X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-ma05.mx.aol.com ([64.12.100.31] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with ESMTP id 4983572 for flyrotary@lancaironline.net; Sat, 14 May 2011 11:05:12 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.100.31; envelope-from=Bktrub@aol.com Received: from imo-da01.mx.aol.com (imo-da01.mx.aol.com [205.188.169.199]) by imr-ma05.mx.aol.com (8.14.1/8.14.1) with ESMTP id p4EF4UKN020350 for ; Sat, 14 May 2011 11:04:30 -0400 Received: from Bktrub@aol.com by imo-da01.mx.aol.com (mail_out_v42.9.) id q.1093.62ee5f1 (45497) for ; Sat, 14 May 2011 11:04:26 -0400 (EDT) Received: from smtprly-de02.mx.aol.com (smtprly-de02.mx.aol.com [205.188.249.169]) by cia-mc08.mx.aol.com (v129.10) with ESMTP id MAILCIAMC084-b2344dce99f62bb; Sat, 14 May 2011 11:04:25 -0400 Received: from webmail-d068 (webmail-d068.sim.aol.com [205.188.59.133]) by smtprly-de02.mx.aol.com (v129.10) with ESMTP id MAILSMTPRLYDE021-b2344dce99f62bb; Sat, 14 May 2011 11:04:22 -0400 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: Engine Tuning Date: Sat, 14 May 2011 11:04:22 -0400 X-AOL-IP: 50.46.100.112 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: bktrub@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CDE05F5778873E_1AF8_6280D_webmail-d068.sysops.aol.com" X-Mailer: AOL Webmail 33668-STANDARD Received: from 50.46.100.112 by webmail-d068.sysops.aol.com (205.188.59.133) with HTTP (WebMailUI); Sat, 14 May 2011 11:04:22 -0400 Message-Id: <8CDE05F5771631E-1AF8-3D16B@webmail-d068.sysops.aol.com> X-Spam-Flag:NO X-AOL-SENDER: Bktrub@aol.com ----------MB_8CDE05F5778873E_1AF8_6280D_webmail-d068.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" I've had the same thought- that up at higher rpms I might be having some= sort of ignition problem. Adjusting the mixture does seem to mitigate it= somewhat, so that leads me to think that it is not an igntion problem. Al= so, it only seems to happen in flight, not on the ground, where the loads= are a little different. So, I still have questions about this, but I'm go= ing to approach this from the mixture angle. If I am having an igntion pro= blem, it's only happening at almost full throttle and in flight, so I'm sc= ratching my head trying to see how to test for this.=20 Brian Trubee -----Original Message----- From: Steven W. Boese To: Rotary motors in aircraft Sent: Fri, May 13, 2011 10:28 pm Subject: [FlyRotary] Re: Engine Tuning Brian (and anyone else with more experience than me), =20 With my engine stand, primary injectors as small as 21 lb and secondary in= jectors from 30 to 50 lb have been used, with MAP up to 30 inches. Mixtur= es from lean misfire to rich misfire have been set with RPM up to 5800. = Although misfires can be induced with mixture, at no time was there anyth= ing that could be considered a backfire and certainly nothing like a grena= de. In flight, I have induced misfires with rich as well as lean mixtures= again with nothing like the results you describe. My plane=E2=80=99s muf= fler is a hollow tube about 6 inches in diameter 3 feet long with a slight= ly less than 2=E2=80=9D diameter outlet and two chambers inside separated= by a conical wall. This muffler would seem to be more of a bomb than a= grenade if a backfire were to happen. Doesn=E2=80=99t the fact that ther= e is a viable fuel-air mixture in the exhaust system seem to indicate that= the problem may be ignition rather than mixture? This is just a question= , not intended to be an answer. =20 Steve Boese RV6A 1986 13B NA RD1A EC2 =20 =20 =20 =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Be= half Of bktrub@aol.com Sent: Friday, May 13, 2011 3:35 PM To: Rotary motors in aircraft Subject: [FlyRotary] Engine Tuning =20 Since the weather has been cooperating lately, I've had the opportunity to= put a few more hours on the airplane. On the ground, I can go from an idl= e up to full throttle and the engine will be smooth. But when I take off,= it seems that as soon as I'm up a few hundred feet off the runway, I get= hellacious backfiring at full throttle. I can mitigate it a bit by thrott= ling back to about 5100 rpm, and turning the mixture knob to near full ric= h. It's getting to be a bit nerve wracking to take off thinking I've got= it smoothed out and then get a series of hand grenades going off under my= butt. I'm thinking that I'm still running too lean up at map address 106= or so. So, I go into the edit page and richen up the mixture around those= addresses. I think I'm creeping up on smooth full throttle running. =20 The good news is that my coolant runs at 175 degrees and oil at less- so= the cooling is more than effective, I just need to close up my air inlet= a bit or restrict the outflow. =20 Brian Trubee =3D=20 ----------MB_8CDE05F5778873E_1AF8_6280D_webmail-d068.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8"
I've had the same thought- that up at higher rpms I might be having= some sort of ignition problem.  Adjusting the mixture does seem to= mitigate it somewhat, so that leads me to think that it is not an igntion= problem. Also, it only seems to happen in flight, not on the ground, wher= e the loads are a little different. So, I still have questions about this,= but I'm going to approach this from the mixture angle. If I am having an= igntion problem, it's only happening at almost full throttle and in fligh= t, so I'm scratching my head trying to see how to test for this.
 
