X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from aspensprings.uwyo.edu ([129.72.10.32] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTPS id 4233743 for flyrotary@lancaironline.net; Sun, 25 Apr 2010 14:29:49 -0400 Received-SPF: none receiver=logan.com; client-ip=129.72.10.32; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht2.uwyo.edu (ponyexpress-ht2.uwyo.edu [10.84.60.209]) by aspensprings.uwyo.edu (8.14.2/8.14.2) with ESMTP id o3PIT9gV024719 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL) for ; Sun, 25 Apr 2010 12:29:09 -0600 (MDT) (envelope-from SBoese@uwyo.edu) Received: from ponyexpress-mb5.uwyo.edu ([fe80::9c55:bfd9:7a5b:5a4]) by ponyexpress-ht2 ([10.84.60.209]) with mapi; Sun, 25 Apr 2010 12:29:09 -0600 From: "Steven W. Boese" To: Rotary motors in aircraft Date: Sun, 25 Apr 2010 12:29:08 -0600 Subject: RE: [FlyRotary] Re: getting lost in the tuning process Thread-Topic: [FlyRotary] Re: getting lost in the tuning process Thread-Index: AcrkfSfUUmN9ADjiSX65GvnNVIrTpgABNurc 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_E1AA3B1AF41D8049B1E3FBD5E225626004BF75FE24ponyexpressmb_" MIME-Version: 1.0 --_000_E1AA3B1AF41D8049B1E3FBD5E225626004BF75FE24ponyexpressmb_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable If I may relate my own recent experience with the tuning process... There are two systems that I have been working with. One is my flying RV6A= with a 1986 13B NA with 4 stock peak and hold (low resistance) fuel inject= ors, stock CAS, an intake manifold with no intentional dynamic tuning, and = GM ignition coils. The other is a test stand with a 1987 13B NA with 4 sto= ck saturated (high resistance) fuel injectors, stock CAS, also with GM igni= tion coils. The propellers are quite similar although of different manufac= turers. Both systems have EC2's with chips that were updated early in 2010= . After installing the updated chips in the plane's EC2, I made sure that I h= ad studied the latest copy of the installation manual. I also had the IPAQ= EC2 recording system described elsewhere set up to document my tuning step= s so I could review it after the fact to assure myself that I had done thin= gs in a reasonable fashion. Starting with the default settings in the EC2,= I found to my great dissapointment ;) that no changes in the default setti= ngs were needed. I could use just the manual mixture control to run from r= ich of peak to lean of peak EGT at any throttle setting available. Max MAP= for my location with a field elveation of 7200 ft is always near 23 inches= of Hg. A couple of days ago, I flew from home (Laramie, WY) to Benson, MN= at altitudes ranging from 12000 ft to 1300 ft and OAT's ranging from the 2= 0's to 60's, with those default EC2 settings and using the manual mixture c= ontrol to select the desired operating conditions. There wasn't any hint o= f an improvement to be gained from tuning the power plant any differently. The engine stand which we took to the Contact Magazine fly-in last month ha= s performed similarly. No change from the default settings has been requir= ed using either the stock automotive intake system with the dynamic chamber= or a second intake system that I got with the engine. This second intake = system has secondary runners controlled by the double butterfly of a cut do= wn stock throttle body and primary runners controlled by the single butterf= ly of that throttle body. There is no pneumatic connection between the pri= mary and secondary runners except for MAP sensing lines tee'd together and = going to the EC2. There is a mechanical linkage on the throttle body betwe= en the primary butterfly and and the double butterfly, of course. I tested= this manifold just because it was available, thinking that there was no wa= y this would work very well. It performed very nearly as well as the stock= dynamic chamber, again with the default EC2 settings. Probably, the the important thing that these systems have in common are the= 4 stock fuel injectors all of the same flow characteristics. Personally, it has been most useful (if I set the staging point different t= han default) to set the staging point to a setting such that the two primar= y injectors are used to as high a MAP as possible without them limiting the= fuel flow at about 80% duty cycle. I do this because there is a lower lim= it to the amount of fuel that the injectors can deliver reliably. This low= er limit occurs at about 1.5 to 2 ms pulse width with the injectors I have = tested. Below this limit, the amount of fuel delivered is more a function = of the injector dynamics than it is a function of what the EC2 is requestin= g of it. If the staging point is set too low, one is just getting into the= range where the two injectors are working predictably and then the system = switches to using 4 injectors, each one trying to deliver fuel in such smal= l amounts that they are somewhat unpredictable. The dynamic range adjustme= nt in the EC2 may be able to compensate for the low flow non-linearity to s= ome extent, but it seems to me that this would be most useful to obtain goo= d idle characteristics with two injectors rather than using 4 injectors at = relatively low but non-idle power settings. Setting the staging point to a= low MAP may be useful as an exercise in learning the steps involved in tun= ing the EC2 while avoid cooling porblems on the ground, but I suspect that = it will be frustrating if the resulting parameters are expected to work wel= l in flight. It seems to me that it will be much more productive to tempor= arily resolve the ground cooling issue and program the EC2 under conditions= as close to the power levels that would be encountered in flight as possib= le. Please note that these are just my thoughts based on the special cases I ha= ve to work with and there is absolutely no criticism intended toward anyone= . This email may also be the result of being away from home on a gloomy da= y unfit for flying. Steve Boese ________________________________ From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf Of = Bill Bradburry [bbradburry@bellsouth.net] Sent: Sunday, April 25, 2010 7:41 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: getting lost in the tuning process You certainly have it right about the better understanding part! :>) So, since it has no effect, why, in step 1, do you say, =93with the engine = running below the staging point, select mode 6 and turn the program knob sl= ightly to the left of the 12:00 oclock position and press the program store= switch=94??? Is this some kind of arming step?? The mixture is really rich before I start this step. I have the mixture co= ntrol knob at probably 9:00 oclock on both sides of 15=94 of map. Is this = going to have an effect on that? Or is it just in case the mixture changes= when you go from below 15 to above 15? With the 4 yellow injectors, where do you recommend the staging point be se= t? I have it set now at 15 mostly so I can do stuff like this without runn= ing at high power and causing ground cooling problems. If I get every thin= g set and then later change the staging point, will this cause a need for a= do over? I will clear and start over. When would be a good time to call if need be? Thanks for the response that helps to clear it up. By the way, to those carb guys, this is a little confusing, but no way bad = enough to justify going with a carburetor!!! Bill B --_000_E1AA3B1AF41D8049B1E3FBD5E225626004BF75FE24ponyexpressmb_ Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
If I ma= y relate my own recent experience with the tuning process...
 
