X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-mb01.mx.aol.com ([64.12.207.164] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with ESMTP id 4983875 for flyrotary@lancaironline.net; Sat, 14 May 2011 21:33:19 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.207.164; envelope-from=Lehanover@aol.com Received: from imo-ma03.mx.aol.com (imo-ma03.mx.aol.com [64.12.78.138]) by imr-mb01.mx.aol.com (8.14.1/8.14.1) with ESMTP id p4F1WZqJ032238 for ; Sat, 14 May 2011 21:32:35 -0400 Received: from Lehanover@aol.com by imo-ma03.mx.aol.com (mail_out_v42.9.) id q.d03.83e2ee79 (55712) for ; Sat, 14 May 2011 21:32:30 -0400 (EDT) Received: from magic-m25.mail.aol.com (magic-m25.mail.aol.com [172.20.22.198]) by cia-md01.mx.aol.com (v129.10) with ESMTP id MAILCIAMD013-d9a04dcf2d2e25b; Sat, 14 May 2011 21:32:30 -0400 From: Lehanover@aol.com Message-ID: <1e6af.40cfe971.3b00872e@aol.com> Date: Sat, 14 May 2011 21:32:30 EDT Subject: Re: [FlyRotary] Re: Engine Tuning To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_1e6af.40cfe971.3b00872e_boundary" X-Mailer: AOL 9.6 sub 130 X-AOL-IP: 173.88.24.45 X-Spam-Flag:NO X-AOL-SENDER: Lehanover@aol.com --part1_1e6af.40cfe971.3b00872e_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en If the problem reduces or vanishes when you reduce throttle, then it is = =20 probably a secondary ignition problem. Over-lean mixture would do that. So= if=20 it improves with richer mixture, there you are. Props on the ground are= =20 generally partially stalled and may not load the engine as well as a flyi= ng=20 prop. Higher airspeed reduces effective angle of attack. =20 There are several RPM where cylinder filling is slightly better than all= =20 other RPM. This is where you would see ignition problems if it is a margin= al =20 system. Try new plugs or shorten plug gap to .015" all around.=20 If the problem is gone, the ignition is having trouble lighting the mixtur= e=20 provided. So richer is easy to light and it becomes more difficult as you= =20 go leaner. The higher the cylinder pressure (best cylinder filling) the= =20 less likely to get an arc.=20 =20 Lynn E. Hanover=20 =20 =20 In a message dated 5/14/2011 11:05:25 A.M. Paraguay Standard Time, =20 bktrub@aol.com writes: I've had the same thought- that up at higher RPM I might be having some= =20 sort of ignition problem. Adjusting the mixture does seem to mitigate it= =20 somewhat, so that leads me to think that it is not an ignition problem.= Also,=20 it only seems to happen in flight, not on the ground, where the loads are= a=20 little different. So, I still have questions about this, but I'm going to= =20 approach this from the mixture angle. If I am having an ignition problem,= =20 it's only happening at almost full throttle and in flight, so I'm scratch= ing=20 my head trying to see how to test for this.=20 =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 =20 =20 Brian (and anyone else with more experience than me), =20 With my engine stand, primary injectors as small as 21 lb and secondary= =20 injectors from 30 to 50 lb have been used, with MAP up to 30 inches. =20 Mixtures from lean misfire to rich misfire have been set with RPM up to= 5800. =20 Although misfires can be induced with mixture, at no time was there anyth= ing=20 that could be considered a backfire and certainly nothing like a grenade.= =20 In flight, I have induced misfires with rich as well as lean mixtures aga= in=20 with nothing like the results you describe. My plane=E2=80=99s muffler= is a hollow=20 tube about 6 inches in diameter 3 feet long with a slightly less than 2= =E2=80=9D=20 diameter outlet and two chambers inside separated by a conical wall. Thi= s=20 muffler would seem to be more of a bomb than a grenade if a backfire were= to=20 happen. Doesn=E2=80=99t the fact that there is a viable fuel-air mixture= in the=20 exhaust system seem to indicate that the problem may be ignition rather= than=20 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_=20 (mailto:flyrotary@lancaironline.net?) ] On Behalf Of _bktrub@aol.com_=20 (mailto:bktrub@aol.com)=20 Sent: Friday, May 13, 2011 3:35 PM To: Rotary motors in aircraft Subject: [FlyRotary] Engine Tuning =20 =20 Since the weather has been cooperating lately, I've had the opportunity= to=20 put a few more hours on the airplane. On the ground, I can go from an idl= e=20 up to full throttle and the engine will be smooth. But when I take off,= it=20 seems that as soon as I'm up a few hundred feet off the runway, I get=20 hellacious backfiring at full throttle. I can mitigate it a bit by thrott= ling=20 back to about 5100 rpm, and turning the mixture knob to near full rich.= It's=20 getting to be a bit nerve wracking to take off thinking I've got it=20 smoothed out and then get a series of hand grenades going off under my bu= tt. I'm=20 thinking that I'm still running too lean up at map address 106 or so. So,= I=20 go into the edit page and richen up the mixture around those addresses.= I=20 think I'm creeping up on smooth full throttle running. =20 =20 The good news is that my coolant runs at 175 degrees and oil at less- so= =20 the cooling is more than effective, I just need to close up my air inlet= a=20 bit or restrict the outflow. =20 =20 Brian Trubee =3D=20 --part1_1e6af.40cfe971.3b00872e_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en <= FONT id=3Drole_document color=3D#000000 size=3D3 face=3DArial>
If the problem reduces or vanishes when you reduce throttle, then it= is=20 probably a secondary ignition problem. Over-lean mixture would do that. So= if it=20 improves with richer mixture, there you are. Props on the ground are gener= ally=20 partially stalled and may not load the engine as well as a flying prop. Hi= gher=20 airspeed reduces effective angle of attack.
 
