---------------------------------------------------------- Zenith701801-List Digest Archive --- Total Messages Posted Sat 04/18/09: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:40 PM - Re: test (kmccune) 2. 05:28 PM - Re: testtest (Jim McBurney) 3. 05:50 PM - Zenith Family Problems? (Bob Collins) 4. 06:02 PM - Re: Zenith Family Problems? (Craig Payne) 5. 07:21 PM - Re: Zenith Family Problems? (MacDonald Doug) 6. 09:32 PM - Re: Zenith Family Problems? (Bob Percival) 7. 09:53 PM - Re: Zenith Family Problems? (John Marzulli) ________________________________ Message 1 _____________________________________ Time: 04:40:12 PM PST US Subject: Zenith701801-List: Re: test From: "kmccune" :D The discussion over there makes glad we have a STOL list! bob(at)frontrange-pc.com wrote: > I thought that might be the case but didn't want to miss out on any > constructive STOL conversations. > I'll resume my role as long time lurker, painfully slow builder. > Thanks > Do Not Archive > > Bob Percival > 701/Vair > > -- -------- Mark Twain: Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=239974#239974 ________________________________ Message 2 _____________________________________ Time: 05:28:44 PM PST US From: "Jim McBurney" Subject: Re: Zenith701801-List: testtest Thanks, Matt, for a separate 701801 list. 242 messages in the last four days in the Zenith list! Thanks again Blue skies and tailwinds Jim CH-801 DeltaHawk diesel Augusta GA 90% done, 90% left ________________________________ Message 3 _____________________________________ Time: 05:50:47 PM PST US From: Bob Collins Subject: Zenith701801-List: Zenith Family Problems? I have a question for you long-time STOL aficionados. Is there any reason to worry about flutter of the flaperon on the Zenith STOL designs? I have been following the "discussion" about potential 601XL aileron flutter problems on the Zenith-List. One point seems to come through is that using a mass-balanced aileron is a relatively common practice in modern designs to reduce/eliminate flutter and, apparently, the 601XL depends on proper tension on the control cables to satisfy this need (Zenith has stated this). My personal observation is that, if what I just stated is true, using mass-balanced ailerons would be preferable because they require less frequent inspection and oversight. My current interest is in the CH750, which of course has no history other than what may be extrapolated from the 701 and 801. I don't see any evidence of mass-balancing on the STOL models. Now, in many ways the STOL planes are different than the 600 series designs, but is there any reason to worry about similar issues on the 750? My first pass observation is that the STOL planes are slower, have heavier control surfaces, and the flaperon linkage (probably) has more inherent mass. These would all point to flutter being less likely a problem on the STOL designs that on the 600 designs. In addition to concern about any (potential) real design issues, there is the effect this whole issue might have on the reputation of Zenith and the Zenith designs. A strong selling point for the Zenith designs is the sterling reputation of the chief designer. If there are valid criticisms of his design choices, particularly in an area that affects safety, this would affect the whole Zenith ecosystem. I am interested in your thoughts. Also, for those of you going to Sun'N'Fun, please report anything you learn that would be of help to us in the Zenith STOL community. Thank you, Bob Collins Sunnyvale CA USA ________________________________ Message 4 _____________________________________ Time: 06:02:58 PM PST US From: "Craig Payne" Subject: RE: Zenith701801-List: Zenith Family Problems? Well, the 701 has been flying for a lot longer than the 601XL. I believe that there hadn't been a fatal accident in the US until a year or two ago when a new owner died doing some inappropriate low-level maneuvers in front of his family. -- Craig (incomplete 601XL and 701) -----Original Message----- From: owner-zenith701801-list-server@matronics.com [mailto:owner-zenith701801-list-server@matronics.com] On Behalf Of Bob Collins Sent: Saturday, April 18, 2009 6:50 PM Subject: Zenith701801-List: Zenith Family Problems? I have a question for you long-time STOL aficionados. Is there any reason to worry about flutter of the flaperon on the Zenith STOL designs? I have been following the "discussion" about potential 601XL aileron flutter problems on the Zenith-List. One point seems to come through is that using a mass-balanced aileron is a relatively common