---------------------------------------------------------- Zenith-List Digest Archive --- Total Messages Posted Sat 07/11/09: 31 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:13 AM - Chris' Last Letter (roger lambert) 2. 06:34 AM - Any builders/flyers in the Camarillo, CA area (Keith Ashcraft) 3. 06:39 AM - Re: Re: A Note About Moding G's instead of Weight (Juan Vega) 4. 07:03 AM - Re: Chris' Last Letter (Paul Mulwitz) 5. 07:09 AM - Re: Re: A Note About Moding G's instead of Weight (Juan Vega) 6. 07:15 AM - Re: Re: A Note About Moding G's instead of Weight (Rene Felker) 7. 07:17 AM - Re: Re: A Note About Moding G's instead of Weight (Paul Mulwitz) 8. 07:25 AM - Re: Re: A Note About Moding G's instead of Weight (Jay Maynard) 9. 07:39 AM - Re: Re: A Note About Moding G's instead of Weight (Carlos Sa) 10. 07:39 AM - Re: Re: A Note About Moding G's instead of Weight (Paul Mulwitz) 11. 07:47 AM - Re: Re: A Note About Moding G's instead of Weight (Paul Mulwitz) 12. 08:05 AM - Re: A Note About Moding G's instead of Weight (Ken Arnold) 13. 08:17 AM - Re: tight fit tool (bryanekholm) 14. 10:44 AM - Re: Chris' Last Letter (Dave) 15. 02:13 PM - Re: A Note About Moding G's instead of Weight (vayuwings) 16. 02:43 PM - Re: Re: A Note About Moding G's instead of Weight () 17. 02:55 PM - Re: Chris' Last Letter (JohnDRead@aol.com) 18. 03:57 PM - Re: Chris' Last Letter (Jay Maynard) 19. 03:58 PM - Re: Re: A Note About Moding G's instead of Weight (Juan Vega) 20. 04:11 PM - Re: Chris' Last Letter (Juan Vega) 21. 04:15 PM - Re: Chris' Last Letter (Dave) 22. 04:22 PM - Re: Chris' Last Letter (Dave) 23. 04:31 PM - Re: Chris' Last Letter (Jay Maynard) 24. 04:33 PM - Re: Re: A Note About Moding G's instead of Weight (Bryan Martin) 25. 04:34 PM - Re: Chris' Last Letter (T. Graziano) 26. 06:22 PM - Removing Duct Tape residue from Canopy...? (PatrickW) 27. 06:25 PM - SECOND FLIGHT (GLJSOJ1) 28. 06:35 PM - Re: Removing Duct Tape residue from Canopy...? (Paul Mulwitz) 29. 07:21 PM - Re: A Note About Moding G's instead of Weight (vayuwings) 30. 07:27 PM - Re: SECOND FLIGHT (leinad) 31. 08:36 PM - Re: Removing Duct Tape residue from Canopy...? (MHerder) ________________________________ Message 1 _____________________________________ Time: 06:13:15 AM PST US Subject: Zenith-List: Chris' Last Letter From: roger lambert "We appear to be fairly reassured that flutter is not an issue with cables at proper tension, adding balances is not required." Agreed. "On the other hand they need not be heavy or complex" Agreed with the proviso that some real engineering would be necessary, including the possibility that additional GVT testng would be necessary. See the recomendations at the end of the GVT report done by Zenith's contractor. " and then flutter mitigation would not require a specific cable tension (although flight control would certainly require some tension). If they are added the ailerons would certainly not flutter even with no tension, controls disconnected (the ultimate slack) flutter would then never be an issue, under any circumstances. " Flutter mitigation, within the flight envelope, and a properly maintained airplane is already not an issue without adding additional structures. As there would have to be a specific cable tension maintained, even with mass balanced ailerons, that would have to be checked as part of your maintainance schedule, you have gained nothing by the addition of the balanced ailerons except redundancy. "Now I regard that as an improvement. I don't think the author was advocating for flight minus controls. " Actually the author is on record as demanding that Zenith's GVT testing be done with the control cables without tension. Try to imagine flying the Zenith without tension between the stick and the ailerons. Your problem would not be flutter if the cables loosened to zero in flight. "If such a mod is approved, it should be optional," Agreed, but who will design and approve it. " but any further attempt to vilify ZBAG simply because of this wording will only serve to further split the Zenith community" ZBAG is a group of adults who sent the results unverified computer models to virtually every government regulating aircraft insisting that flutter was the cause of the crashes. They also haven't used the GVT testing rsults from Zenith to verify their model. They are big boys who should be able to stand their statements being analyzed. ________________________________ Message 2 _____________________________________ Time: 06:34:16 AM PST US From: Keith Ashcraft Subject: Zenith-List: Any builders/flyers in the Camarillo, CA area All, I am TDY here in the Camarillo area and was wondering if any body is close buy and wanted to get together. I should be free from work on Sunday afternoon (July 12th) Let me know. Thanks, Keith 719-332-4364 Ch701 -- scratch N 38.9940 W 105.1305 Alt. 9,100' ________________________________ Message 3 _____________________________________ Time: 06:39:38 AM PST US From: Juan Vega Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight Paul, your shitting me right? Juan -----Original Message----- >From: Paul Mulwitz >Sent: Jul 10, 2009 7:00 PM >To: zenith-list@matronics.com >Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight > > >OK, Juan. I'll bite. > >What outcome would you expect from flying over gross weight? > >We all know it will reduce the climb rate. We also know that Va >increases with increased weight. This would seem to suggest that >structure failures are less likely with excess weight rather than >more likely (the plane is more likely to stall than sustain high G's). > >So, what is the big problem with excess weight? > >Paul >do not archive > >At 03:52 PM 7/10/2009, you wrote: >>Paul, >>Ignoring MTOW is playing Russian roullette. PLay at your own peril. >> >> >>Juan > > ________________________________ Message 4 _____________________________________ Time: 07:03:17 AM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Chris' Last Letter Hi Roger, This one little part of your post caught my attention. At 06:11 AM 7/11/2009, you wrote: >you have gained nothing by the addition of the balanced ailerons >except redundancy. I think my view of this situation would be better stated if you changed the word redundancy to robustness. We all know that the Zodiac XL is basically a very sound design that meets not only the specific criteria of ASTM LSA standards but also is desirable enough to have sold hundreds or thousands of copies to builders and flyers. It has passed