X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao104.cox.net ([68.230.241.42] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3902788 for flyrotary@lancaironline.net; Wed, 28 Oct 2009 11:56:07 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.42; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao104.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20091028155533.LLPJ14181.fed1rmmtao104.cox.net@fed1rmimpo01.cox.net> for ; Wed, 28 Oct 2009 11:55:33 -0400 Received: from BigAl ([72.192.133.78]) by fed1rmimpo01.cox.net with bizsmtp id yFvX1c00T1hf1Cg03FvXWM; Wed, 28 Oct 2009 11:55:32 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=Ia-xEzejAAAA:8 a=__2eySsw0JWRynWDOD8A:9 a=FjALZygIfE65v5SqokYA:7 a=MQikVjX24RmzFC1m7eD3NhnUG-EA:4 a=EzXvWhQp4_cA:10 a=ucQd5eOvEM-8-kgf:21 a=SxzQH_IEPZ7C0QtR:21 a=-nnnL6qmd9izNStXrE8A:9 a=LvwLprayhqx8Npn8LmsA:7 a=MOnZ581Y1hpJoyUs8wxq4sK-PpQA:4 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Prop Loads Date: Wed, 28 Oct 2009 08:56:35 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0015_01CA57AC.8D6F1820" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6856 Importance: Normal Thread-Index: AcpXeEgNx0N5M0NXTSWNhesVtnPtWQAdLtkg In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0015_01CA57AC.8D6F1820 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Greg; =20 I had the same dilemma when running my engine on the dyno. =20 The primary reason I wanted to simulate a prop load so I could do tuning = of the EC2 on the dyno. But that never happened. I generated an = approximate prop load curve but could never follow it - IIRC, it was because you = can't set the load, and there is more than one RPM/MAP combination for a given load. Dyno work is basically about generating WOT HP and torque curves. = You set the mixture according to the A/F ratio. And you always learn some = other things along the way - flow rates, EGTs, fuel burn, etc. =20 And Gary, I don't think prop load varies as the square of the rpm - does = it? I think some aspects, like thrust, go as the square; but the drag goes = more like the cube. I generated one both ways, and neither is the real = world. =20 Al G =20 =20 =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Greg Ward Sent: Tuesday, October 27, 2009 6:43 PM To: Rotary motors in aircraft Subject: [FlyRotary] Prop Loads =20 Hey Troops; Finally in the dyno room building the mount plate to begin testing. = Tracy says that the engine should be tested with the prop on, and this is kind = of hard in a dyno room. We are mounting the engine without the PSRU, so = that we don't tear it up in testing, and instead hooking directly to the = shaft which is loaded by means of a water brake. We can put any load on it = that we want, problem is, how to calculate that prop load in foot-pounds, at different settings. Talked to Craig Cato, and he is leaving for Europe, = so doesn't have time to run the calcs, and I am just a dumb high country nail-banger. Any thoughts? Greg Ward Lancair 20B N178RG in progress ------=_NextPart_000_0015_01CA57AC.8D6F1820 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Greg;

 

I had the same dilemma when = running my engine on the dyno.

 

The primary reason I wanted to = simulate a prop load so I could do tuning of the EC2 on the dyno.  But that = never happened.  I generated an approximate prop load curve but could = never follow it – IIRC, it was because you can’t set the load, and = there is more than one RPM/MAP combination for a given load.  Dyno work is basically = about generating WOT HP and torque curves. You set the mixture according to = the A/F ratio.  And you always learn some other things along the way = – flow rates, EGTs, fuel burn, etc.

 

And Gary, I = don’t think prop load varies as the square of the rpm – does it?  I think = some aspects, like thrust, go as the square; but the drag goes more like the = cube.  I generated one both ways, and neither is the real = world.

 

Al G

 

 

 

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Greg Ward
Sent: Tuesday, October = 27, 2009 6:43 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Prop = Loads

 

Hey = Troops;

Finally in the dyno room building the mount plate to begin testing.  Tracy says = that the engine should be tested with the prop on, and this is kind of hard in a = dyno room.  We are mounting the engine without the PSRU, so that we = don't tear it up in testing, and instead hooking directly to the shaft which is = loaded by means of a water brake.  We can put any load on it that we want, = problem is, how to calculate that prop load in foot-pounds, at different settings.  Talked to Craig Cato, and he is leaving for Europe, so = doesn't have time to run the calcs, and I am just a dumb high country nail-banger.  Any thoughts?

Greg Ward

Lancair 20B N178RG in progress

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