X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 23 Apr 2009 20:40:50 -0400 Message-ID: X-Original-Return-Path: Received: from mail960c35.nsolutionszone.com ([209.235.152.150] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTPS id 3592808 for lml@lancaironline.net; Wed, 22 Apr 2009 10:41:25 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.235.152.150; envelope-from=rsmiley2@centurytel.net X-Authenticated-User: rsmiley2.centurytel.net Received: from PC294771894831 (71-220-145-119.tcsn.qwest.net [71.220.145.119]) (authenticated bits=0) by mail960c35.nsolutionszone.com (8.13.6/8.13.1) with ESMTP id n3MEegYr023895 for ; Wed, 22 Apr 2009 14:40:44 GMT X-Original-Message-ID: <8C135B7892CE47A39CC68D2AE1326B93@PC294771894831> From: "Bob Smiley" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Re: Balancing MkII Elevators X-Original-Date: Wed, 22 Apr 2009 07:40:36 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01C9C31D.A051E7C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0009_01C9C31D.A051E7C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable A suggestion, I did this on my 360 on the vertidal stabilizer. The couterweights were = placed on the leading edge of the rudder and in the counterweight = overhang on top of the rudder. The moment arm on the leadig edge was = about 2 inches verses about 6 inches thus you need only about 1/3rd the = weight on the top of the rudder. My solution was to add 1.5 inches to = the height of the rudder and vertical stab. More room for more lead. = overall weight was reduced. An addditional benefit I received was I increased the demonstrated cross = wind component for landing. I landed in a 24 knot crosswind at Jackson = Hole Wyoming one time.=20 Bob Smiley ----- Original Message -----=20 From: rwolf99@aol.com=20 To: lml@lancaironline.net=20 Sent: Wednesday, April 22, 2009 6:26 AM Subject: [LML] Re: Balancing MkII Elevators I, too, was surprised at how much lead I needed to balance my 360 = ailerons. In fact, I have those lead half-rounds going nearly full-span = (two of them, flat surface to flat surface). But let's stop to think = about it. We need as much "moment" (mass x distance) in front of the = hinge line as behind it. In practice, we have more weight (balance = weight) forward of the hinge line than we do behind it (the control = surface itself) since the CG of the control surface is generally much = further behind the hinge line than the balance weights are forward of = it. This is certainly the case with the ailerons, but less so for the = rudder and elevators, since they have those forward overhangs for = aerodynamic balance. For preliminary design purposes, my airplane design group assumes that = the balance weights weigh 1.5 times the weight of the control surface = alone. Bottom line -- your balance weights need to be at least as heavy as = the control surface, and up to 50% more. Yup, it's a lot. - Rob Wolf -------------------------------------------------------------------------= ----- The Average US Credit Score is 692. See Yours in Just 2 Easy Steps! ------=_NextPart_000_0009_01C9C31D.A051E7C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
A suggestion,
 
I did this on my 360 on the vertidal=20 stabilizer.  The couterweights were placed on the leading edge of = the=20 rudder and in the counterweight overhang on top of the rudder.  The = moment=20 arm on the leadig edge was about 2 inches verses about 6 inches thus you = need=20 only about 1/3rd the weight on the top of the rudder.  My solution = was to=20 add 1.5 inches to the height of the rudder and vertical stab.  More = room=20 for more lead. overall weight was reduced.
 
An addditional benefit I received was I = increased=20 the demonstrated cross wind component for landing.  I landed in a = 24 knot=20 crosswind at Jackson Hole Wyoming one time.
 
Bob Smiley
----- Original Message -----
From:=20 rwolf99@aol.com=20
Sent: Wednesday, April 22, 2009 = 6:26=20 AM
Subject: [LML] Re: Balancing = MkII=20 Elevators

I, too, was surprised at how much lead I needed to = balance my=20 360 ailerons.  In fact, I have those lead half-rounds going = nearly=20 full-span (two of them, flat surface to flat surface).  But let's = stop to=20 think about it.  We need as much "moment" (mass x distance) = in front=20 of the hinge line as behind it.  In practice, we have more weight = (balance weight) forward of the hinge line than we do behind it (the = control=20 surface itself) since the CG of the control surface is generally much = further=20 behind the hinge line than the balance weights are forward of = it.  This=20 is certainly the case with the ailerons, but less so for the rudder = and=20 elevators, since they have those forward overhangs for aerodynamic=20 balance.

For preliminary design purposes, my airplane design = group=20 assumes that the balance weights weigh 1.5 times the weight of the = control=20 surface alone.

Bottom line -- your balance weights need to be = at least=20 as heavy as the control surface, and up to 50% more.

Yup, it's = a=20 lot.

- Rob Wolf
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