There are two systems tha= t I have been working with.  One is my flying RV6A with a 1986 13B NA = with 4 stock peak and hold (low resistance) fuel injectors, stock CAS,= an intake manifold with no intentional dynamic tuning, and GM ignition coils.  The other is a test stand w= ith a 1987 13B NA with 4 stock saturated (high resistance) fuel injectors, = stock CAS, also with GM ignition coils.  The propellers are = quite similar although of different manufacturers.  Both systems have EC2's with chips that were updated early in 2010.
 
After installing the upda= ted chips in the plane's EC2, I made sure that I had studied the lates= t copy of the installation manual.  I also had the IPAQ EC2 recording = system described elsewhere set up to document my tuning steps so I could review it after the fact to assure myself that I h= ad done things in a reasonable fashion.  Starting with the default set= tings in the EC2, I found to my great dissapointment ;) that no changes in = the default settings were needed.  I could use just the manual mixture control to run from rich of pe= ak to lean of peak EGT at any throttle setting available.  Max MAP for= my location with a field elveation of 7200 ft is always near 23 inches of = Hg.  A couple of days ago, I flew from home (Laramie, WY) to Benson, MN at altitudes ranging from 12000 ft to 1300 ft and O= AT's ranging from the 20's to 60's, with those default EC2 settin= gs and using the manual mixture control to select the desired operating con= ditions.  There wasn't any hint of an improvement to be gained from tuning the power plant any differently.
 
