X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.224] verified) by logan.com (CommuniGate Pro SMTP 5.2.11) with ESMTP id 3410247 for flyrotary@lancaironline.net; Sun, 04 Jan 2009 11:46:29 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.224; envelope-from=msteitle@gmail.com Received: by rv-out-0506.google.com with SMTP id f6so8722445rvb.7 for ; Sun, 04 Jan 2009 08:45:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:in-reply-to:mime-version:content-type:references; bh=ak6w5ALrFGpB2e71Pyvs5GVbcIi/AOekOVonezPueNc=; b=J/KvJ64nt8OpWeJxZyIzFQXyTdAmMU3VXx4UsTgBPmFYINX4c5Pjko6qCzCO04jpAi wwhYhHQHKjtwdSwtphUj9EltoL3OTap2c38+givAzANpe9myvJYBdWfzFe4xYXrWUGcC l6lGimIDlWmi8iV8zWU6jTuxy2yZhqWYQ78MA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version :content-type:references; b=iRl08xtk03eJflpnnfyOXX7jVwTQt4mHlqYWZDZWx4S2ffuuZ7OOkVhx+2y1dM14UD CrN9TfZedufIjrWgvojEAEsxn+dGIJTHhnpaFgQxo3hXtvxl04Dady698bf9+b0KDe3G zpf0yr9xrn2kVPZYXhj+a8TYy9OOOwFhywDEQ= Received: by 10.141.210.21 with SMTP id m21mr9908199rvq.204.1231087551786; Sun, 04 Jan 2009 08:45:51 -0800 (PST) Received: by 10.140.166.4 with HTTP; Sun, 4 Jan 2009 08:45:51 -0800 (PST) Message-ID: <5cf132c0901040845g6aa3564btdb2bc7f09552fff@mail.gmail.com> Date: Sun, 4 Jan 2009 10:45:51 -0600 From: "Mark Steitle" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: 20B install issues overcome In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_94530_29302735.1231087551779" References: ------=_Part_94530_29302735.1231087551779 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline I guess the prop chopping the noise stream could account for some of the perception of quietness. As for the muffler/resonator, 6db is a significan= t reduction. I think I still have the drawings you provided. The nice thing about the tangential muffler design is that it will fit inside my cowl. Th= e muffler/resonator should fit where the Hushpower 2 is now. We'll see. Mark On Sun, Jan 4, 2009 at 10:17 AM, Al Gietzen wrote: > *Subject:* [FlyRotary] Re: 20B install issues overcome > > > > My exhaust exits about 6-7 inches from prop and goes through near the roo= t > of the blades (pusher). It occurs to me that having my exhaust exit throu= gh > the prop may help reduce or mask the exhaust noise. On a takeoff roll th= ere > is a prop blade breaking that exhaust stream about 130 times per second. > Let's see, that's about 1 blade passing for every two exhaust pulses on t= he > 20B =96 could make a difference. > > > > The secondary muffler/resonator I have also helps. On the dyno we measur= ed > that resulted in about 6 db reduction. > > > > Al G > > Agree. Unfortunately, that's not a comment I hear. On the contrary, the= y > usually tell me that they can hear me before they can see me. ;-( > > Mark S. > ANR headsets mandatory > > On Sun, Jan 4, 2009 at 12:22 AM, Al Gietzen wrote: > > I'm presently gathering materials to fabricate a tangential muffler made > from inconel, similar to your design. I take it from your report that yo= ur > muffler is holding up well? > > Mark S. > > > > So far it is doing fine. And the inconel tangential and the 321SS > secondary muffler (my own design) quiet it down nicely. A few days ago I > picked up my brother to go for a ride, while my sister-in-law waited and > watched other planes come and go. When we got back her remark was that m= y > plane was quieter than all the rest. I consider that to be 'expert > testimony'J. > > Al G > > On Sat, Jan 3, 2009 at 5:47 PM, Al Gietzen wrote: > > Al, > > That's a great shot. Have you had any "significant issues" with your > install? If so, how did you overcome them? > Mark S. > > I had 2 issues that required some time and determination. The first was t= he > RWS EC2. I had an early version for the 3-rotor, and perhaps the first > installed in a composite airplane. I had some kind of electrical noise > related corruption of settings which persisted through a lot of effort fo= r > over a years time. It has been resolved, and the engine running fine. Th= at > has been discussed here more than once in the past. > > The other was less-than-expected performance of an oil cooler built into > the wing root, without much of a scoop for the inlet below the wing. The > theory was that the differential pressure below/above the wing would help > provide the necessary air flow. Not the case here as the location is too > far back on the wing; and behind the strake (the inboard section on the > canard airplane). The pressure differential turned out to be only about = 1" > H20 =96 very little help. I added a ram scoop, and installed a small > oil/water heat exchanger in the cowl. Currently oil temps are fine, and = the > coolant temp is running a bit lower than I like at cruise. I may eventua= lly > install some sort of air flow adjustment, or even consider installing a > thermostat in the engine. You may recall discussion of these changes her= e > in the past as well. > > I'm just past 140 hours flying time, and feel quite fortunate with how we= ll > things have worked out. Performance and economy are great. > > Al G http://members.cox.net/alg3/airplane.htm > > > > > > > > > ------=_Part_94530_29302735.1231087551779 Content-Type: text/html; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline I guess the prop chopping the noise stream could account for some of the pe= rception of quietness.  As for the muffler/resonator, 6db is a signifi= cant reduction.  I think I still have the drawings you provided. = The nice thing about the tangential muffler design is that it will fit ins= ide my cowl.  The muffler/resonator should fit where the Hushpower 2 i= s now.  We'll see.

