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From: Bulent Aliev <atlasyts@bellsouth.net>
Subject: Re: [FlyRotary] Re: Intake design 101
Date: Sat, 29 Jul 2006 07:50:49 -0400
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>

Joe, Burns Stainess sells oval stainless tube and bends. I had the  
same idea, but my airplane budget was exhausted :). I'll have to do  
with round tubes,
Bulent "Buly" Aliev
FXE Ft lauderdale, FL
http://tinyurl.com/s5xw8


On Jul 29, 2006, at 7:35 AM, Joe Berki wrote:

> Ed,
> Thanks for the explanation.  Now i know why they are separated.   
> Looking at the ports I was wondering if an oval tube shape for the  
> runners would be appropriate.  I don't think that it is available,  
> however.
>
> Joe
> ----- Original Message -----
> From: Ed Anderson
> To: Rotary motors in aircraft
> Sent: Thursday, July 27, 2006 10:02 PM
> Subject: [FlyRotary] Re: Intake design 101
>
> Hi Joe,
>
> Each chamber has a secondary and a primary port (six ports have an  
> auxiliary port which is like an additional secondary port).  Even  
> thought a chamber has a primary and secondary, the primary and  
> secondary for a port  normally have different intake timing.   
> Additionally, the opening of the intake port generally generates a  
> very strong pulse (residue exhaust gas bursting out of the intake  
> when it opens).   Since the intake and secondary port of each rotor  
> are 60 deg out of phase timing wise with the other rotor, the pulse  
> generated by each port can interfere or assist with intake airflow  
> (depending on rpm, manifold air temp, density, etc).
>
> I personally prefer to keep the intake ports separate to preclude  
> interference.  Having said that - I have successfully flow with a  
> system that combined the secondary intakes and primary intakes, so  
> what you propose can be done. However, after trying six different  
> intake configurations,  I have found though that I get the best  
> performance (for our rpm) with 4 separate tubes feeding the  
> throttle body.  Keeping in mind I have a "Plugs Up" installation  
> which generally gives me a bit more room in running intake tubes.    
> Other arrangements have been tired and certainly work, so this is  
> no magic formula - just  based on my personal experience.
>
> Yes, the tuning (length) of the tubes should be determined by the  
> rpm band that you want the most airflow enhancement.  It appears  
> that a tube length from block to Throttle body between 17 and 21"  
> generally gives good results.  Also, avoid excessive large tubes   
> diameters as intake air velocity is important in stuffing the  
> chambers and larger tubes results in  less velocity.  I found that  
> 1.25" dia tubes for the primary and 1.5" dia tubes for the  
> secondary works well.
>
> I originally had my intakes merged into a two runner Weber style  
> manifold.  A two port Weber style throttle body with two 2" dia  
> intakes.  While this was the cats' meow for a racer turning 9000+  
> rpm, it turned out to be disappointing  in aircraft use with lower  
> 5000-6000 rpm.   When I replace this "racers'" set up with 4  
> smaller dia tubes my ROC increased by 300 fpm immediately.    
> Unfortunately my original fuel injection system died and I  did not  
> get to collect further data on my old six port 1986 engine before  
> deciding to switch to a 91 turbo block.
>
> Hope this helps.
>
> Ed
>
> Ed Anderson
> Rv-6A N494BW Rotary Powered
> Matthews, NC
> eanderson@carolina.rr.com
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
>
> 1----- Original Message -----
> From: Joe Berki
> To: Rotary motors in aircraft
> Sent: Thursday, July 27, 2006 9:24 PM
> Subject: [FlyRotary] Intake design 101
>
> I am using a 89 block for mock up and maybe rebuild.  Looking at  
> the intake ports, there are two ports at the front and rear of the  
> block then there are two rectangular ports in the center housing  
> close to each other.  Others have fabricated intakes using 4 tubes.  
> I assume it is OK for the two outboard front and rear of block to  
> be fed by one tube while the center two ports need to be fed  
> individually. Is this correct?  The length of the tubes is  
> determined by where on the rpm vs Hp band you want to operate at?  
> Thanks
>
> Joe Berki
> Limo EZ
>
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