X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from elasmtp-masked.atl.sa.earthlink.net ([209.86.89.68] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 1980171 for flyrotary@lancaironline.net; Wed, 11 Apr 2007 17:06:05 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.68; envelope-from=jerryhey@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=SGtfxv6HIdIsKrayRZq8XG4Hgs0WgpacUKNX3XTWe/3dJ2C+6b6kGjd39vwGbbWe; h=Received:Mime-Version:In-Reply-To:References:Content-Type:Message-Id:From:Subject:Date:To:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [71.54.80.210] (helo=[192.168.0.101]) by elasmtp-masked.atl.sa.earthlink.net with asmtp (Exim 4.34) id 1Hbk0E-0001ck-DE for flyrotary@lancaironline.net; Wed, 11 Apr 2007 17:05:18 -0400 Mime-Version: 1.0 (Apple Message framework v752.3) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-12-449821987 Message-Id: From: Jerry Hey Subject: Re: [FlyRotary] Re: Mount offset Date: Wed, 11 Apr 2007 17:05:17 -0400 To: "Rotary motors in aircraft" X-Mailer: Apple Mail (2.752.3) X-ELNK-Trace: 8104856d7830ec6b1aa676d7e74259b7b3291a7d08dfec79646c7ff3448896c3d01ad6a6d32c3604350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 71.54.80.210 --Apple-Mail-12-449821987 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed It has certainly been done that way by many. The only problem I can see is that it kicks the nose over and may not fit in the center of the cowl opening. Of course, if you are building the cowl, you can make it look good. Jerry On Apr 11, 2007, at 4:56 PM, bmears9413@aol.com wrote: > My kit suggest to install washers between my mount and the firewall > to get the thrust I need. This doesnt sound like a very good way to > do it to me. Is this really the norm for adjusting thrust? > > Bob Mears > Supermarine Spitfire > > -----Original Message----- > From: jerryhey@earthlink.net > To: flyrotary@lancaironline.net > Sent: Wed, 11 Apr 2007 3:22 PM > Subject: [FlyRotary] Re: Mount offset > > Bobby, I am sure we can get it right. I am interested in Blake's > suggestion because I can do the drilling of the S-beam on the mill > where I have more control. We can also do something like you > have just suggested by measuring from a point on the S beam back to > the firewall. And then instead of moving the motor around, I can > just move the firewall. Same thing in reverse. Jerry > > > On Apr 11, 2007, at 5:05 PM, Bobby J. Hughes wrote: > >> >>> Your correct Ernest. I should have specified an RV. I think all >>> of the >>> RV's are designed the same. I have read somewhere it is 1.25 >>> degrees. >>> Just trying to confirm. >>> >>> Bobby >>> >>> The direction of the engine offset, and any fin offset would also >>> depend on the direction of propeller rotation. The fin and engine >>> offset must agree. >>> >>> >>> Lynn E. Hanover >> >> Also, you might ask your engine mount builder if he can truly >> resolve a quarter of a degree. I am sure he is pondering this >> issue and wondering the same :) Jerry >>> My simple (hanger engineering) approach would be to draw a >>> straight line the length of the left side tubes. This should be a >>> known length. Then using a protractor draw another line the same >>> length at a 1.25 degree offset. Measure the difference at the >>> end of the lines. Then draw a line 47.5 inches (firewall to C- >>> drive face) and repeat with a 1.25 degree offset. Measure the >>> difference and subtract first set of measurements. That should >>> provide a good estimate for how much shorter to make the right >>> side tubes. Washers could be use for fine tuning if needed. The >>> flying RV10's seem to be as much as 1/2 ball out to the right in >>> cruse. Not sure how much it would be without the offset. It does >>> vary with airspeed. Some are installing rudder trim. Van's >>> mounts have the offset build in. Tracy also has offset built into >>> his RV8 mount. I think it is needed to make the plane fly correctly. >>> >>> Bobby >>> >>> >>> >>> See what's free at AOL.com. >> > > = > AOL now offers free email to everyone. Find out more about what's > free from AOL at AOL.com. > --Apple-Mail-12-449821987 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 It has certainly been done that = way by many.=A0 The only problem I can see is that it kicks the nose = over and may not fit in the center of the cowl opening.=A0 Of course, if = you are building the cowl, you can make it=A0 look good.=A0 =A0 = =A0Jerry




On Apr 11, = 2007, at 4:56 PM, bmears9413@aol.com = wrote:

My kit suggest to install washers between my mount and the = firewall to get the thrust I need. This doesnt sound like a very good = way to do it to me. Is this really the norm for adjusting = thrust?
=A0
Bob Mears
Supermarine Spitfire
=A0
-----Original Message-----
From: jerryhey@earthlink.netTo: flyrotary@lancaironline.net
Sent: Wed, 11 Apr 2007 3:22 PM
Subject: [FlyRotary] Re: Mount offset

Bobby,=A0 =A0I am sure we can get it right.=A0 I am = interested in Blake's suggestion because I can do the drilling of the = S-beam on the mill where I have more control. =A0 =A0We can also do = something like you have just suggested by measuring from a point on the = S beam back to the firewall. =A0 =A0And then instead of moving the motor = around, I can just move the firewall.=A0 =A0Same thing in reverse.=A0 = Jerry

On Apr 11, 2007, at 5:05 PM, Bobby J. Hughes = wrote:

=A0

Bobby

The direction = of the engine offset, and any fin offset would also depend on the = direction of propeller rotation. The fin and engine offset must = agree.
=A0

Also, you = might ask your engine mount builder if he can truly=A0 resolve a quarter = of a degree.=A0 =A0I am sure he is pondering this issue=A0 and = wondering=A0 the same=A0 :)=A0 =A0Jerry
My simple (hanger engineering) approach would = be to draw a straight line the length of the left side tubes.=A0This = should be a known length. Then using a protractor draw another line=A0the = same length at a=A01.25 degree offset.=A0 Measure the difference at the = end of the lines. Then draw a line 47.5 inches (firewall to C-drive = face) and repeat with a 1.25 degree offset. =A0Measure the difference = and subtract=A0first set of =A0measurements. That should provide a good = estimate for how much shorter to make the right side tubes. Washers = could be use for fine tuning if needed. The flying RV10's seem to be as = much as 1/2 ball=A0out to the right in cruse. Not sure how much it would = be without the offset. It does vary with airspeed.=A0Some are installing = rudder trim.=A0=A0Van's mounts have the offset build in. Tracy also has = offset built into his=A0RV8 mount.=A0I think it is needed to make the = plane fly correctly.=A0


=3D
AOL now offers free email to everyone. Find out = more about what's free from AOL at .


= --Apple-Mail-12-449821987--