X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao107.cox.net ([68.230.241.39] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3636927 for flyrotary@lancaironline.net; Sat, 09 May 2009 11:06:36 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.39; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao107.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090509150559.EGRM18948.fed1rmmtao107.cox.net@fed1rmimpo01.cox.net> for ; Sat, 9 May 2009 11:05:59 -0400 Received: from wills ([68.105.85.56]) by fed1rmimpo01.cox.net with bizsmtp id pT5w1b00P1CvZmk03T5zad; Sat, 09 May 2009 11:05:59 -0400 X-Authority-Analysis: v=1.0 c=1 a=2d7qRJAEPIAA:10 a=EEhfZQHbKQgA:10 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=kviXuzpPAAAA:8 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=1q_Mh7ndguj_-egj8goA:9 a=gF92FClTCkSFen437pwA:7 a=snFUmsAxlTsB1BlrVNveHLTxuZsA:4 a=zqXRXsriYoUA:10 a=EzXvWhQp4_cA:10 a=SSmOFEACAAAA:8 a=MSIrFWRBXYMxAu05tD8A:9 a=nFrwHj-JF4f_hTBmn0oA:7 a=UWteNODyYZ4Pgx0I_4YDkV9yVXoA:4 X-CM-Score: 0.00 Message-ID: <5E6A30197D7641A1B34AF06EA5F42930@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Lean Surge?: [FlyRotary] Initial Tuning at Low RPM - surging? Date: Sat, 9 May 2009 08:05:55 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000F_01C9D07C.FA9439B0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_000F_01C9D07C.FA9439B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed's story makes me glad I'm doing my test flying off of an 8,000' = runway. :-) Although doing any testing for the past coule of weeks has = been a real pain - the Red Bull Air Race is in town and they've pretty = much taken over the airport. Pretty cool to see their operation up = close. The airplanes these guys fly are unbelievable. Ed says it would not be impossible to tune without an graphical = representation of the MCT of some sort. He may be right about that, but = I doubt you could ever get it as well tuned as you could with the proper = instrumentation. At near idle settings the MCT shifts from MAP based to = RPM based. In this region the resolution becomes much finer. I just dont = see how you could tune this section of the MCT properly without being = able to see it - you are highly likely to leave gaps. At least that was = my experience. I thought my engine was tuned pretty well before I installed the EFISM. = Well enough to do my first flight. Had some engine surging on base and = final approach - nothing serious, just enough to get your attention. = This surging had not been evident on the ground. Decided to bite the = bullet and install the EFISM. I was shocked at how many gaps there were = in the MCT and this was after about 15 hours of ground running/tuning. Mike Wills RV-4 N144MW ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Saturday, May 09, 2009 4:57 AM Subject: [FlyRotary] Lean Surge?: [FlyRotary] Initial Tuning at Low = RPM - surging? Hi Mike, =20 As mentioned by others, improper fuel ratio is likely the cause. In = my case, I once had to abort a takeoff early in my project when I still = used an aftermarket EFI. You could only set the values for rpm higher = than static after take off and the rpm started to increase. I had just = lifted off with the engine rpm inching past static rpm when the engine = began a radical surge - would swing from 4800 - 5500 rpm. Not knowing = the cause at the time, I elected to abort the take off and put her back = on the 2200 ft runway. Touched down 300 ft from the end doing approx = 70-80 mph and managed to get most stopped on the runway (did go off the = end about 10-12 ft).=20 =20 The problem was when the engine started to using the part of the fuel = map that I had to extrapolate the values for (rpm higher than static), = it was too lean. As a consequence when the engine hit this region and = found less fuel than needed to maintain the rpm, the engine being = 'leaned out" loss power and the rpm dropped back until it found a region = of the fuel map that was "rich" enough to support it, it would then = start to run back up the fuel map into regions of increasing richness = until it again hit the lean region, would drop back, etc. If I had been = more knowledgeable, had more time and thought of it, I would have = simply reached over and increase the manual mixture control - would have = certainly been less interesting than my panic 300 ft track of tire = rubber left on the tarmac {:>)-=20 =20 As was noted by Mike Wills, not having a visual representation of the = fuel map (EM2/3 or my EFISM) and where the engine is operating makes it = harder (but not impossible) to identify and fix these problems. My = EFISM shows the fuel map, the engine operating point on the map, an = Air/Fuel ratio indicator, as well as the values for each bar of the fuel = map all on one screen at one time. Tracy's EM2/3 provides similar = information. So if your engine hits a fuel bin and the A/F goes lean = and you get a hesitation in the engine - then the responsible fuel bin = probably needs adjustment. =20 Also, make certain that your EC2/3 manifold pressure sensors are = reading manifold pressure. If they have a leak then they will see = ambient pressure and not manifold. This generally will make the mixture = way too rich at idle and low rpm, and then if you adjust the EC2/3 to = compensate for this overly richness at idle it becomes too lean at high = power settings. =20 =20 Ed =20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Mike Fontenot Sent: Saturday, May 09, 2009 12:10 AM To: Rotary motors in aircraft Subject: [FlyRotary] Initial Tuning at Low RPM - surging? =20 Tracy, >>Large changes in the MAP table values can do that but you did not = say at what point in the tuning procedure this turned up. What have you = done or tried so far?<< I was not specifically tuning, and have not started that seriously. My = question was a general one about why surging happens in something like = my GEO. I'm hoping to tie the trike down on Sunday and really start = tuning (if the weather holds out). Thanks, --=20 Mike = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D Mike Fontenot Apex Consulting & Services LLC Lakewood, Colorado 303 / 731-6645 mikef AT apexconsultingservices DOT com = =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D ------=_NextPart_000_000F_01C9D07C.FA9439B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed's story makes me glad I'm doing my = test flying=20 off of an 8,000' runway. :-)  Although doing any testing for the = past coule=20 of weeks has been a real pain - the Red Bull Air Race is in town and = they've=20 pretty much taken over the airport. Pretty cool to see their operation = up close.=20 The airplanes these guys fly are unbelievable.
 
