X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ew0-f52.google.com ([209.85.215.52] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4600149 for flyrotary@lancaironline.net; Thu, 02 Dec 2010 14:04:23 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.215.52; envelope-from=msteitle@gmail.com Received: by ewy23 with SMTP id 23so5516961ewy.25 for ; Thu, 02 Dec 2010 11:03:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=8wesiVkKywsXqFzof6U+F+v0vy+sR5OiCQQRoaTXmdg=; b=IcWdwhqHrWPc0EfBKQK3b0YSCJZg+Paj86OQH6YvLMvMkQAqPotdXJmsDsCxtBmWQU 411ue7ZhL7R2MldTu5RCqQ0jV7bDhXhVT4yVoJe2VkOtOaaTitguwYnkhLiPps939LN6 9ld1LSCT0BWUiYbmBqwaZEin8oia96s3fMBbM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=iFqvau0sJFipQ/o5AKgwlhrajOx8PBXLgvaaJZadVqRpqkeAU2vGFyRT0wY3ikj0dO 8oFZ2m0g3FX9ctNoFeNgajJuYiHjcWokDrnkZFadWP+HemWUVhp/1L4+nCFqvX07VSOz bt2uTlgnSuFaH6mNOJa/yiv5YPgNG5L0ikGnM= MIME-Version: 1.0 Received: by 10.213.26.15 with SMTP id b15mr1489167ebc.13.1291316626414; Thu, 02 Dec 2010 11:03:46 -0800 (PST) Received: by 10.213.34.212 with HTTP; Thu, 2 Dec 2010 11:03:46 -0800 (PST) In-Reply-To: References: Date: Thu, 2 Dec 2010 13:03:46 -0600 Message-ID: Subject: Re: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] Re: Modified header Calculations From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015174a050acf603d049672148d --0015174a050acf603d049672148d Content-Type: text/plain; charset=ISO-8859-1 Brian, Same story with mine, and also Bobby Hughes'. My 3-rotor actually destroyed the perforated cone, but that was long after the packing had melted. The HP II is not robust enough for my needs. Check out the Spin Tech racing mufflers. They don't use any packing. Mark On Thu, Dec 2, 2010 at 11:22 AM, wrote: > I removed my Hushpower the other day to re-do the heat sheilding around it. > It's supmerged and does not get enough cooling air around it. I used an > aluminum heat sheild and some woven ceramic insulation with aluminized > mylar, I don't know what that particular heat sheilding is called, but, the > aluminum burned through and the maylar melted. So, I'm doing a re-design > where I have double stainless steel heat shielding with forced air going > through the air space. Backing that up will be a layer of fiberfrax. > > But, back to the Hushpower. When I pulled it off, I shook it and it sounds > like a baby rattle. So, I'm going to use a bore scope and see what's what > with it. Hmmm.... > > Brian Trubee > > > > -----Original Message----- > From: Ed Anderson > To: Rotary motors in aircraft > Sent: Thu, Dec 2, 2010 8:30 am > Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] Re: > Modified header Calculations > > I agree, Finn. It probably would not take much, but I just got to the > point I was tired of messing with it and put on the HushPower II. I always > felt I was just one more step away from making it successful - but did not > take it. Just too leery of learning to weld with only one good eye ball > left {:>) > > The 5/8" SS threaded shaft ran through the middle of the tube/discs with a > jam nut on each side of each disc. The shaft/rod was not anchored > otherwise. However, I did have a squished "Fishtail" end so that the last > disc could not back out of the tube. > > Ed > > *From:* Finn Lassen > *Sent:* Thursday, December 02, 2010 10:45 AM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] > Re: