X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3816975 for flyrotary@lancaironline.net; Tue, 18 Aug 2009 12:25:40 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from computername ([75.191.186.236]) by cdptpa-omta02.mail.rr.com with ESMTP id <20090818162502526.OMZR8845@cdptpa-omta02.mail.rr.com> for ; Tue, 18 Aug 2009 16:25:02 +0000 From: "Ed Anderson" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Swirl pots ... coolant and dish soap. Date: Tue, 18 Aug 2009 12:23:38 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000C_01CA1FFE.B7678710" X-Mailer: Microsoft Office Outlook, Build 11.0.5510 Thread-Index: AcogHTDlFnEPNthxTliDaoPzhrD5+gAArkSA In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Message-Id: <20090818162502526.OMZR8845@cdptpa-omta02.mail.rr.com> This is a multi-part message in MIME format. ------=_NextPart_000_000C_01CA1FFE.B7678710 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Good question, Jeff, I tried some commercial water "wetter" in my cooling system early on when I was having cooling problems as I had heard it could reduce temps by 10F or more. Well, it may work for some, but in my case, I could not tell any difference at all. Now, it may be at the time I was only using water and no antifreeze which may have some bearing on the lack of any detectible results. So I too would like to know if anyone has used it with measurable benefits. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Jeff Whaley Sent: Tuesday, August 18, 2009 12:01 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Swirl pots ... coolant and dish soap. I believe adding dish soap or water wetter is supposed to reduce surface tension between coolant and block. What is the measured net benefit of either additive? 1%-5% improved cooling? Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lynn Hanover Sent: Tuesday, August 18, 2009 11:24 AM To: Rotary motors in aircraft Subject: [FlyRotary] Swirl pots Ed has all of the smarts on this. So pay attention when he writes anything. And now the Larch..................... I hate to see a rotary engine go down the drain because the engine overheated on the first start. And a lot of them do die that way. The water pump is installed at the top of the engine, and will use any excuse to cavitate and stop pumping coolant. It has no head on it. Pump talk for water pressure caused by the weight of water above the pump. So a very small amount of air behind the pump will stop it. I have a Shrader valve on my make up tank, and charge the system to relief pressure before starting the engine. In the olden days, that center iron had a flat spot with some kind of fat sensor stuck in it with two nice threaded holes along side. That hole got a flat plate with a Shrader valve sans core installed. A nice metal cap on the valve body kept the coolant inside. On a new fill up, you take that cap off and pour in coolant until it came out of the Shrader valve with no bubbles. Then put the cap back on. Fast, simple, cheap. I should have removed the restrictor from the drawing before posting it. It begs for comment. It is probably of no value in an aircraft application. Here is my thinking on that piece of the system, backed up by observation only and no technical understanding or evidence. On my flow bench I see a vena contracta around all exposed tube ends, (like the raw end of the shop vac hose) that reduces the effective diameter of the hose. The air making a 180 degree turn around the end of the tube impinges on air flowing into the tube at any angle less than 180 into the tube. So the CFM you would calculate for the tube diameter and pressure will be about half of the calculated flow when tested. The smaller the tube diameter the more profound the effect. Now look into the tank on a radiator and notice the flattened tubes sticking up from the flat tank floor. Any vena contracta going on in there? And it is in a liquid, way worse than flowing air. While raising the pressure around the end of the tube, flow does not improve as an exact function of pressure. Or, doubling the pressure does not double the flow. And now more bad news. The same construction at the outlet end of the tubes creates another interesting condition, where high velocity flow from the raw tube end, creates a high pressure differential between the flow and coolant at rest in the tank, that caused the low speed coolant to constrict the flow exiting the tube. You can see this on a humid day when a war bird revs up for take off. The vapor rings from the prop tips are compressed inward and stay closely attached to the fuselage. Or, a vena contracta observable in broad daylight. I deduce from this that there is a considerable restriction involved in forcing coolant through a radiator. I am not alone in this thinking. Notice that the lower radiator hoses on cars have a spiral of wire installed to prevent the collapse of the hose at high engine speed. Even with the use of modern higher pressure caps now common. Notice also that the lower hoses are larger in diameter than the upper hoses. So, the radiator, like the power valve or restrictor in a Freon system, where a restriction of some sort is required to generate a pressure differential. Unlike a Freon system that pressure differential is of no value in our cooling systems. So, the radiator(s) are the biggest restrictor in the loop, and the lowest system pressure is likely to be found between the radiator(s) and the pump inlet. When that pressure drops below local air pressure the lower hose would collapse if it were not for the wire inside, your 22 pound pressure cap be damned. So, the restrictor, limits the pressure differential across the radiator, and helps prevent pump cavitation that shortens the vanes on the pump and renders it ineffective. When you are shifting at 9,600 RPM and miss the shift, (the rev chips are 9,600s) or the driver selects 1st instead of 3rd successfully (easy with dog rings) and the revs go to the moon, then the restrictor is a help. For airplanes, not so much.................Sorry for any confusion. Lynn E. Hanover __________ Information from ESET NOD32 Antivirus, version of virus signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_000C_01CA1FFE.B7678710 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Good question, Jeff,  I tried = some commercial water “wetter” in my cooling system early on when I was = having cooling problems as I had heard it could reduce temps by 10F or = more.  Well, it may work for some, but in my case, I could not tell any = difference at all.  Now, it may be at the time I was only using water and no = antifreeze which may have some bearing on the lack of any detectible = results.

