X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 17 Mar 2006 13:43:34 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m25.mx.aol.com ([64.12.137.6] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 1037433 for lml@lancaironline.net; Fri, 17 Mar 2006 13:10:53 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.6; envelope-from=CustomACProp@aol.com Received: from CustomACProp@aol.com by imo-m25.mx.aol.com (mail_out_v38_r7.3.) id q.32c.1b542a (2168) for ; Fri, 17 Mar 2006 13:10:04 -0500 (EST) From: CustomACProp@aol.com X-Original-Message-ID: <32c.1b542a.314c557c@aol.com> X-Original-Date: Fri, 17 Mar 2006 13:10:04 EST Subject: Re: [LML] Re: MT Prop for Legacy X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1142619004" X-Mailer: 9.0 SE for Windows sub 5021 X-Spam-Flag: NO -------------------------------1142619004 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Hi Colyn, I've flown in a Harmon Rocket 2 with the Lyc. 540 engine. There was some vibration with a 2 blade Hartzell propeller. We installed a 3 blade Rocket propeller (the MTV-9-B/198-52 MT Propeller), and the engine seemed to have been replaced by an electric motor. We then installed a different 2 blade Hartzell propeller, and the original vibration was back. John Harmon has flown both the same MT 3 blade propeller and a 4 blade propeller on his Harmon Rocket 3. John said the 4 blade propeller was slightly smoother than the 3 blade propeller. MT Propeller says there is a 2nd order harmonic present with a 2 blade propeller that is not present with the 3 blade propeller. I believe there is a 3rd order harmonic with the 3 blade propeller that isn't present with a 4 blade propeller. Regards, Jim Ayers _jim@lessdrag.com_ (mailto:jim@lessdrag.com) Less Drag Propucts, Inc. - An MT Propeller distributor and FAA MT Propeller repair station. Custom Aircraft Propellers - MT Propeller sales of custom designed propellers PS I will have a 4 blade counterweighted blade MT propeller on my Harmon Rocket 2. In a message dated 03/15/2006 9:46:15 PM Pacific Standard Time, colyncase@earthlink.net writes: Kevin, I have no experience with the MT. However, some observe that a 6-cylinder engine makes 3 pulses per revolution and so does at 3 blade prop. So a 4-blade might be less apparent noise and vibration. I have not personally experimented with this but maybe some on the list have. Colyn -------------------------------1142619004 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Hi Colyn,
 
I've flown in a Harmon Rocket 2 with the Lyc. 540 engine.  There w= as=20 some vibration with a 2 blade Hartzell propeller.
We installed a 3 blade Rocket propeller (the MTV-9-B/198-52 M= T=20 Propeller), and the engine seemed to have been replaced by an electric=20 motor.
We then installed a different 2 blade Hartzell propeller, and the origi= nal=20 vibration was back.
 
John Harmon has flown both the same MT 3 blade propeller and a 4 b= lade=20 propeller on his Harmon Rocket 3.  John said the 4 blade propeller was=20 slightly smoother than the 3 blade propeller.
 
MT Propeller says there is a 2nd order harmonic present with a 2 blade=20 propeller that is not present with the 3 blade propeller.  I believe th= ere=20 is a 3rd order harmonic with the 3 blade propeller that isn't present with a= 4=20 blade propeller.
 
Regards,
Jim Ayers
Less Drag Propucts, Inc. - An MT Propeller distributor and FAA MT Prope= ller=20 repair station.
Custom Aircraft Propellers - MT Propeller sales of custom designed=20 propellers
 
PS I will have a 4 blade counterweighted blade MT propeller on my Harmo= n=20 Rocket 2.
 
In a message dated 03/15/2006 9:46:15 PM Pacific Standard Time,=20 colyncase@earthlink.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000=20 size=3D2>Kevin,
    I have no experience with the MT.
&nbs= p;=20   However, some observe that a 6-cylinder engine makes 3 pulses per=20
revolution and so does at 3 blade prop.
    So a 4-blade=20 might be less apparent noise and vibration.   I have not=20
personally experimented with this but maybe some on the list=20 have.

Colyn
 
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