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Mon, 28 Feb 2022 01:07:35 +0000 Received: by kubenode531.mail-prod1.omega.bf1.yahoo.com (VZM Hermes SMTP Server) with ESMTPA ID 8e68605bf0bad171b2470bab8dabbcaa; Mon, 28 Feb 2022 01:07:30 +0000 (UTC) Subject: Re: [FlyRotary] Re: Ed's spreadsheet To: Rotary motors in aircraft References: Message-ID: <0382be5b-7331-c663-1dbb-9c9f7d7ca0dd@verizon.net> Date: Sun, 27 Feb 2022 20:07:28 -0500 User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------F66BFD6C2975B36CE630281B" Content-Language: en-US X-Antivirus: Avast (VPS 220227-6, 02/27/2022), Outbound message X-Antivirus-Status: Clean X-Mailer: WebService/1.1.19797 mail.backend.jedi.jws.acl:role.jedi.acl.token.atz.jws.hermes.aol Content-Length: 62036 This is a multi-part message in MIME format. --------------F66BFD6C2975B36CE630281B Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Thank you La Roux. According to a few runs near full power at altitude I have adequate cooling at cruise and near top speed. It's during take off and continuous full power climbs I have an issue. I can make it to1,000' pattern altitude or more before I have to reduce power even on a 80-90F day. Depends on airspeed, but typically100 -120 mph. That makes sense because of increased angle of attack of ducts (diffusers) and inlets in climb attitude. Brief glimpses at tufts on bottom side of duct (using Bluetooth pencil camera) shows smooth flow changing to turbulent as AOA is increased. Keeping the engine from overheating during extended taxi is an area I haven't explored yet. With my two 198 cu in radiators (A/C cores), I'm definitely at the low end for180 HP.  This will require smooth airflow (excellent pressure recovery) evenly over the entire rad surface. Using bigger radiators, I think you can get away with less efficient ducting. I was obsessed with weight reduction (less radiator, less coolant) and these two A/C cores were cheap ($34 for two shipped). Well, I'm paying for that now in time and duct experimentation (already paid a welder more than $100 to get elbows welded on). My recent excursion into coolant flow was to be sure that that is not a factor in my system. I've spent considerable time on exit ducting and more recently started looking at inlets and diffusers again. My left rad diffuser is a challenge because it's quite short and share inlet area with engine air intake. I'm currently speculating on how to extend the inlet closer to the prop and perhaps further out towards prop tip and shaping it to pick up more air at climb AOA. In retrospect I should have hung radiator under the engine (where oil cooler is now) and put the oil cooler in the right cowl cheek. As it is, I have no oil temperature problems (except when I narrow its exit duct too much). Finn On 2/27/2022 2:00 PM, Le Roux Breytenbach breytenbachleroux@gmail.com wrote: > Finn : I am still building my engine and FFW set-up , >  but this is the fundamentals on coolant flo ,that i got on cooling a > 2 Rotary 13 B , > think that many of these principles is the same on other models too > like the Renesis > The coolant - 50% ethylene glycol and 50% water. > The flo must be 35 - 40 gallons per minute through the system at more > or less 6000 rpm. > The averaged pump on these flowrates need more or less 3 Hp > The pump can “cavitate” and loose efficiency if there is too much > friction in the system , and the flo rate is to slow. > This cooling is based on a heat exhancher (radiator) of 600 cube inch. > I think that the basics is to start with bigger cooling hoses. 