Brian Trubee



-----Original Message-----
From: Steven W. Boese <SBoese@uwyo.edu>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Fri, May 13, 2011 10:28 pm
Subject: [FlyRotary] Re: Engine Tuning

Brian (and anyone else with more experience than me),
 
With my engine stand, primary injectors as small as 21 lb= and secondary injectors from 30 to 50 lb have been used, with MAP up to= 30 inches.  Mixtures from lean misfire to rich misfire have been set= with RPM up to 5800.  Although misfires can be induced with mixture,= at no time was there anything that could be considered a backfire and cer= tainly nothing like a grenade.  In flight, I have induced misfires wi= th rich as well as lean mixtures again with nothing like the results you= describe.  My plane=E2=80=99s muffler is a hollow tube about 6 inche= s in diameter 3 feet long with a slightly less than 2=E2=80=9D diameter ou= tlet and two chambers inside separated by a conical wall.  This muffl= er would seem to be more of a bomb than a grenade if a backfire were to ha= ppen.  Doesn=E2=80=99t the fact that there is a viable fuel-air mixtu= re in the exhaust system seem to indicate that the problem may be ignition= rather than mixture?  This is just a question, not intended to be an= answer.
          = ;            &= nbsp;           &nb= sp;            = ;            &= nbsp;     
Steve Boese
RV6A 1986 13B NA RD1A EC2
 
 
    
 
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of bktrub@aol.com
Sent: Friday, May 13, 2011 3:35 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Engine Tuning
 

Since the weather has been cooperating lately, I've had the opportunity to= put a few more hours on the airplane. On the ground, I can go from an idl= e up to full throttle and the engine will be smooth. But when I take off,= it seems that as soon as I'm up a few hundred feet off the runway, I get= hellacious backfiring at full throttle. I can mitigate it a bit by thrott= ling back to about 5100 rpm, and turning the mixture knob to near full ric= h. It's getting to be a bit nerve wracking to take off thinking I've got= it smoothed out and then get a series of hand grenades going off under my= butt. I'm thinking that I'm still running too lean up at map address 106= or so. So, I go into the edit page and richen up the mixture around those= addresses. I think I'm creeping up on smooth full throttle running.
 
The good news is that my coolant runs at= 175 degrees and oil at less- so the cooling is more than effective, I jus= t need to close up my air inlet a bit or restrict the outflow.
 
Brian Trubee
=3D
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