Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3147715 for flyrotary@lancaironline.net; Mon, 05 Apr 2004 21:43:02 -0400 Received: from EDWARD (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i361gxs2017903 for ; Mon, 5 Apr 2004 21:43:00 -0400 (EDT) Message-ID: <001401c41b78$7ddf2ce0$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: : Percent Power, Throttle position, & RD-1C performance Date: Mon, 5 Apr 2004 21:42:59 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01C41B56.F683B2A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0011_01C41B56.F683B2A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable It sounds like matching the prop and cleaning up the hub area is key to = this outstanding performance with the "C" drive. Let's see, I hope to = arrive around noon on Friday. A day for carving a right hand rotation = prop out of a local tree, 3 hours to swap my "B" for a "C" and on to = Sun & Fun {:>)...... I like it, sounds like you can eat and have your = cake both . Some day in the near future, tied the tail to a tree and see what static = rpm you get. I am particularly interested in the take off and climb = acceleration. Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Monday, April 05, 2004 8:31 PM Subject: [FlyRotary] Re: : Percent Power, Throttle position, & RD-1C = performance Took closer note of throttle position on todays flight. At 2000 ft = the throttle was only about 1/3 open (position of throttle quadrant, but = it closely mirrors butterfly position) at economy cruise setting which = was 6.0 GPH. This is about 42% power, 82 HP according to the EM2 which = is fairly close but not perfectly calibrated yet. The same power = setting with the -B drive would bave been a bit further open. I did a quick check of MAP at 1000 ft at full throttle and found I was = not getting any drop at 150 MPH and had .5" boost at 220 MPH (ram air = recovery I assume). I did not get around to checking it in slow climb = which would more accurately compare to what you would see on a dyno. Finally got some reasonably calm air to do performance comparisons of = -C drive vs -B drive. Without the prop blade cuffs it looks like the = break even point is at 203 MPH. Above that -C burned more fuel than the = -B. After installation of the cuffs, the break even point was off the = scale! i.e., above top speed with -B drive. I had a good data point on = the -B drive while burning 17 GPH (209 mph during SUN 100 race). At the = same speed, the C drive was burning 15.8 gph. This was better than I = had hoped for. Tracy Thanks, Tracy. I was hoping there would be someone out there flying = with the same TB diameters. Like most things, TB diameter is a tradeoff. My conclusion from the = dyno data is that 44mm per rotor (1 =BE) is a bit small as the MAP is = dropping off over 5000 RPM. But if you want to idle at 1500, and have a = decent transition from there to 3000; 1 =BE is good. For a 2.85 to = redrive, I'd want to increase that flow area by 30% or so - to about 2" = dia for each rotor.=20 My data may not be representative because of restricted flow to the = TB. The 'airbox' size is restricted by the cowl, and may have = restricted the flow a bit. In hindsight, it would have been smart (and = easy) to make a run with the airbox off and see what difference it made. Al ------=_NextPart_000_0011_01C41B56.F683B2A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
It sounds like matching the prop and = cleaning up=20 the hub area is key to this outstanding performance with the "C" = drive. =20 Let's see, I hope to arrive around noon on Friday.  A day for = carving a=20 right hand rotation prop out of a local tree, 3 hours to swap my = "B"=20 for  a "C" and on to Sun & Fun {:>)......  I like it, = sounds=20 like you can eat and have your cake both .
 
Some day in the near future, tied the = tail to a=20 tree and see what static rpm you get.  I am particularly interested = in the=20 take off and climb acceleration.
 
Ed
 
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 Tracy = Crook
Sent: Monday, April 05, 2004 = 8:31=20 PM
Subject: [FlyRotary] Re: : = Percent Power,=20 Throttle position, & RD-1C performance

Took closer note of throttle position = on todays=20 flight.  At 2000 ft the throttle was only about 1/3 open = (position of=20 throttle quadrant, but it closely mirrors butterfly position) at = economy=20 cruise setting which was 6.0 GPH.  This is about 42% power, = 82 HP=20 according to the EM2 which is fairly close but not perfectly = calibrated=20 yet.  The same power setting with the -B drive would bave been a = bit=20 further open.
 
I did a quick check of MAP at 1000 ft = at full=20 throttle and found I was not getting any drop at 150 MPH and had .5" = boost at=20 220 MPH (ram air recovery I assume).  I did not get around to = checking it=20 in slow climb which would more accurately compare to what you would = see on a=20 dyno.
 
Finally got some reasonably calm air = to do=20 performance comparisons of -C drive vs -B drive.  Without the = prop blade=20 cuffs it looks like the break even point is at 203 MPH.  Above=20 that -C burned more fuel than the -B.  After installation of = the=20 cuffs, the break even point was off the scale! i.e., above top speed = with -B=20 drive.  I had a good data point on the -B drive = while burning 17 GPH=20 (209 mph during SUN 100 race).  At the same speed, the C drive = was=20 burning 15.8 gph.  This was better than I had hoped = for.
 
Tracy
 

Thanks, = Tracy. I was = hoping=20 there would be someone out there flying with the same TB=20 diameters.

 

Like = most things,=20 TB diameter is a tradeoff.  My conclusion from the dyno data is = that=20 44mm per rotor (1 =BE) is a bit small as the MAP is dropping off = over 5000=20 RPM.  But if you want to idle at 1500, and have a decent = transition=20 from there to 3000; 1 =BE is good.  For a 2.85 to redrive, = I=92d want to=20 increase that flow area by 30% or so =96 to about 2=94 dia for each = rotor.=20

 

My data = may not=20 be representative because of restricted flow to the TB.  The = =91airbox=92=20 size is restricted by the cowl, and may have restricted the flow a = bit.=20  In hindsight, it would have been smart (and easy) to make a = run with=20 the airbox off and see what difference it made.

 

Al

 

 

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