---------------------------------------------------------- Kolb-List Digest Archive --- Total Messages Posted Fri 11/27/20: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:00 AM - Re: Re: 3.47:1 gear box (John Hauck) 2. 08:44 PM - Re: 3.47:1 gear box (Richard Pike) ________________________________ Message 1 _____________________________________ Time: 05:00:36 AM PST US From: John Hauck Subject: RE: Kolb-List: Re: 3.47:1 gear box I flew with a 72" WARP Drive Prop on my 912 powered MKIII. Had 3/4" prop to tail boom clearance. Was not a problem. I personally do not recommend raising the thrust line. High thrust line in the pusher configuration is a problem to start with. Increasing thrust line height increases that problem. Is there a difference between center of thrust of a 912 and 582 on a MKIII? I flew with both engines on my MKIII, but cannot remember. john h Titus, Alabama -----Original Message----- From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of Richard Pike Sent: Thursday, November 26, 2020 9:37 PM Subject: Kolb-List: Re: 3.47:1 gear box You guys are great, that is just what I needed to know, thanks. So now it looks like the only real task is fabricating new taller motor mounts to fit the 72" prop? Anybody want to send some pictures of how you did it? -------- Richard Pike Kolb MKIII N420P (420ldPoops) Kolb Firefly Part 103 legal Kingsport, TN 3TN0 Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=499543#499543 ________________________________ Message 2 _____________________________________ Time: 08:44:31 PM PST US Subject: Kolb-List: Re: 3.47:1 gear box From: "Richard Pike" jhauck wrote: > I flew with a 72" WARP Drive Prop on my 912 powered MKIII. Had 3/4" prop to tail boom clearance. Was not a problem. > > I personally do not recommend raising the thrust line. High thrust line in the pusher configuration is a problem to start with. Increasing thrust line height increases that problem. > > Is there a difference between center of thrust of a 912 and 582 on a MKIII? I flew with both engines on my MKIII, but cannot remember. > > john h > Titus, Alabama > -- Thanks for checking in John, I was planning to try and contact you tomorrow. For a number of years I have been using a 68" prop with 1.5" of clearance between the prop tips and the boom tube. The motor mounts have 1.5" spacers which you can see in two of the pictures here: http://oh2fly.net/oldpoops/pg2.htm Obviously I do not want to raise the engine any higher, but going from a 68" to a 72", the prop blades are 2" longer and I don't see any way around it. Just went out and measured both the B box and the E box, and each seems to have 3" between the crank centerline and the hub centerline so that would be a constant. Open to suggestions - thanks. -------- Richard Pike Kolb MKIII N420P (420ldPoops) Kolb Firefly Part 103 legal Kingsport, TN 3TN0 Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=499555#499555 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message kolb-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Kolb-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/kolb-list Browse Digests http://www.matronics.com/digest/kolb-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.