---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Thu 02/10/11: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 11:56 AM - Engine down thrust angle (Gary Vogt) 2. 12:06 PM - Re: Engine down thrust angle (n26390@AOL.COM) 3. 12:38 PM - Re: Engine down thrust angle (Gary Vogt) 4. 05:08 PM - Re: Engine down thrust angle (FLYaDIVE) ________________________________ Message 1 _____________________________________ Time: 11:56:18 AM PST US From: Gary Vogt Subject: TeamGrumman-List: Engine down thrust angle I'm doing an annual on a Tiger that came in with the engine visibly too far up. I measured the angle: .8 degrees up. The bottom mounts had two shims each. I removed one each of the bottom shims. The engine is now at .3 degrees up. RIght now, there is one shim on each mount. Note: This plane just had a new engine installed. During the engine overhaul period, the engine mount was sent to Kosola Engine mounts for overhaul and painting. The installation also got all new -59 engine shock mounts. The cowling is still below the spinner (i.e., spinner is higher than the cowling.) It could still use an extra shim in the top mounts; that would make two each on the top mounts, just like mine with the jaguar cowling. ________________________________ Message 2 _____________________________________ Time: 12:06:28 PM PST US Subject: Re: TeamGrumman-List: Engine down thrust angle From: n26390@AOL.COM Gary: Aside from the mismatch between the cowling and spinner, what is the effect on performance/groundspeed of too much angle up or down? Thanks, Roger Rucker AA5A '78 HWO -----Original Message----- From: Gary Vogt Sent: Thu, Feb 10, 2011 2:57 pm Subject: TeamGrumman-List: Engine down thrust angle I'm doing an annual on a Tiger that came in with the engine visibly too far up. I measured the angle: .8 degrees up. The bottom mounts had two shim s each. I removed one each of the bottom shims. The engine is now at .3 d egrees up. RIght now, there is one shim on each mount. Note: This plane just had a new engine installed. During the engine overh aul period, the engine mount was sent to Kosola Engine mounts for overhaul and painting. The installation also got all new -59 engine shock mounts. The cowling is still below the spinner (i.e., spinner is higher than the co wling.) It could still use an extra shim in the top mounts; that would ma ke two each on the top mounts, just like mine with the jaguar cowling. -= - The TeamGrumman-List Email Forum - -= Use the Matronics List Features Navigator to browse -= the many List utilities such as List Un/Subscription, -= Archive Search & Download, 7-Day Browse, Chat, FAQ, -= Photoshare, and much much more: - -= --> http://www.matronics.com/Navigator?TeamGrumman-List - -======================== -= - MATRONICS WEB FORUMS - -= Same great content also available via the Web Forums! - -= --> http://forums.matronics.com - -======================== -= - List Contribution Web Site - -= Thank you for your generous support! -= -Matt Dralle, List Admin. -= --> http://www.matronics.com/contribution -======================== ________________________________ Message 3 _____________________________________ Time: 12:38:24 PM PST US From: Gary Vogt Subject: Re: TeamGrumman-List: Engine down thrust angle >From what I've found on the internet, a down thrust angle is preferred over an up or zero thrust angle. With a down thrust angle, there is less requirement for pitch changes with throttle changes. I have also noticed there is less requirement for elevator down (nose down) with an engine down thrust angle. That in itself should lessen overall drag. ________________________________ From: "n26390@AOL.COM" Sent: Thu, February 10, 2011 12:03:57 PM Subject: Re: TeamGrumman-List: Engine down thrust angle Gary: Aside from the mismatch between the cowling and spinner, what is the effect on performance/groundspeed of too much angle up or down? Thanks, Roger Rucker AA5A '78 HWO -----Original Message----- From: Gary Vogt Sent: Thu, Feb 10, 2011 2:57 pm Subject: TeamGrumman-List: Engine down thrust angle I'm doing an annual on a Tiger that came in with the engine visibly too far up. I measured the angle: .8 degrees up. The bottom mounts had two shims each. I removed one each of the bottom shims. The engine is now at .3 degrees up. RIght now, there is one shim on each mount. Note: This plane just had a new engine installed. During the engine overhaul period, the engine mount was sent to Kosola Engine mounts for overhaul and painting. The installation also got all new -59 engine shock mounts. The cowling is still below the spinner (i.e., spinner is higher than the cowling.) It could still use an extra shim in the top mounts; that would make two each on the top mounts, just like mine with the jaguar cowling. st" target=_blank>http://www.matronics.com/Navigator?TeamGrumman-List p://forums.matronics.com blank>http://www.matronics.com/contribution ________________________________ Message 4 _____________________________________ Time: 05:08:47 PM PST US Subject: Re: TeamGrumman-List: Engine down thrust angle From: FLYaDIVE Gary & Team: >From my experienced down thrust is a good thing ... IN MODERATION. - There is a down thrust on the elevator to keep the nose up and that is created by the air flow. - There is a lateral pivot point which balances down thrust of the elevator against down thrust of the engine. - AND this is a BIG ONE - It is much easier to land a plane with down-thrust to an engine than one with up-thrust. With up-thrust you have to fly the plane onto the runway. SO, what happens with ZERO Thrust? - There is more of a neutral feel and WHICH I PREFER - And when power is cut there is only a small pitch change. - With Up-Thrust when the power in cut the plane wants to DIVE - Since a lot of down elevator is used to keep the plane S&L. So what happens with Down-Thrust? - When the power is cut the plane will start to balloon just a little... Most people will not even notice it. And in many cases you will already be trimmed very close to best glide SO there is less work to do when setting up for a landing. - NOW! ALL this information is dependent on HOW MUCH thrust we are talking about. - If the feel is that noticeable you have some major thrust errors to correct. Barry "Chop'd Liver" ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message teamgrumman-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/TeamGrumman-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/teamgrumman-list Browse Digests http://www.matronics.com/digest/teamgrumman-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.