X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wproxy.gmail.com ([64.233.184.200] verified) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 917994 for flyrotary@lancaironline.net; Sun, 08 Jan 2006 19:30:32 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.200; envelope-from=russell.duffy@gmail.com Received: by wproxy.gmail.com with SMTP id 69so3073789wra for ; Sun, 08 Jan 2006 16:29:47 -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; b=PFDWvEqj+ACjGOofvi3MHADdpUJApQfCrcQRHf0TSH37vmo1tbL63RtjtS+a/Qk24HuWLAO/nHYkHjCwhnY4GqkyTUIPkqZcVWyPkhVcEP+V68pDcKqGg2OvthilZtORZcef4NJzNcnHCuyvTyuI2J3I1zOnb8LvfSfLpTuD76M= Received: by 10.54.126.20 with SMTP id y20mr7622188wrc; Sun, 08 Jan 2006 16:29:47 -0800 (PST) Return-Path: Received: from rd ( [65.6.194.9]) by mx.gmail.com with ESMTP id 27sm9027096wrl.2006.01.08.16.29.21; Sun, 08 Jan 2006 16:29:43 -0800 (PST) From: "Russell Duffy" To: "Flyrotary List" Subject: More single rotor running Date: Sun, 8 Jan 2006 18:29:22 -0600 Message-ID: <000a01c614b3$ca28a280$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000B_01C61481.7F907C70" 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 This is a multi-part message in MIME format. ------=_NextPart_000_000B_01C61481.7F907C70 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Greetings, =20 Below are the notes from today's adventure. As you'll read, there are certainly some vibration issues. =20 =20 A question for Richard- Have you run your single rotor with a realistic sized prop, or just with the drive itself? Have you added any flywheel weight? =20 =20 Rusty=20 =20 =20 Spent quite a bit of time running the engine today, and tying some = various tests. The good news is that the fluids all stay inside the engine = where they belong, so no more leaks. The bad news is that there are certainly some vibration issues. =20 Running the engine without the prop does not show any significant = vibration, except for the expected roughness at low rpms, below about 1800 or so. =20 =20 Running the engine with the 3 blade Warp Drive prop, gives a few = different vibrations. The best bet for "idle" is about 2200 rpm right now. = Reducing rpm below that point hits a pretty severe "rattle" at about 2000 rpm. = This is the same as the rattle I got with the redrive on the 13B, but it was around 1100 rpm on that engine. Reducing below that will get out of the severe rattle, but into the expected single rotor roughness. It's = possible to idle around 900 rpm, but you wouldn't want to. =20 =20 If you start at 2200 rpm, and slowly increase the throttle, all is well until about 2500 rpm, then a high frequency vibration starts. The = vibration increases in frequency, and amplitude as the rpm increases, right up to = 3100 rpm. At 3100, as you increase throttle, initially nothing happens, but = then the engine will suddenly jump to 3300-3400 rpm, and be smooth. It's = just like someone flipped a switch to get rid of the vibration. This = vibration is pretty severe, and you can see things like the air filter shaking = until they're just a blur. =20 =20 The 3rd problem is an odd "beat frequency" sort of vibration that = happens at all rpms. If you stand directly in line with the prop arc, you can see = the prop tips oscillating forward and back about every second or so. I only watched this at idle, but other observers said that it gets much worse = at higher rpms, and I can certainly feel it. I don't really have a clue = what this is, unless it's some sort of interaction between the 2.85 drive, = and the ratio of eshaft to rotor rpm. 3 blade prop??? Gotta think about = this some.=20 ------=_NextPart_000_000B_01C61481.7F907C70 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Greetings,

 

Below are the notes from = today's=20 adventure.    As you'll read, there are certainly some = vibration=20 issues. 

 

A question for Richard- = Have you run=20 your single rotor with a realistic sized prop, or just with the drive=20 itself?  Have you added any flywheel weight?  =

 

Rusty

 

 

Spent quite a=20 bit of time running the engine today, and tying some various tests.  The good news is that the = fluids all=20 stay inside the engine where they belong, so no more leaks.  The bad news is that there are = certainly=20 some vibration issues.

 

Running the=20 engine without the prop does not show any significant vibration, except = for the=20 expected roughness at low rpms, below about 1800 or so. 

 

Running the=20 engine with the 3 blade Warp=20 Drive prop, gives a few different = vibrations.  The best bet for = “idle” is about 2200=20 rpm right now.  Reducing = rpm below=20 that point hits a pretty severe “rattle” at about 2000 rpm. = This is the same as=20 the rattle I got with the redrive on the 13B, but it was around 1100 rpm = on that=20 engine.  Reducing below = that will=20 get out of the severe rattle, but into the expected single rotor = roughness.  It’s possible to idle = around 900 rpm,=20 but you wouldn’t want to. =20

 

If = you start at=20 2200 rpm, and slowly increase the throttle, all is well until about 2500 = rpm,=20 then a high frequency vibration starts. =20 The vibration increases in frequency, and amplitude as the rpm = increases,=20 right up to 3100 rpm.  At = 3100, as=20 you increase throttle, initially nothing happens, but then the engine = will=20 suddenly jump to 3300-3400 rpm, and be smooth.  It’s just like someone = flipped a switch=20 to get rid of the vibration.  = This=20 vibration is pretty severe, and you can see things like the air filter = shaking=20 until they’re just a blur.  =

 

The=20 3rd problem is an odd “beat frequency” sort of = vibration that happens=20 at all rpms.  If you stand = directly=20 in line with the prop arc, you can see the prop tips oscillating forward = and=20 back about every second or so.  = I=20 only watched this at idle, but other observers said that it gets much = worse at=20 higher rpms, and I can certainly feel it. =20 I don’t really have a clue what this is, unless it’s = some sort of=20 interaction between the 2.85 drive, and the ratio of eshaft to rotor = rpm.  3 blade prop???  Gotta think about this some.=20

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