Mailing List flyrotary@lancaironline.net Message #66927
From: Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Exhaust taming
Date: Tue, 20 Jul 2021 14:15:32 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>


On Mon, Jul 19, 2021 at 8:10 PM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
Hi people

After only ~40 hours of flight + ground testing the mild steel 2.5” resonator in our system was looking a lilt worse for wear.
The leading edge of the internal auger/spiral was disintegrating.

We have purchased a 304 stainless version that’s an inch longer and having it ceramic coated inside and out before reinstalling.

When I had the Glasair on the apron at full tilt the other day for some tuning of the newly installed EC3, a guy 
commented on its noise being similar to other quiet Lycomings. As in loudness, not pitch. 

I don’t know how much back pressure this type generates. Here they are called a “Gonzo”. They claim to be used in drag rotary application.
Would be interesting to instrument it, but I don’t think I can be bothered, as it seems to be developing good horsepower.

I expect this new stainless version will last much longer and be at least as effective.
But the proof will be when I run it up and next annual.

Here are some photos

Cheers

Steve Izett
Glasair Super IIRG

Looks, in concept, very similar to what Ed Anderson tried many years ago with split-washers-on-allthread. Would be interesting to know what it costs in power, & what it actually does to the exhaust. It *should* strip off the high frequency energy, which is the biggest battle for the rotary. Gotta wonder about power loss, though. It's amazing what a good job Mazda did with manifolds on the old 13Bs in the cars. Paul Conner's SQ2000 was the quietest rotary (or at least the least offensive) that I'd ever heard, until hearing Dennis Haverlah's Renesis.
Attached is a pic of Paul's installation. It sounded almost like a small block V8; very pleasing. And the total weight (~15 lbs) probably isn't any worse than most of the custom stuff we come up with today.

Charlie

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