Mailing List flyrotary@lancaironline.net Message #30045
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Why?? Re: [FlyRotary] RX-8
Date: Tue, 7 Feb 2006 20:19:10 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
That's certainly interesting, Randy,  in that the 6 port and 4 port Rx-8 engine both use identical internal parts.  True the induction system and port openings on the castings is different due to the number of ports - similar to the difference between the  older 13B six port and 4 port turbo engines.

While the 6 port will reportedly produce higher HP, its only when you get up into the 8500+ rpm range that is true.  Then the better high rpm breathing of the 6 port induction system gives it an edge in producing power. However, I know of no one who has exceeded 7500 rpm in aircraft application at this point.  Tracy Crook as probably a couple hundred hours on a  4 port .  I believe his conclusion was that the complexity of the six port intake Vs its potential adaptation for aircraft use made the 4 port preferable.

In any case, hard to understand why one engine would be junk when it shares the same design and parts as the other engine - sure would like to know some particulars about it.

Ed


----- Original Message ----- From: "randy echtinaw" <rjechtinaw@ia4u.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, February 07, 2006 7:17 PM
Subject: [FlyRotary] RX-8


Gentlemen,
   I have the opportunity to purchase a 4 port or a 6 port RX-8  engine. I thought I wanted a 4 port because I thought it would be  easier to muffel. I just heard a "rumor" that the 4 port is junk and  go with the 6 port. I need 220-230 hp using the 2.85 PSRU, no turbo.  I would consider P-porting if absolutely necessary to get the HP.  Obviously, I know very little about engines and want to start with  the best I can get so, considering my needs which one do I want?
Thank you,
Randy

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