Return-Path: Received: from [65.54.169.106] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2560725 for flyrotary@lancaironline.net; Thu, 28 Aug 2003 10:09:02 -0400 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Thu, 28 Aug 2003 07:09:01 -0700 Received: from 65.137.50.250 by bay3-dav76.bay3.hotmail.com with DAV; Thu, 28 Aug 2003 14:09:00 +0000 X-Originating-IP: [65.137.50.250] X-Originating-Email: [lors01@msn.com] Reply-To: "Tracy Crook" From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] MSD injector test results Date: Thu, 28 Aug 2003 10:10:58 -0400 Organization: Real World Solutions Inc. MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00EC_01C36D4C.ACEC1140" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Message-ID: X-OriginalArrivalTime: 28 Aug 2003 14:09:01.0101 (UTC) FILETIME=[EE28A5D0:01C36D6D] This is a multi-part message in MIME format. ------=_NextPart_000_00EC_01C36D4C.ACEC1140 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageThe other posible reason for the big difference in apparent flow = rate is injector response time. When running at low manifold pressure, = a small difference can make a big difference. Most injectors take about = 1 millisecond to open. At idle, the injector on time is only about 1.4 = ms. A difference of only .1 ms would look like a 25% difference in = flow rate even if the injectors were perfectly matched at 100% duty = cycle. Another reason to use same brand of injectors in all the holes! Tracy ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Wednesday, August 27, 2003 7:55 PM Subject: [FlyRotary] MSD injector test results Greetings, RC Engineering seems to be a very fast and efficient operation. They = just got my injectors today, and have already called with test results. = I sent 4 very slightly used Mazda 550's, and 2 new MSD-2013's, which are = supposed to be 50 lb/hr (525 cc/min). They said all 6 injectors were = clean, and needed no service at all. The MSD's flowed less than = advertised, but not by nearly as much as I figured. Here are the = results: MSD- 498, 503 Mazda- 547, 549, 551, 551 I'm sure these are static flow rates, and I think they also do pulsed = flow tests, but I forgot to ask about that. I'll get them back in a = week, so I'll check the results when I get the data sheets. 50 cc's = difference only represents about a 10% difference in flow, and doesn't = really explain the large difference in mixture that I see on the EC-2. = I have to wonder if maybe there's more effect than the number would = indicate, since my MSD's are at the throttle body, with about a 20 inch = run to get to the rotors. I can see how this reduced efficiency might = make them seem smaller than they are, but I would also think that Ed = would see the same thing, and maybe he is. =20 If you guys (Ed and Al) don't mind, I'd like to propose a test. At = your convenience, and I'm not kidding- don't make any special trips, or = go to any real effort. Could each of you run at low power, below the = staging point, maybe 1500 rpm, and enable only one set of injectors at a = time. I'd be interested to see what position on the mixture knob you = have to use for each set. On mine, I have to turn the mixture knob to = about 9:00 for the Mazda 550's, and about 3:00 for the MSD's. =20 The test will be interesting, since (as I recall) Al has Mazda 550's = as primaries, and also has the same MSD's that flow about 500 as = secondaries. I can't recall if I've ever seen the physical layout of = these though. Are they all the same distance from the rotors? Ed, I believe, has matched injectors, with a large distance between = the secondaries and the rotors. Any difference in his mixture setting = will indicate a loss of efficiency resulting from the large distance.=20 Sorry to keep dragging everyone through this, but the difference bugs = me. Rusty (T minus 3 days to liftoff) PS- speaking of fast, efficient operations, I sent my ailing = Lightspeed Thirty-3G headset for repair Monday via next day UPS. = Lightspeed got it Tuesday, fixed it, and shipped it out the same day, = via next day UPS. The repaired headset is back in my hands today, and = they threw in a free holder for the battery box that I told them I = wanted to purchase. Bummer that it broke, but mighty friendly folks, = and GREAT service!=20 =20 ------=_NextPart_000_00EC_01C36D4C.ACEC1140 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
The other posible reason for the big = difference in=20 apparent flow rate is injector response time.   When = running at=20 low manifold pressure, a small difference can make a big = difference.  Most=20 injectors take about 1 millisecond to open.  At idle, the injector = on time=20 is only about 1.4 ms.  A difference of only .1  ms  = would=20 look like a 25% difference in flow rate even if the injectors were = perfectly=20 matched at 100% duty cycle.
 
Another reason to use same brand of = injectors in=20 all the holes!
 
Tracy
 
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Wednesday, August 27, = 2003 7:55=20 PM
Subject: [FlyRotary] MSD = injector test=20 results

Greetings,
 
RC = Engineering seems to=20 be a very fast and efficient operation.  They just got my = injectors=20 today, and have already called with test results.  I sent 4 very = slightly=20 used Mazda 550's, and 2 new MSD-2013's, which are supposed to = be 50 lb/hr=20 (525 cc/min).  They said all 6 injectors were clean, and needed = no=20 service at all.  The MSD's flowed less than advertised, but not = by nearly=20 as much as I figured.  Here are the  = results:
 
MSD- 498,=20 503
Mazda- 547, = 549, 551,=20 551
 
I'm sure = these are static=20 flow rates, and I think they also do pulsed flow tests, but I forgot = to ask=20 about that.  I'll get them back in a week, so I'll check the = results when=20 I get the data sheets.  50 cc's difference only represents about = a 10%=20 difference in flow, and doesn't really explain the large difference in = mixture=20 that I see on the EC-2.  I have to wonder if maybe there's more = effect=20 than the number would indicate, since my MSD's are at the throttle = body, with=20 about a 20 inch run to get to the rotors.  I can see how this = reduced=20 efficiency might make them seem smaller than they are, but I would = also think=20 that Ed would see the same thing, and maybe he is.  =
 
If you guys = (Ed and Al)=20 don't mind, I'd like to propose a test.  At your = convenience, and=20 I'm not kidding- don't make any special trips, or go to any real = effort. =20 Could each of you run at low power, below the staging point, maybe = 1500 rpm,=20 and enable only one set of injectors at a time.  I'd be = interested=20 to see what position on the mixture knob you have to use for each = set. =20 On mine, I have to turn the mixture knob to about 9:00 for the Mazda = 550's,=20 and about 3:00 for the MSD's.   
 
The test will = be=20 interesting, since (as I recall) Al has Mazda 550's as primaries, = and=20 also has the same MSD's that flow about 500 as secondaries.  I = can't=20 recall if I've ever seen the physical layout of = these though.  Are=20 they all the same distance from the rotors?
 
Ed, I = believe, has=20 matched injectors, with a large distance between the secondaries and = the=20 rotors.  Any difference in his mixture setting will indicate a = loss of=20 efficiency resulting from the large = distance. 
 
Sorry to keep = dragging=20 everyone through this, but the difference bugs me.
 
Rusty (T = minus 3 days to=20 liftoff)
 
PS- speaking = of fast,=20 efficient operations, I sent my ailing Lightspeed Thirty-3G headset = for repair=20 Monday via next day UPS.  Lightspeed got it Tuesday, fixed it, = and=20 shipped it out the same day, via next day UPS.  The repaired = headset is=20 back in my hands today, and they threw in a free holder for the = battery box=20 that I told them I wanted to purchase.  Bummer that it = broke, but=20 mighty friendly folks, and GREAT service! 
 
  
 
 
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