X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: <13brv3@bellsouth.net> Received: from imf24aec.mail.bellsouth.net ([205.152.59.72] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 911032 for flyrotary@lancaironline.net; Tue, 03 Jan 2006 07:29:40 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.72; envelope-from=13brv3@bellsouth.net Received: from ibm58aec.bellsouth.net ([65.6.194.9]) by imf16aec.mail.bellsouth.net with ESMTP id <20060101002607.QQVN6446.imf16aec.mail.bellsouth.net@ibm58aec.bellsouth.net> for ; Sat, 31 Dec 2005 19:26:07 -0500 Received: from rd ([65.6.194.9]) by ibm58aec.bellsouth.net with ESMTP id <20060101002607.EOMC11466.ibm58aec.bellsouth.net@rd> for ; Sat, 31 Dec 2005 19:26:07 -0500 From: "Russell Duffy" <13brv3@bellsouth.net> To: "Flyrotary List" Subject: Single rotor runs, but.... Date: Sat, 31 Dec 2005 18:26:08 -0600 Message-ID: <000001c60e69$f62e9240$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C60E37.AB942240" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2527 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C60E37.AB942240 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Greetings, =20 Made the first attempt to crank the engine today. This turned out to be = a good news/ bad news event. The good news is that it fired up instantly, = and everything seems to work. The bad news is that it's rough as a cob :-0=20 =20 It would appear that my worst fears about the torque reversals with the RD-1C drive have come true. I didn't notice the rpm, but the engine = barely made it over the speed the starter turns it. In fact, the starter = stayed engaged a couple times, because the engine didn't accelerate enough to = push the gear back. Did I mention that's it's rough :-) It shook the living crap out of the plane, but the engine mounts work well. The main gear of = the plane was actually jumping slightly off the ground. Good thing I was sitting in the plane, or it really might have been interesting. =20 =20 While the engine was running, no amount of throttle changes anything. = It's simply impossible for the engine to accelerate out of this mode. BTW, = this is EXACTLY how the 912S used to behave on this plane. If you didn't = crank the engine with enough throttle opening, it would get stuck in the = gearbox shaking mode, and the best thing you could do was shut it down, and try again. Rotax came out with a "slipper clutch" to eliminate the problem = on the 912S. =20 =20 Next step will be to remove the prop, and try it that way. Eliminating = the rotational mass of the prop should make it better, if not eliminate the problem altogether. If that works OK, then I may have to try a = different hardness of rubber dampeners on the redrive thrust plate. Mainly, I = just want to get the engine to the point where I can run it routinely, to = keep it happy while I'm building the RV-8. =20 Happy New Years. The down under boys should have a nice hangover about = now :-) =20 Rusty =20 ------=_NextPart_000_0001_01C60E37.AB942240 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Greetings,

 

Made the first=20 attempt to crank the engine today. =20 This turned out to be a good news/ bad news event.  The good news is that it fired = up=20 instantly, and everything seems to work. =20 The bad news is that it’s rough as a cob :-0

 

It = would appear=20 that my worst fears about the torque reversals with the RD-1C drive have = come=20 true.  I didn’t = notice the rpm, but=20 the engine barely made it over the speed the starter turns it.  In fact, the starter stayed = engaged a=20 couple times, because the engine didn’t accelerate enough to push = the gear=20 back.  Did I mention = that’s it’s=20 rough :-)  It shook = the living=20 crap out of the plane, but the engine mounts work well. The main gear of = the=20 plane was actually jumping slightly off the ground.  Good thing I was sitting in = the plane,=20 or it really might have been interesting.  

 

While the engine=20 was running, no amount of throttle changes anything.  It’s simply impossible = for the engine to=20 accelerate out of this mode.  =20 BTW, this is EXACTLY how the 912S used to behave on this = plane.  If you didn’t crank the = engine with=20 enough throttle opening, it would get stuck in the gearbox shaking mode, = and the=20 best thing you could do was shut it down, and try again.  Rotax came out with a  “slipper clutch” to = eliminate the problem=20 on the 912S.    

 

Next step will=20 be to remove the prop, and try it that way.  Eliminating the rotational mass = of the=20 prop should make it better, if not eliminate the problem = altogether.   If that works OK, then I may = have to try=20 a different hardness of rubber dampeners on the redrive thrust = plate.  Mainly, I just want to get the engine = to the=20 point where I can run it routinely, to keep it happy while I'm building = the=20 RV-8.

 

Happy New Years. The down = under boys=20 should have a nice hangover about now = :-)

 

Rusty

 

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