Mark

On Sun, Jan 4, 2009 at 10:17 AM,= Al Gietzen <ALV= entures@cox.net> wrote:

Subject:= [FlyRotary] Re: 20B install issues overcome

=  

My exhaust exits about 6-7 inc= hes from prop and goes through near the root of the blades (pusher). It occurs to me that having my exhaust exit through the prop may help reduce or mask the exhaust noise.  On a takeoff roll there is a prop blade breaking that exhaust stream about 130 times per second. Let's see, that's about 1 blade passing for every two exhaust pulses on the 20B =96 could make a difference.

 

The secondary muffler/resonato= r I have also helps.  On the dyno we measured that resulted in about 6 db reduc= tion.

 

Al G

Ag= ree.  Unfortunately, that's not a comment I hear.  On the contrary, they= usually tell me that they can hear me before they can see me.  ;-( 

Mark S.
ANR headsets mandatory

= On Sun, Jan 4, 2009 at 12:22= AM, Al Gietzen <ALVentures@cox.net> wrote:

I= 9;m presently gathering materials to fabricate a tangential muffler made from inconel, similar to your design.  I take it from your report that your muffler = is holding up well?        

Mark S.

 

So far it is doing fine.  And = the inconel tangential and the 321SS secondary muffler (my own design) quiet it down nicely.  A few d= ays ago I picked up my brother to go for a ride, while my sister-in-law waited = and watched other planes come and go.  When we got back her remark was tha= t my plane was quieter than all the rest.  I consider that to be 'exper= t testimony'J= .

Al G

On Sat, Jan 3, 2009 at 5:47 PM= , Al Gietzen <AL= Ventures@cox.net> wrote:

Al= ,

That's a great shot.  Have you had any "significant issues&qu= ot; with your install?  If so, how did you overcome them?
Mark S. 

I had 2 issues that required some tim= e and determination. The first was the RWS EC2.  I had an early version for the 3-rotor, and perhaps = the first installed in a composite airplane.  I had some kind of electrica= l noise related corruption of settings which persisted through a lot of effor= t for over a years time. It has been resolved, and the engine running fine.&n= bsp; That has been discussed here more than once in the past.

The other was less-than-expected perf= ormance of an oil cooler built into the wing root, without much of a scoop for the inlet below the wing.  The theory was that the differential pressure below/above the wing wo= uld help provide the necessary air flow.  Not the case here as the location is = too far back on the wing; and behind the strake (the inboard section on the can= ard airplane).  The pressure differential turned out to be only about 1&qu= ot; H20 =96 very little help.  I added a ram scoop, and installed a small oil/water heat exchanger in the cowl.  Currently oil temps are fine, a= nd the coolant temp is running a bit lower than I like at cruise.  I may eventually install some sort of air flow adjustment, or even consider insta= lling a thermostat in the engine.  You may recall discussion of these change= s here in the past as well.

I'm just past 140 hours flying ti= me, and feel quite fortunate with how well things have worked out.  Performance and economy are great.

Al G   http://members.cox.net/a= lg3/airplane.htm

 

 

 

=  


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