Return-Path: <13brv3@bellsouth.net> Received: from imf22aec.mail.bellsouth.net ([205.152.59.70] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 604936 for flyrotary@lancaironline.net; Wed, 12 Jan 2005 13:40:11 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.70; envelope-from=13brv3@bellsouth.net Received: from rd ([65.6.194.9]) by imf22aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050112183922.NSFZ2069.imf22aec.mail.bellsouth.net@rd> for ; Wed, 12 Jan 2005 13:39:22 -0500 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: props again Date: Wed, 12 Jan 2005 12:39:33 -0600 Message-ID: <000501c4f8d6$0f6fee20$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C4F8A3.C4D57E20" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C4F8A3.C4D57E20 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable You are correct in that the MicroTech ECU has a hard and soft rev = limiting feature..I will get back into the manual and see what I can learn. =20 =20 My understanding of rev limits is that a hard limit will shut you down completely, at least until the condition is cleared, and you'd certainly notice that :-) Soft limits are supposed to reduce power as needed to = keep you where the limit is set. I've read that some of these are pretty = smooth, and you won't necessarily even know it's happening. One technique is to remove ignition pulses in an intelligent manner. For example, perhaps = it will remove every 4th ignition pulse if you start to approach the limit, then if you continue to advance the throttle, maybe it has to take out = every 3rd, then maybe every other pulse. This might even explain your engine behavior on the first flight. Some systems can do this with fuel as = well, but I think it's more common to do ignition. Again, I'm not familiar = with the MicroTech, so this is just a guess based on reading about other = ECUs. =20 Good luck, Rusty=20 =20 ------=_NextPart_000_0006_01C4F8A3.C4D57E20 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
You are = correct in that=20 the MicroTech ECU has a hard and soft rev = limiting=20 feature….I will get back into the manual and see what I can = learn.   
 
My understanding of rev limits is that a = hard limit=20 will shut you down completely, at least until the condition is = cleared, and=20 you'd certainly notice that :-)  Soft limits are supposed to reduce = power=20 as needed to keep you where the limit is set.  I've read that some = of these=20 are pretty smooth, and you won't necessarily even know it's = happening.  One=20 technique is to remove ignition pulses in an intelligent manner.  = For=20 example, perhaps it will remove every 4th ignition pulse if you start to = approach the limit, then if you continue to advance the throttle, maybe = it has=20 to take out every 3rd, then maybe every other pulse. This might even=20 explain your engine behavior on the first flight.  Some = systems can do=20 this with fuel as well, but I think it's more common to do=20 ignition.  Again, I'm not familiar with the MicroTech, so this = is just=20 a guess based on reading about other=20 ECUs.
 
Good = luck,
Rusty =
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