Modified header Calculations > > Hi Ed, > > Not that I'm going to jump on this right away, but it seems that it would > be relatively easy to rosette weld the tips of the discs. Drill 1/8" (or > slightly bigger) holes through the tube at the center of each disc tip. > > But, how did you secure the 5/8" shaft itself? > > Finn > > On 12/1/2010 5:45 PM, Ed Anderson wrote: > > Mark, > > Since you have not gotten to the muffler part of your design, here are some > thoughts (Yes, I did do 6 muffler experiments - don't ask me why) > > The one design that was "almost" totally successful in achieving my goals > is attached. Hard to make out the details, but enough to give you the > general ideal. > > My objective was trying to decided how to muffler the shock wave (which > creates most of the ear problems) but let the exhaust gas flow freely. My > conclusion was that reactive design muffler was the only acceptable choice > given our constraints. > > What I came up with was the idea of stuffing (I put five but I think three > would make a considerable difference) disc with outer parts cut into blades > and bent at a 45 deg angle into a tube. Looked a bit like an old farm > windmill. > > The idea behind this approach was if you looked head on at the fan-disc - > you see basically a solid metal front. That is what the shock wave would > see and most (a lot?) of the energy would be reflected back toward the > engine (actually to the next disc in the tube). The bent blades on the > other hand would permit exhaust gas to flow with minimum restriction. > > It really did deaden the sound where folks could stand by the wing tip with > no problem hearing someone else talk. I was thrilled. It also met my > minimum restriction as I could still get my 6000 rpm static. > > Ok, what went wrong - well, not being a welder I resorted to other methods > - which ultimately failed. > > Two things occurred - > > one if the disc broke loose of the small 5/8" thread SS shaft from the Jam > nuts on each side holding the disc, well, the disc could (and did) begin to > spin inside the tube like the turbine wheel of a jet engine. This > windmilling effect acted just like a windmilling prop on the exhaust gas and > definitely impeded gas flow. So can not permit the disc to spin (the tips > polished the inside of the tube where the spun) > > Second because I donot weld, I did not secure the tips of the blades of > the disc to the sides of the tube. Well the shock wave naturally causes > those blades to flex and eventually break off. > > The SS disc were 2" in diam 1/8 thick and fit really nice inside the 2 1/4" > tubes. I cut slots in the outer part of the SS disc and then used pliers to > bend the tabs to an approx 45 deg angle (see attached Jep). > > So none of this was difficult to fabricate (tedious perhaps but not > difficult). > > I gave up on it because without welding skills I could not figure out away > to secure the tips of the blades to the tube to give them better support. > Perhaps better than disc would have been cones but couldn't find any {:>). > > So since I couldn't see any way around my lack of welding (and too cheap to > hire someone), I went the hushpower II route. > > Just thought I would throw some fuel on your fire {:>) > > FWIW > > Ed > > > > --0015174a050acf603d049672148d Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Brian,=A0

