---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Sun 05/29/11: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:19 AM - Re: fun and games with a manometer (Lynn Matteson) 2. 08:52 AM - Re: fun and games with a manometer (zeprep251@aol.com) 3. 11:33 AM - Re: fun and games with a manometer (Lynn Matteson) 4. 12:11 PM - fun and games with a manometer (BobsV35B@aol.com) ________________________________ Message 1 _____________________________________ Time: 03:19:13 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: fun and games with a manometer Absolutely, positively, pretty damn certain that isn't happening, G. This is a 4-cylinder Jabiru after all, and it doesn't move hardly at all, let alone 1/2"+ of movement. The cowl flex is the culprit. This cowl is a Skyfox cowl, and is unsupported across the whole bottom of the exit-air opening. It has a built-in lip of about 1", but it's only at about a 15-degree angle to the rest of the cowl, so it doesn't offer a lot in the way of stiffening. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop (64 x 30, P-tip) Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with "Ramcharger" intake manifold...1110 hrs (since 3-27-2006) On May 29, 2011, at 12:24 AM, zeprep251@aol.com wrote: > Lynn, > Are you certain that the engine torque at max throttle does not > rotate the engine in it's mounts far enough to cause contact with > the cowl? > G.Aman > ________________________________ Message 2 _____________________________________ Time: 08:52:40 AM PST US Subject: Re: JabiruEngine-List: fun and games with a manometer From: zeprep251@aol.com Lynn, Just a thought.My 2200 is a pusher and I have to rotate the mounts in their sockets every couple years because they take a set that can be seen easily ,especially the fronts.It drops the engine almost 1/4 "Do you have dyna-foc al mounts in the Kit-Fox? . G.Aman -----Original Message----- From: Lynn Matteson Sent: Sun, May 29, 2011 3:19 am Subject: Re: JabiruEngine-List: fun and games with a manometer Absolutely, positively, pretty damn certain that isn't happening, G. This is a 4-cylinder Jabiru after all, and it doesn't move hardly at all, let alone 1/2"+ of movement. The cowl flex is the culprit. This cowl is a Skyfox cowl, and is unsupported across the whole bottom of the exit-air opening. It has a built-in lip of about 1", but it's only at about a 15-degree angle to the rest of the cowl, so it doesn't offer a lot in the way of stiffening. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop (64 x 30, P-tip) Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with "Ramcharger" intake manifold...1110 hrs (since 3-27-2006) On May 29, 2011, at 12:24 AM, zeprep251@aol.com wrote: > Lynn, > Are you certain that the engine torque at max throttle does not > rotate the engine in it's mounts far enough to cause contact with > the cowl? > G.Aman > ________________________________ Message 3 _____________________________________ Time: 11:33:06 AM PST US From: Lynn Matteson Subject: Re: JabiruEngine-List: fun and games with a manometer They are not dyna-focal, but almost...the mounting bolts point straight ahead, so the rubbers sit vertically, and the holes through them, horizontally. I changed rubbers for the very reason you described....sag. The rubbers I got from USJabiru are soft, while ones I got from Sonex (and subsequently removed right after installation) are hard as a rock, and transmit vibrations. I went back to the Jabiru-supplied rubbers after feeling vibrations from the others. Last June I had the engine out for work, and the new rubbers...then a year old, and now two years old, are still without the tell-tale signs of needing to be rotated or replaced. The first set I used for 3 years and they were distorted when I finally scrapped them. I made a brace today to keep the lower edge of the cowl from blowing upward and diminishing the exit-air area. It works well, but didn't make a lot of difference in the readings I was getting with the manometer. The 2.45-3.0" figure still stands....hard to nail the figure down because of the bounce of the liquid in the manometer. But the numbers are bearing out the validity of doing this test, coupled with the very good CHT temperatures....287-304 degrees F. during today's flight, and that's pretty typical. OAT today is 79 F. Looking back at the temporary lip that I made....1" deep, 20" long, and at a 60-degree angle to the wind...might have been what caused the cowl to deform and touch the exhaust pipe. After all, that's a pretty good "airbrake" sticking down into the airstream, and being mounted to a flexible cowl, it would want to take the easy route and deflect upwards to avoid the wind. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop (64 x 30, P-tip) Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with "Ramcharger" intake manifold...1110 hrs (since 3-27-2006) On May 29, 2011, at 11:49 AM, zeprep251@aol.com wrote: > Lynn, > Just a thought.My 2200 is a pusher and I have to rotate the mounts > in their sockets every couple years because they take a set that > can be seen easily,especially the fronts.It drops the engine almost > 1/4 "Do you have dyna-focal mounts in the Kit-Fox? . > > G.Aman > ________________________________ Message 4 _____________________________________ Time: 12:11:13 PM PST US From: BobsV35B@aol.com Subject: JabiruEngine-List: fun and games with a manometer Good Afternoon Lynn, You mentioned that you used a sixty degree lip. Seems to me I once read that anything beyond thirty degrees of "lip" actually decreases the airflow. It causes too much turbulence in the area. No knowledge from me. just a memory from a long time ago. Happy Skies, Old Bob Do Not Archive In a message dated 5/29/2011 1:33:13 P.M. Central Daylight Time, lynnmatt@jps.net writes: --> JabiruEngine-List message posted by: Lynn Matteson They are not dyna-focal, but almost...the mounting bolts point straight ahead, so the rubbers sit vertically, and the holes through them, horizontally. I changed rubbers for the very reason you described....sag. The rubbers I got from USJabiru are soft, while ones I got from Sonex (and subsequently removed right after installation) are hard as a rock, and transmit vibrations. I went back to the Jabiru-supplied rubbers after feeling vibrations from the others. Last June I had the engine out for work, and the new rubbers...then a year old, and now two years old, are still without the tell-tale signs of needing to be rotated or replaced. The first set I used for 3 years and they were distorted when I finally scrapped them. I made a brace today to keep the lower edge of the cowl from blowing upward and diminishing the exit-air area. It works well, but didn't make a lot of difference in the readings I was getting with the manometer. The 2.45-3.0" figure still stands....hard to nail the figure down because of the bounce of the liquid in the manometer. But the numbers are bearing out the validity of doing this test, coupled with the very good CHT temperatures....287-304 degrees F. during today's flight, and that's pretty typical. OAT today is 79 F. Looking back at the temporary lip that I made....1" deep, 20" long, and at a 60-degree angle to the wind...might have been what caused the cowl to deform and touch the exhaust pipe. After all, that's a pretty good "airbrake" sticking down into the airstream, and being mounted to a flexible cowl, it would want to take the easy route and deflect upwards to avoid the wind. Lynn Matteson Kitfox IV Speedster, taildragger Jabiru 2200, #2062 Prince prop (64 x 30, P-tip) Electroair direct-fire ignition system Rotec TBI-40 injection (sleeved to 36mm) Status: flying with "Ramcharger" intake manifold...1110 hrs (since 3-27-2006) On May 29, 2011, at 11:49 AM, zeprep251@aol.com wrote: > Lynn, > Just a thought.My 2200 is a pusher and I have to rotate the mounts > in their sockets every couple years because they take a set that > can be seen easily,especially the fronts.It drops the engine almost > 1/4 "Do you have dyna-focal mounts in the Kit-Fox? . > > G.Aman > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message jabiruengine-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/JabiruEngine-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/jabiruengine-list Browse Digests http://www.matronics.com/digest/jabiruengine-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.