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The 90 degrees out of phase Enya .29

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The 90 degrees out of phase Enya .29

Post  rsv1cox on Wed Jan 04, 2017 9:24 am

I have to try it, but I'm unsure about the prop. Why can't I just reverse it and achieve the same results with pulling power while running backwards? I know that Cox sells left hand propellers but I never see them outside of 1/2A.







Look Ma, no head gasket, no case gasket either or a venturi insert.



I couldn't make up my mind as to the orientation of the NVA. I decided the needle toward the bottom rather than adjusting it between the rotating prop and the cylinder. Would work better in C/L on vertical beams that way too. There has been discussion here relating to the position of the hole in the spray bar. Some say straight down may not be the best option. It's a crap shoot anyway as you can't see in there. Sometimes I put a magic marker dot 180 out, but in later engines Enya actually stamped a dot there, a big help.



Bob
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Re: The 90 degrees out of phase Enya .29

Post  balogh on Wed Jan 04, 2017 12:14 pm

Bob,

I am a bit perplexed at the 90 degrees off-set of the Venturi, but need to think it over a bit deeper. The porting on the crankshaft of rotary valve engines may have been originally set so as to have the Venturi and cylinder axis in parallel. If you rotate the venturi by 90 degrees the venturi porting will not be open when the piston moves upwards and designed to suck in the fuel-air mixture, so I am afraid the engine will not work in this 90 degree off-set assembly.
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Re: The 90 degrees out of phase Enya .29

Post  rsv1cox on Wed Jan 04, 2017 12:21 pm

balogh wrote:Bob,

I am a bit perplexed at the 90 degrees off-set of the Venturi, but need to think it over a bit deeper. The porting on the crankshaft of rotary valve engines may have been originally set so as to have the Venturi and cylinder axis in parallel. If you rotate the venturi by 90 degrees the venturi porting will not be open when the piston moves upwards and designed to suck in the fuel-air mixture, so I am afraid the engine will  not work in this 90 degree off-set assembly.

This gives a little history. Bottom of page one and some on page two.

https://www.coxengineforum.com/t10471-cleaned-up-and-ready-for-prime-time

Bob
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Re: The 90 degrees out of phase Enya .29

Post  fredvon4 on Wed Jan 04, 2017 12:24 pm

Think about when the intake port first opens when rotating the crank counter clockwise and then after shifting the crankcase venturi opening by 90 Degrees where the Crankshaft port will now Open first, if rotated Clockwise...
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Re: The 90 degrees out of phase Enya .29

Post  balogh on Wed Jan 04, 2017 12:48 pm

Sorry I missed the "history" but it really looks to make sense with clockwise rotation..
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Re: The 90 degrees out of phase Enya .29

Post  pkrankow on Wed Jan 04, 2017 1:10 pm

This is a test stand run right?

The prop, reversed, with reverse rotation, will present the proper edge leading into the rotation. The airflow will be away from the engine. This may cause cooling concern as there will not be a strong air blast, instead a less strong air draw, over the cooling fins. It likely will be fine with no issue on the test stand. I would be surprised if the airflow is inadequate for cooling.

Phil
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Re: The 90 degrees out of phase Enya .29

Post  rsv1cox on Wed Jan 04, 2017 2:09 pm

pkrankow wrote:This is a test stand run right?

The prop, reversed, with reverse rotation, will present the proper edge leading into the rotation.  The airflow will be away from the  engine.  This may cause cooling concern as there will not be a strong air blast, instead a less strong air draw, over the cooling fins.  It likely will be fine with no issue on the test stand.  I would be surprised if the airflow is inadequate for cooling.

Phil

Yes, test run only just to prove the concept to myself. I don't want to harm the engine. As soon as the test is over the front end gets rotated back to the proper position. I love these little pot bellied external intake Enyas.

I'm going to wait until I receive the new test stand too. Test both at the same time. Smile

Bob
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Re: The 90 degrees out of phase Enya .29

Post  Oldenginerod on Wed Jan 04, 2017 3:05 pm

rsv1cox wrote:

Look Ma, no head gasket, no case gasket either or a venturi insert.




Does it use a head gasket?  I think most of my Enyas that I've stripped down don't use a gasket.  The head just laps to the liner.
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Re: The 90 degrees out of phase Enya .29

Post  rsv1cox on Wed Jan 04, 2017 3:10 pm

Oldenginerod wrote:
rsv1cox wrote:

Look Ma, no head gasket, no case gasket either or a venturi insert.




Does it use a head gasket?  I think most of my Enyas that I've stripped down don't use a gasket.  The head just laps to the liner.

You have to look real close Rod, but on most later models they are there. I have actually had a couple come loose. I have a picture somewhere.

Bob
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Re: The 90 degrees out of phase Enya .29

Post  rsv1cox on Wed Jan 04, 2017 3:17 pm

fredvon4 wrote:Think about when the intake port first opens when rotating the crank counter clockwise and then after shifting the crankcase venturi opening by 90 Degrees where the Crankshaft port will now Open first, if rotated Clockwise...

Bob Allan talks about the size of that port Fred, it's comparatively huge.  He thinks that it is one of the things that makes the .29 so special.  It's cut rectangular not oval like most.



BTW, I would love to have a wood burning cast iron stove made in that design for the shed.  Firebox the front end opening etc. Smile

I gotta get out of the house......... Sorta nice today, snow the next couple then the bottom falls out over the weekend temperature wise.

Bob
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Re: The 90 degrees out of phase Enya .29

Post  Cribbs74 on Wed Jan 04, 2017 8:53 pm

Bob,

While it appears that having the needle on the bottom would make it safer, the reality is it will cause you to access it from an awkward angle. I have had needles that pointed down and it was uncomfortable at best to adjust. Just a suggestion.

Ron
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