practice in modern designs to reduce/eliminate flutter and, apparently, the 601XL depends on proper tension on the control cables to satisfy this need (Zenith has stated this). My personal observation is that, if what I just stated is true, using mass-balanced ailerons would be preferable because they require less frequent inspection and oversight. My current interest is in the CH750, which of course has no history other than what may be extrapolated from the 701 and 801. I don't see any evidence of mass-balancing on the STOL models. Now, in many ways the STOL planes are different than the 600 series designs, but is there any reason to worry about similar issues on the 750? My first pass observation is that the STOL planes are slower, have heavier control surfaces, and the flaperon linkage (probably) has more inherent mass. These would all point to flutter being less likely a problem on the STOL designs that on the 600 designs. In addition to concern about any (potential) real design issues, there is the effect this whole issue might have on the reputation of Zenith and the Zenith designs. A strong selling point for the Zenith designs is the sterling reputation of the chief designer. If there are valid criticisms of his design choices, particularly in an area that affects safety, this would affect the whole Zenith ecosystem. I am interested in your thoughts. Also, for those of you going to Sun'N'Fun, please report anything you learn that would be of help to us in the Zenith STOL community. Thank you, Bob Collins Sunnyvale CA USA ________________________________ Message 5 _____________________________________ Time: 07:21:17 PM PST US From: MacDonald Doug Subject: Re: Zenith701801-List: Zenith Family Problems? Bob, I am by no means an aeronautical engineer but my thumbnail engineering opinion would be becasue of the mounting method of the flapperons on the STOL design, they have semi mass balanced flapperons. Since they are mounted on the flapperon spar line, there is a significant portion of their mass infront of the mounting point. Do Not Archive Doug MacDonald CH-701 Scratch builder NW Ontario, Canada > I have a question for you long-time STOL aficionados. Is > there any reason to worry about flutter of the flaperon on > the Zenith STOL designs? > ________________________________ Message 6 _____________________________________ Time: 09:32:41 PM PST US Subject: RE: Zenith701801-List: Zenith Family Problems? From: "Bob Percival" Bob, I'm no expert, but a quick browse of the NTSB accident database over the last 20 years returned 27 '701' accidents. As Craig said, only one fatality and a quick read of the probable cause on that accident would not lead you to suspect the design. I saw no mention of flutter or vibration in any of the reports. However, it appears that dead stick landing technique might be worth practicing. Bob Percival 701/Vair -----Original Message----- From: owner-zenith701801-list-server@matronics.com [mailto:owner-zenith701801-list-server@matronics.com] On Behalf Of Bob Collins Sent: Saturday, April 18, 2009 6:50 PM Subject: Zenith701801-List: Zenith Family Problems? I have a question for you long-time STOL aficionados. Is there any reason to worry about flutter of the flaperon on the Zenith STOL designs? I have been following the "discussion" about potential 601XL aileron flutter problems on the Zenith-List. One point seems to come through is that using a mass-balanced aileron is a relatively common practice in modern designs to reduce/eliminate flutter and, apparently, the 601XL depends on proper tension on the control cables to satisfy this need (Zenith has stated this). My personal observation is that, if what I just stated is true, using mass-balanced ailerons would be preferable because they require less frequent inspection and oversight. My current interest is in the CH750, which of course has no history other than what may be extrapolated from the 701 and 801. I don't see any evidence of mass-balancing on the STOL models. Now, in many ways the STOL planes are different than the 600 series designs, but is there any reason to worry about similar issues on the 750? My first pass observation is that the STOL planes are slower, have heavier control surfaces, and the flaperon linkage (probably) has more inherent mass. These would all point to flutter being less likely a problem on the STOL designs that on the 600 designs. In addition to concern about any (potential) real design issues, there is the effect this whole issue might have on the reputation of Zenith and the Zenith designs. A