static load testing multiple times. It has passed ground vibration testing. We don't know the results of the other "Engineering design studies" since some have been kept secret from the general public, but I think we can assume there have been no "Smoking Guns" found to explain the real world structure failures. Nearly everyone who flies a Zodiac XL has a great experience with it. However there have been enough fatal accidents involving structural failure in flight that there is cause for alarm. So the nature of the "Problem" with the XL is it lacks sufficient robustness to have a great safety record instead of a pretty good one. The XL design works fine in most cases. Some times in some unknown set of conditions it fails to hold up. Stated differently: We need to have more robustness in this design rather than a fix for a part of the design which is broken. The latest round of discussion of the aileron controls seems to suggest that complete loss of aileron control due to slack cables is an unthinkable situation. This is simply not true. Aileron control is not required to allow for controlled flight. There are three cables in the aileron control system. If any one of them were severed then the tension in the system would be removed. If it were the balance cable then the control stick would still activate one of the ailerons when moved in either direction and the pilot would be able to control movement about the aircraft's roll axis. If either of the other cables (the ones going directly to one wing) were severed, roll in one direction would still be controlled and the other direction would be uncontrolled - as far as the aileron system is concerned. However, roll in that direction and turning in general would still be controllable through the rudder. Indeed if the stick had no connection at all to the ailerons the rudder could still be used to get the plane to fly in the direction desired by the pilot. Yes, it would be uncoordinated flight, but that would only make it a little bit uncomfortable for the occupants of the plane. Put together this adds up to a robust system. Even complete loss of aileron control leaves you with a controllable and flyable plane. If loss of aileron cable tension leads to flutter and wing separation, then the aileron cables become a critical system for flight. Adding balance to the ailerons seems to change this by removing any possibility of flutter when the aileron cable tension is lost. This addition would restore some of the robustness to the design that should have been there all along. Paul XL grounded ________________________________ Message 5 _____________________________________ Time: 07:09:40 AM PST US From: Juan Vega Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight Ladies, I am headed to Wickee Wachee SPrings with the Kids, in the Mean Time, chew on this piece from a n article from Mr. McGee. It starts on the basics of Overweight issues on a lite wing loaded aircraft. Very Basic info but to the point. ASk your self the questions after you read it,"do I want to deal with an over maxed aircraft, and do I have the hours flown to understand how the plane will behave at manuvering speeds at over gross" "WHat is my new stall speeds?". As quoted from an article by Art Mcgee; Aside from building a light plane, there is another option to achieve a reasonable useful load. Under the FAA's Amateur Built Experimental aircraft guidelines, the manufacturer (the builder) sets the gross weight of the aircraft. With this flexibility you can increase the maximum gross weight to more than 800lbs. Although the builder can assign any weight he feels appropriate, when doing so he should keep in mind the original design load and the G load factor used to determine the designed gross weight. As you increase your gross weight, you must decrease the G rating of the aircraft to keep from going over the design load of the aircraft. With this in mind, let's go back to the information provided earlier about G rating, gross weight and design load. If you are willing to reduce your G ratings and use more precautions in rough conditions, then you can increase your gross weight. Let's look back to the example airplane. The gross weight was 800 lbs. and the empty weight was 472-lbs. and left room after pilot fuel, and oil for 117.2 lbs. of passenger. If I were to increase the gross weight to 900 pounds that would give me room for a 217.2-pound passenger, which would give more flexibility in passengers. I knew that if I lowered the maximum G ratings for my plane, that would increase my gross weight. If you take the positive design load of 4800 lbs. and divide it by the new maximum G rating of +5, that would give a gross weight of 960 lbs. If you take the negative design load of 2400 lbs. and divide it by 960lbs, you get a G rating of -2.5G's. This change leaves a fairly large margin of safety in turbulence and also gives some increased utility since there is now a higher gross weight. This change would now give me room for a passenger who weighed 277.2 pounds and would allow me to carry anyone that I know who would want to fly. Increasing the gross weight does not come without its drawbacks though. The Down Side to Increasing Gross Weight Like anything else in aviation, a gain in one place means a loss in another place. There are some things to consider when raising the gross weight. Among those things are decreased performance, increased fuel consumption, possible center of gravity problems, and, of course, decreased G ratings. Because of the higher gross weight, the take-off distance, landing distance and stall speed will be increased and the climb rate will decrease. The pilot will have to be aware of the G ratings when flying in turbulence and when doing yank and bank flying. The pilot will have to remember when flying at the increased weight to slow down more in turbulence and be easier on the controls. He will also need to remember that stall speed will be higher and it will take more distance to take off and land. He will also have to pay more attention to the center of gravity. The Challenger has a wide center of gravity envelope, but all of the weight that is placed in the cockpit moves the CG forward. With higher payloads, you may go past the forward limit for center of gravity. The good news is that if you are flying solo, then you are most likely below 800 pound gross weight flying a plane with a designed +6 and -3G range. -----Original Message----- >From: Paul Mulwitz >Sent: Jul 10, 2009 