X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from willowsprings.uwyo.edu ([129.72.10.31] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with ESMTPS id 4983278 for flyrotary@lancaironline.net; Sat, 14 May 2011 01:28:59 -0400 Received-SPF: none receiver=logan.com; client-ip=129.72.10.31; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht2.uwyo.edu (ponyexpress-ht2.uwyo.edu [10.84.60.209]) by willowsprings.uwyo.edu (8.14.4/8.14.4) with ESMTP id p4E5SKSM015251 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Fri, 13 May 2011 23:28:21 -0600 (MDT) (envelope-from SBoese@uwyo.edu) Received: from ponyexpress-mb5.uwyo.edu ([fe80::9813:248c:2d68:a28b]) by ponyexpress-ht2 ([10.84.60.209]) with mapi; Fri, 13 May 2011 23:28:20 -0600 From: "Steven W. Boese" To: Rotary motors in aircraft Date: Fri, 13 May 2011 23:28:16 -0600 Subject: RE: [FlyRotary] Engine Tuning Thread-Topic: [FlyRotary] Engine Tuning Thread-Index: AcwRtcIUTqZwzT67RH+a5vPk+WFAwAAPnNSw Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_E1AA3B1AF41D8049B1E3FBD5E2256260088BC0E5FFponyexpressmb_" MIME-Version: 1.0 --_000_E1AA3B1AF41D8049B1E3FBD5E2256260088BC0E5FFponyexpressmb_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Brian (and anyone else with more experience than me), With my engine stand, primary injectors as small as 21 lb and secondary inj= ectors 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. Alth= ough misfires can be induced with mixture, at no time was there anything th= at could be considered a backfire and certainly nothing like a grenade. In= flight, I have induced misfires with rich as well as lean mixtures again w= ith nothing like the results you describe. My plane's muffler is a hollow = tube about 6 inches in diameter 3 feet long with a slightly less than 2" di= ameter outlet and two chambers inside separated by a conical wall. This mu= ffler would seem to be more of a bomb than a grenade if a backfire were to = happen. Doesn't the fact that there is a viable fuel-air mixture in the ex= haust system seem to indicate that the problem may be ignition rather than = mixture? This is just a question, not intended to be an answer. Steve Boese RV6A 1986 13B NA RD1A EC2 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf 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 idle = 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 hella= cious backfiring at full throttle. I can mitigate it a bit by throttling ba= ck to about 5100 rpm, and turning the mixture knob to near full rich. It's = getting to be a bit nerve wracking to take off thinking I've got it smoothe= d out and then get a series of hand grenades going off under my butt. I'm t= hinking 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 t= hink 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 th= e cooling is more than effective, I just need to close up my air inlet a bi= t or restrict the outflow. Brian Trubee --_000_E1AA3B1AF41D8049B1E3FBD5E2256260088BC0E5FFponyexpressmb_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Brian (and anyone else with mo= re experience than me),

 

With my engine stand, primary injectors as small as 21 lb and s= econdary injectors from 30 to 50 lb have been used, with MAP up to 30 inche= s.  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 certainly nothi= ng like a grenade.  In flight, I have induced misfires with rich as we= ll as lean mixtures again with nothing like the results you describe. = My plane’s muffler is a hollow tube about 6 inches in diameter 3 fee= t long with a slightly less than 2” diameter outlet and two chambers = inside separated by a conical wall.  This muffler would seem to be mor= e of a bomb than a grenade if a backfire were to happen.  Doesn’= t the fact that there is a viable fuel-air mixture in the exhaust system se= em to indicate that the problem may be ignition rather than mixture?  = This is just a question, not intended to be an answer.

           &= nbsp;           &nbs= p;            &= nbsp;           &nbs= p;            &= nbsp;   

Steve Boese=

RV6A 1986 13B NA RD1A EC2

 

 

    

 

From:<= /b> Rota= ry 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 grou= nd, I can go from an idle 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 o= ff the runway, I get hellacious backfiring at full throttle. I can mitigate= it a bit by throttling back to about 5100 rpm, and turning the mixture kno= b to near full rich. It's getting to be a bit nerve wracking to take off th= inking I've got it smoothed out and then get a series of hand grenades goin= g 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 a= round those addresses. I think I'm creeping up on smooth full throttle runn= ing.

 

The good news is that my c= oolant runs at 175 degrees and oil at less- so the cooling is more than eff= ective, I just need to close up my air inlet a bit or restrict the outflow.=

 <= /span>

Brian Trubee=

= --_000_E1AA3B1AF41D8049B1E3FBD5E2256260088BC0E5FFponyexpressmb_--