Return-Path: Received: from frontend3.cwpanama.net ([201.225.225.169] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 528619 for flyrotary@lancaironline.net; Thu, 11 Nov 2004 22:28:36 -0500 Received-SPF: none receiver=logan.com; client-ip=201.225.225.169; envelope-from=rijakits@cwpanama.net Received: from [201.224.93.110] (HELO usuarioq3efog0) by frontend3.cwpanama.net (CommuniGate Pro SMTP 4.2.1) with SMTP id 29962868 for flyrotary@lancaironline.net; Thu, 11 Nov 2004 22:39:03 -0500 Message-ID: <015701c4c867$4e70d2a0$6e5de0c9@usuarioq3efog0> From: "rijakits" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Belts- nobody's perfect - off topic - answering Rusty's R-22 notice Date: Thu, 11 Nov 2004 22:25:49 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0154_01C4C83D.656D7910" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2741.2600 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2742.200 This is a multi-part message in MIME format. ------=_NextPart_000_0154_01C4C83D.656D7910 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Thursday, November 11, 2004 8:45 AM Subject: [FlyRotary] Re: Belts- nobody's perfect Thomas Jakits=20 (I have abour 5000 hrs flying time in front of belts double-v-typ as = the only means of powertransfer from the engine to the rotor....)=20 Sorry, but this showed up in my Avweb email, and I couldn't resist. Rusty R-22 Drive-Belt Problem Focus Of Probe The Canadian Transportation Safety Board is trying to figure out why = the drive belt came off a Robinson R-22 helicopter, resulting in a crash = that killed its pilot in August. The chopper suffered the "sudden loss = of power" over a lake on Vancouver Island. Spokesman Bill Yearwood said = that although the pilot initiated autorotation, he apparently flared too = high and the aircraft plunged vertically into McGyver Lake, near = Campbell River. Yearwood said safety board technicians have spent the = last couple of months going through the helicopter's drive system to see = if the problem is a design fault or a maintenance error. He did say the = belt appears to be the wrong size for the helicopter. Technicians are = also examining the electrically operated belt-tensioning system. =20 No sorrys here Rusty! I am glad you pointed this one out! We have 2 R22s in the hangar, and = didn't hear about this one yet! Now lets wait to find out if the belt WAS the wrong size. a) As far as I understand there is only 1 size of belt for this = application. They always come in matched pairs too. b) If the tensioning system was wrong the pilot should notice (time = needed to engage, clutch operating warning light) c) If the clutch (belt) engaged correctly and then fails to retension, = it still would not lead to slippage at a power level needed to fly = straight and level. d) We had one case where on a customer helicopter the pilot failed to = observe that the engage process was about twice as long as normal, and = that since the aircraft was new. It was a defect (new) microswitch that = didn't stop the tensioning system at the right tension, but alway ran to = the very end where another (safety)switch stopped the electricmotor. It = took more than 200 hrs of running time in over-tensioned condition for = the belts to fail.........perfect reaction by the pilot this time - = successful autorotation - changed belts and tensioner microswitch - the = bird flies perfect since then... Now IF they had a wrong belt, someone messed up big time. Also, if the sheaves are not correctly aligned it might eat up the = belt in a hurry, although in this case the belt will also mess up the = sheaves and in any case this will not happen fast enough to get wrong in = the first flights after the incorrect maintenance. Latest at the next = preflight (you preflight your flying machine, do you?), the frayed = condition of the belts and the worn edges on the sheaves should alert = the pilot and then the maintenance personal. But it is always easy to suspect, lets wait what the CTSB finds = out........ Thomas J. ------=_NextPart_000_0154_01C4C83D.656D7910 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Thursday, November 11, = 2004 8:45=20 AM
Subject: [FlyRotary] Re: Belts- = nobody's=20 perfect

Thomas = Jakits 
 (I have abour 5000 hrs = flying time in=20 front of belts double-v-typ as the only means of powertransfer from = the engine=20 to the rotor....) 
 
 
Sorry, but this showed up in my Avweb = email,=20 and I couldn't resist.
 
Rusty
 
 
R-22 Drive-Belt = Problem Focus Of=20 Probe
 
The=20 Canadian Transportation Safety Board is trying to figure out why the = drive=20 belt came off a Robinson R-22 helicopter, resulting in a crash that = killed its=20 pilot in August. The chopper suffered the "sudden loss of power" over = a lake=20 on Vancouver Island. Spokesman Bill Yearwood said that although the = pilot=20 initiated autorotation, he apparently flared too high and the aircraft = plunged=20 vertically into McGyver Lake, near Campbell River. Yearwood said = safety board=20 technicians have spent the last couple of months going through the=20 helicopter's drive system to see if the problem is a design fault or a = maintenance error. He did say the belt appears to be the wrong size = for the=20 helicopter. Technicians are also examining the electrically operated=20 belt-tensioning system.  
 
 
 
No sorrys here Rusty!
I am glad you pointed this one out! We have 2 R22s in = the hangar,=20 and didn't hear about this one yet!
Now lets wait to find out if the belt WAS the wrong=20 size.
 
a) As far as I understand there is only 1 size of belt for = this=20 application. They always come in matched pairs = too.
b) If the tensioning system was wrong the pilot should notice = (time=20 needed to engage, clutch operating warning = light)
c) If the clutch (belt) engaged correctly and then fails to = retension,=20 it still would not lead to slippage at a power level needed to fly = straight=20 and level.
d) We had one case where on a customer helicopter the pilot = failed to=20 observe that the engage process was about twice as long as normal, and = that=20 since the aircraft was new. It was a defect (new) microswitch = that didn't=20 stop the tensioning system at the right tension, but alway ran to the = very end=20 where another (safety)switch stopped the electricmotor. It took more = than 200=20 hrs of running time in over-tensioned condition for the belts to=20 fail.........perfect reaction by the pilot this time - successful = autorotation=20 - changed belts and tensioner microswitch - the bird flies perfect = since=20 then...
 
Now IF they had a = wrong belt,=20 someone messed up big time.
Also, if the = sheaves are not=20 correctly aligned it might eat up the belt in a hurry, although in = this case=20 the belt will also mess up the sheaves and in any case this will not = happen=20 fast enough to get wrong in the first flights after the incorrect = maintenance. Latest at the next preflight (you preflight your flying = machine,=20 do you?), the frayed condition of the belts and the worn edges on the = sheaves=20 should alert the pilot and then the maintenance = personal.
 
But it is always = easy to=20 suspect, lets wait what the CTSB finds out........
 
Thomas=20 J.
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