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Exhaust Pipe Size

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vk3eka(at)bigpond.net.au
Guest

Posted: Sat Nov 28, 2015 3:18 am Post subject: Exhaust Pipe Size

Hi Guys,





I have an O-200 on my Zodiac 601XLB. I have around 160 hours on the engine.

I built the exhaust system using 1 1/4 inch tubing for the total system.

You can see a picture at�http://zodiac.cpc-world.com/images/IMG_0085_JPG.jpg

Would I get more power if I used 1 1/2 inch tubing from the area where the two down pipes join?

Cheers

Peter

Wonthaggi Australia

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BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Mon Nov 30, 2015 12:32 pm Post subject: Exhaust Pipe Size

Peter:

There is no simple answer, well, in a way there is:  YES!  

It would, it should, decrease the flow resistance.  BUT!  

Is it worth it?

Use the basic formulas for fluid dynamics and you will see that there is a lowering of resistance.  BUT!

Then you have to work out the formulas for Open End Resonance to see if the exhaust at the end of the pipe is at a Null or a Peak?

The other question I would ask, because it is not clear in the picture is: Do you have a CrossOver from the left to the right side?

A CrossOver will do more for the system than increasing the size of the pipe.

What is the Volume of the Pipe as compared to the Volume of the Cylinder? 

See what I mean by No Simple Answer?

Barry

On Sat, Nov 28, 2015 at 6:18 AM, Peter Johnson <vk3eka(at)bigpond.net.au (vk3eka(at)bigpond.net.au)> wrote:

 	  Quote: 	
		  Hi Guys,





I have an O-200 on my Zodiac 601XLB. I have around 160 hours on the engine.

I built the exhaust system using 1 1/4 inch tubing for the total system.

You can see a picture at http://zodiac.cpc-world.com/images/IMG_0085_JPG.jpg

Would I get more power if I used 1 1/2 inch tubing from the area where the two down pipes join?

Cheers

Peter

Wonthaggi Australia

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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ftyoder(at)yoderbuilt.com
Guest

Posted: Mon Nov 30, 2015 3:50 pm Post subject: Exhaust Pipe Size

Peter,

  

 Since you are looking for better performance, along with  Barry's comments I would question the prop. Warp Drive and IVO props are not the  best design once you get to 100 HP. A two blade wood prop by a manufacturer that  has built many for the Cont.0-200 in the Zodiac or a metal prop if you don't  want wood would probably make a positive improvement in speed. I flew a 3  blade Warp Drive on my KIS TR-1 with the Cont. IO-240  and got a  good 15 mph increase at WOT when I replaced it with a 2  blade wood Sensenich, a Cato will do better than that. I am not familiar  with the prop manufacturers in the "Down Under" but you may have  choices closer than the USA.

  

 I also fly a Thorp T-211 with a Jabiru 3300, it has 625hrs and  is running good with a Ed Sterba wood 2 blade.

  

 G'day, Tim 



   From:  owner-continental-list-server(at)matronics.com  [mailto:owner-continental-list-server(at)matronics.com] On Behalf Of  FLYaDIVE

Sent: Monday, November 30, 2015 1:32 PM

To:  continental-list(at)matronics.com

Subject: Re: Exhaust  Pipe Size

 

  Peter:

 



 There is no  simple answer, well, in a way there is:  YES!  

 It would, it  should, decrease the flow resistance.  BUT!  

 Is it worth  it?

 Use the basic  formulas for fluid dynamics and you will see that there is a lowering of  resistance.  BUT!

 Then you have  to work out the formulas for Open End Resonance to see if the exhaust at the end  of the pipe is at a Null or a Peak?

 The other  question I would ask, because it is not clear in the picture is: Do you have a  CrossOver from the left to the right side?

 A CrossOver  will do more for the system than increasing the size of the pipe.

 What is the  Volume of the Pipe as compared to the Volume of the Cylinder? 

 See what I  mean by No Simple Answer?

 



 Barry



 

 On Sat, Nov 28, 2015 at 6:18 AM, Peter Johnson <vk3eka(at)bigpond.net.au (vk3eka(at)bigpond.net.au)> wrote:

  	  Quote: 	
		              Hi Guys,

      



   I have an O-200 on my Zodiac 601XLB. I have around 160 hours on the    engine.

   



   I built the exhaust system using 1 1/4 inch tubing for the total    system.

   



   You can see a picture at http://zodiac.cpc-world.com/images/IMG_0085_JPG.jpg

   



   Would I get more power if I used 1 1/2 inch tubing from the area where    the two down pipes join?

