X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wproxy.gmail.com ([64.233.184.204] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 974723 for flyrotary@lancaironline.net; Wed, 08 Feb 2006 12:38:28 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.204; envelope-from=russell.duffy@gmail.com Received: by wproxy.gmail.com with SMTP id i21so1640504wra for ; Wed, 08 Feb 2006 09:37:44 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:from:to:subject:date:message-id:mime-version:content-type:x-priority:x-msmail-priority:x-mailer:importance:x-mimeole:in-reply-to; b=OnB4BLjrgKd2soYxoZsWZw6Mgd6CpGWp3TluVrDnpf1tqmgZGZHOGpLG0eGdIgi+rFQ7Z+zmGYXuvsVl06AFKo7l1xPuhChnKKMmWceZse/DWO0lu8Bl1WnPt6OKQo7dEQC0PDY68LCb9l7nt+PpT4M8aBxjXaxySz51v+wnJY8= Received: by 10.54.127.3 with SMTP id z3mr9370457wrc; Wed, 08 Feb 2006 09:37:44 -0800 (PST) Return-Path: Received: from rd ( [65.6.194.9]) by mx.gmail.com with ESMTP id 28sm203615wrl.2006.02.08.09.37.43; Wed, 08 Feb 2006 09:37:43 -0800 (PST) From: "Russell Duffy" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Lycoming conspiracy theory Re: 6 port? Date: Wed, 8 Feb 2006 11:37:44 -0600 Message-ID: <01b901c62cd6$5ea8ebb0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_01BA_01C62CA4.140E7BB0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2670 In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_01BA_01C62CA4.140E7BB0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable There is ample evidence. After a thousand or so hours in the dyno room, = you can develop a feel for such things. Look at the ID of the carb or TB on = the 180. How many CFM? Enough to support the advertised HP? At what rpm is = that HP rating? Can't get a dyno sheet for your new engine? And if you could, what is the date on that sheet? Is it for your engine, or for an engine built years ago? =20 =20 It's true that dyno sheets are hard to come by, but then I've never = received one with a car, or with my engine from Bruce, or from Rotax, etc. =20 =20 Typical of the breed is a HP rating at 3,200 to 3,400 RPM (from years = ago) and with a prop on them they won't turn up 2,700 on the ground. =20 =20 So you're saying that you can buy New Lycoming O-360's, rated at = 180HP/2700 rpm, then take them to a dyno and show that they make "nothing close to their advertised HP"? If so, you'll be a rich man when you sue them. I wouldn't start spending the money though :-) =20 Since the rotary does outrun most of the 160 HP powered planes, would = you assume that those rotaries have way more than 160 HP? Or, perhaps the = 160s had a bit less. =20 =20 One thing to remember is the difference in how dyno results are = collected. For the Lycoming, they test an engine under best case conditions in a = test cell. The aircraft manufacturer can lower these numbers a bit during installation with restrictive filters, exhaust systems, etc. For the = car, the test is done under worst case conditions, so we assume the actual installed power in an aircraft to be a bit higher. If you look at it = this way, it might be fair to compare a "160" HP car engine to a "200" HP aircraft engine. =20 =20 Take off in a Cessna 150. Alone, so it won't be over gross. Did that = feel like 150HP?=20 Did it feel more like 79HP? Why yes it did. =20 =20 Considering that it only has a 108 HP O-235 engine, that sounds about = right for a fixed pitch prop :-) =20 Don't get me wrong, I hope to see lots of rotary engine clearly outperforming Lycoming in reliability, and performance, but I frankly = don't think that day has come. I'm rooting for Bill Dube's 6 port intake, = though. =20 Cheers, Rusty (someone has to play the bad guy)=20 ------=_NextPart_000_01BA_01C62CA4.140E7BB0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
There is ample evidence. After a thousand or so hours in the dyno = room, you=20 can develop a feel for such things. Look at the ID of the carb or = TB on the=20 180. How many CFM? Enough to support the advertised HP? At what rpm is = that HP=20 rating? Can't get a dyno sheet for your new engine? And if you could, = what is=20 the date on that sheet? Is it for your engine, or for an engine built = years=20 ago?   
 
It's true that=20 dyno sheets are hard to come by, but then I've never received one with a = car, or=20 with my engine from Bruce, or from Rotax, = etc.  
 
Typical of the breed is a HP rating at 3,200 to 3,400 RPM (from = years ago)=20 and with a prop on them they won't turn up 2,700 on the = ground.  
 
So = you're saying=20 that you can buy New Lycoming O-360's, rated at 180HP/2700 rpm, = then take=20 them to a dyno and show that they make "nothing close to their advertised HP"?  If so,=20 you'll be a rich man when you sue them.  I wouldn't start = spending the=20 money though :-)
 
Since the rotary does outrun most of the 160 HP powered planes, = would you=20 assume that those rotaries have way more than 160 HP? Or, perhaps = the 160s=20 had a bit less.   
 
One = thing to=20 remember is the difference in how dyno results are collected.  = For the=20 Lycoming, they test an engine under best case conditions in a=20 test cell.  The aircraft manufacturer can lower these numbers=20 a bit during installation with restrictive filters, exhaust=20 systems, etc.  For the car, the test is done under worst case=20 conditions, so we assume the actual installed power in an aircraft = to be a=20 bit higher.   If you look at it this way, it might be fair to = compare=20 a "160" HP car engine to a "200" HP aircraft engine. =20  
 
 Take off in a Cessna = 150.=20 Alone, so it won't be over gross. Did that feel like 150HP?
Did it feel more like 79HP? Why yes it did.    
 
Considering that=20 it only has a 108 HP O-235 engine, that sounds about right for a = fixed=20 pitch prop :-)
 
Don't get me=20 wrong, I hope to see lots of rotary engine clearly outperforming = Lycoming in=20 reliability, and performance, but I frankly don't think that day has = come. =20 I'm rooting for Bill Dube's 6 port=20 intake, though.  
 
Cheers,
Rusty (someone=20 has to play the bad guy) 
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