There are several RPM where cylinder filling is slightly better than= all=20 other RPM. This is where you would see ignition problems if it is a margin= al=20 system. Try new plugs or shorten plug gap to .015" all around.
If the problem is gone, the ignition is having trouble lighting the= mixture=20 provided. So richer is easy to light and it becomes more difficult as you= go=20 leaner. The higher the cylinder pressure (best cylinder filling) the less= likely=20 to get an arc.
 
Lynn E. Hanover 
 
In a message dated 5/14/2011 11:05:25 A.M. Paraguay Standard Time,=20 bktrub@aol.com writes:
I've had the same thought- that up at higher RPM I might be ha= ving=20 some sort of ignition problem.  Adjusting the mixture does seem to= =20 mitigate it somewhat, so that leads me to think that it is not an igniti= on=20 problem. Also, it only seems to happen in flight, not on the ground, whe= re the=20 loads are a little different. So, I still have questions about this, but= I'm=20 going to approach this from the mixture angle. If I am having an ignitio= n=20 problem, it's only happening at almost full throttle and in flight, so= I'm=20 scratching my head trying to see how to test for this.
 
Brian Trubee



-----Original=20 Message-----
From: Steven W. Boese <SBoese@uwyo.edu>
To: Rot= ary=20 motors in aircraft <flyrotary@lancaironline.net>
Sent: Fri, May= 13,=20 2011 10:28 pm
Subject: [FlyRotary] Re: Engine Tuning

Brian (and anyone else=20 with more experience than me),
 
With my engine stand,=20 primary injectors as small as 21 lb and secondary injectors from 30 to= 50 lb=20 have been used, with MAP up to 30 inches.  Mixtures from lean misfi= re to=20 rich misfire have been set with RPM up to 5800.  Although misfires= can be=20 induced with mixture, at no time was there anything that could be consid= ered a=20 backfire and certainly nothing like a grenade.  In flight, I have= induced=20 misfires with rich as well as lean mixtures again with nothing like the= =20 results you describe.  My plane=E2=80=99s muffler is a hollow tube= about 6 inches=20 in diameter 3 feet long with a slightly less than 2=E2=80=9D diameter ou= tlet and two=20 chambers inside separated by a conical wall.  This muffler would se= em to=20 be more of a bomb than a grenade if a backfire were to happen.  Doe= sn=E2=80=99t=20 the fact that there is a viable fuel-air mixture in the exhaust system= seem to=20 indicate that the problem may be ignition rather than mixture?  Thi= s is=20 just a question, not intended to be an answer.
         &= nbsp;           &nb= sp;            = ;            &= nbsp;           &nb= sp;      =20
Steve=20 Boese
RV6A 1986 13B NA RD1A=20 EC2
 
 
 =20   
 
From: Rotary motors in=20 aircraft [mailto:flyrotary@lancaironline.net]= =20 On Behalf Of bktrub@aol.com
Sent: Friday, May=20 13, 2011 3:35 PM
To: Rotary motors in aircraft
Subject:<= /B>=20 [FlyRotary] Engine Tuning
 

Since=20 the weather has been cooperating lately, I've had the opportunity to put= a few=20 more hours on the airplane. On the ground, I can go from an idle up to= full=20 throttle and the engine will be smooth. But when I take off, it seems th= at as=20 soon as I'm up a few hundred feet off the runway, I get hellacious backf= iring=20 at full throttle. I can mitigate it a bit by throttling back to about 51= 00=20 rpm, and turning the mixture knob to near full rich. It's getting to be= a bit=20 nerve wracking to take off thinking I've got it smoothed out and then ge= t a=20 series of hand grenades going off under my butt. I'm thinking that I'm= still=20 running too lean up at map address 106 or so. So, I go into the edit pag= e and=20 richen up the mixture around those addresses. I think I'm creeping up on= =20 smooth full throttle running.
 
The=20 good news is that my coolant runs at 175 degrees and oil at less- so the= =20 cooling is more than effective, I just need to close up my air inlet a= bit or=20 restrict the outflow.
 
Brian=20 Trubee
=3D=20
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