7:00 PM >To: zenith-list@matronics.com >Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight > > >OK, Juan. I'll bite. > >What outcome would you expect from flying over gross weight? > >We all know it will reduce the climb rate. We also know that Va >increases with increased weight. This would seem to suggest that >structure failures are less likely with excess weight rather than >more likely (the plane is more likely to stall than sustain high G's). > >So, what is the big problem with excess weight? > >Paul >do not archive > >At 03:52 PM 7/10/2009, you wrote: >>Paul, >>Ignoring MTOW is playing Russian roullette. PLay at your own peril. >> >> >>Juan > > ________________________________ Message 6 _____________________________________ Time: 07:15:08 AM PST US From: "Rene Felker" Subject: RE: Zenith-List: Re: A Note About Moding G's instead of Weight Juan, I don't think he is..... For my RV-10, I added 100lbs to my gross weight after looking at the numbers. Had an AE look at it and in the end had to reduce my max G loading by .2 G's at the new gross weight. I tested at that weight to include aft C/G....could not test forward CG "limit" since there is no way of getting up on the forward with that much weight. The only real concern I had was with the gear and what affect the 100 lbs would have. But since I would not be landing at the gross weight and since in almost all scenarios it is nearly impossible to load to max and keep it there, I accepted that risk. Rene' Felker RV-10 N423CF Flying 801-721-6080 -----Original Message----- From: owner-zenith-list-server@matronics.com [mailto:owner-zenith-list-server@matronics.com] On Behalf Of Juan Vega Sent: Saturday, July 11, 2009 7:38 AM Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight Paul, your shitting me right? Juan -----Original Message----- >From: Paul Mulwitz >Sent: Jul 10, 2009 7:00 PM >To: zenith-list@matronics.com >Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight > > >OK, Juan. I'll bite. > >What outcome would you expect from flying over gross weight? > >We all know it will reduce the climb rate. We also know that Va >increases with increased weight. This would seem to suggest that >structure failures are less likely with excess weight rather than >more likely (the plane is more likely to stall than sustain high G's). > >So, what is the big problem with excess weight? > >Paul >do not archive > >At 03:52 PM 7/10/2009, you wrote: >>Paul, >>Ignoring MTOW is playing Russian roullette. PLay at your own peril. >> >> >>Juan > > ________________________________ Message 7 _____________________________________ Time: 07:17:14 AM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight Hi Juan, No. I am being completely serious. I really believe the impact of being over gross weight is predictable and reasonably safe. There are obvious impacts to required runway length and climb rates, but for the most part a small excess of weight results in a small reduction in performance. Of course, this assumes that the CG for the plane is still within normal limits. My understanding of the FAA regs on this matter is that the pilot is required to be aware of the weight situation but he is not required to remain within the weight specified on the aircraft documents. Indeed the MTOW specified in the documents is totally arbitrary - based on a set of conditions that may or may not be the ones faced for a given flight. I still await your answer about what happens if you are over gross weight. (Keep in mind that this happens every day on some aircraft like the C-150, and will probably also happen on most dual flights of the new C-162). Paul XL grounded do not archive At 06:37 AM 7/11/2009, you wrote: > >Paul, >your shitting me right? >Juan > >-----Original Message----- > >From: Paul Mulwitz > >Sent: Jul 10, 2009 7:00 PM > >To: zenith-list@matronics.com > >Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight > > > > > >OK, Juan. I'll bite. > > > >What outcome would you expect from flying over gross weight? > > > >We all know it will reduce the climb rate. We also know that Va > >increases with increased weight. This would seem to suggest that > >structure failures are less likely with excess weight rather than > >more likely (the plane is more likely to stall than sustain high G's). > > > >So, what is the big problem with excess weight? > > > >Paul > >do not archive > > > >At 03:52 PM 7/10/2009, you wrote: > >>Paul, > >>Ignoring MTOW is playing Russian roullette. PLay at your own peril. > >> > >> > >>Juan > > > > > > > > > > > > > > ________________________________ Message 8 _____________________________________ Time: 07:25:25 AM PST US From: Jay Maynard Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight On Sat, Jul 11, 2009 at 07:13:34AM -0700, Paul Mulwitz wrote: > My understanding of the FAA regs on this matter is that the pilot is > required to be aware of the weight situation but he is not required to > remain within the weight specified on the aircraft documents. ...except for an LSA, which may not be operated contrary to the amnufacturer's instructions. The POH carries the force of law for an LSA. -- Jay Maynard, K5ZC, PP-ASEL, CFI-SP http://www.conmicro.com http://jmaynard.livejournal.com http://www.tronguy.net Fairmont, MN (KFRM) (Yes, that's me!) AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml ________________________________ Message 9 _____________________________________ Time: 07:39:03 AM PST US Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight From: Carlos Sa Folks, there is a pertinent article in Flying (July 2009), page 32, by Peter Garrison: "Aftermath / the myth of gross weight", which you can read here: http://www.flyingmag.com/accidents/1593/the-myth-of-gross-weight.html Carlos 2009/7/11 Paul Mulwitz > > Hi Juan, > > No. I am being completely serious. I really believe the impact of being > over gross weight is predictable and reasonably safe. There are obvious > impacts to required runway length and climb rates, but for the most part a > small excess of weight results in a small reduction in performance. > ________________________________ Message 10 ____________________________________ Time: 07:39:03 AM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight Hi Juan, I agree with everything said in your quoted article except for the turbulence comment. I'm afraid the author got this point backwards. Increasing actual gross weight increases Va rather than decreasing it. So, in theory, you could fly faster in the same