X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from ms-smtp-01.southeast.rr.com ([24.25.9.100] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1913400 for flyrotary@lancaironline.net; Sat, 10 Mar 2007 12:11:56 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-103-061.carolina.res.rr.com [24.74.103.61]) by ms-smtp-01.southeast.rr.com (8.13.6/8.13.6) with SMTP id l2AHAVb8021577 for ; Sat, 10 Mar 2007 12:10:32 -0500 (EST) Message-ID: <000701c76337$04e64760$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: The truth??? / Injector flow rate mystery solved Date: Sat, 10 Mar 2007 12:10:35 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C7630D.1BBA7E40" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0004_01C7630D.1BBA7E40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageHi Joe, First, thanks for the offer. You've been there, done that, so you know = how significant accounting for any and all time delays in an industrial = process is. I've also used simple curve fitting algorithms (mainly like those that = in Excel spreadsheet - of course, they don't provide any = recommendations) to get coefficients for some equations (not related to = EFI).. However, one of the reasons I've taken the approach I have on the fuel = meter is to avoid the cost of an aircraft quality fuel flow transducer - = like Tracy said they run on the order of $250 (for one and you need two = if returning fuel to a tank). The traducers I am somewhat familiar with also require calibration to = the installation as well (if you want the most accurate results). While = it would be nice to compare the "actual" flow rate to my imputed = (computed?) flow rate base on the injector timing - I am just not = inclined to spring $250 for one or $500 for two {:>). Actually, my fuel flow readings are less than 0.1% in error - far better = than the flow transducer method - once I calibrated it. However, I = always had to add a "fudge" factor to my equation - really did not like = that at all. The problem was the injectors appeared to flow more than = my calculations - implying that if my calculations (and equation) was = correct then the injectors "must" flow more fuel than stated. BUT, now we know the reason - a diode in the ECU apparently keeps the = injector magnetic field coil energized for some time after the pulse has = terminated - apparently according to Tracy up to 5 msec under some = conditions - well, that really is keeping the injector open longer, = therefore the additional fuel flow over what I would have calculated = based on the pulse duration and the rated flow spec for the injector. So very much appreciate you offer, Joe. However, at this time, I think = I will wait and see what Tracy comes up with for the moment. Ed ----- Original Message -----=20 From: Joe Ewen=20 To: Rotary motors in aircraft=20 Sent: Saturday, March 10, 2007 11:37 AM Subject: [FlyRotary] Re: The truth??? / Injector flow rate mystery = solved Ed, It has been my experience, in industrial control, environment that = there are several sources of latency (delay time) on and off delay time = of the IO circuitry, clock speed of the IO controller, on and off delay = times for the controlled device, mechanical delays etc. When a machine = operator presses a control button, expecting a action to occur such as = starting a motor conveyor, a stacked latency of 5 or even 100 mS is not = perceivable. But trying to put a patterned glue line on a web moving 5 = to 10 feet per second, requires accounting for the IO delay time, = pneumatic solenoid delay, air line charging time, glue head mechanical = delay, glue reaction (like a dripping faucet, the glue will form a = droplet before becoming a stream.) =20 When I have been up against applications like the latter, I have found = a curve fitting program that has worked very well. In the example = cited, I have run a rudimentary control algorithm and collected the = resultant data. Dump the data into the curve fitting program, and the = program will crunch the data and make recommendations for the closest = formula as well as the required formula constants. This has worked very = well for some difficult applications. IMO a great way to work your fuel flow situation might be to install a = flow sensor. Run your engine at various RPMs recording EC2 indications = and actual fuel flow sensor readings. Dump the data into a curve = fitting program and viola. One of the best fitting programs I have = found is called XLFit (VBA add on to Excel). The program cost is $725, = but it has a 30 day fully functioning trial. =20 If you would like to try an approach such as this, I could provide IO = for capturing fuel flow sensor data, curve fitting program, as well as = coming up to give you a hand (since I am less than an hour's drive from = your location.) =20 Joe (If I stop rambling, I might actually be able to turn on the = battery masters and fire up the CPU this week end.) ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Friday, March 09, 2007 8:30 PM Subject: [FlyRotary] Re: The truth??? / Injector flow rate mystery = solved Ah, the old induced current caused by the collapsing magnetic field = of the injector has no place to go (quickly at least) due to the diode. = That would indeed tend to prolong the closing - hummm up to 5 msec - now = the duration - that is surprising. =20 That's at least part (if not all) of the reason why I always had to = add a "fudge factor" increase over the number I calculated for the = specified flow rate. The injectors were staying on a bit longer and = therefore flowing more fuel than the specified flow rate would indicate. = OK! so now I know why I had to have a fudge factor - I feel better and = will finally be able to sleep {:>) Thanks for the additional information, Tracy. It will keep the = rumors to a minimum {:>) Ed ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Friday, March 09, 2007 5:20 PM Subject: [FlyRotary] Re: The truth??? / Injector flow rate mystery = solved Still refining the exact numbers but here is the basic cause. The diode clamp on the injector drivers (in EC2) serves 3 = purposes. It limits the inductive flyback voltage to protect the driver = transistor. It recovers some of the energy used to open the injector = thus reducing the current consumption of the system. It eliminates = arcing at the A/B injector switching relay that can cause noise problems = with the processor chips. Unknown to me until recently, it also significantly increases the = closing time of the injector after the driver pulse ends. I thought the = delay would be negligible. The actual delay depends on several factors = but may be as much as 5 ms (!) Ed will know what a big deal this is. = The factors that go into this and how much it is magnified by the diode = clamp is still under investigation. The good news is that there is a very simple fix. (Note, Do NOT = go out and remove the diode clamps! That isn't the fix! Tracy ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Friday, March 09, 2007 7:13 AM Subject: [FlyRotary] Re: The truth??? / Injector flow rate = mystery solved I certainly don't know, Rusty. Like I said the only thing that = Tracy and I could conclude was that Mazda was under-rating their = injectors - I wondered whether it might have something to do with the = way an engine is taxed in Japan. In any case, Tracy is clearly ignoring our pleas for more = information - poor guy is undoubtedly working furiously getting orders = completed before Sun & Fun. But, he really shouldn't tease like that = {:>) Yes, I understand what you mean about measured flow rates - I = suspect there is something subtle about this matter. Perhaps the = current profile used to open the injectors plays some role in this as = Tracy indicated he was working on a Fix. Perhaps a two stage or = progressive flow rate profile - opens and provides normal flow for = typical automobile usage but, when wide open (like ours are at cruise) = perhaps the flow rate is more. Who knows - Tracy Crook that's who. Ed ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Friday, March 09, 2007 12:19 AM Subject: [FlyRotary] Re: The truth??? / Injector flow rate = mystery solved Tracy and I have been discussing this injector flow rate = anomaly for years - =20 For some reason, I was certain that the Mazda injectors flowed = more than they were rated for, but after sifting through some old logs, = that's not true for all Mazda injectors. I sent 4 slightly used 550's = to RC Engineering, and they tested them at 547, 549, 551, and 551. If = that ain't 550, I don't know what is :-) =20 I guess I'm baffled now. Does Mazda operate them at 5 volts = or something, rather than 12V? That would slow down the response time. = =20 Hey the HKS is a good little engine in my opinion - not as = good as a light weight rotary (which we don't have yet - Richard! get a = move on {:>)), but it'll get you flying again.=20 Thanks for the comments. It can't hurt much to try it, = because I've already got people who want to buy it if it doesn't work = out. Still, it's as much trouble to install as the rotary, so it really = comes down to a weight issue, and perhaps whether I'll ever get my = redrive from Autoflight... =20 Rusty ------=_NextPart_000_0004_01C7630D.1BBA7E40 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Hi Joe,
 
