flyrotary@lancaironline.net Mailing List Archive

From your 24 Aug 2012 post about cooling section in the spreadsheet:

"Cooling mass flow is dependent on:

1. A 0.7 cp compared to pure water of 1.0 Cp - this compensates for the typical anitfreeze dilution of the specific heat of water. "

Roughly weighing a 1 Gal 50/50 antifreeze jug I get maybe 7.9 pounds after subtracting 0.3 pound for the jug). Pure water about 8.3 pounds. That's about 5%.
I realize it changes somewhat with temperature but nowhere near 30% ?

https://www.engineeringtoolbox.com/ethylene-glycol-d_146.html

Difference between water and 50/50 at 100C: 1000/1030 or 3%. Not 30%.

Difference in specific heat (whatever that is): 1.0079 / 0.88807 = 13% (for 50/50 at 100C).

What am I missing?

Finn

On 2/26/2022 10:48 AM, eanderson@carolina.rr.com wrote:

I agree, must have got it from someplace credible - like Bill Shertz.

CP was 1.0 for pure H20 and somewhat less with antifreeze mixed in.

I had a primary pully from MazdaTrix that reduced water pump speed - since engine was turning faster than normal in automobile, did not want to have any cavitation. So my water pump did turn a bit slower than stock.

Not necessarily - note that water flow drops off if pump speed increases into the "caviation range"

------ Original Message ------

From: "Finn Lassen finn.lassen@verizon.net" <flyrotary@lancaironline.net>

To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

Sent: 2/25/2022 10:39:43 AM

Subject: [FlyRotary] Re: Ed's spreadsheet

Thanks Ed.

But 185.85 seems pretty detailed for a SWAG.
Any chance you got it from Bill Shertz's tests (which I unfortunately can't find the posts about)?

What determines "Cp Coolant"?
Heat transfer efficiency from engine to water and water to rad?

From measuring the rims of the e-shaft pulley (122mm) and water pump pulley (112mm) it looks like the Renesis water pump runs a bit slower (factor 1.09 compared to your 1.18).

Should water flow be directly proportional to water pump RPM?

Finn

On 2/25/2022 10:07 AM, eanderson@carolina.rr.com wrote:

Sorry, Finn.

Too much water under the bridge, pretty sure I did not make it up out of thin air. I suspect I visited some pump websites to arrive at a SWAG.

Ed

------ Original Message ------

From: "Finn Lassen finn.lassen@verizon.net" <flyrotary@lancaironline.net>

To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

Sent: 2/24/2022 2:25:56 PM

Subject: [FlyRotary] Ed's spreadsheet

Hi Ed,

From where did you get the 13B coolant flow numbers (Pump Factor)?

I want to be certain that I have adequate coolant flow.

Finn

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