Return-Path: Received: from [65.54.169.132] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2951543 for flyrotary@lancaironline.net; Tue, 27 Jan 2004 13:30:02 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Tue, 27 Jan 2004 10:30:01 -0800 Received: from 67.24.247.49 by bay3-dav102.bay3.hotmail.com with DAV; Tue, 27 Jan 2004 18:30:01 +0000 X-Originating-IP: [67.24.247.49] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Torsionals Date: Tue, 27 Jan 2004 13:29:58 -0500 MIME-Version: 1.0 X-Mailer: MSN Explorer 7.02.0011.2700 Content-Type: multipart/alternative; boundary="----=_NextPart_001_0001_01C3E4D9.A8BB7700" Message-ID: X-OriginalArrivalTime: 27 Jan 2004 18:30:01.0394 (UTC) FILETIME=[9335B920:01C3E503] ------=_NextPart_001_0001_01C3E4D9.A8BB7700 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message ----- From: Perry Mick Sent: Sunday, January 25, 2004 9:59 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Torsionals Tracy Crook wrote: Don't know if anyone has commented on this already Pete, but yes, the sin= gle 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 t= he 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, would= n't a one rotor be similar to a 2 cylinder 4 stroke engine? Lamar has pub= lished the plots many times showing no torque reversals for a two rotor b= ut very strong torque reversals for a one rotor. -- =20 Perry Ahh yes, the never ending debate on how to compare the rotary with a pist= on 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, the= y overlap exactly like those of a 6 cyl. This is relavant because tortio= nal resonance has nothing to do with rpm that the system happens to be tu= rning. 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 term= s of this excitation energy, the one rotor probably has double or more t= he amount that a 2 rotor has (all else being equal). Notice that this ex= citation energy is not directly related to engine horsepower. Somehow I doubt that I have made things any clearer. Tracy Yes it does make it clearer, thanks. I thought about that after I posted = the last message (maybe I just reread your previous message!). It is clea= r that the PSRU will be under more "stress" with a one-rotor. Has anyone = ever bolted your PSRU to a one-rotor? Do you even approve it for a one-ro= tor? =20 -- =20 Perry Never been tried. It might work great or it might be a disaster. Theore= tically, this could be figured out on paper and predicted. In the real w= orld, it would be easier to test the actual parts (instrumented appropria= tely). Tracy ------=_NextPart_001_0001_01C3E4D9.A8BB7700 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

<= DIV>

=
----- Original Message -----

From: Perry Mick

Sent: Sunday, J= anuary 25, 2004 9:59 AM

To: = Rotary motors in aircraft

Subjec= t: [FlyRotary] Re: Torsionals

Tracy Crook wrote:
=
Don't know if anyone has commented on this already Pete, but yes, the s= ingle rotor does have torque reversals.

Don't know how much of a probl= em 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 e= ngine. Raven had a challenging time developing a redrive for the Su= zi/Geo 3 cyl. engine if that is any clue.

=
Tracy
If the tw= o 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 th= e plots many times showing no torque reversals for a two rotor but very s= trong torque reversals for a one rotor.
-- Perry

A= hh yes, the never ending debate on how to compare the rotary with a pisto= n engine.

The reason I said to ignore the rpm when comparing torque s= ignatures was to compare ONLY the relative torque amplitude variation of = the engines. The two rotor engine looks just like a 6 cylinder in t= his respect. Yes, I know the 2 rotor rotary only has two power stro= kes per rev but they are 50% longer (270 degrees vs 180) than those of&nb= sp;a piston engine, thus, they overlap exactly like those of a 6 cyl.&nbs= p; This is relavant because tortional resonance has nothing to do with rp= m that the system happens to be turning.

<= DIV>The torque variation represents the amoun= t of excitation energy fed into the system. The higher t= his energy, the more critical the damper is if the system has to spend an= y time at or near the resonant point. In terms of this excita= tion energy, the one rotor probably has double or more the amount t= hat a 2 rotor has (all else being equal). Notice that this excitati= on energy is not directly related to engine horsepower.=

Somehow I doubt that = I have made things any clearer.

Tracy
Yes it= does make it clearer, thanks. I thought about that after I posted the la= st message (maybe I just reread your previous message!). It is clear that= the PSRU will be under more "stress" with a one-rotor. Has anyone ever b= olted your PSRU to a one-rotor? Do you even approve it for a one-rotor? <= PRE class=3Dmoz-signature cols=3D"$mailwrapcol">-- Perry

Never been tried. It might work great or it might be a d= isaster. Theoretically, this could be figured out on paper and pred= icted. In the real world, it would be easier to test the actual par= ts (instrumented appropriately).

Tracy
------=_NextPart_001_0001_01C3E4D9.A8BB7700--