Mailing List flyrotary@lancaironline.net Message #67185
From: Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Ed's spreadsheet
Date: Sat, 26 Feb 2022 21:29:22 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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 ------
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 ------
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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