From: " eanderson@carolina.rr.com" <flyrotary@lancaironline.net>
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To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Inlet cooling article
Date: Thu, 22 Jul 2021 15:38:27 +0000
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Yes, thanks Jeff for clarifying "Eds Workbook".

I believe that different solutions work for different cases, no -=20
one-fit-all in the case of aircraft cooling.  As several have already=20
mentioned their are 3 key elements of our cooling systems.  I might add=20
there is a 4th - Risk Tolerance.

The 1st/number uno requirement is to remove adequate heat from the=20
engine (in our case via a coolant).  If your systems doesn't do that,=20
then the rest is for naught.

Having said that  - the next (2nd) requirement in my book is to ensure=20
that the radiator sheds sufficient heat from the coolant to the air flow=20
that permits the heat level of the engine to be maintain within a=20
satisfactory (small) range.  Too cold and you loose some power/fuel=20
efficiency and too hot -well, you know what that will lead to.

  The 3rd element is to do 1 and 2 with minimum possible drag.  Now,=20
trying to optimize the three key elements so that the total system meets=20
your objective is where a lot of experimenting (and dare I say some=20
"Luck") comes in.  The key difficulty is trying to "simplify" some=20
fairly esoteric properties and equations so that they are understood=20
well enough to aim us in the right direction in our practical=20
application.  I dare say few of us have the resources or access to the=20
test beds/laboratories that produce the studies that we attempt to=20
comprehend and apply.

Saving the 4th for last - your approach is likely to be influenced a=20
great deal by your risk tolerance.  For some  having the temperature=20
exceed 180F might be too risky.  I was content to takeoff and climb-out=20
so long as coolant temp did not exceed 220F and would decrease from that=20
during cruise climb.  Some would not feel comfortable doing that.  But,=20
for me the reduce drag at speeds where I spent most of the time flying=20
was worth a bit higher temps on take off.

Now, I greatly admire Tracy Crooks ability to assess and accept risk=20
factors that I could not bring myself to do.

Example, I used expensive/heavy  1" stainless steel braided hose with=20
heavy fittings welded to the coolant cores.  In contrast, I saw Tracy=20
successful use light weight stretch bands clamps, rubber hose and some=20
of his coolant fittings were epoxied to the cooling core.  Too risky for=20
my taste, but on the other hand Tracy undoubtedly had the best=20
performing RV-4 and Rv-8 around.  I've not heard of any of his "risky"=20
approaches ever failing, but they would have made me a bit more than=20
anxious if I flew with them.  So whether you consciously assess your=20
risk factor or not it will be there influencing your decisions and=20
choices.

But, hey guys, if it were easy there would be no challenge and there=20
would be a reduce sense of satisfaction at succeeding when you finally=20
get it nailed down.

Ed

------ Original Message ------
From: "Jeff Whaley jwhaley@datacast.com" <flyrotary@lancaironline.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: 7/22/2021 7:51:01 AM
Subject: [FlyRotary] Re: Inlet cooling article

>Ed's cooling workbook sits on Ed's bookshelf and inside his head ... just=
 a metaphor never published, except for the advice he has presented to this=
 forum over the years.  Great to see you Ed adding a few 02 cents worth late=
ly.
>
>I will never claim to have all the answers but I have managed to get my in=
stallation to operate at cruise settings with an OAT of 100F and a cruise s=
peed of only 100 mph.
>My journey has been a long and hard one, so I've been reluctant to stick m=
y neck out too far on this forum ... however at the risk of being harshly j=
udged by my peers, below is a  link to a playlist of youtube videos I've pu=
t out there on the subject ... you may or may not like them ... you may or=
 may not learn anything from them ... I think they are worth sharing or they =
wouldn't exist ... my latest edition will be released early Saturday morni=
ng.
>Jeff
>https://www.youtube.com/playlist?list=3DPLYDy_YhIDvshT9--FR37aywJbyD1UXNof
>
>
>I know only from the cooling book of the late Paul Lamar
>Has purchased one from him when was on his rotaryforum years ago.
>
>https://www.aircraftspruce.com/catalog/bvpages/coolYourWankel.php
>
>Le Roux
>
>Sent from my iPhone
>Le Roux Breytenbach
>
>This is the first time I've heard of Ed's workbook!
>All a bit late for me at this stage, but would be interested in reading th=
rough it as I've still git sooooo much to learn.
>
>Steve Iz
>
>--
>Homepage:  http://www.flyrotary.com/
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>