Message

Return-Path: <13brv3@bellsouth.net> Received: from imf25aec.mail.bellsouth.net ([205.152.59.73] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2578756 for flyrotary@lancaironline.net; Sun, 14 Sep 2003 00:08:12 -0400 Received: from rad ([68.212.12.251]) by imf25aec.mail.bellsouth.net (InterMail vM.5.01.05.27 201-253-122-126-127-20021220) with ESMTP id <20030914040811.HBGQ1843.imf25aec.mail.bellsouth.net@rad> for ; Sun, 14 Sep 2003 00:08:11 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Good news, Bad news Date: Sat, 13 Sep 2003 23:08:12 -0500 Message-ID: <000001c37a75$d0b793c0$0201a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C37A4B.E7E18BC0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C37A4B.E7E18BC0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Have you tested climb rate at lower speeds, where drag is less = important? Also, you could try reducing the size of the inlet to the Radiator scoop = to see if that reduces cooling drag, since you have excess cooling = available.=20 =20 On the average RV-#, best rate of climb is about 100 kts, or 120 mph. That's what it was on my RV-8, and also on a friend's RV-3. I'm seeing = best climb rate down around 80 kts, which was about the best angle of climb = on my RV-8. I think this is an indication that drag is becoming too much of a factor in the higher speed climbs. There's no questioning the airframe. The normal performance of an RV-3 is well known. I also can't doubt the power the engine is putting out. It really slams you back in the seat = on takeoff. I think the only logical conclusion is that there's an overwhelming amount of drag from the cowl. =20 As for the cooling drag, I do have a huge opening for an air intake, but = I just can't imagine that being the majority of the problem. I'm afraid = the whole cowl will need to be re-worked, which means a smaller radiator, = and a new intake manifold. I just don't see any other option, since I'm = really not interested in flying it like it is.=20 =20 Cheers, Rusty =20 ------=_NextPart_000_0001_01C37A4B.E7E18BC0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Have you tested climb rate at = lower speeds,=20 where drag is less important? Also, you could try reducing the size of = the inlet=20 to the Radiator scoop to see if that reduces cooling drag, since you = have excess=20 cooling available.

On the average RV-#, best rate of climb is = about 100 kts,=20 or 120 mph. That's what it was on my RV-8, and also on a = friend's=20 RV-3. I'm seeing best climb rate down around 80 kts, = which was=20 about the best angle of climb on my RV-8. I think this is an = indication=20 that drag is becoming too much of a factor in the higher speed=20 climbs. There's no questioning the=20 airframe. The normal performance of an RV-3 is well = known. =20 I also can't doubt the power the engine is putting out. It = really=20 slams you back in the seat on takeoff. I think the = only logical=20 conclusion is that there's an overwhelming amount of drag from the=20 cowl.

As for the cooling drag, I do have a huge = opening for an=20 air intake, but I just can't imagine that being the majority of the=20 problem. I'm afraid the whole cowl will need to be = re-worked,=20 which means a smaller radiator, and a new intake manifold. I = just=20 don't see any other option, since I'm really not interested in = flying it=20 like it is.

Cheers,

Rusty

= ------=_NextPart_000_0001_01C37A4B.E7E18BC0--