---------------------------------------------------------- RV7-List Digest Archive --- Total Messages Posted Mon 09/06/10: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 11:33 AM - Cut Exhaust Stacks (RV7ASask) 2. 01:53 PM - Re: Cut Exhaust Stacks (Max Hegler) 3. 03:06 PM - Re: Cut Exhaust Stacks (John Myers) 4. 06:44 PM - Re: Cut Exhaust Stacks (rvaitor@comcast.net) ________________________________ Message 1 _____________________________________ Time: 11:33:16 AM PST US Subject: RV7-List: Cut Exhaust Stacks From: "RV7ASask" I marked my Vetterman Exhaust to cut the pipes off parallel to the bottom of the aircraft. That would mean the hole is parallel to the airflow and the pipes would come to a bit of a point. My local mechanic suggested I should leave them as delivered, the hole 90 degrees to the pipe and the airflow. He said there was better thrust/power/drag. Looking at Larry Vetterman's Skunkworks http://www.vettermanexhaust.com/ he has cut the pipes as I proposed in a couple of his iterations. The one advantage I can immediately see is there is less pipe hanging out to drag plus it looks better. Can anyone come up with a good reason one way or the other to cut or not to cut? Thanks David Lamb RV7A Read this topic online here: http://forums.matronics.com/viewtopic.php?p=311556#311556 ________________________________ Message 2 _____________________________________ Time: 01:53:18 PM PST US From: Max Hegler Subject: RE: RV7-List: Cut Exhaust Stacks Maybe a little more thrust with the pipes cut off at 90 degrees. Other than that=2C I would suggest contacting Vetterman and see if they have any pro' s and con's either way. Max RV-7 (#2) > Subject: RV7-List: Cut Exhaust Stacks > From: rv7alamb@sasktel.net > Date: Mon=2C 6 Sep 2010 11:32:16 -0700 > To: rv7-list@matronics.com > > > I marked my Vetterman Exhaust to cut the pipes off parallel to the bottom of the aircraft. That would mean the hole is parallel to the airflow and t he pipes would come to a bit of a point. My local mechanic suggested I shou ld leave them as delivered=2C the hole 90 degrees to the pipe and the airfl ow. He said there was better thrust/power/drag. > > Looking at Larry Vetterman's Skunkworks http://www.vettermanexhaust.com/ he has cut the pipes as I proposed in a couple of his iterations. The one advantage I can immediately see is there is less pipe hanging out to drag p lus it looks better. > > Can anyone come up with a good reason one way or the other to cut or not to cut? > > Thanks > > David Lamb > RV7A > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=311556#311556 > > > > > > > =========== =========== =========== =========== > > > ________________________________ Message 3 _____________________________________ Time: 03:06:45 PM PST US From: "John Myers" Subject: Re: RV7-List: Cut Exhaust Stacks ________________________________ Message 4 _____________________________________ Time: 06:44:41 PM PST US From: rvaitor@comcast.net Subject: Re: RV7-List: Cut Exhaust Stacks ----- Original Message ----- From: "John Myers" Sent: Monday, September 6, 2010 4:53:41 PM Subject: Re: RV7-List: Cut Exhaust Stacks In my opinion, you probably get the most positive results from slanting the existing length pipes at between 25 and 30 degrees down. Le ss and you get exhaust pulses "thumping" on the bottom of the fuselage, more than that and you get more drag. 25-30 degrees should give you a miniscu le amount of positive thrust. I seem to get a little vibration on the floorboards and have exhaust extensions that tilt down. When I lift my feet off the floor I can feel the vibration. Any ideas or suggestions would be appreciated. Shelby Smith RV7 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv7-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV7-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/rv7-list Browse Digests http://www.matronics.com/digest/rv7-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.