Same story with mine, and also Bobby Hughes= 9;. =A0My 3-rotor actually destroyed the perforated cone, but that was long= after the packing had melted. =A0The HP II is not robust enough for my nee= ds. =A0Check out the Spin Tech racing mufflers. =A0They don't use any p= acking.

Mark =A0

On Thu, Dec = 2, 2010 at 11:22 AM, <bktrub@aol.com> wrote:
I removed my Hushpower the= other day to re-do the heat sheilding around it. It's supmerged and do= es not get enough cooling air around it. I used an aluminum heat sheild and= some woven=A0ceramic insulation=A0 with aluminized mylar, I don't know= what that particular heat sheilding is called, but, the aluminum burned th= rough and the maylar melted. So, I'm doing a re-design where I have dou= ble stainless steel heat shielding with forced air going through the air sp= ace.=A0Backing that up will be a layer of fiberfrax.
=A0
But, back to the Hushpower. When I pulled it off,=A0I shook it and=A0i= t sounds like a baby rattle. So, I'm going to=A0use a bore scope and=A0= see what's what with it. =A0Hmmm....
=A0
Brian Trubee



-----= Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, Dec 2, 2010 8:30 am
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] Re:= Modified header Calculations

I agree, Finn.=A0 It probably would=A0 not take m= uch, but I just got to the point I was tired of messing with it and put on = the HushPower II.=A0 I always felt I was just one more step away from makin= g it successful - but did not take it.=A0 Just too leery of learning to wel= d with only one good eye ball left {:>)
=A0
The 5/8" SS threaded shaft ran through the m= iddle of the tube/discs with a jam nut on each side of each disc.=A0 The sh= aft/rod was not anchored otherwise.=A0 However, I did have a squished "= ;Fishtail" end so that the last disc could not back out of the tube.
=A0
Ed

Sent: Thursday, December 02, 2010 10:45 AM
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [Fl= yRotary] Re: Modified header Calculations

Hi Ed,

Not that I'm going to jump on this right away, but it seems that it wou= ld be relatively easy to rosette weld the tips of the discs. Drill 1/8"= ; (or slightly bigger) holes through the tube at the center of each disc ti= p.

But, how did you secure the 5/8" shaft itself?

Finn

On 12/1/2010 5:45 PM, Ed Anderson wrote:=20
Mark,
=A0
Since you have not gotten to the muffler part of = your design, here are some thoughts (Yes, I did do 6 muffler experiments - = don't ask me why)
=A0
The one design=A0that was "almost" tota= lly successful in achieving my goals is attached.=A0 Hard to make out the d= etails, but enough to give you the general ideal.
=A0
My objective was trying to decided how to muffler= the shock wave (which creates most of the ear problems) but let the exhaus= t gas flow freely.=A0 My conclusion was that reactive design muffler was th= e only acceptable choice given our constraints.
=A0
What I came up with was the idea of stuffing (I= =A0 put five but I think three would make a considerable difference) disc w= ith outer parts cut into blades and bent at a 45 deg angle into a tube.=A0 = Looked a bit like an old farm windmill.
=A0
=A0 The idea behind this approach was if you look= ed head on at the fan-disc - you see basically a solid metal front.=A0 That= is what the shock wave would see and most (a lot?) of the energy would be = reflected back toward the engine (actually to the next disc in the tube).= =A0 The bent blades on the other hand would permit exhaust gas to flow with= minimum restriction.
=A0
It really did deaden the sound where folks could = stand by the wing tip with no problem hearing someone else talk.=A0I was th= rilled.=A0 It also met=A0 my minimum restriction as I could still get my 60= 00 rpm static.
=A0
Ok, what went wrong - well, not being a welder I = resorted to other methods - which ultimately failed.=A0
=A0
=A0Two things occurred -
=A0
one if the disc broke loose of the small 5/8"= ; thread SS shaft from the Jam nuts on each side holding the disc, well, th= e disc could (and did) begin to spin inside the tube like the turbine wheel= of a jet engine.=A0This windmilling effect acted just like a windmilling p= rop on the exhaust gas and definitely impeded gas flow.=A0 So can not permi= t the disc to spin (the tips polished the inside of the tube where the spun= )
=A0
=A0Second because I donot weld, I did not secure = the tips of the blades of the disc to the sides of the tube.=A0 Well the sh= ock wave naturally causes those blades to flex and eventually break off.
=A0
The SS disc were 2" in diam 1/8 thick=A0and = fit really nice inside the 2 1/4" tubes.=A0 I cut slots in the outer p= art of the SS=A0disc and then used pliers to bend the tabs to an approx 45 = deg angle (see attached Jep).
=A0
So none of this was difficult to fabricate (tedio= us perhaps but not difficult).
=A0
I gave up on it because without welding skills I = could not figure out away to secure the tips of the blades to the tube to g= ive them better support.=A0 Perhaps better than disc would have been cones = but couldn't find any {:>).
=A0
So since I couldn't see any way around my lac= k of welding (and too cheap to hire someone), I went=A0 the hushpower II ro= ute.
=A0
Just thought I would throw some fuel on your fire= {:>)
=A0
FWIW
=A0
Ed




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