X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf18aec.mail.bellsouth.net ([205.152.59.66] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTP id 2083405 for flyrotary@lancaironline.net; Mon, 04 Jun 2007 12:13:12 -0400 Received-SPF: none receiver=logan.com; client-ip=205.152.59.66; envelope-from=rusty@radrotary.com Received: from ibm61aec.bellsouth.net ([65.6.194.9]) by imf18aec.mail.bellsouth.net with ESMTP id <20070604161233.LIVW18329.imf18aec.mail.bellsouth.net@ibm61aec.bellsouth.net> for ; Mon, 4 Jun 2007 12:12:33 -0400 Received: from rd ([65.6.194.9]) by ibm61aec.bellsouth.net with ESMTP id <20070604161233.DHVA25479.ibm61aec.bellsouth.net@rd> for ; Mon, 4 Jun 2007 12:12:33 -0400 From: "Russell Duffy" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Single rotor video Date: Mon, 4 Jun 2007 11:12:34 -0500 Message-ID: <00a801c7a6c3$297d75b0$6e01a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00A9_01C7A699.40A76DB0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6822 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 Importance: Normal Thread-Index: AcemvHKYCDaPCH3sTnmvC9KKC3DnRgABWxWw In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_00A9_01C7A699.40A76DB0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable I wonder if having only one rotor if torque reversal between firing = pulse might have more of an effect at slower rpm in loading/unloading prop = blades than at higher. =20 =20 Hi Ed, =20 No doubt at all that slower speed is the main problem. If I understand = this all correctly, what's needed is enough inertia to carry through the compression stroke without slowing down significantly. At higher rpms, = the rotating mass has enough inertia to take care of the problem, but at = lower rpms, a flywheel would be needed. The weight of the flywheel would be determined by how low you want to go in rpm. =20 =20 Adding weight is sort of the brute force way to fix it, but it could = also be fixed by adding enough damping to absorb the speed changes. My understanding is that I need something really soft, and even the softest damper I can get is probably not going to work as well as I'd like it = to. With any luck though, it will be good enough to get around 2000 rpm for "idle". =20 =20 BTW, to make everyone feel better, my EC-2 is doing something I haven't = been able to explain either. I have to run with cold start on to have enough fuel to run, which would imply that I'm only getting half the fuel I'm supposed to get with it off. I'm sure I've goofed something up, and I haven't really taken the time to figure it out yet, but I do have a = small Holley carb on the way to test as well :-) =20 Rusty=20 ------=_NextPart_000_00A9_01C7A699.40A76DB0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
I wonder if having only one rotor if torque = reversal=20 between firing pulse might have more of an effect at slower rpm in=20 loading/unloading prop blades than at higher.   
 
Hi=20 Ed,
 
No=20 doubt at all that slower speed is the main problem.  If I = understand this=20 all correctly, what's needed is enough inertia to carry through the = compression=20 stroke without slowing down significantly.  At higher rpms, the = rotating=20 mass has enough inertia to take care of the problem, but at lower rpms, = a=20 flywheel would be needed.  The weight of the flywheel would be = determined=20 by how low you want to go in rpm.  
 
Adding weight=20 is sort of the brute force way to fix it, but it could also be fixed by = adding=20 enough damping to absorb the speed changes.  My understanding is = that I=20 need something really soft, and even the softest damper I can get is = probably=20 not going to work as well as I'd like it to.  With any luck though, = it will=20 be good enough to get around 2000 rpm for "idle".  =
 
BTW, to make=20 everyone feel better, my EC-2 is doing something I haven't been able to = explain=20 either.  I have to run with cold start on to have enough fuel to = run, which=20 would imply that I'm only getting half the fuel I'm supposed to get with = it=20 off.  I'm sure I've goofed something up, and I haven't really taken = the=20 time to figure it out yet, but I do have a small Holley carb on the way = to test=20 as well :-)
 
Rusty=20
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