40 mm > Try to keep them as straight as possible and avoid bends to the minnimum. >  Then the airflo and distribution and heat exhange is a topic on its own. > > Included are data and work by Fred Moreno (revised oct 21 1999) > What is interesting in Fred’s work is that a 10 gph increase in > coolant flow reduced cooling drag by 15 % > > https://drive.google.com/file/d/1JVh3KTa0LyiKQLKmaR4pRpDnLuuA_y17/view?usp=drivesdk > > > > > Sent from my iPhone > Le Roux Breytenbach > >> On 27 Feb 2022, at 18:20, eanderson@carolina.rr.com >> wrote: >> >>  >> >> >> Well Looking at the chart you referernced it looks like the >> mixture for 50/50 the CP could range from 0.79 at -30F to 0.88 >> at 100F.  IF 100 % glyco then at -10F we have a CP of 0.53 and >> at 100 0f 0.66  So looks like I picked a worst/best case >> condition.  But, using your example I get a cp of 0.8807.  Not >> a 30% difference but more than 5% >> >> >> In any case, I would suggest if you find data you feel more confident >> in, do not hesitate to subsitute it. >> >> Ed >> >> >> pecific Heat of Ethylene Glycol based Water Solutions >> >> Specific Heat >>  - /c_p >> / - of ethylene glycol >>  based >> water solutions at various temperatures are indicated below >> >> Specific Heat - /c_p //(Btu/lb ^o F)/ // >> Ethylene Glycol Solution >> /(% by weight)/ Temperature /(°C)/ >> -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 >> *0* >> >> >> >> >> 1.0038 1.0018 10004 0.99943 0.99902 0.99913 0.99978 1.0009 >> 1.0026 1.0049 1.0076 >> *10* >> >> >> >> >> 0.97236 0.97422 0.97619 0.97827 0.98047 0.98279 0.98521 >> 0.98776 0.99041 0.99318 0.99607 >> *20* >> >> >> >> >> 0.93576 093976 0.94375 0.94775 0.95175 0.95574 0.95974 >> 0.96373 0.96773 0.97173 0.97572 >> *30* >> >> >> >> 0.89373 0.89889 0.90405 0.90920 0.91436 0.91951 0.92467 >> 0.92982 0.93498 0.94013 0.94529 0.95044 >> *40* >> >> >> 0.84605 0.85232 0.85858 0.86484 0.87111 0.87737 0.88364 >> 0.88990 0.89616 0.90243 0.90869 0.91496 0.92122 >> 50 >> >> 0.79288 0.80021 0.80753 0.81485 0.82217 0.82949 0.83682 >> 0.84414 0.85146 0.85878 0.86610 0.87343 0.88075 0.88807 >> *60* 0.72603 073436 0.74269 0.75102 0.75935 0.76768 0.77601 >> 0.78434 0.79267 0.80100 0.80933 0.81766 0.82599 0.83431 >> 0.84264 0.85097 >> *70* 0.67064 0.67992 0.68921 0.69850 0.70778 0.71707 072636 >> 0.73564 0.74493 0.75422 0.76350 0.77279 0.78207 0.79136 >> 0.80065 0.80993 >> *80* 0.61208 0.62227 0.63246 0.64265 0.65285 0.66304 0.67323 >> 0.68343 0.69362 0.70381 0.71401 0.72420 0.73439 0.74458 >> 0.75478 0.76497 >> *90* >> >> >> 0.58347 0.59452 0.60557 0.61662 0.62767 0.63872 0.64977 >> 0.66082 0.67186 0.68291 0.69396 0.70501 0.71606 >> *100* >> >> >> >> 0.53282 0.54467 0.55652 0.56838 0.58023 0.59209 0.60394 >> 0.61579 0.62765 0.63950 0.65136 0.66321 >> >> I'm not sure how >> ------ Original Message ------ >> From: "Finn Lassen finn.lassen@verizon.net >> " > > >> To: "Rotary motors in aircraft" > > >> Sent: 2/26/2022 9:29:22 PM >> Subject: [FlyRotary] Re: Ed's spreadsheet >> >>> 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 >>>> " >>> > >>>> To: "Rotary motors in aircraft" >>> > >>>> 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 >>>>>> " >>>>> > >>>>>> To: "Rotary motors in aircraft" >>>>> > >>>>>> 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 >>>>>>> --- >>>>> >>>>> >>>>> >>>>> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> >>> >>> --------------F66BFD6C2975B36CE630281B Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
Thank you La Roux.