First, thanks for the = offer. You've been=20 there, done that, so you know how significant accounting for any and all = time=20 delays in an industrial process is.
 
 I've also used  simple curve = fitting=20 algorithms (mainly like those that in Excel spreadsheet - of course, = they don't=20 provide any recommendations) to get coefficients for some equations (not = related=20 to EFI)..
 
However, one of the reasons I've taken = the approach=20 I have on the fuel meter is to avoid the cost of an aircraft quality = fuel flow=20 transducer - like Tracy said they run on the order of $250 (for one and = you need=20 two if returning fuel to a tank).
 
The traducers I am somewhat familiar = with also=20 require calibration to the installation as well (if you want the most = accurate=20 results).  While it would be nice to compare the "actual" flow rate = to my=20 imputed (computed?) flow rate base on the injector timing - I am just = not=20 inclined to spring $250 for one or $500 for = two {:>).
 
Actually, my fuel flow readings are = less than 0.1%=20 in error - far better than the flow transducer method - once I = calibrated=20 it.  However, I always had to add a "fudge" factor to my equation - = really=20 did not like that at all.    The problem was the = injectors=20 appeared to flow more than my calculations - implying that if my = calculations=20 (and equation) was correct then the injectors "must" flow more fuel than = stated.
 
BUT, now we know the reason - a diode = in the ECU=20 apparently keeps the injector magnetic field coil energized for some = time after=20 the pulse has terminated - apparently according to Tracy up to 5 msec = under some=20 conditions - well, that really is keeping the injector open longer, = therefore=20 the additional fuel flow over what I would have calculated based on the = pulse=20 duration and the rated flow spec for the injector.
 
So very much appreciate you offer, = Joe. =20 However, at this time, I think I will wait and see what Tracy comes up = with for=20 the moment.
 
Ed
 
 
----- Original Message -----
From:=20 Joe = Ewen=20
Sent: Saturday, March 10, 2007 = 11:37=20 AM
Subject: [FlyRotary] Re: The = truth??? /=20 Injector flow rate mystery solved

Ed,
It has been my experience, in industrial = control,=20 environment that there are several sources of latency (delay time) on = and off=20 delay time of the IO circuitry, clock speed of the IO controller, on = and off=20 delay times for the controlled device, mechanical delays etc.  = When a=20 machine operator presses a control button, expecting a action to occur = such as=20 starting a motor conveyor, a stacked latency of 5 or even 100 mS is = not=20 perceivable.  But trying to put a patterned glue line on a = web=20 moving 5 to 10 feet per second, requires accounting for the IO delay = time,=20 pneumatic solenoid delay, air line charging time, glue head mechanical = delay,=20 glue reaction (like a dripping faucet, the glue will form a droplet = before=20 becoming a stream.) 
 
When I have been up against applications like = the=20 latter, I have found a curve fitting program that has worked very = well.  In the example cited, I have run a rudimentary control = algorithm=20 and collected the resultant data.  Dump the data into the curve = fitting=20 program, and the program will crunch the data and make recommendations = for the=20 closest formula as well as the required formula constants.  This = has=20 worked very well for some difficult applications.
 
IMO a great way to work your fuel flow = situation might=20 be to install a flow sensor.  Run your engine at various=20 RPMs recording EC2 indications and actual fuel flow sensor=20 readings.  Dump the data into a curve fitting program and = viola. =20 One of the best fitting  programs I have found is called XLFit = (VBA add=20 on to Excel).  The program cost is $725, but it has a 30 day = fully=20 functioning trial. 
 
If you would like to try an approach such as = this, I=20 could provide IO for capturing fuel flow sensor data, curve fitting = program,=20 as well as coming up to give you a hand (since I am less than an = hour's drive=20 from your location.) 
 
Joe  (If I stop rambling, I might = actually be able=20 to turn on the battery masters and fire up the CPU this week=20 end.)
 
 
 
----- Original Message -----
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Friday, March 09, 2007 = 8:30=20 PM
Subject: [FlyRotary] Re: The = truth??? /=20 Injector flow rate mystery solved

Ah, the old induced current caused =  by the=20 collapsing magnetic field of the injector has no place to go = (quickly at=20 least) due to the diode.  That would indeed tend to prolong the = closing=20 - hummm up to 5 msec - now the duration -  that=20 is surprising. 
 
