X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from ms-smtp-05.southeast.rr.com ([24.25.9.104] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1912372 for flyrotary@lancaironline.net; Fri, 09 Mar 2007 20:31:53 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.104; 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-05.southeast.rr.com (8.13.6/8.13.6) with SMTP id l2A1UvSi021564 for ; Fri, 9 Mar 2007 20:30:57 -0500 (EST) Message-ID: <000701c762b3$c2237480$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: The truth??? / Injector flow rate mystery solved Date: Fri, 9 Mar 2007 20:30:59 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C76289.D8F9F550" 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_01C76289.D8F9F550 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageAh, 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_01C76289.D8F9F550 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Ah, the old induced current caused =  by the=20 collapsing magnetic field of the injector has no place to go (quickly at = least)=20 due to the diode.  That would indeed tend to prolong the closing - = hummm up=20 to 5 msec - now the duration -  that is surprising.  =
 
That's at least part (if not all) of = the reason why=20 I always had to add a "fudge factor" increase over the number I = calculated for=20 the specified flow rate.  The injectors were staying on a bit = longer and=20 therefore flowing more fuel than the specified flow rate would = indicate. =20 OK! so now I know why I had to have a fudge factor - I feel better and = will=20 finally be able to sleep {:>)
 
Thanks for the additional information, = Tracy. =20 It will keep the rumors to a minimum {:>)
 
Ed
----- Original Message -----
From:=20 Tracy = Crook
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 = purposes. =20 It limits the inductive flyback voltage to protect the driver=20 transistor.  It recovers some of the energy used to open the = injector=20 thus reducing the current consumption of the system.  It = eliminates=20 arcing at the A/B injector switching relay that can cause noise = problems with=20 the processor chips.
 
Unknown to me until recently, it also significantly increases the = closing=20 time of the injector after the driver pulse ends.  I thought the = delay=20 would be negligible.  The actual delay depends on several factors = but may=20 be as much as 5 ms (!)  Ed will know what a big deal this = is.  The=20 factors that go into this and how much it is magnified by the diode = clamp is=20 still under investigation.
 
The good news is that there is a very simple fix.  (Note, Do = NOT go=20 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 = truth??? /=20 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 measured=20 flow rates - I suspect there is something subtle about this = matter. =20 Perhaps the current profile used to open the injectors plays some = role in=20 this as Tracy indicated he was working on a Fix.  Perhaps a two = stage=20 or progressive flow rate profile - opens and provides normal flow = for=20 typical automobile usage but, when wide open (like ours are at = cruise)=20 perhaps the flow rate is more.  Who knows - Tracy Crook that's=20 who.
 
Ed
----- Original Message ----- =
From:=20 Russell Duffy
To: Rotary motors in = aircraft=20
Sent: Friday, March 09, = 2007 12:19=20 AM
Subject: [FlyRotary] Re: = The truth???=20 / Injector flow rate mystery solved

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