 

So I too would like to know if = anyone has used it with measurable benefits.

 

Ed

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Jeff Whaley
Sent: Tuesday, August 18, = 2009 12:01 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Swirl pots ... coolant and dish soap.

 

I believe = adding dish soap or water wetter is supposed to reduce surface tension between = coolant and block.

What is the = measured net benefit of either additive? 1%-5% improved = cooling?

Jeff

 <= /o:p>

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Lynn Hanover
Sent: Tuesday, August 18, = 2009 11:24 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] = Swirl pots

 

Ed has all of the smarts on this. So pay attention when he = writes anything.

 

And now the Larch..................... =

 

I hate to see a rotary engine go down the drain because the = engine overheated on the first start. And a lot of them do die that way. The = water pump is installed at the top of the engine, and will use any excuse to = cavitate and stop pumping coolant. It has no head on it. Pump talk for water pressure caused by the weight of water above the pump. So a very small = amount of air behind the pump will stop it.

 

I have a Shrader valve on my make up tank, and charge the system = to relief pressure before starting the engine. =

 

In the olden days, that center iron had a flat spot with some = kind of fat sensor stuck in it with two nice threaded holes along side. That = hole got a flat plate with a Shrader valve sans core installed. A nice metal cap on = the valve body kept the coolant inside. On a new fill up, you take that cap = off and pour in coolant until it came out of the Shrader valve with no bubbles. = Then put the cap back on. Fast, simple,

cheap.  

 

I should have removed the restrictor from the drawing before = posting it. It begs for comment. It is probably of no value in an aircraft = application.

 

Here is my thinking on that piece of the system, backed up  = by observation only and no technical understanding or evidence. =

 

On my flow bench I see a vena contracta around all exposed tube = ends, (like the raw end of the shop vac hose) that reduces the effective = diameter of the hose. The air making a 180 degree turn around the end of the tube = impinges on air flowing into the tube at any angle less than 180 into the tube. = So the CFM you would calculate for the tube diameter and pressure will be about = half of the calculated flow when tested.

 

The smaller the tube diameter the more profound the effect. Now = look into the tank on a radiator and notice the flattened tubes sticking up = from the flat tank floor. Any vena contracta going on in = there?

And it is in a liquid, way worse than flowing = air.

 

While raising the pressure around the end of the tube, flow = does not improve as an exact function of pressure. Or, doubling the pressure = does not double the flow. And now more bad news. The same construction = at the outlet end of the tubes creates another interesting condition, where = high velocity flow from the raw tube end, creates a high pressure = differential between the flow and coolant at rest in the tank, that caused the low = speed coolant to constrict the flow exiting the tube. You can see this on a = humid day when a war bird revs up for take off. The vapor rings from the prop tips = are compressed inward and stay closely attached to the fuselage. Or, a vena contracta observable in broad = daylight. 

 

I deduce from this that there is a considerable restriction = involved in forcing coolant through a radiator. 

 

I am not alone in this thinking. Notice that the lower radiator = hoses on cars have a spiral of wire installed to prevent the collapse of the = hose at high engine speed. Even with the use of modern higher pressure caps now = common.  Notice also that the lower hoses are larger in diameter than the = upper hoses.

 

So, the radiator, like the power valve or restrictor in a Freon = system, where a restriction of some sort is required to generate a pressure differential. Unlike a Freon system that pressure differential is of no = value in our cooling systems.

 

So, the radiator(s) are the biggest restrictor in the loop, and = the lowest system pressure is likely to be found between the radiator(s) and = the pump inlet. When that pressure drops below local air = pressure

the lower hose would collapse if it were not for the wire = inside, your 22 pound pressure cap be damned.

 

So, the restrictor, limits the pressure differential across the radiator, and helps prevent pump cavitation that shortens the vanes on = the pump and renders it ineffective. When you are shifting at 9,600 RPM and miss = the shift, (the rev chips are 9,600s) or the driver selects 1st instead of = 3rd successfully (easy with dog rings) and the revs go to the moon, then the restrictor is a help.  

 

For airplanes, not so much.................Sorry for any = confusion.

 

Lynn E. Hanover  

 



__________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

------=_NextPart_000_000C_01CA1FFE.B7678710--