turbulence with more gross weight rather than needing to fly slower. OK, it is a small point. The simple answer for most pilots in most conditions is to keep under gross weight specified in the airplane's documents. However, I still believe flying over gross weight can be done safely, and legally, in some planes under some conditions. Paul do not archive At 07:08 AM 7/11/2009, you wrote: >The pilot will have to remember when flying at the increased weight >to slow down more in turbulence ________________________________ Message 11 ____________________________________ Time: 07:47:01 AM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight Hi Jay, This is a very interesting distinction. I wonder how the C-162 will be certified. It seems if it is certified under part 23 you can do dual instruction in it but if it is certified as S-LSA you can't do dual legally. If I remember correctly from my original calculations with full fuel and a normal adult in one seat the other one will have to weigh 50 pounds or so to stay under MTOW. Paul do not archive At 07:24 AM 7/11/2009, you wrote: > >On Sat, Jul 11, 2009 at 07:13:34AM -0700, Paul Mulwitz wrote: > > My understanding of the FAA regs on this matter is that the pilot is > > required to be aware of the weight situation but he is not required to > > remain within the weight specified on the aircraft documents. > >...except for an LSA, which may not be operated contrary to the >amnufacturer's instructions. The POH carries the force of law for an LSA. >-- ________________________________ Message 12 ____________________________________ Time: 08:05:04 AM PST US From: "Ken Arnold" Subject: Zenith-List: Re: A Note About Moding G's instead of Weight Over time, it has been proffered that inane speculation often subtracts from the sum total of human intelligence. Regards, Ken do not archive ________________________________ Message 13 ____________________________________ Time: 08:17:02 AM PST US Subject: Zenith-List: Re: tight fit tool From: "bryanekholm" I thought mine was a bit sloppy too but it does end up drilling a decent hole. Not bad for a $40 tool. Bryan Ekholm -------- Bryan Ekholm Read this topic online here: http://forums.matronics.com/viewtopic.php?p=252566#252566 ________________________________ Message 14 ____________________________________ Time: 10:44:35 AM PST US From: "Dave" Subject: Re: Zenith-List: Chris' Last Letter It may be issued as a result of OTHER gov't's demands, it doesn't look like the U.S. gov't has much interest. If it isn't issued and or approved it would be fine with me if any individual designed their own and self-evaluated the result. If it works well other builders could use it. If Zenith saw no harm in it that would likely be the extend of factory approval but we'll see. Frankly i think flutter is now a dead issue, doesn't mean the airframe can't be improved. I would regard these balance as desirable but not high priority. I see ZBAG as a bunch of interested and engaged owners, not an enemy. I don't believe they had much influence on the Gov't and I don't believe they've grounded anything. They MAY have had a very small part in getting a very small and so far unenforced recommendation made by a safety agency. I believe the actions of foriegn gov'ts and the accidents will have had much more influence. All in all I see ZBAG as exactly what they say they are, a group of interested builders. Mostly irrelevant to the rest of us, certainly not worth all the electrons and angst required to hate their guts the way most of the zenith builders have decided to. I would certainly analyse any "statement" made by the group as a whole as an official statement, but there has been none and unless they find something definitive I would not expect that. Any statements by a person who happens to be a member would hold no more weight than any other of the vast array of opinions I've read here. I encourage ZBAG to do their thing, so far I percieve them as irrelevant. I'm unsure who the author who wants the GVT done with slack cables is, but he's free to want anything. I want the accidents to stop, after that I want to understand the reason this airframe appears to have a disproportionate rate of failure. I bet my wish happens before his. ----- Original Message ----- From: roger lambert To: zenith-list@matronics.com Sent: Saturday, July 11, 2009 10:11 AM Subject: Zenith-List: Chris' Last Letter Agreed, but who will design and approve it. " but any further attempt to vilify ZBAG simply because of this wording will only serve to further split the Zenith community" ZBAG is a group of adults who sent the results unverified computer models to virtually every government regulating aircraft insisting that flutter was the cause of the crashes. They also haven't used the GVT testing rsults from Zenith to verify their model. They are big boys who should be able to stand their statements being analyzed. ________________________________ Message 15 ____________________________________ Time: 02:13:29 PM PST US Subject: Zenith-List: Re: A Note About Moding G's instead of Weight From: "vayuwings" 'Over time, it has been proffered that inane speculation often subtracts from the sum total of human intelligence.' Hmm... making the assumptive leap that 'human intelligence' is not a conflict in terms, and those doing the proffering are proven by all to be the Wise, methinks speculation of any sort can be classified either as inane or not - praytell, whom dost say whether inane or not? so as the river winding to the sea is never direct, but flows inanely across the land to the ocean..... Let it flow and enjoy the shore a bit, eh? just might find a cove of great surprise Dave 601XL building temporarily frozen in the phoenix heat Read this topic online here: http://forums.matronics.com/viewtopic.php?p=252588#252588 ________________________________ Message 16 ____________________________________ Time: 02:43:14 PM PST US From: Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight > Dave > 601XL > building temporarily frozen in the phoenix heat My garage temperature was over 120. Outside temp just over 113. Also waiting for heat to subside. Jerry ________________________________ Message 17 ____________________________________ Time: 02:55:08 PM PST US From: JohnDRead@aol.com Subject: Re: Zenith-List: Chris' Last Letter How about we bag the Zbaggers and get on with life? Personally I have had it with their unfounded accusations of the 601. John Read CH701 - Elbert CO - Jabiru 3300 Phone: 