That's at least part (if not all) = of the reason=20 why I always had to add a "fudge factor" increase over the number I=20 calculated for the specified flow rate.  The injectors were = staying on=20 a bit longer and therefore flowing more fuel than the specified flow = rate=20 would indicate.  OK! so now I know why I had to have a fudge = factor - I=20 feel better and will finally be able to sleep {:>)
 
Thanks for the additional = information,=20 Tracy.  It will keep the rumors to a minimum = {:>)
 
Ed
----- Original Message ----- =
From:=20 Tracy = Crook=20
To: Rotary motors in = aircraft=20
Sent: Friday, March 09, = 2007 5:20=20 PM
Subject: [FlyRotary] Re: = The truth???=20 / Injector flow rate mystery solved

Still refining the exact numbers but here is the basic = cause.
 
The diode clamp on the injector drivers (in EC2) serves 3=20 purposes.  It limits the inductive flyback voltage to protect = the=20 driver transistor.  It recovers some of the energy used to = open the=20 injector thus reducing the current consumption of the = system.  It=20 eliminates arcing at the A/B injector switching relay that can = cause noise=20 problems with the processor chips.
 
Unknown to me until recently, it also significantly increases = the=20 closing time of the injector after the driver pulse ends.  I = thought=20 the delay would be negligible.  The actual delay depends on = several=20 factors but may be as much as 5 ms (!)  Ed will know what a = big deal=20 this is.  The factors that go into this and how much it is = magnified=20 by the diode clamp is still under investigation.
 
The good news is that there is a very simple fix.  = (Note, Do NOT=20 go out and remove the diode clamps! That isn't the fix!
 
Tracy
----- Original Message ----- =
From: Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Friday, March 09, = 2007 7:13=20 AM
Subject: [FlyRotary] Re: = The=20 truth??? / Injector flow rate mystery solved

I certainly don't know, = Rusty.  Like I=20 said the only thing that Tracy and I could conclude was that = Mazda was=20 under-rating their  injectors - I wondered whether it might = have=20 something to do with the way an engine is taxed in = Japan.
 
In any case, Tracy is clearly = ignoring our=20 pleas for more information - poor guy is undoubtedly working = furiously=20 getting orders completed before Sun & Fun.  But, he = really=20 shouldn't tease like that {:>)
 
Yes, I understand what you mean = about=20 measured flow rates - I suspect there is something subtle about = this=20 matter.  Perhaps the current profile used to open the = injectors=20 plays some role in this as Tracy indicated he was working on a=20 Fix.  Perhaps a two stage or progressive flow rate profile = - opens=20 and provides normal flow for typical automobile usage but, when = wide=20 open (like ours are at cruise) perhaps the flow rate is = more.  Who=20 knows - Tracy Crook that's who.
 
Ed
----- Original Message ----- =
From:=20 Russell Duffy
To: Rotary motors in=20 aircraft
Sent: Friday, March 09, = 2007=20 12:19 AM
Subject: [FlyRotary] = Re: The=20 truth??? / Injector flow rate mystery solved

Tracy and I have been = discussing=20 this injector flow rate anomaly for years -  
 
For some reason, I was certain that = the Mazda=20 injectors flowed more than they were rated for, but after = sifting=20 through some old logs, that's not true for all Mazda=20 injectors.   I sent 4 slightly used 550's to=20 RC Engineering, and they tested them at 547, 549, 551, = and=20 551.  If that ain't 550, I don't know what is=20 :-)  
 
I guess I'm baffled now.  Does = Mazda=20 operate them at 5 volts or something, rather than 12V?  = That=20 would slow down the response=20 time.   
 
 
Hey the HKS is a good = little engine=20 in my opinion - not as good as a light weight rotary (which we = don't=20 have yet - Richard! get a move on {:>)), but it'll get = you =20 flying again. 
 
Thanks for = the=20 comments.  It can't hurt much to try it, because = I've=20 already got people who want to buy it if it doesn't work = out. =20 Still, it's as much trouble to install as the rotary, so it = really=20 comes down to a weight issue, and perhaps whether I'll ever = get my=20 redrive from=20 Autoflight...  
 
Rusty
 
=
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