A few years ago someone built a Lancair (composite light aircraft) here, he was concerned that the chord of one wing was 2mm (5/64") longer than the other. In his research he asked Cessna what their manufacturing tolerance is and they replied "2 inches"! If you were to take a tape measure and measure any major dimension on a Cessna, if its within 2" its within spec.
Greg ----- Original Message ----- From: "Roger" <vrsculp...@hotmail.com> To: <emc-users@lists.sourceforge.net> Sent: Tuesday, March 17, 2009 8:32 PM Subject: Re: [Emc-users] BIG CNC machine for making small airplane? > Tom <kestrel...@...> writes: > > snip > >> OK... I am going to step in here at this point and say "Whoa pardner!" >> >> Yes, you can be a millimeter off in some areas with very little penalty, >> but in >> other respects a millimeter difference can defeat your ability to get off >> the >> ground ... or another millimeter placement of the balance point aft of >> the c.g. >> (center of gravity) will improve control response - but can produce a >> sharp >> stall with a tendency to roll inverted... > > Tom, > I've got to assume you are speaking in hyperbole. A 3m 120kg ultralight is > 3000mm long. Each mm offset of the center of gravity (120kg/3000mm) is 40 > grams > or about 1.5 oz. I would think that what you had for breakfast or which > way you > leaned would have much more of an affect on center of gravity or balance. > People > build ultralights out of pop riveted lawn chair aluminum that fly. I'm > sure that > not all of these are built on surface plates with interferometers. I think > that > 10mm's of accuracy is more than enough for a low performance airplane. > > Peter, > As to large volume routers, the neatest one I saw was a 5 axis robot arm > mounted > on a track used for carving boat hulls. The track was the X axis and the > Y,A,B > and Z were done using the robots native movements. It may have been a > surplus > welding robot. > > I think you would need a mathematician to figure out the kinematics. > > Good Luck, > Roger > > > > > > ------------------------------------------------------------------------------ > Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are > powering Web 2.0 with engaging, cross-platform capabilities. Quickly and > easily build your RIAs with Flex Builder, the Eclipse(TM)based development > software that enables intelligent coding and step-through debugging. > Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.0.237 / Virus Database: 270.11.16/2005 - Release Date: 03/16/09 19:01:00 ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
