actual oil temps.
Highest in climb were 114C (237F) settling back to 110C this is 10C higher than previous flight?? OAT was up 4C ~7F
I would have expected a symbiotic relationship between oil and water temps. Lower coolant yielding lower oil temps.
This is troubling me, Prior to this flight I noticed oil level down on the stick. Its always been very consistently full with no signs of leaks etc. (Standard Renesis pan)
It’s running Mobile 1 and measuring the oil entering the engine after cooler and filter.
Steve
>
> Coolant looks great. Are you running a t-stat?
> What are the oil temps when you say "high"? Synthetic? Weight? Oil pan or inlet temp location?
>
> This is my opinion, with synthetic 20W50 at oil pain temps, I'd be okay during the climb with 240F and hopefully after some air speed it drops down under 220F.
>
> I do agree you might have to open up to 100mm (4 inch) for oil cooler.
>
> - Matt Boiteau
>>
>> Hi there people
>>
>> Over the past month I have updated the cooling system of the Glasair Super II RG in order to continue our phase 1 testing.
>>
>> The previous setup had 540in3 two pass behind the ~20in2 unmodified right cheek inlet.
>> We hadn’t included the left cheek as it was so difficult to get the air across to the right hand side diffuser.
>> The Oil is 250in3 behind a 8in2 under spinner inlet.
>> Initial testing was marginal with OAT below 20C (68F)
>> So having established that cooling was rather marginal above 68F I went for the planned upgrade path which included
>> installing a secondary bike radiator of 130in3 plumbed into the heater circuit behind the ~15in2 left cheek inlet.
>> The diffuser was designed to hopefully be more efficient in a climb configuration.
>> So the total radiators frontal area has been increased by 50% while the air in has increased 75%.
>> The unknown is that being in the heater circuit we don't know the total flow through the secondary rad compared with the primary rad.
>>
>> Testing on the ground yield an approx 15-20C drop in coolant after 30mins of 1800rpm idle.
>>
>> Flight Testing Results the next day: OAT 21C (70F)
>> Coolant Temps max’d on climb at 93C (200F) down 15C on highest Flight 3 climb temp with a 4C higher OAT.
>> Coolant Temps dropped to 83C (181F) as speed got to 147 KIAS (Cruise is published as 192 KIAS but we haven’t expanded the envelope to date)
>> I’m very pleased with this result.
>>
>> Oil Temps are high. I would much prefer them below 80C (176F)
>> I’ll be interested to see what oil temp does as speed rises, but my hunch is it needs more air (increase air to oil cooler from a diameter of 77mm to 100mm)
>>
>> Slow Speed Tests:
>> Vs Clean Stall is at 67 KIAS row 2011 (Glasair claims 70 Knots at Gross)
>> Vso Full Flap Stall is at 57 KIAS row 2062 & 2083 (Glasair claims 59 Knots at Gross)
>>
>> Cheers
>>
>> Steve Izett
>> Perth Western Australia
>>
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