Return-Path: <13brv3@bellsouth.net> Received: from imf18aec.mail.bellsouth.net ([205.152.59.66] verified) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3151784 for flyrotary@lancaironline.net; Wed, 07 Apr 2004 21:46:52 -0400 Received: from rad ([68.221.181.100]) by imf18aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040408014651.FUCU1781.imf18aec.mail.bellsouth.net@rad> for ; Wed, 7 Apr 2004 21:46:51 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Help Rusty pick a prop Date: Wed, 7 Apr 2004 20:46:56 -0500 Message-ID: <038401c41d0b$5fff2920$6001a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0385_01C41CE1.77292120" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 In-Reply-To: Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_0385_01C41CE1.77292120 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I agree that with the pusher, the air is blocked from the center portion = of the prop, so the IVO really doesn't hinder top end speed. It may on the = RV. =20 The IVO Magnum comes with 2 different ranges on the pitch. I have the = high pitch blades which is what they recommend for my plane. I believe that = the pitch range goes from something like 40-45" on the low end, up to = something like 105" on the high end of the pitch range. =20 Steve=20 =20 Hi Steve, =20 I called IVO, and of course they've never heard of such a thing as their props causing drag at high speeds. Imagine that. Tracy probably just = made that up :-) Anyway, they didn't really inspire me with confidence that = they knew much about props. Mostly, they work from numbers that they have archived, and give recommendations based on those. Their best recommendation was for a 3 blade, 68" Magnum, standard pitch prop. = Since I'm planning to run it to 3200+ rpm, they said I don't need the high = pitch range. =20 =20 I took a closer look at my Warp Drive prop (3 blade, 68") today, and = find that the hub area should create far less drag than a typical IVO. Since = IVO didn't have any significantly different recommendation from what I = already have, I'll probably continue working with the Warp to see what I can = get. In fact, I took 3 degrees out of the pitch today, to get the RPM up. =20 =20 After thinking more about it, I really can't make any final decisions = until I get the wheel pants and gear fairings on. I may also need to close up = the rear of the cowl cheeks, though that might have to wait until I can do = some testing in 90-100 degree temps to make sure the lower opening is = adequate. I will also need to send the Warp blades back, so they can taper them. = Only then will I know how they work when they're optimized. =20 =20 Cheers, Rusty (I need more RPM Scotty) ------=_NextPart_000_0385_01C41CE1.77292120 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
I = agree that with=20 the pusher, the air is blocked from the center portion of the prop, so = the IVO=20 really doesn't hinder top end speed. It may on the RV.=20  
 
The = IVO Magnum comes=20 with 2 different ranges on the pitch.  I have the high pitch blades = which=20 is what they recommend for my plane.  I believe that the pitch = range=20 goes from something like 40-45" on the low end, up to something like = 105" on the=20 high end of the pitch range.
 
Steve 
 
Hi=20 Steve,
 
I called = IVO, and of=20 course they've never heard of such a thing as their props = causing drag=20 at high speeds.   Imagine that.  Tracy probably just made = that up=20 :-)  Anyway, they didn't really inspire me with confidence = that they=20 knew much about props.  Mostly, they work from numbers that they = have=20 archived, and give recommendations based on those.  Their best = recommendation was for a 3 blade, 68" Magnum, standard pitch = prop. =20 Since I'm planning to run it to 3200+ rpm, they said I don't need the=20 high pitch=20 range.  
 
I took a = closer look at my=20 Warp Drive prop (3 blade, 68") today, and find that the hub area should = create=20 far less drag than a typical IVO.  Since IVO didn't have any = significantly=20 different recommendation from what I already have, I'll probably = continue=20 working with the Warp to see what I can get.  In fact, I took 3 = degrees out=20 of the pitch today, to get the RPM up. =20
 
After thinking = more about=20 it, I really can't make any final decisions until I get the wheel pants = and gear=20 fairings on.  I may also need to close up the rear of the cowl = cheeks,=20 though that might have to wait until I can do some testing in 90-100 = degree=20 temps to make sure the lower opening is adequate.  I will also need = to send=20 the Warp blades back, so they can taper them.  Only then will I = know how=20 they work when they're optimized. =20
 
Cheers,
Rusty  (I = need more RPM=20 Scotty)
------=_NextPart_000_0385_01C41CE1.77292120--