X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 10 [X] Return-Path: Received: from bay0-omc3-s29.bay0.hotmail.com ([65.54.246.229] verified) by logan.com (CommuniGate Pro SMTP 5.1.4) with ESMTP id 1761216 for flyrotary@lancaironline.net; Mon, 15 Jan 2007 16:39:22 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.246.229; envelope-from=lors01@msn.com Received: from hotmail.com ([65.54.250.78]) by bay0-omc3-s29.bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.2668); Mon, 15 Jan 2007 13:37:27 -0800 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 15 Jan 2007 13:37:26 -0800 Message-ID: Received: from 4.171.129.157 by BAY115-DAV6.phx.gbl with DAV; Mon, 15 Jan 2007 21:37:22 +0000 X-Originating-IP: [4.171.129.157] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: engine surging at low manifold pressure Date: Mon, 15 Jan 2007 16:37:15 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0081_01C738C3.6A626540" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.50.0034.2000 Seal-Send-Time: Mon, 15 Jan 2007 16:37:15 -0500 X-OriginalArrivalTime: 15 Jan 2007 21:37:26.0960 (UTC) FILETIME=[59DFEB00:01C738ED] Return-Path: lors01@msn.com This is a multi-part message in MIME format. ------=_NextPart_000_0081_01C738C3.6A626540 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed asked me about this off-line and thought this might help others. = Here's my reply: Not sure what to make of Al's experience with the secondaries. I = haven't noticed this myself but then again, all our installations are so = different I would not expect them to be the same.=20 I haven't been able to think of a reason for the secondary idle = improvement. If you are seeing this too, try the following first and = see what happens. Swap the primary injector connectors and see if that = also improves the idle. I had accidentally swapped these (in software) = during very early testing on test stand and found that the idle was = worse this way but made no difference at higher power settings. Don't = know why your & Al's engine would be just the opposite but worth a try = (swapping the primary connectors). We can play with this and tuning = when you get here if you like. Injectors are almost never the problem. Don't look there unless ALL = else has failed. Surging at idle while in descent flight (engine probably windmilling) = was fixed on my installation by enrichening the lowest 2 MAP table = addresses in the high (>3000) rpm range. This can only be done while = actually in-flight with the EC2 panel (kind of awkward since you are = normally occupied with landing chores) or using the EM2 to edit the = table off-line. With no EM2, get a bunch of altitude under you so = there is no anxiety about colliding with the ground while doing this = tuning. =20 BTW, in general, I think windmilling operation should be avoided since = this puts the gears in reverse torque and the gear thrust is on the = nylon snubber. Could be a problem if done for prolonged periods = although I have never seen any evidence of this. Lou's idle MAP is way out of the correct range as Al noted so something = is wrong there. I can fly in level flight at MAP of 15 - 18" Hg. This = is not idle. Tracy ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Sunday, January 14, 2007 9:38 PM Subject: [FlyRotary] Re: engine surging at low manifold pressure We have recently tuned the Ec2 on a 20B & although it has helped it run a little smoother we still get alot of roughness & surging at idle from 15 to 18 inches Mp& especially when pulling back power Has anyone experienced this problem? The plane has been run on the ground, however the problem was just as bad in air in a descent.=20 Lou & Paul N ES 117ES Lou; You'll probably need to spend a fair amount of time tuning, with an O2 = sensor readout. But my first question is about the MAP. MAP at idle = ought to be more in the 10 - 11" range. Second question is have = adjusted the mixture knob when it is surging to see if it can be = improved. Surging is most likely with a too lean mixture. The transistion from the 'low' to 'high' table at 3000 rpm on my 20B = occurs around 13.5 -14.5" (table entries 7-9). Tuning in the transition = region needs to be good, or it will cause surging as it transitions back = and forth. Also; if the 3000 rpm transition gets close to the staging = point, it can get really messed up if the tuning on across the stage = point is not well set. I found that moving the stage point up to about = 17" helps stay away from that problem. I found that I could not get smooth running below about 1500 - 1600 = rpm when running on the primary injectors (in the housings). It idled = much better down to about 1000 rpm running on the secondary injectors = that are out at the throttle body. In my case, that puts them about = 8-9" out from the ports; so either the distance, or the MSD injectors, = makes the difference. =20 If you find it runs better on the secondary only, there is a simple = change to make. In the 20B version of the EC2, with the external = staging relay, you can do what I did and put the stage relay in the = primary power circuit so it runs on secondary only at low MAP; and the = primary kick in above the stage point. Hope this helps. Best of luck. Al G = _________________________________________________________________________= ___________ Need Mail bonding? Go to the Yahoo! Mail Q&A for great tips from Yahoo! Answers users. http://answers.yahoo.com/dir/?link=3Dlist&sid=3D396546091 -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ ------=_NextPart_000_0081_01C738C3.6A626540 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed asked me about this off-line and thought this might help = others. =20 Here's my reply:
 
Not sure what to make of Al's experience with the = secondaries.  I=20 haven't noticed this myself but then again, all our installations are so = different I would not expect them to be the same. 
 