303-648-3261 Fax: 303-648-3262 Cell: 719-494-4567 **************Looking for love this summer? Find it now on AOL Personals. (http://personals.aol.com/?ncid=emlcntuslove00000003) ________________________________ Message 18 ____________________________________ Time: 03:57:44 PM PST US From: Jay Maynard Subject: Re: Zenith-List: Chris' Last Letter On Sat, Jul 11, 2009 at 05:57:51PM -0400, JohnDRead@aol.com wrote: > How about we bag the Zbaggers and get on with life? Personally I have had > it with their unfounded accusations of the 601. If I thought there was no foundation for the concerns, I wouldn't have sent in my money to support the effort. Do you think that we're doing this out of a desire to harm the Zenith family of companies? Why on earth would that be something Zenith owners and builders would want to do? -- Jay Maynard, K5ZC, PP-ASEL, CFI-SP http://www.conmicro.com http://jmaynard.livejournal.com http://www.tronguy.net Fairmont, MN (KFRM) (Yes, that's me!) AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml ________________________________ Message 19 ____________________________________ Time: 03:58:02 PM PST US From: Juan Vega Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight Dave, Put down the Bong and get back to building:) Juan -----Original Message----- >From: vayuwings >Sent: Jul 11, 2009 5:10 PM >To: zenith-list@matronics.com >Subject: Zenith-List: Re: A Note About Moding G's instead of Weight > > >'Over time, it has been proffered that inane speculation often subtracts from >the sum total of human intelligence.' > >Hmm... making the assumptive leap that 'human intelligence' is not a conflict in terms, and those doing the proffering are proven by all to be the Wise, methinks speculation of any sort can be classified either as inane or not - praytell, whom dost say whether inane or not? > >so as the river winding to the sea is never direct, but flows inanely across the land to the ocean..... > >Let it flow and enjoy the shore a bit, eh? just might find a cove of great surprise > >Dave >601XL >building temporarily frozen in the phoenix heat > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=252588#252588 > > ________________________________ Message 20 ____________________________________ Time: 04:11:05 PM PST US From: Juan Vega Subject: Re: Zenith-List: Chris' Last Letter Dave, Of all the accidents, There were two, out of all that may have been remotely based on some flutter, but totally unproven. Look at each accident and prior to people seeing the wings fall off, something else occured, crap weather, engine quits, pilot buzzing the field, Even the one in Texas, the witness heard the engine quite, THEN something about the wing failing. The only one that is complete unknown, is the one at Sun N FUn. The rest had something happen right before the claimed flutter. ZBAG latched on to the flutter issue like a Pissed off pit bull. Because some guy claimed he saw flutter over flying a power plant, then couldnt repeat it. 1000 zodiacs flying, and maybe 2 accidents that arte maybe a flutter issue. Where is the disproportionate failure issue? check out the number of accidents of other aircraft. 2 out of how many zodiacs? PULL EVERY NTSB Zodiac accident, and label the ones that were possible flutter or design issue! Maybe 2! And trhe tests and nath can't find it! Build it right, fly it right , maintain it right, its a great plane. Juan -----Original Message----- >From: Dave >Sent: Jul 11, 2009 1:41 PM >To: zenith-list@matronics.com >Subject: Re: Zenith-List: Chris' Last Letter > >It may be issued as a result of OTHER gov't's demands, it doesn't look like the U.S. gov't has much interest. If it isn't issued and or approved it would be fine with me if any individual designed their own and self-evaluated the result. If it works well other builders could use it. If Zenith saw no harm in it that would likely be the extend of factory approval but we'll see. Frankly i think flutter is now a dead issue, doesn't mean the airframe can't be improved. I would regard these balance as desirable but not high priority. > >I see ZBAG as a bunch of interested and engaged owners, not an enemy. I don't believe they had much influence on the Gov't and I don't believe they've grounded anything. They MAY have had a very small part in getting a very small and so far unenforced recommendation made by a safety agency. I believe the actions of foriegn gov'ts and the accidents will have had much more influence. All in all I see ZBAG as exactly what they say they are, a group of interested builders. Mostly irrelevant to the rest of us, certainly not worth all the electrons and angst required to hate their guts the way most of the zenith builders have decided to. I would certainly analyse any "statement" made by the group as a whole as an official statement, but there has been none and unless they find something definitive I would not expect that. Any statements by a person who happens to be a member would hold no more weight than any other of the vast array of opinions I've read here. I encourage ZBAG to do their thing, so far I percieve them as irrelevant. I'm unsure who the author who wants the GVT done with slack cables is, but he's free to want anything. I want the accidents to stop, after that I want to understand the reason this airframe appears to have a disproportionate rate of failure. I bet my wish happens before his. > > ----- Original Message ----- > From: roger lambert > To: zenith-list@matronics.com > Sent: Saturday, July 11, 2009 10:11 AM > Subject: Zenith-List: Chris' Last Letter > > > Agreed, but who will design and approve it. > > > " but any further attempt to vilify ZBAG simply because of this wording will only serve to further split the Zenith community" > > ZBAG is a group of adults who sent the results unverified computer models to virtually every government regulating aircraft insisting that flutter was the cause of the crashes. They also haven't used the GVT testing rsults from Zenith to verify their model. They are big boys who should be able to stand their statements being analyzed. ________________________________ Message 21 ____________________________________ Time: 04:15:57 PM PST US From: "Dave" Subject: Re: Zenith-List: Chris' Last Letter John, I am not clear that they have made any accusations. I believe they have some areas of concern that they are investigating. Any absolute accusations might well have come from a member, or from someone else. Let them do their thing. So far I don't