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It might take a little time to sort out your issues, but you'll get there. It took me 1 1/2 years after my first flight to get 25 hours, but the plane is at the point where I can get in and fly without dealing with "issues". Cooling fortunately was not one of them. I have a 13x18x2 core volume aluminum sprint car rad and a stock 13 oil cooler. inlet is 16x3 frontal area and the rear is completely open -18x18. If anything, it cools too well.
Brian Trubee
-----Original Message-----
From: Tracy <rwstracy@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, Apr 25, 2012 2:51 pm
Subject: [FlyRotary] Re: N774CG, RV-10 20B first flight
Hi Tim,
As you found out, unless you used the draggy barn door approach to engine
cooling, ground cooling means almost nothing as an indicator of how it will
work in-flight.
I'm using the Sam James (holey) cowl and have the same 20B engine on my RV-8.
The stock 4.75" inlets were not adequate for me so probably not for you either.
I ended up with 5.75" inlet for the water and 5.25" for the oil cooler. I also
increased the outlet area but my RV-8 outlet may have been a bit smaller than
the RV-10 version. There are lots of other variables involved besides the
inlet size that have to be right as well (diffuser, inlet shape, etc.).
I doubt you damaged the engine on that short term overtemp. I once had a
malfunction of a coolant cap and lost a lot of coolant, coolant temp went to
258, oil to 230 and flew 8 miles to closest airport (at minimum power) and
engine did not suffer at all.
Keep working on it. First flight is only the beginning : )
Tracy
Sent from my iPad
On Apr 25, 2012, at 11:16 AM, Tiffanie Holt <coastiefamily4@gmail.com> wrote:
> Well, got up this morning and did the first flight on the RV-10. OAT
> 55 Degrees at 7000 ft. Did the taxi to the runway and the water temp
> was 168 and oil was 150. Everything looked full power in and off we
> went. She has plenty of power, RPM was 7000, and here comes the
> temps. I immediatelly turn to down wind at 80kts and the water temp
> came up to 220 and oil at 200. Turned base and temps still climbing
> still at 80 kts, turned attention to land vise temps. I landed
> immediately and taxied back to the hangar and the temps peaked at 245
> water and 240 oil. She got hot, I got boil over once I shut the
> engine down. I took all the cowls off to help the cooling of the
> engine. Check everything over, turned the prop and listened for any
> unusual noise, checked the oil and could smell the 2 stroke oil in it,
> which I understand is normal.
>
> She Flew, but not what I expected on temps. These are the highest
> temps that I have seen so far. I had 11 hours on ground runs, but I
> did not let water temps get above 205 and oil temp normally stayed at
> 180.
>
> At the hangar, I let the temps get to 180 on water and 160 on oil, I
> filled the expansion tank back up and ensure there was coolant and
> started her back up to see if I had normal readings. Oil pressure was
> on the rise, oil temp was at 175 and water temp stabilized at 190,
> Just wanted to ensure I did not do damage to the engine and that she
> would start. She was a little hard to start, but started purring like
> a kitten again. Shut her down, and then started her back up and she
> immediately turn over.
>
> Did not run her much longer, had to shut her down and get to work.
>
> Are there any suggestions or inspections that I will need to do on the
> engine for the high temps?
>
> Things I plan to do before next run:
> 1. Oil Change, Filter Clean: It is time for a cleaning and I can
> inspect the oil.
> 2. Flush the radiator: Ensure everything looks normal
> 3. The highest point in my water system is the expansion tank, but the
> water return is at a level slightly below the expansion tank. I plan
> to install a fill/bleed valve in it to ensure all the air is out of
> the system.
> 4. Move the Water Temp Sensor from the block to the return line to the
radiator
> 5. Place the Louvers in the cowling. I did put the louvers in per
> Van's Plans, but I put then in the cowl to help pull the heat from the
> exhaust system.
> 6. I will also open up the inlet to the Radiator as well. The
> standard Sam James Cowl has a 4 3/4 inch Diameter opening, I will open
> it up more and give it at try.
>
> Any suggestions would be greatly appreciated.
>
> Tim
>
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