X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost06.isp.att.net ([207.115.11.56] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTP id 5566729 for flyrotary@lancaironline.net; Tue, 29 May 2012 17:24:23 -0400 Received-SPF: none receiver=logan.com; client-ip=207.115.11.56; envelope-from=bbradburry@bellsouth.net Received: from desktop (adsl-98-85-108-233.mco.bellsouth.net[98.85.108.233]) by isp.att.net (frfwmhc06) with SMTP id <20120529212348H0600703gqe>; Tue, 29 May 2012 21:23:48 +0000 X-Originating-IP: [98.85.108.233] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Injector balancing Date: Tue, 29 May 2012 17:23:50 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000A_01CD3DBF.D09EFA60" X-Mailer: Microsoft Office Outlook 11 Thread-Index: Ac093IGZX3TV30zzR/qyYtXdgNYC8wAA+38Q X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18463 This is a multi-part message in MIME format. ------=_NextPart_000_000A_01CD3DBF.D09EFA60 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Mark, Are you starving the back (#1 rotor) for air? It seems you said you had a 4" scat tube feeding the airbox. That is 12.56 sq in. divide that by three, divide that by 3.14, take the sq root, and you come up with 1.15 diameter for your runners. You probably have runners of 2" or so. They may require more air than the scat tube can deliver??? Remove the airbox and see what happens?? B2 _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle Sent: Tuesday, May 29, 2012 4:49 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Injector balancing Ernest, I don't understand how that could happen if my injectors are after the airbox (see attached pic). Mark On Tue, May 29, 2012 at 1:23 PM, Ernest Christley wrote: Mark Steitle wrote: > Ernest, > > Not sure you intake and mine are very similar. I assume that you have a > single TB. Since I'm running a p-port motor, I needed to have the > throttle plates as close to the intake ports as possible. So, I'm > running three separate 46mm throttle bodies. The primary injectors are > between the butterflies and the intake ports. The primary injector > bungs are cast into the TB's. They share a 1-piece throttle shaft. > > The secondary injectors are located further out on the runners ahead of > the butterflies. Each runner connects to a single airbox. The #1 > intake is at the rear of the airbox, #2 in the middle, and #3 in the > front. Air is fed in from the front corner with a 4" SCAT. I could > test your theory by removing the airbox. This would make all three > intake runners identical. May be worth a try. > For the purposes of my theory, your setup is nearly identical to what I started with. The air came in the front, blew past the first rotor, and the rotor in the back wound up with its fuel and part of the front's. The plate I put in made it so that the incoming air did not blow past the front rotor's intake toward the second. Instead, it now has to pressurize the manifold, and then roll around the plate to approach both runners directly. I had idle EGT differences of 400* to 500*, and only evened out when the speed got really fast. They now hang within 100* at idle, and are dead even over 2000rpm. Verifying even flow is a necessary exercise, but from your description I strongly suspect that you have a pressure distribution problem in your plenum. -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_000A_01CD3DBF.D09EFA60 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Mark,

Are you starving the back (#1 = rotor) for air?  It seems you said you had a 4” scat tube feeding the airbox.  That is 12.56 sq in.  divide that by three, divide = that by 3.14, take the sq root, and you come up with 1.15 diameter for your runners.  You probably have runners of 2” or so.  They = may require more air than the scat tube can deliver???

 

Remove the airbox and see what = happens??

 

B2

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Tuesday, May 29, = 2012 4:49 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Injector balancing

 

Ernest, 

 

I don't understand how that could happen if my injectors are = after the airbox (see attached pic).  

 

Mark

On Tue, May 29, 2012 at 1:23 PM, Ernest Christley <echristley@att.net> wrote:

Mark Steitle = wrote:
> Ernest,
>
> Not sure you intake and mine are very similar.  I assume that = you have a
> single TB.  Since I'm running a p-port motor, I needed to have = the
> throttle plates as close to the intake ports as possible.  So, = I'm
> running three separate 46mm throttle bodies.  The primary = injectors are
> between the butterflies and the intake ports.  The primary = injector
> bungs are cast into the TB's.  They share a 1-piece throttle = shaft.
>
> The secondary injectors are located further out on the runners = ahead of
> the butterflies.  Each runner connects to a single airbox. =  The #1
> intake is at the rear of the airbox, #2 in the middle, and #3 in = the
> front.  Air is fed in from the front corner with a 4" = SCAT.  I could
> test your theory by removing the airbox.  This would make all = three
> intake runners identical.  May be worth a try.
>

For the purposes of my theory, your setup is nearly identical to = what I started with.  The air came in the front, blew
past the first rotor, and the rotor in the back wound up with its fuel = and part of the front's.  The plate I put in made
it so that the incoming air did not blow past the front rotor's intake = toward the second.  Instead, it now has to
pressurize the manifold, and then roll around the plate to approach both runners directly.  I had idle EGT differences
of 400* to 500*, and only evened out when the speed got really fast. =  They now hang within 100* at idle, and are dead
even over 2000rpm.

Verifying even flow is a necessary exercise, but from your description I strongly suspect that you have a pressure
distribution problem in your plenum.

 

------=_NextPart_000_000A_01CD3DBF.D09EFA60--