believe they have harmed anyone, on the other hand, unexplained failures have. I hope they keep looking, maybe they'll help find an answer. ----- Original Message ----- From: JohnDRead@aol.com To: zenith-list@matronics.com Sent: Saturday, July 11, 2009 6:57 PM Subject: Re: Zenith-List: Chris' Last Letter How about we bag the Zbaggers and get on with life? Personally I have had it with their unfounded accusations of the 601. John Read CH701 - Elbert CO - Jabiru 3300 ________________________________ Message 22 ____________________________________ Time: 04:22:37 PM PST US From: "Dave" Subject: Re: Zenith-List: Chris' Last Letter I don't believe they are out to harm anybody Jay, I believe you/they are doing their best to satisfy themselves that their aircraft are as good as they can be. Not sure how ZBAG got tagged an enemy that must be attacked at every turn, miht be that old "If yer not with us, yer agin us us!!" crap. ----- Original Message ----- From: "Jay Maynard" Sent: Saturday, July 11, 2009 7:56 PM Subject: Re: Zenith-List: Chris' Last Letter > > If I thought there was no foundation for the concerns, I wouldn't have > sent > in my money to support the effort. Do you think that we're doing this out > of > a desire to harm the Zenith family of companies? Why on earth would that > be > something Zenith owners and builders would want to do? ________________________________ Message 23 ____________________________________ Time: 04:31:49 PM PST US From: Jay Maynard Subject: Re: Zenith-List: Chris' Last Letter On Sat, Jul 11, 2009 at 08:22:17PM -0300, Dave wrote: > I don't believe they are out to harm anybody Jay, I believe you/they are > doing their best to satisfy themselves that their aircraft are as good as > they can be. I can't speak for everyone involved, but that's certainly my motivation. > Not sure how ZBAG got tagged an enemy that must be attacked at every turn, > miht be that old "If yer not with us, yer agin us us!!" crap. I don't know either, but I'm getting goddamned tired of it. -- Jay Maynard, K5ZC, PP-ASEL, CFI-SP http://www.conmicro.com http://jmaynard.livejournal.com http://www.tronguy.net Fairmont, MN (KFRM) (Yes, that's me!) AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml ________________________________ Message 24 ____________________________________ Time: 04:33:08 PM PST US From: Bryan Martin Subject: Re: Zenith-List: Re: A Note About Moding G's instead of Weight It's not quite that simple. For a given MTOW and flight load factor (FLF), Va is the speed where, when the plane is actually loaded to the MTOW, the wing will stall before the FLF is exceeded. This assumes that the aircraft is in coordinated flight and the G loading is being increased at a defined rate. In this situation, the wing generating the maximum amount of lift that it can at that speed, the wing spar to fuselage attachment is experiencing the maximum stress it is designed to handle in flight, the engine mount may also be carrying the maximum load it is designed to carry and the mounts for many other fixed objects in the airplane may be carrying their maximum loads. For example, an airplane with a 1000 lb MTOW and 4 G FLF and Va of 100 mph. At Va and the stall angle of attack the wing will be producing 4000 lbs of lift. If the each wing weighs 100 lb, the fuselage weighs 800 lb so: 800 lb * 4 = 3200 lb of load on the wing spar-fuselage joint (1600 lb per side). If this same airplane (same MTOW and FLF) is loaded to less than MTOW and flying at 100 mph, the airplane will still produce the same maximum lift when it stalls but, since the airplane is lighter, the G factor will be higher. For example, if the airplane actually weighs 900 lb: 4000 / 900 gives a G factor of 4.44. If the weight was all removed from the fuselage then, 700 lb * 4.44 G = 3111 lb load at the spar-fuselage joint. In this situation, the wing spar will not be over loaded even though the G factor is higher, but the engine mounts may be overloaded, or some other structure may be overloaded. If instead, you are carrying 100 lb less fuel in the wing tanks but the same load in the fuselage then, 800 * 4.44 G = 3556 lb load at the spar-fuselage joint. In this situation, the wing is overloaded as well as the rest of the aircraft structures. This is why Va should be reduced when flying with a lighter load with a given FLF. If the MTOW is increased on this airplane, for instance to 1050 lb, the maximum flight load factor would have to be decreased to prevent overloading the spar. But this is the same airplane, so the spar is the same strength: it can still carry the same a maximum load at the spar-fuselage joint. Assuming the extra weight is in the fuselage: 3200 / 850 = 3.76 G. So the new FLF is 3.76 G for the airplane. Now: 3.76 G * 1050 = 3953 lb = the lift the wings will need to generate at 3.76 G. Since the lift needed at the new FLF is lower than it was for the 1000 lb MTOW case, you have to fly slower if you want the wing to stall before it exceeds this maximum lift value. So Va will decrease if you increase MTOW and decrease FLF. In this discussion, I have neglected any lift generated by the fuselage and the down force generated by the horizontal stabilizer. These may have some effect on the actual load carried by the wings. > > Hi Juan, > > I agree with everything said in your quoted article except for the > turbulence comment. I'm afraid the author got this point backwards. > > Increasing actual gross weight increases Va rather than decreasing > it. So, in theory, you could fly faster in the same turbulence with > more gross weight rather than needing to fly slower. > > OK, it is a small point. The simple answer for most pilots in most > conditions is to keep under gross weight specified in the airplane's > documents. However, I still believe flying over gross weight can be > done safely, and legally, in some planes under some conditions. > > Paul > do not archive > > > At 07:08 AM 7/11/2009, you wrote: >> The pilot will have to remember when flying at the increased weight >> to slow down more in turbulence -- Bryan Martin N61BM, CH 601 XL, RAM Subaru, Stratus redrive. ________________________________ Message 25 ____________________________________ Time: 04:34:28 PM PST US From: "T. Graziano" Subject: Re: Zenith-List: Chris' Last Letter IRT "some guy claimed he saw flutter over flying a power plant, then couldnt repeat it." See below from my archives; Tony Graziano; XL/Jab N493TG w 510 hrs to date - Hi Bill,Glad everything came out OK. Looks like