The engine stand which we= took to the Contact Magazine fly-in last month has performed similarly.&nb= sp; No change from the default settings has been required using either the = stock automotive intake system with the dynamic chamber or a second intake system that I got with the engine.  This s= econd intake system has secondary runners controlled by the double butterfl= y of a cut down stock throttle body and primary runners controlled by = the single butterfly of that throttle body.  There is no pneumatic connection between the primary and secondary runners= except for MAP sensing lines tee'd together and going to the EC2= .  There is a mechanical linkage on the throttle body between the prim= ary butterfly and and the double butterfly, of course.  I tested this manifold just because it was available, thinki= ng that there was no way this would work very well.  It performed very= nearly as well as the stock dynamic chamber, again with the default EC2 se= ttings.
 
Pro= bably, the the important thing that these systems have in common are the 4 = stock fuel injectors all of the same flow characteristics.
 
Personally, it has been m= ost useful (if I set the staging point different than default) to set = the staging point to a setting such that the two primary injector= s are used to as high a MAP as possible without them limiting the fuel flow at about 80% duty cycle.  I do this = because there is a lower limit to the amount of fuel that the injectors can= deliver reliably.  This lower limit occurs at about 1.5 to 2 ms = pulse width with the injectors I have tested.  Below this limit, the amount of fuel delivered is more a function of the injector dyn= amics than it is a function of what the EC2 is requesting of it.  If t= he staging point is set too low, one is just getting into the range where t= he two injectors are working predictably and then the system switches to using 4 injectors, each one trying to= deliver fuel in such small amounts that they are somewhat unpred= ictable.  The dynamic range adjustment in the EC2 may be able to compe= nsate for the low flow non-linearity to some extent, but it seems to me that this would be most useful to obtain good idle char= acteristics with two injectors rather than using 4 injectors at r= elatively low but non-idle power settings.  Setting the staging point = to a low MAP may be useful as an exercise in learning the steps involved in tuning the EC2 while avoid cooling porblems on = the ground, but I suspect that it will be frustrating if the resulting = ;parameters are expected to work well in flight.  It seems to me that = it will be much more productive to temporarily resolve the ground cooling issue and program the EC2 under conditions= as close to the power levels that would be encountered in flight as possib= le.
 
Ple= ase note that these are just my thoughts based on the special cases I have = to work with and there is absolutely no criticism intended toward anyo= ne.  This email may also be the result of being away from home on a gloomy day unfit for flying.
 
Steve Boese
 
 
    &= nbsp;     
 
     =
From: Rotary motors in aircraft [fl= yrotary@lancaironline.net] On Behalf Of Bill Bradburry [bbradburry@bellsout= h.net]
Sent: Sunday, April 25, 2010 7:41 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: getting lost in the tuning process

You certainly h= ave it right about the better understanding part!  :>)

&= nbsp;

So, since it ha= s no effect, why, in step 1, do you say, =93with the engine running below t= he staging point, select mode 6 and turn the program knob slightly to the left of the 12:00 oclock position and press t= he program store switch=94???

Is this some ki= nd of arming step??

&= nbsp;

The mixture is = really rich before I start this step.  I have the mixture control knob= at probably 9:00 oclock on both sides of 15=94 of map.  Is this going to have an effect on that?  Or is it just in= case the mixture changes when you go from below 15 to above 15?

&= nbsp;

With the 4 yell= ow injectors, where do you recommend the staging point be set?  I have= it set now at 15 mostly so I can do stuff like this without running at high power and causing ground cooling problems.&nb= sp; If I get every thing set and then later change the staging point, will = this cause a need for a do over? 

&= nbsp;

I will clear an= d start over.  When would be a good time to call if need be?

&= nbsp;

Thanks for the = response that helps to clear it up.

&= nbsp;

By the way, to = those carb guys, this is a little confusing, but no way bad enough to justi= fy going with a carburetor!!!

&= nbsp;

Bill B

&= nbsp;

&= nbsp;

<= /p>

<= /span>

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