According to a few runs near full power at altitude I have adequate cooling at cruise and near top speed.

It's during take off and continuous full power climbs I have an issue. I can make it to1,000' pattern altitude or more before I have to reduce power even on a 80-90F day. Depends on airspeed, but typically100 -120 mph.

That makes sense because of increased angle of attack of ducts (diffusers) and inlets in climb attitude. Brief glimpses at tufts on bottom side of duct (using Bluetooth pencil camera) shows smooth flow changing to turbulent as AOA is increased.

Keeping the engine from overheating during extended taxi is an area I haven't explored yet.

With my two 198 cu in radiators (A/C cores), I'm definitely at the low end for180 HP.  This will require smooth airflow (excellent pressure recovery) evenly over the entire rad surface. Using bigger radiators, I think you can get away with less efficient ducting. I was obsessed with weight reduction (less radiator, less coolant) and these two A/C cores were cheap ($34 for two shipped). Well, I'm paying for that now in time and duct experimentation (already paid a welder more than $100 to get elbows welded on).

My recent excursion into coolant flow was to be sure that that is not a factor in my system.

I've spent considerable time on exit ducting and more recently started looking at inlets and diffusers again.
My left rad diffuser is a challenge because it's quite short and share inlet area with engine air intake.
I'm currently speculating on how to extend the inlet closer to the prop and perhaps further out towards prop tip and shaping it to pick up more air at climb AOA.
In retrospect I should have hung radiator under the engine (where oil cooler is now) and put the oil cooler in the right cowl cheek.
As it is, I have no oil temperature problems (except when I narrow its exit duct too much).

Finn

On 2/27/2022 2:00 PM, Le Roux Breytenbach breytenbachleroux@gmail.com wrote:
Finn : I am still building my engine and FFW set-up ,
 but this is the fundamentals on coolant flo ,that i got on cooling a 2 Rotary 13 B ,
think that many of these principles is the same on other models too like the Renesis 
The coolant - 50% ethylene glycol and 50% water.
The flo must be 35 - 40 gallons per minute through the system at more or less 6000 rpm.
The averaged pump on these flowrates need more or less 3 Hp
The pump can “cavitate” and loose efficiency if there is too much friction in the system , and the flo rate is to slow.
This cooling is based on a heat exhancher (radiator) of 600 cube inch.
I think that the basics is to start with bigger cooling hoses. 40 mm
Try to keep them as straight as possible and avoid bends to the minnimum.
 Then the airflo and distribution and heat exhange is a topic on its own.

Included are data and work by Fred Moreno (revised oct 21 1999)
What is interesting in Fred’s work is that a 10 gph increase in coolant flow reduced cooling drag by 15 %





Sent from my iPhone
Le Roux Breytenbach 

On 27 Feb 2022, at 18:20, eanderson@carolina.rr.com <flyrotary@lancaironline.net> wrote:



Well Looking at the chart you referernced it looks like the mixture for 50/50 the CP could range from 0.79 at -30F to 0.88 at 100F.  IF 100 % glyco then at -10F we have a CP of 0.53 and at 100 0f 0.66  So looks like I picked a worst/best case condition.  But, using your example I get a cp of 0.8807.  Not a 30% difference but more than 5%


In any case, I would suggest if you find data you feel  more confident in, do not hesitate to subsitute it.

Ed

pecific Heat of Ethylene Glycol based Water Solutions

Specific Heat - cp - of ethylene glycol based water solutions at various temperatures are indicated below

Specific Heat - cp (Btu/lb oF) 
Ethylene Glycol Solution
(% by weight)		 Temperature (°C) 
-50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
0




1.0038 1.0018 10004 0.99943 0.99902 0.99913 0.99978 1.0009 1.0026 1.0049 1.0076
10




0.97236 0.97422 0.97619 0.97827 0.98047 0.98279 0.98521 0.98776 0.99041 0.99318 0.99607
20




0.93576 093976 0.94375 0.94775 0.95175 0.95574 0.95974 0.96373 0.96773 0.97173 0.97572
30



0.89373 0.89889 0.90405 0.90920 0.91436 0.91951 0.92467 0.92982 0.93498 0.94013 0.94529 0.95044
40


0.84605 0.85232 0.85858 0.86484 0.87111 0.87737 0.88364 0.88990 0.89616 0.90243 0.90869 0.91496 0.92122
50

0.79288 0.80021 0.80753 0.81485 0.82217 0.82949 0.83682 0.84414 0.85146 0.85878 0.86610 0.87343 0.88075 0.88807
60 0.72603 073436 0.74269 0.75102 0.75935 0.76768 0.77601 0.78434 0.79267 0.80100 0.80933 0.81766 0.82599 0.83431 0.84264 0.85097
70 0.67064 0.67992 0.68921 0.69850 0.70778 0.71707 072636 0.73564 0.74493 0.75422 0.76350 0.77279 0.78207 0.79136 0.80065 0.80993
80 0.61208 0.62227 0.63246 0.64265 0.65285 0.66304 0.67323 0.68343 0.69362 0.70381 0.71401 0.72420 0.73439 0.74458 0.75478 0.76497
90


0.58347 0.59452 0.60557 0.61662 0.62767 0.63872 0.64977 0.66082 0.67186 0.68291 0.69396 0.70501 0.71606
100



0.53282 0.54467 0.55652 0.56838 0.58023 0.59209 0.60394 0.61579 0.62765 0.63950 0.65136 0.66321
I'm not sure how
------ Original Message ------
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: 2/26/2022 9:29:22 PM
Subject: [FlyRotary] Re: Ed's spreadsheet

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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