Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 763747 for flyrotary@lancaironline.net; Mon, 28 Feb 2005 19:18:24 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-185-127.carolina.rr.com [24.74.185.127]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j210HaCi018468 for ; Mon, 28 Feb 2005 19:17:38 -0500 (EST) Message-ID: <001501c51df4$1a5c00b0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: injector life and reliability Date: Mon, 28 Feb 2005 19:17:47 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0010_01C51DCA.2FF56DA0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0010_01C51DCA.2FF56DA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Good to know, Tracy. I would rather have the injector give up first = than the driver - easier to replace the injector {:>). I felt certain = that your drivers would be designed to survive if a P&H were connected - = good to have it confirmed. Ed ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Monday, February 28, 2005 3:34 PM Subject: [FlyRotary] Re: injector life and reliability Correct on all points Ed. Except that I changed the injector drivers = to a higher current version about 6 years ago. This was after a couple = of "peak & hold injectors connected as saturated" incidents. Now the = injector gives up first. But I think it still takes a long time to kill = an injector this way. Tracy Subject: [FlyRotary] Re: injector life and reliability Bernie, Your injectors should be fine, the drivers won't hurt the injectors = - however, the injectors can hurt the drivers. Because a saturation = driver is expecting more resistance (less current requirement) from a = saturated type injector of around 12-16 ohms. If you stick a Peak and Hold (around = 2.5 ohms) in a circuit designed for saturation injectors, they (Peak = and hold) will draw considerably more current and may exceed the design limit = of the saturation injector driver thereby damaging it. On the other hand, = if the designer "over-designed" the driver it may cause no damage at all. If you put a saturation injectors in a circuit designed for Peak and = Hold, you will not damage the drivers because the saturation injector will = never exceed the current draw the P&H circuit was designed for - but, you = may not get very good injection especially at the lower rpms. So if anything could have been damaged - it would have been the EC2, = but Tracy has done a good job of providing a bit of margin there as = well. I don't doubt you had a bad injectors ( I have had several - they are = just getting old), but I doubt it was caused by the lack of resistors. Tracy, of course, will correct any incorrect reference to his design = work {:>) Ed A ------=_NextPart_000_0010_01C51DCA.2FF56DA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Good to know, Tracy. I would rather have = the=20 injector give up first than the driver - easier to replace the injector=20 {:>). I felt certain that your drivers would be designed to = survive if=20 a P&H were connected - good to have it confirmed.

Ed

----- Original Message -----
From:=20 Tracy = Crook
To: Rotary motors in = aircraft

Sent: Monday, February 28, 2005 = 3:34=20 PM

Subject: [FlyRotary] Re: = injector life=20 and reliability

Correct on all points Ed. Except that I changed the = injector=20 drivers to a higher current version about 6 years ago. This was = after a=20 couple of "peak & hold injectors connected as saturated" = incidents. =20 Now the injector gives up first. But I think it still takes a = long time=20 to kill an injector this way.

Tracy

Subject: [FlyRotary] Re: injector life and = reliability

Bernie,

Your injectors should be fine, the = drivers=20 won't hurt the injectors -
however, the injectors can hurt the=20 drivers. Because a saturation driver is
expecting more = resistance=20 (less current requirement) from a saturated type
injector of = around 12-16=20 ohms. If you stick a Peak and Hold (around 2.5
ohms) in a = circuit=20 designed for saturation injectors, they (Peak and = hold)
will draw=20 considerably more current and may exceed the design limit of=20 the
saturation injector driver thereby damaging it. On the = other=20 hand, if the
designer "over-designed" the driver it may cause no = damage=20 at all.

If you put a saturation injectors in a circuit = designed for=20 Peak and Hold,
you will not damage the drivers because the = saturation=20 injector will never
exceed the current draw the P&H circuit = was=20 designed for - but, you may not
get very good injection = especially at the=20 lower rpms.

So if anything could have been damaged - it would = have=20 been the EC2, but
Tracy has done a good job of providing a bit of = margin=20 there as well. I
don't doubt you had a bad injectors ( I = have had=20 several - they are just
getting old), but I doubt it was caused = by the=20 lack of resistors.

Tracy, of course, will correct any = incorrect=20 reference to his design work
{:>)

Ed=20 A

------=_NextPart_000_0010_01C51DCA.2FF56DA0--