Mailing List flyrotary@lancaironline.net Message #43703
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: RE: [FlyRotary] Exhaust inserts
Date: Mon, 11 Aug 2008 19:32:15 -0400
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

Giff, both model engines have harden metal inserts in the aluminum housing to protect the soft aluminum from the exhaust heat.  Without them the aluminum would erode away very quickly. 

 

However, the difference between the inserts in the N/A and Turbo is the N/A has a horizontal plate across the exit (approx mid way) with a bit of a twist that according to reports I have seen knocks 8 db off the exhaust noise.  The turbo block does not have this “splitter” because it was designed to be used with a turbocharger which would knock down the exhaust nose.

 

Some folks believe (I’m one of them) that device that takes 8 db of energy out of the exhaust must restrict the exhaust flow to some degree.  Ergo – turbo blocks should make a few more HP at higher rpm – however, I’ve never seen any dyno data to support this supposition.  I can also tell you that without the splitters or the turbocharger the exhaust noise of a turbo block without some sort of muffler is indeed awesome.  I measured 125 db 12 feet from mine (without muffler) – and that was as high as the sound meter went – so it could have been even more.  It’s not loud – its ear shattering!! 

 

So whether the supposed few HP increase is worth the “ear ache” of dealing with the louder exhaust is worth it – is up for you to decide.

 

Ed

 

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.dmack.net/mazda/index.html


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Giffen Marr
Sent: Monday, August 11, 2008 4:46 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Exhaust inserts

 

Question

 

Are the exhaust inserts only used in the NA engines and not the turbo versions?

 

Giff Marr

LIV-P/Mistral 70%



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