you ran into some really weird turbulence from the power-plant, giving you an "E" ticket ride. If you were really experiencing wing or control surface flutter, your diving and picking up speed should have exacerbated the problem with the amplitude going divergent very rapidly, until something(s) bends or more likely breaks off. Only saw this once in a film of a dynamic model in a wind tunnel - once flutter started the entire model was gonzo in a second or two. Do you recall experiencing any feed back in the stick/rudder?In 199 hours in my XL, I have had some bumpy rides and the airplane has handled it ok - just glad I always have my seat belt tight. I have also had some GREAT*, almost I would have believed, GOOD*, landings and I agree the airplane is tough. *GREAT Landing - Airplane is still flyable. GOOD Landing - You can walk away from the airplane.Please let us know if you find anything after your in-depth inspection. I kind of suspect you will not find anything amiss, but if you do it would be a good data point for all of us for tailoring our structural inspections. Tony Graziano XL; N493TG--------Ben, maybe I did not explain well, but it was not control flutter. The aileron did not move independent of the wing. What occurred is the whole wing fluttered with aileron moving with it., best regards, Bill------------------------- Dear Thread Friends, I went flying this afternoon. Took a fellow with me and just wanted an hour in the clear blue. Conditions were perfect, clear, cool and only a slight wind. The only big thing around much to see nearby is Lake Juliette which has a big coal fired power station in the middle. Three huge steam towers that look like a nuclear power station. We flew around the lake about two miles away at 5000 feet so my pal could get a good look see. On the down wind side we flew into an invisible killer. We were doing above 140 when we flew into it. Instantly the left wing fluttered at a fast pitch, aileron and all and it looked to be moving maybe two inched up and down. I figured a couple seconds would break it off. I didn't have time to look around the passenger to see if the right wing was fluttering, but I suspect it was. I chopped power and did a hard diving wing over to the left and out of it. The flutter sound was great even over my Lightspeed AN system and the whole thing probably last maybe 5 or 6 seconds. I regained control out of the snap dive, maxing above 170 and flew slow and easy back to the field before I tested the controls. Everything felt okay and I could see no wrinkles in the top skin so I landed. Didn't really have much choice. Upon inspection I found no sign of stress, no skin deform, no paint cracked around rivets, nothing. I will take off all inspection panels for a close inspection this weekend and check bolts, controls, etc., but I cannot believe such a prolonged violent movement of the wing did not damage something other than my pride. Two things learned. Don't fly anywhere near a power station. Even at 5000 feet and miles away the invisible heat rises and is most extreme. Maybe intensified in cold weather. The other thing is the XL is very, very tough. Oh, there is a third thing. How could I have been so stupid not to know the first thing !! I am interested though in knowing why the wings fluttered in this thermal? What theory of air dynamics would cause this extreme reaction? Was is just the level of heat and speed the invisible air was streaming past? This was my 90th flight in her and she made me proud again. Best regards to you all, Bill of Georgia N505WP 601XL-3300 ----- Original Message ----- From: "Juan Vega" Sent: Saturday, July 11, 2009 6:10 PM Subject: Re: Zenith-List: Chris' Last Letter > > Dave, > Of all the accidents, There were two, out of all that may have been > remotely based on some flutter, but totally unproven. Look at each > accident and prior to people seeing the wings fall off, something else > occured, crap weather, engine quits, pilot buzzing the field, Even the > one in Texas, the witness heard the engine quite, THEN something about > the wing failing. The only one that is complete unknown, is the one at > Sun N FUn. The rest had something happen right before the claimed > flutter. ZBAG latched on to the flutter issue like a Pissed off pit bull. > Because some guy claimed he saw flutter over flying a power plant, then > couldnt repeat it. 1000 zodiacs flying, and maybe 2 accidents that > arte maybe a flutter issue. > > Where is the disproportionate failure issue? check out the number of > accidents of other aircraft. 2 out of how many zodiacs? PULL EVERY NTSB > Zodiac accident, and label the ones that were possible flutter or design > issue! Maybe 2! And trhe tests and nath can't find it! > > Build it right, fly it right , maintain it right, its a great plane. > > Juan > > > -----Original Message----- >>From: Dave >>Sent: Jul 11, 2009 1:41 PM >>To: zenith-list@matronics.com >>Subject: Re: Zenith-List: Chris' Last Letter >> >>It may be issued as a result of OTHER gov't's demands, it doesn't look >>like the U.S. gov't has much interest. If it isn't issued and or approved >>it would be fine with me if any individual designed their own and >>self-evaluated the result. If it works well other builders could use it. >>If Zenith saw no harm in it that would likely be the extend of factory >>approval but we'll see. Frankly i think flutter is now a dead issue, >>doesn't mean the airframe can't be improved. I would regard these balance >>as desirable but not high priority. >> >>I see ZBAG as a bunch of interested and engaged owners, not an enemy. I >>don't believe they had much influence on the Gov't and I don't believe >>they've grounded anything. They MAY have had a very small part in getting >>a very small and so far unenforced recommendation made by a safety agency. >>I believe the actions of foriegn gov'ts and the accidents will have had >>much more influence. All in all I see ZBAG as exactly what they say they >>are, a group of interested builders. Mostly irrelevant to the rest of us, >>certainly not worth all the electrons and angst required to hate their >>guts the way most of the zenith builders have decided to. I would >>certainly analyse any "statement" made by the group as a whole as an >>official statement, but there has been none and unless they find something >>definitive I would not expect that. Any statements by a person who happens >>to be a member would hold no more weight than any other of the vast array >>of opinions