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Ed, you did say he cooling chart is not quite where it should be …
Plugging some numbers in there is very interesting; however, not to be too critical but I think the constants used to calculate HP Vs OAT Vs Cooling Capacity are a bit fuzzy.
For example, at any RPM, AF, HP, simply increasing the OAT value in the spreadsheet results in improved cooling capacity … My installation’s capacity to cool was much more influenced by OAT than the resulting change in HP due to OAT .
I had no cooling problems at 50F but had big problems at 100F … The spreadsheet indicates opposite.
Jeff
From:
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Ernest Christley <echristley@att.net>
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Subject:
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Re: [FlyRotary] Spreadsheet Cooling Section
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Date:
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Fri, 24 Aug 2012 10:41:30 -0400
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To:
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Rotary motors in aircraft <flyrotary@lancaironline.net>
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Ed Anderson wrote:
> But, as stated before the cooling section is on less solid ground due to
> the fact that installation variables play such a large role in cooling
> and they are not taken into consideration. But, you can play with it to
> see the effects of changing several variables on cooling.
>
> Ed
>
Just been playing with this, pulling data out of my data logs. I don't have all my numbers exact yet, but I think this
will be useful for making a SWAG at determining if the system will stay within safety margins during various phases of
flight.
Would it be to much to ask those with flying machines if they can go out and determine where their system starts to warm
up, which would be a rough indication of where the cooling capacity is exceeded? I thinking of doing a steep climbout
and slowly dropping the nose until the temps start coming down, noting the temp, MAP, airspeed and AFR at that point. I
don't think it is necessary to tell grown people that built their own airplane that they need to be careful about
airspeed while doing something like this. If we can get a variety of samples, we can put error bars around the
numbers that the spreadsheet gives.
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