X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wproxy.gmail.com ([64.233.184.194] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 918262 for flyrotary@lancaironline.net; Sun, 08 Jan 2006 23:49:43 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.194; envelope-from=russell.duffy@gmail.com Received: by wproxy.gmail.com with SMTP id 37so3259705wra for ; Sun, 08 Jan 2006 20:48:58 -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:x-mimeole:importance:in-reply-to; b=uMlL+dnV0CBiBxg8ZP4xtMxsAy77iVW78Of3xsDEv2TNIZ3vXSupHP3VvdUCg4PUOpTw7nDBg1NPaSYXHkobiyIGiKs1/tjVUgV1jGhinRBm3HFkRByD/v2oQX0lX9ZEGfS8IfWtuiWLqTC1v0RTG67Wyg/gZqVP4K0W1OIE1fE= Received: by 10.54.135.17 with SMTP id i17mr7276567wrd; Sun, 08 Jan 2006 20:48:58 -0800 (PST) Return-Path: Received: from rd ( [65.6.194.9]) by mx.gmail.com with ESMTP id 43sm2331224wri.2006.01.08.20.48.58; Sun, 08 Jan 2006 20:48:58 -0800 (PST) From: "Russell Duffy" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: More single rotor running Date: Sun, 8 Jan 2006 22:48:59 -0600 Message-ID: <000d01c614d8$015f44b0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000E_01C614A5.B6C4D4B0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2527 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_000E_01C614A5.B6C4D4B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I was reading about harmonic virbrations during the development of the BD-5 on a website somewhere that described this exact same problem. They determined that the resonance would absorb all the energy that the engine could put out (until things broke!), and not allow the engine to accelerate. Every now and then, they engine would be able to break out of the resonance and then would run fine at other RPMs. Well, at least you know for sure where your resonant frequency is. =20 Hi Ernest, =20 We were just talking about this a week or so ago, and I read the article = at that time. Unfortunately, this vibration is pretty severe, and I have = no doubt that it will start breaking things if it's allowed to continue. = The first casualty would probably be the intake, where it welds to the = flange at the engine. =20 =20 I've got a number of thoughts about trying to modify it's behavior, but = it's not a high priority project right now, and I'll just continue to tinker = with it as time allows. =20 =20 Cheers, Rusty =20 ------=_NextPart_000_000E_01C614A5.B6C4D4B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

I was reading about harmonic virbrations during the = development=20 of the
BD-5 on a website somewhere that described this exact same = problem.=20 They
determined that the resonance would absorb all the energy that=20 the
engine could put out (until things broke!), and not allow the = engine=20 to
accelerate. Every now and then, they engine would be able to break = out
of the resonance and then would run fine at other RPMs. Well, at=20 least
you know for sure where your resonant frequency is.

 
Hi=20 Ernest,
 
We were = just talking=20 about this a week or so ago, and I read the article at that time. =20 Unfortunately, this vibration is pretty severe, and I have no doubt that = it will=20 start breaking things if it's allowed to continue.  The first = casualty=20 would probably be the intake, where it welds to the flange at the = engine. =20
 
I've got = a number of=20 thoughts about trying to modify it's behavior, but it's not a high = priority=20 project right now, and I'll just continue to tinker with it as time=20 allows. 
 
Cheers,
Rusty
 



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