I've read here. I encourage ZBAG to! > do their thing, so far I percieve them as irrelevant. I'm unsure who the > author who wants the GVT done with slack cables is, but he's free to want > anything. I want the accidents to stop, after that I want to understand > the reason this airframe appears to have a disproportionate rate of > failure. I bet my wish happens before his. >> >> ----- Original Message ----- >> From: roger lambert >> To: zenith-list@matronics.com >> Sent: Saturday, July 11, 2009 10:11 AM >> Subject: Zenith-List: Chris' Last Letter >> >> >> >> >> Agreed, but who will design and approve it. >> >> >> " but any further attempt to vilify ZBAG simply because of this wording >> will only serve to further split the Zenith community" >> >> ZBAG is a group of adults who sent the results unverified computer >> models to virtually every government regulating aircraft insisting that >> flutter was the cause of the crashes. They also haven't used the GVT >> testing rsults from Zenith to verify their model. They are big boys who >> should be able to stand their statements being analyzed. > > > ________________________________ Message 26 ____________________________________ Time: 06:22:07 PM PST US Subject: Zenith-List: Removing Duct Tape residue from Canopy...? From: "PatrickW" I covered my canopy hoops with Duct Tape with the intent of protecting the soft interior of the canopy bubble from scratches. During the course of all the fitting, sliding around, cursing, and generally getting the bubble to fit the hoops, a lot of the duct tape residue rubbed onto the interior of the canopy. Anybody know what I can use to safely remove that gunk from the inside of my canopy...? Thanks, - Pat -------- Patrick XL/650/Corvair N63PZ (reserved) Read this topic online here: http://forums.matronics.com/viewtopic.php?p=252611#252611 ________________________________ Message 27 ____________________________________ Time: 06:25:33 PM PST US Subject: Zenith-List: SECOND FLIGHT From: "GLJSOJ1" Hi everyone Made my second flight today after making some adjustments. first adjustment was to re pitch the prop from 13.5 to 12 degrees. Second adjustment was to re-check the wings and their rigging. I found now issues here that may cause a heavy left wing. Along with this as some suggested, I moved 5 gallons of fuel from the left inboard tank to the the right inboard tank. The right tank is full (12 gal) and the left tank has about 4 gallons .. third adjustment was to right up the cooling intakes by 1" X 5 " on the left side and 3/4 " x 6 " on the right side. I rotated at about 55 KIAS and lifted of at 60 KIAS, then gained speed to 80 KIAS to climb out at abut 400 to 500 RPM. I no longer have a heavy left wing. The airplane will climb and oil temps are no longer approaching the red line. I was able to fly level at 2300 RPM and indicated 94 knots. I was able to trim it to fly hands off. Now the real testing will begin as Learn more about my airplane Thanks to all the offered suggestions and ideas -------- 601XL N676L reserved ALMOST DONE CHESAPEAKE VA Read this topic online here: http://forums.matronics.com/viewtopic.php?p=252612#252612 ________________________________ Message 28 ____________________________________ Time: 06:35:39 PM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Removing Duct Tape residue from Canopy...? Hi Pat, Mineral Spirits should work - available at paint and hardware stores. Try some on a hidden corner first . . . Paul XL grounded At 06:21 PM 7/11/2009, you wrote: > >I covered my canopy hoops with Duct Tape with the intent of >protecting the soft interior of the canopy bubble from scratches. > >During the course of all the fitting, sliding around, cursing, and >generally getting the bubble to fit the hoops, a lot of the duct >tape residue rubbed onto the interior of the canopy. > >Anybody know what I can use to safely remove that gunk from the >inside of my canopy...? > >Thanks, > >- Pat > >-------- >Patrick >XL/650/Corvair >N63PZ (reserved) ________________________________ Message 29 ____________________________________ Time: 07:21:54 PM PST US Subject: Zenith-List: Re: A Note About Moding G's instead of Weight From: "vayuwings" Juan - ah, if only I could..... build, that is- this is where the mind goes with 114 degree heat - no need for costly bongs and required inducements... but see how you have proven my point? flow river flow... :) Dave Read this topic online here: http://forums.matronics.com/viewtopic.php?p=252615#252615 ________________________________ Message 30 ____________________________________ Time: 07:27:18 PM PST US Subject: Zenith-List: Re: SECOND FLIGHT From: "leinad" Thanks for the report. Sounds great! Dan Dempsey Do not archive GLJSOJ1 wrote: > Hi everyone > > Made my second flight today after making some adjustments. > > first adjustment was to re pitch the prop from 13.5 to 12 degrees. > > Second adjustment was to re-check the wings and their rigging. I found now issues here that may cause a heavy left wing. Along with this as some suggested, I moved 5 gallons of fuel from the left inboard tank to the the right inboard tank. The right tank is full (12 gal) and the left tank has about 4 gallons .. > > third adjustment was to right up the cooling intakes by 1" X 5 " on the left side and 3/4 " x 6 " on the right side. > > I rotated at about 55 KIAS and lifted of at 60 KIAS, then gained speed to 80 KIAS to climb out at abut 400 to 500 RPM. I no longer have a heavy left wing. The airplane will climb and oil temps are no longer approaching the red line. I was able to fly level at 2300 RPM and indicated 94 knots. I was able to trim it to fly hands off. > > Now the real testing will begin as Learn more about my airplane > > Thanks to all the offered suggestions and ideas -------- Scratch building XL with Corvair Engine Read this topic online here: http://forums.matronics.com/viewtopic.php?p=252617#252617 ________________________________ Message 31 ____________________________________ Time: 08:36:59 PM PST US Subject: Zenith-List: Re: Removing Duct Tape residue from Canopy...? From: "MHerder" 70% isopropyl rubbing alchohol has worked for me, and it won't leave an oily residue like Im afraid rubbbing spirits might. Again, try in non visible corner first on your canopy! Worked great for me, and remember only use plexus or similar cleaning agent as approved for that purpose. DO NOT USE PAPER TOWELS AND WINDEX!!!!! -------- One Rivet at a Time! 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