I haven't been able to think of a reason for the secondary idle=20 improvement.   If you are seeing this too, try the following = first and=20 see what happens.  Swap the primary injector connectors and see if = that=20 also improves the idle.  I had accidentally swapped these (in = software)=20 during very early testing on test stand and found that the idle was = worse this=20 way but made no difference at higher power settings.  Don't know = why your=20 & Al's engine would be just the opposite but worth a try (swapping = the=20 primary connectors).  We can play with this and tuning when you get = here if=20 you like.
 
Injectors are almost never the problem.  Don't look there = unless ALL=20 else has failed.
 
Surging at idle while in descent flight (engine = probably windmilling)=20 was fixed on my installation by enrichening the lowest 2 MAP table = addresses in=20 the high (>3000) rpm range.  This can only be done while = actually=20 in-flight with the EC2 panel (kind of awkward since you are normally = occupied=20 with landing chores)  or using the EM2 to edit the table=20 off-line.   With no EM2, get a bunch of altitude under you so = there is=20 no anxiety about colliding with the ground while doing this = tuning. 
 
BTW, in general, I think windmilling operation should be avoided = since this=20 puts the gears in reverse torque and the gear thrust is on the nylon=20 snubber.  Could be a problem if done for prolonged periods although = I have=20 never seen any evidence of this.
 
Lou's idle MAP is way out of the correct range as Al noted so = something is=20 wrong there.  I can fly in level flight at MAP of 15 - = 18"=20 Hg.  This is not idle.
 
Tracy
----- Original Message -----
From: Al Gietzen
To: Rotary motors in = aircraft
Sent: Sunday, January 14, 2007 = 9:38=20 PM
Subject: [FlyRotary] Re: engine = surging=20 at low manifold pressure

 

We have recently tuned the Ec2 on a 20B = & although=20 it

has helped it run a little smoother we still = get=20 alot

of roughness & surging at idle from 15 = to 18=20 inches

Mp& especially when pulling back power = Has=20 anyone

experienced this problem? The plane has been = run=20 on

the ground, however the problem was just as = bad in=20 air

in a descent.

 

Lou & Paul  N ES = 117ES

 

Lou;

 

You=92ll = probably=20 need to spend a fair amount of time tuning, with an O2 sensor = readout. =20 But my first question is about the MAP.  MAP at idle ought to be = more in=20 the 10 =96 11=94 range.  Second question is have adjusted the = mixture knob=20 when it is surging to see if it can be improved.  Surging is most = likely=20 with a too lean mixture.

 

The = transistion=20 from the =91low=92 to =91high=92 table at 3000 rpm on my 20B occurs = around 13.5 -14.5=94=20 (table entries 7-9).  Tuning in the transition region needs to be = good,=20 or it will cause surging as it transitions back and forth.  Also; = if the=20 3000 rpm transition gets close to the staging point, it can get really = messed=20 up if the tuning on across the stage point is not well set.  I = found that=20 moving the stage point up to about 17=94 helps stay away from that=20 problem.

 

I found = that I=20 could not get smooth running below about 1500 =96 1600 rpm when = running on the=20 primary injectors (in the housings).  It idled much better down = to about=20 1000 rpm running on the secondary injectors that are out at the = throttle=20 body.  In my case, that puts them about 8-9=94 out from the = ports; so=20 either the distance, or the MSD injectors, makes the difference.=20  

 

If you = find it=20 runs better on the secondary only, there is a simple change to make. =  In=20 the 20B version of the EC2, with the external staging relay, you can = do what I=20 did and put the stage relay in the primary power circuit so it runs on = secondary only at low MAP; and the primary kick in above the stage=20 point.

 

Hope = this=20 helps.  Best of luck.

 

Al=20 G

 

 

 

 

 

 

___________________________________________________________________= _________________

Need Mail bonding?

Go to the Yahoo! Mail Q&A for great tips = from=20 Yahoo! Answers users.

http://answers.yahoo.com/dir/?link=3Dlist&sid=3D396546091

 

--

Homepage: =20 http://www.flyrotary.com/

Archive and UnSub:  =20 = http://mail.lancaironline.net/lists/flyrotary/

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