X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 24 Jun 2013 13:24:52 -0400 Message-ID: X-Original-Return-Path: Received: from mta31.charter.net ([216.33.127.82] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with ESMTP id 6346611 for lml@lancaironline.net; Mon, 24 Jun 2013 12:42:29 -0400 Received-SPF: pass receiver=logan.com; client-ip=216.33.127.82; envelope-from=cscheid@charter.net Received: from imp09 ([10.20.200.9]) by mta31.charter.net (InterMail vM.8.01.05.02 201-2260-151-103-20110920) with ESMTP id <20130624164154.OYVP24708.mta31.charter.net@imp09> for ; Mon, 24 Jun 2013 12:41:54 -0400 Received: from CarlHP ([75.135.80.179]) by imp09 with smtp.charter.net id sGhs1l00G3s7mSK05GhuvJ; Mon, 24 Jun 2013 12:41:54 -0400 X-Authority-Analysis: v=2.0 cv=Cp/n6QED c=1 sm=1 a=x2gRzuQ+4LD806tH7ypwsg==:17 a=yUnIBFQkZM0A:10 a=hOpmn2quAAAA:8 a=L2DLCel4NYYA:10 a=z01mXgzvFRLIipOzvn4A:9 a=QEXdDO2ut3YA:10 a=lfvBDTNmfnOfu2BR--0A:9 a=_W_S_7VecoQA:10 a=iS0clVSASxg1wcYy:21 a=x2gRzuQ+4LD806tH7ypwsg==:117 X-Original-Message-ID: <4D9122A159AD4A7A9E8915CA580DA596@CarlHP> From: "Carl Scheid" X-Original-To: "Lancair Mailing List" Subject: Propeller efficiency X-Original-Date: Mon, 24 Jun 2013 11:41:52 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0066_01CE70CF.D232F860" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 15.4.3555.308 X-MimeOLE: Produced By Microsoft MimeOLE V15.4.3555.308 This is a multi-part message in MIME format. ------=_NextPart_000_0066_01CE70CF.D232F860 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Our flight testing of N304R (IO550G LIV) is progressing and I=E2=80=99ve = been using a performance spread sheet to convert test results to = standard atmosphere and maximum weight. My approach is to guess at a = propeller efficiency curve and then adjust lift efficiency (.65) and = parasite drag (2.15 ft2) to match climb performance test results. = I=E2=80=99m assuming that my 3 blade Hartzell (F7490) has the following = parabola shaped efficiency curve: eff =3D = -.253*(J-1.5)2 + .85 where peak = efficiency =3D .85 at an advance ratio (J) of 1.5 and a second = efficiency of .7 for J=3D .73. Is this reasonable for the = Hartzell/IO550 combination? I=E2=80=99d be interested in any propeller = performance results that have worked for a spread sheet performance = model. Thanks, Carl Scheid ------=_NextPart_000_0066_01CE70CF.D232F860 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Our flight testing of N304R (IO550G LIV) is = progressing=20 and I=E2=80=99ve been using a performance spread sheet to convert test = results to=20 standard atmosphere and maximum weight. =20 My approach is to guess at a propeller efficiency curve and then = adjust=20 lift efficiency (.65) and parasite drag (2.15 ft2) to match = climb=20 performance test results. I=E2=80=99m assuming that my 3 blade Hartzell = (F7490) has the=20 following parabola shaped efficiency curve:           &nbs= p;           =20 eff =3D -.253*(J-1.5)2 + .85           &nbs= p;   =20            &nbs= p;   =20 where   peak = efficiency =3D .85=20 at an advance ratio (J) of 1.5 and a second efficiency of  .7 for J=3D .73. Is this = reasonable for=20 the Hartzell/IO550 combination?  I=E2=80=99d=20 be interested in any propeller performance results that have worked for = a spread=20 sheet performance model. Thanks, Carl=20 Scheid

------=_NextPart_000_0066_01CE70CF.D232F860--