Return-Path: Received: from [65.54.168.121] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2947382 for flyrotary@lancaironline.net; Sat, 24 Jan 2004 21:28:04 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sat, 24 Jan 2004 18:16:26 -0800 Received: from 67.25.179.169 by bay3-dav17.bay3.hotmail.com with DAV; Sun, 25 Jan 2004 02:16:26 +0000 X-Originating-IP: [67.25.179.169] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Torsionals Date: Sat, 24 Jan 2004 21:14:18 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00A4_01C3E2BF.0726CC80" 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 Message-ID: X-OriginalArrivalTime: 25 Jan 2004 02:16:26.0864 (UTC) FILETIME=[3C9C4F00:01C3E2E9] This is a multi-part message in MIME format. ------=_NextPart_000_00A4_01C3E2BF.0726CC80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tracy Crook wrote: Don't know if anyone has commented on this already Pete, but yes, = the single rotor does have torque reversals.=20 Don't know how much of a problem this will be but the torque = signature (IGNORE RPM FOR THIS COMPARISON, it doesn't matter) will be = the same as the three cylinder piston engine. Raven had a challenging = time developing a redrive for the Suzi/Geo 3 cyl. engine if that is any = clue. Tracy If the two rotor is similar to a 4 cylinder 4 stroke piston engine, = wouldn't a one rotor be similar to a 2 cylinder 4 stroke engine? Lamar = has published the plots many times showing no torque reversals for a two = rotor but very strong torque reversals for a one rotor. --=20 Perry Mick http://www.ductedfan.com Ahh yes, the never ending debate on how to compare the rotary with a = piston engine. =20 The reason I said to ignore the rpm when comparing torque signatures = was to compare ONLY the relative torque amplitude variation of the = engines. The two rotor engine looks just like a 6 cylinder in this = respect. Yes, I know the 2 rotor rotary only has two power strokes per = rev but they are 50% longer (270 degrees vs 180) than those of a piston = engine, thus, they overlap exactly like those of a 6 cyl. This is = relavant because tortional resonance has nothing to do with rpm that the = system happens to be turning. The torque variation represents the amount of excitation energy fed = into the system. The higher this energy, the more critical the damper = is if the system has to spend any time at or near the resonant point. = In terms of this excitation energy, the one rotor probably has double or = more the amount that a 2 rotor has (all else being equal). Notice that = this excitation energy is not directly related to engine horsepower. Somehow I doubt that I have made things any clearer. Tracy ------=_NextPart_000_00A4_01C3E2BF.0726CC80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
 
Tracy Crook wrote:
Don't know if anyone has commented = on this=20 already Pete, but yes, the single rotor does have torque=20 reversals. 
 
 Don't know how much of a = problem this=20 will be but the torque signature (IGNORE RPM FOR THIS COMPARISON, it = doesn't=20 matter)  will be the same as the three cylinder piston = engine. =20 Raven had a challenging time developing a redrive for the Suzi/Geo 3 = cyl.=20 engine if that is any clue.
 
Tracy
If = the two rotor=20 is similar to a 4 cylinder 4 stroke piston engine, wouldn't a one = rotor be=20 similar to a 2 cylinder 4 stroke engine? Lamar has published the plots = many=20 times showing no torque reversals for a two rotor but very strong = torque=20 reversals for a one rotor.
--=20
Perry Mick
http://www.ductedfan.com

Ahh yes, the never ending debate = on how to=20 compare the rotary with a piston engine.  
 
The reason I said to ignore the rpm = when=20 comparing torque signatures was to compare ONLY the relative torque = amplitude=20 variation of the engines.  The two rotor engine looks just like a = 6=20 cylinder in this respect.  Yes, I know the 2 rotor rotary only = has two=20 power strokes per rev but they are 50% longer (270 degrees vs 180) = than those=20 of a piston engine, thus, they overlap exactly like those of a 6=20 cyl.  This is relavant because tortional resonance has nothing to = do with=20 rpm that the system happens to be turning.
 
The torque variation represents the = amount of=20 excitation energy fed into the system.   The higher = this=20 energy, the more critical the damper is if the system has to spend any = time at=20 or near the resonant point.   In terms of this excitation = energy,=20 the one rotor probably has double or more  the amount that a 2 = rotor has=20 (all else being equal).  Notice that this excitation = energy is not=20 directly related to engine horsepower.
 
Somehow I doubt that I have made = things any=20 clearer.
 
Tracy
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