   



   Cheers

   



   Peter

   Wonthaggi Australia

   



   



      



	


    	 		 			 				 			 		 		 			

 				This email has been checked for viruses by Avast antivirus software. 				

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- The Matronics Continental-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Continental-List

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Mon Nov 30, 2015 5:19 pm Post subject: Exhaust Pipe Size

Very good point about the prop Peter.  I did not consider this as Tim's picture shows under construction.

It will take a bit of experimentation but if you can find an Aluminum prop something around 70" Diameter and 53" to 57" of Pitch...  

Put it on and: See what your Static RPM is.  It should be 2300 to 2400 RPM.

If it is under that take SUBTRACT 1" of Diameter for every 50 RPM until you reach 2300 RPM - - - BUT!  Do not go under the recommended diameter.

Next:  ADD 1" of Pitch until you 2300 RPM.  

A couple of Prop Rules:

Diameter is PULL

Pitch is Speed

A flat / low pitch is Vertical Speed (VSI)

NOW!  Remember the Aluminum prop is only for experimentation.  All you want to do is collect the numbers- NO cutting or twisting.

Then give me the numbers and I will suggest a CATO prop and what Diameter & Pitch for the job.  I developed a spreadsheet for the job.

NOTE:  My numbers are different than what CATO recommends.  I developed my spreadsheet from what I found to be Under-Pitched CATO props. AND, if you purchase a CATO make sure you get a Serial Nr on the Prop, and certification for Diameter and pitch; and a Logbook.  They are a bit lax on proper paperwork

Another point:  Weight is a consideration.  The CATO prop will be half the weight of the aluminum, this weight savings is HP and Speed.  AND unlike the wood you will be able to keep it outside and fly in the rain.

Barry

On Mon, Nov 30, 2015 at 6:50 PM, Tim Yoder <ftyoder(at)yoderbuilt.com (ftyoder(at)yoderbuilt.com)> wrote:

 	  Quote: 	
		       Peter,

  

 Since you are looking for better performance, along with  Barry's comments I would question the prop. Warp Drive and IVO props are not the  best design once you get to 100 HP. A two blade wood prop by a manufacturer that  has built many for the Cont.0-200 in the Zodiac or a metal prop if you don't  want wood would probably make a positive improvement in speed. I flew a 3  blade Warp Drive on my KIS TR-1 with the Cont. IO-240  and got a  good 15 mph increase at WOT when I replaced it with a 2  blade wood Sensenich, a Cato will do better than that. I am not familiar  with the prop manufacturers in the "Down Under" but you may have  choices closer than the USA.

  

 I also fly a Thorp T-211 with a Jabiru 3300, it has 625hrs and  is running good with a Ed Sterba wood 2 blade.

  

 G'day, Tim 



   From:  owner-continental-list-server(at)matronics.com (owner-continental-list-server(at)matronics.com)  [mailto:owner-continental-list-server(at)matronics.com (owner-continental-list-server(at)matronics.com)] On Behalf Of  FLYaDIVE

Sent: Monday, November 30, 2015 1:32 PM

To:  continental-list(at)matronics.com (continental-list(at)matronics.com)

Subject: Re: Exhaust  Pipe Size

 

  Peter:

 



 There is no  simple answer, well, in a way there is:  YES!  

 It would, it  should, decrease the flow resistance.  BUT!  

 Is it worth  it?

 Use the basic  formulas for fluid dynamics and you will see that there is a lowering of  resistance.  BUT!

 Then you have  to work out the formulas for Open End Resonance to see if the exhaust at the end  of the pipe is at a Null or a Peak?

 The other  question I would ask, because it is not clear in the picture is: Do you have a  CrossOver from the left to the right side?

 A CrossOver  will do more for the system than increasing the size of the pipe.

 What is the  Volume of the Pipe as compared to the Volume of the Cylinder? 

 See what I  mean by No Simple Answer?

 



 Barry



 

 On Sat, Nov 28, 2015 at 6:18 AM, Peter Johnson <vk3eka(at)bigpond.net.au (vk3eka(at)bigpond.net.au)> wrote:

  	  Quote: 	
		              Hi Guys,

      



   I have an O-200 on my Zodiac 601XLB. I have around 160 hours on the    engine.

   



   I built the exhaust system using 1 1/4 inch tubing for the total    system.

   



   You can see a picture at http://zodiac.cpc-world.com/images/IMG_0085_JPG.jpg

   



   Would I get more power if I used 1 1/2 inch tubing from the area where    the two down pipes join?

