Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Sun, 05 Jan 2003 11:46:23 -0500 Message-ID: X-Original-Return-Path: <13brv3@mchsi.com> Received: from sccmmhc01.mchsi.com ([204.127.203.183] verified) by logan.com (CommuniGate Pro SMTP 4.0.3) with ESMTP id 1945482 for flyrotary@lancaironline.net; Sun, 05 Jan 2003 10:08:22 -0500 Received: from rad ([12.218.64.232]) by sccmmhc01.mchsi.com (InterMail vM.4.01.03.27 201-229-121-127-20010626) with ESMTP id <20030105150821.UYDY18244.sccmmhc01.mchsi.com@rad> for ; Sun, 5 Jan 2003 15:08:21 +0000 Reply-To: <13brv3@mchsi.com> From: <13brv3@mchsi.com> X-Original-To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] props X-Original-Date: Sun, 5 Jan 2003 09:08:17 -0600 X-Original-Message-ID: <004b01c2b4cc$4a638780$0201a8c0@rad> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Importance: Normal In-Reply-To: Rusty; I guess the old recollecter isn't what it used to be, as tonite = I was looking back to last April, and an e-mail from Jim Mosur stated the = prop he has for a backup is an Ivo and not a Warp Drive. =20 ------------------ Thanks for the correction. I just took a brief look at some of the = other brands you mentioned, and as I found before, they're made for 2-stroke power. At the moment, I'd say Warp Drive is still my prop of choice.=20 To anyone else who might be interested, here are my notes from about a = year ago when I spoke with Warp Drive. =20 Rusty 12-7-01 Spoke with Warp Drive today about a prop. Their number is 641-357-6000, = and they have a dealer in Ft Walton (Able Aircraft Engines). They said I = would require at least 3 blades for 180-200 HP from a Mazda with 2.178 = redrive. Over about 220 HP, I'd have to go with 4 blades. A 2.85 redrive would = also require a 4 blade even for 180 HP. This is to be able to absorb the = power without overstressing the blades. They said a 3 blade prop on the Mazda would be extraordinarily smooth. Gotta like that. They recommend that I start with the standard blade, rather than the = tapered blade, because they think I'll need all the tip area I can get for the power. Once it's flying, and I give them some numbers, they can = determine if some tapering will help, and the blades can be tapered at that time. = There's really no limit to the blade angle, other than cavitation. They said 22 degrees (about 82") pitch was the limit before some cavitation = would occur. =20 Rain will erode the prop leading edge, unless you slow the prop down to = 2200 RPM or less, or unless you have the Nickel leading edge strips. They = cost $40 per blade, and are always added as the last step, so they can be = added at any time after the prop has been in service. In fact, they recommend flying the prop first to finalize the length and shape of the blades, = then having the LE strips added. It might be worth flying the prop until the rain proves to be a problem, then having the strips added if necessary. Probably won't be needed for me. =20 They recommend a max prop tip speed of 850 fps, which is about what I'll = end up with at cruise. The prop can be run faster, and 3400 rpm for a 7000 = RPM engine run should be no problem. =20 They sell fiberglass spinners as well, and have a 12" available for = about $160. It will completely cover the prop hub. =20 At this time, nobody makes a variable pitch hub for the warp blades at = this power level. =20 They did warn me that their prop will always be a bit slower on top = speed than a properly made 2-blade wood prop. He said it should be within 10 = mph though. Small price to pay for an adjustable prop.