strong selling point for the Zenith designs is the sterling reputation of the chief designer. If there are valid criticisms of his design choices, particularly in an area that affects safety, this would affect the whole Zenith ecosystem. I am interested in your thoughts. Also, for those of you going to Sun'N'Fun, please report anything you learn that would be of help to us in the Zenith STOL community. Thank you, Bob Collins Sunnyvale CA USA Checked by AVG - www.avg.com 04/18/09 09:55:00 ________________________________ Message 7 _____________________________________ Time: 09:53:54 PM PST US Subject: Re: Zenith701801-List: Zenith Family Problems? From: John Marzulli Our EAA chapter is lucky to have Ron Wantaja speak to us from time to time. I asked him once if he had found anything interesting about Zeniths during his safety studies. His insight was the Zeniths have a much higher rate of auto-conversions engines. When you subtract out the autoconversion accidents, the fleet safety is much better than the EAB average. The engine failures are more likely the result of the R&D part of creating a new conversion/installation than anything else. Personally I am planning on have more than a few people look over my Rotax installation. Safe flying. John Marzulli http://www.GenevieveMarzulli.org/ http://marzulli.smugmug.com/ http://701Builder.blogspot.com/ http://www.JohnMarzulli.net/ On Sat, Apr 18, 2009 at 9:49 PM, Bob Percival wrote: > bob@frontrange-pc.com> > > Bob, > > I'm no expert, but a quick browse of the NTSB accident database over the > last 20 years returned 27 '701' accidents. As Craig said, only one > fatality and a quick read of the probable cause on that accident would > not lead you to suspect the design. I saw no mention of flutter or > vibration in any of the reports. However, it appears that dead stick > landing technique might be worth practicing. > > Bob Percival > 701/Vair > > -----Original Message----- > From: owner-zenith701801-list-server@matronics.com > [mailto:owner-zenith701801-list-server@matronics.com] On Behalf Of Bob > Collins > Sent: Saturday, April 18, 2009 6:50 PM > To: zenith701801-list@matronics.com > Subject: Zenith701801-List: Zenith Family Problems? > > > > I have a question for you long-time STOL aficionados. Is there any > reason to worry about flutter of the flaperon on the Zenith STOL > designs? > > I have been following the "discussion" about potential 601XL aileron > flutter problems on the Zenith-List. One point seems to come through is > that using a mass-balanced aileron is a relatively common practice in > modern designs to reduce/eliminate flutter and, apparently, the 601XL > depends on proper tension on the control cables to satisfy this need > (Zenith has stated this). My personal observation is that, if what I > just stated is true, using mass-balanced ailerons would be preferable > because they require less frequent inspection and oversight. > > My current interest is in the CH750, which of course has no history > other than what may be extrapolated from the 701 and 801. I don't see > any evidence of mass-balancing on the STOL models. Now, in many ways the > > STOL planes are different than the 600 series designs, but is there any > reason to worry about similar issues on the 750? My first pass > observation is that the STOL planes are slower, have heavier control > surfaces, and the flaperon linkage (probably) has more inherent mass. > These would all point to flutter being less likely a problem on the STOL > > designs that on the 600 designs. > > In addition to concern about any (potential) real design issues, there > is the effect this whole issue might have on the reputation of Zenith > and the Zenith designs. A strong selling point for the Zenith designs is > > the sterling reputation of the chief designer. If there are valid > criticisms of his design choices, particularly in an area that affects > safety, this would affect the whole Zenith ecosystem. > > I am interested in your thoughts. Also, for those of you going to > Sun'N'Fun, please report anything you learn that would be of help to us > in the Zenith STOL community. > > Thank you, > > Bob Collins > Sunnyvale CA USA > > > Checked by AVG - www.avg.com > 04/18/09 09:55:00 > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message zenith701801-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Zenith701801-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/zenith701801-list Browse Digests http://www.matronics.com/digest/zenith701801-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.