Ed says it would not be impossible to = tune without=20 an graphical representation of the MCT of some sort. He may be right = about that,=20 but I doubt you could ever get it as well tuned as you could with the = proper=20 instrumentation. At near idle settings the MCT shifts from MAP based to = RPM=20 based. In this region the resolution becomes much finer. I just dont see = how you=20 could tune this section of the MCT properly without being able to see it = - you=20 are highly likely to leave gaps. At least that was my = experience.
 
I thought my engine was tuned pretty = well before I=20 installed the EFISM. Well enough to do my first flight. Had some engine = surging=20 on base and final approach - nothing serious, just enough to get your = attention.=20 This surging had not been evident on the ground. Decided to bite the = bullet and=20 install the EFISM. I was shocked at how many gaps there were in the MCT = and this=20 was after about 15 hours of ground running/tuning.
 
Mike Wills
RV-4 N144MW
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Saturday, May 09, 2009 = 4:57=20 AM
Subject: [FlyRotary] Lean = Surge?:=20 [FlyRotary] Initial Tuning at Low RPM - surging?

Hi=20 Mike,

 

As = mentioned by=20 others, improper fuel ratio is likely the cause.  In my case, I = once had=20 to abort a takeoff early in my project when I still used an = aftermarket=20 EFI.  You could only set the values for rpm higher than static = after take=20 off and the rpm started to increase.  I had just lifted off with = the=20 engine rpm inching past static rpm when the engine began a radical = surge =96=20 would swing from 4800 =96 5500 rpm.  Not knowing the cause at the = time, I=20 elected to abort the take off and put her back on the 2200 ft = runway. =20 Touched down 300 ft from the end doing approx 70-80 mph and managed to = get=20 most stopped on the runway (did go off the end about 10-12 ft).=20

 

The problem = was when=20 the engine started to using the part of the fuel map that I had to = extrapolate=20 the values for (rpm higher than static), it was too lean.  As a=20 consequence when the engine hit this region and found less fuel than = needed to=20 maintain the rpm, the engine being =91leaned out=94 loss power and the = rpm dropped=20 back until it found a region of the fuel map that was =93rich=94 = enough to support=20 it, it would then start to run back up the fuel map into regions of = increasing=20 richness until it again hit the lean region, would drop back, = etc.  If I=20 had been more knowledgeable, had more time and thought of it,  I = would=20 have simply reached over and increase the manual mixture control =96 = would have=20 certainly been less interesting than my panic 300 ft track of tire = rubber left=20 on the tarmac {:>)-

 

As was = noted by Mike=20 Wills, not having a visual representation of the fuel map (EM2/3 or my = EFISM)=20 and where the engine is operating makes it harder (but not impossible) = to=20 identify and fix these problems.  My EFISM shows the fuel map, = the engine=20 operating point on the map, an Air/Fuel ratio indicator, as well as = the values=20 for each bar of the fuel map all on one screen at one time. Tracy=92s = EM2/3 provides=20 similar information.   So if your engine hits a fuel bin and = the A/F=20 goes lean and you get a hesitation in the engine =96 then the = responsible fuel=20 bin probably needs adjustment.

 

Also, make = certain=20 that your EC2/3 manifold pressure sensors are reading manifold = pressure. =20 If they have a leak then they will see ambient pressure and not=20 manifold.  This generally will make the mixture way too rich at = idle and=20 low rpm, and then if you adjust the EC2/3 to compensate for this = overly=20 richness at idle it becomes too lean at high power settings. =20

 

Ed

 

Ed=20 Anderson

Rv-6A = N494BW Rotary=20 Powered

Matthews,=20 NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Mike Fontenot
Sent: Saturday, May 09, 2009 = 12:10=20 AM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Initial = Tuning at=20 Low RPM - surging?

 

Tracy,

>>Large=20 changes in the MAP table values can do that but you did not say at = what point=20 in the tuning procedure this turned up.  What have you done or = tried so=20 far?<<

I was not specifically tuning, and have not = started that=20 seriously. My question was a general one about why surging happens in=20 something like my GEO. I'm hoping to tie the trike down on Sunday and = really=20 start tuning (if the weather holds out).

Thanks,

--=20 =
Mike

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Mike Fontenot
Apex=20 Consulting & Services LLC
Lakewood, Colorado
303 / = 731-6645
mikef AT=20 apexconsultingservices DOT=20 = com
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

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