   



   Cheers

   



   Peter

   Wonthaggi Australia

   



   



      



	


 



 



  	 		 			 				 			 		 		 			

 				This email has been checked for viruses by Avast antivirus software. 				

www.avast.com

- The Matronics Continental-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Continental-List

vk3eka(at)bigpond.net.au
Guest

Posted: Mon Nov 30, 2015 10:13 pm Post subject: Exhaust Pipe Size

Hi Guys,



Thanks for the replies.



I don’t have a crossover pipe between the two sides. Maybe able to add quite easily.



I have been carrying out some testing with the prop.



I have the warp drive set for 9 degrees at the moment and only get 2150rpm static. I’ll tweak it a little to see if I can get some more static rpm.



I do have a wooden prop that came off a O-200 powered tailwind. I’ll check that out as well.



Thanks for your responses.



Cheers



Peter



From:  <owner-continental-list-server(at)matronics.com> on behalf of FLYaDIVE <flyadive(at)gmail.com>

Reply-To:  <continental-list(at)matronics.com>

Date:  Tuesday, 1 December 2015 at 12:19 PM

To:  <continental-list(at)matronics.com>

Subject:  Re: Exhaust Pipe Size



Very good point about the prop Peter.  I did not consider this as Tim's picture shows under construction.



It will take a bit of experimentation but if you can find an Aluminum prop something around 70" Diameter and 53" to 57" of Pitch...  

Put it on and: See what your Static RPM is.  It should be 2300 to 2400 RPM.

If it is under that take SUBTRACT 1" of Diameter for every 50 RPM until you reach 2300 RPM - - - BUT!  Do not go under the recommended diameter.

Next:  ADD 1" of Pitch until you 2300 RPM.  

A couple of Prop Rules:

Diameter is PULL

Pitch is Speed

A flat / low pitch is Vertical Speed (VSI)

NOW!  Remember the Aluminum prop is only for experimentation.  All you want to do is collect the numbers- NO cutting or twisting.

Then give me the numbers and I will suggest a CATO prop and what Diameter & Pitch for the job.  I developed a spreadsheet for the job.

NOTE:  My numbers are different than what CATO recommends.  I developed my spreadsheet from what I found to be Under-Pitched CATO props. AND, if you purchase a CATO make sure you get a Serial Nr on the Prop, and certification for Diameter and pitch; and a Logbook.  They are a bit lax on proper paperwork

Another point:  Weight is a consideration.  The CATO prop will be half the weight of the aluminum, this weight savings is HP and Speed.  AND unlike the wood you will be able to keep it outside and fly in the rain.



Barry



On Mon, Nov 30, 2015 at 6:50 PM, Tim Yoder <ftyoder(at)yoderbuilt.com> wrote:

Peter,

 

Since you are looking for better performance, along with Barry's comments I would question the prop. Warp Drive and IVO props are not the best design once you get to 100 HP. A two blade wood prop by a manufacturer that has built many for the Cont.0-200 in the Zodiac or a metal prop if you don't want wood would probably make a positive improvement in speed. I flew a 3 blade Warp Drive on my KIS TR-1 with the Cont. IO-240  and got a good 15 mph increase at WOT when I replaced it with a 2 blade wood Sensenich, a Cato will do better than that. I am not familiar with the prop manufacturers in the "Down Under" but you may have choices closer than the USA.

 

I also fly a Thorp T-211 with a Jabiru 3300, it has 625hrs and is running good with a Ed Sterba wood 2 blade.

 

G'day, Tim 



From: owner-continental-list-server(at)matronics.com [mailto:owner-continental-list-server(at)matronics.com] On Behalf Of FLYaDIVE

Sent: Monday, November 30, 2015 1:32 PM

To: continental-list(at)matronics.com

Subject: Re: Exhaust Pipe Size



Peter:



There is no simple answer, well, in a way there is:  YES!  

It would, it should, decrease the flow resistance.  BUT!  

Is it worth it?

Use the basic formulas for fluid dynamics and you will see that there is a lowering of resistance.  BUT!

Then you have to work out the formulas for Open End Resonance to see if the exhaust at the end of the pipe is at a Null or a Peak?

The other question I would ask, because it is not clear in the picture is: Do you have a CrossOver from the left to the right side?

A CrossOver will do more for the system than increasing the size of the pipe.

What is the Volume of the Pipe as compared to the Volume of the Cylinder? 

See what I mean by No Simple Answer?



Barry



On Sat, Nov 28, 2015 at 6:18 AM, Peter Johnson <vk3eka(at)bigpond.net.au> wrote:

 

 

 

 

Hi Guys,

 

 



 

I have an O-200 on my Zodiac 601XLB. I have around 160 hours on the  engine

- The Matronics Continental-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Continental-List

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