---------------------------------------------------------- Zenith601-List Digest Archive --- Total Messages Posted Tue 10/27/09: 33 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:11 AM - Re: Nose wheel fork failure (Thruster87) 2. 05:22 AM - Re: Nose wheel fork failure/ why not fix problem? (fritz) 3. 05:53 AM - 601 nose gear (meltonoso) 4. 06:01 AM - Re: 601 nose gear (Paul Mulwitz) 5. 06:06 AM - Re: 601 nose gear/ flap actuator (fritz) 6. 06:32 AM - Re: 601 nose gear (mhubel) 7. 06:33 AM - Re: Nose wheel fork failure (Gig Giacona) 8. 06:39 AM - Re: Re: 601 nose gear/ flap actuator (Craig Payne) 9. 07:56 AM - Re: 601 nose gear (KARL POLIFKA) 10. 08:20 AM - Re: Re: 601 nose gear (Paul Mulwitz) 11. 09:42 AM - Re: Re: 601 nose gear (Doug - SportAviation) 12. 10:09 AM - Re: Re: 601 nose gear (Paul Mulwitz) 13. 11:37 AM - Re: Re: 601 nose gear (KARL POLIFKA) 14. 12:15 PM - Re: Re: 601 nose gear (Rick Lindstrom) 15. 12:15 PM - Re: Re: 601 nose gear (Terry Turnquist) 16. 12:23 PM - Re: Re: 601 nose gear (Jim Belcher) 17. 12:26 PM - Re: Re: 601 nose gear (Jim Belcher) 18. 12:51 PM - Re: Re: 601 nose gear (Paul Mulwitz) 19. 02:15 PM - Re: Nose wheel fork failure (Thruster87) 20. 02:40 PM - Re: Nose wheel fork failure (Gig Giacona) 21. 02:42 PM - Re: Re: Nose wheel fork failure () 22. 02:50 PM - Re: Nose wheel fork failure (Gig Giacona) 23. 03:34 PM - Fw: Nose fork failure (Bill Naumuk) 24. 03:53 PM - Re: Re: Nose wheel fork failure (Dave Austin) 25. 04:04 PM - Re: Nose wheel fork failure (chris Sinfield) 26. 04:32 PM - Re: Re: Nose wheel fork failure (Dave Austin) 27. 04:45 PM - (no subject) (Afterfxllc@aol.com) 28. 04:57 PM - Re: Nose wheel fork failure (Thruster87) 29. 07:51 PM - Jabiru USA 3300 engine mount NOT to Specs (Thruster87) 30. 07:51 PM - Re: Re: Nose wheel fork failure (Bryan Martin) 31. 09:24 PM - Re: Jabiru USA 3300 engine mount NOT to Specs (chuck960) 32. 09:33 PM - Re: Jabiru USA 3300 engine mount NOT to Specs (Thruster87) 33. 09:39 PM - Re: Re: Jabiru USA 3300 engine mount NOT to Specs (Craig Payne) ________________________________ Message 1 _____________________________________ Time: 01:11:41 AM PST US Subject: Zenith601-List: Re: Nose wheel fork failure From: "Thruster87" It would be nice to come up with a mod to strengthen the fork to side loading especially for sealed runways which is not as forgiving as grass strips.My confidence in the design of the fork has been dented, and as such would appreciate if anyone else has any ideas for improvements or arguments to leave it as is, considering the number flying.Cheers T87 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269614#269614 ________________________________ Message 2 _____________________________________ Time: 05:22:42 AM PST US From: "fritz" Subject: Zenith601-List: Re: Nose wheel fork failure/ why not fix problem? My question is: If you guys knows that the XL "lands hard on the nose tire", why aren't you veversing your MLG "spring assembly" ????? This was to be a correction for the "heavy nose, landings". Simple fit, remove main landing gear, weld notches closed, reverse gear, make new notches. Fritz ----- Original Message ----- From: "Thruster87" Sent: Tuesday, October 27, 2009 4:11 AM Subject: Zenith601-List: Re: Nose wheel fork failure > > > It would be nice to come up with a mod to strengthen the fork to side > loading especially for sealed runways which is not as forgiving as grass > strips.My confidence in the design of the fork has been dented, and as > such would appreciate if anyone else has any ideas for improvements or > arguments to leave it as is, considering the number flying.Cheers T87 > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=269614#269614 > > > ________________________________ Message 3 _____________________________________ Time: 05:53:50 AM PST US From: "meltonoso" Subject: Zenith601-List: 601 nose gear >From Alan Melton (meltonoso@cox.net). Our airplane likewise landed nose heavy, resulting in excessive wear on the plastic block through which the strut runs, and ultimately warping of the firewall. Our solution, which so far seems to be working very well, is to use no more than half flaps and a 60 knot airspeed on final. The result is much less nose drop on landing. ________________________________ Message 4 _____________________________________ Time: 06:01:14 AM PST US From: Paul Mulwitz Subject: Re: Zenith601-List: 601 nose gear That sounds great for solving the crash-down nose gear problem on landing. However, I wonder what such a high speed with limited flaps does to the landing distance over an obstacle or just the required runway length with or without an obstacle on the landing approach. Paul XL awaiting (STILL) engineering changes At 05:53 AM 10/27/2009, you wrote: > From Alan Melton > (meltonoso@cox.net). Our airplane > likewise landed nose heavy, resulting in excessive wear on the > plastic block through which the strut runs, and ultimately warping > of the firewall. Our solution, which so far seems to be working > very well, is to use no more than half flaps and a 60 knot airspeed > on final. The result is much less nose drop on landing. > > ________________________________ Message 5 _____________________________________ Time: 06:06:33 AM PST US From: "fritz" Subject: Zenith601-List: Re: 601 nose gear/ flap actuator Not sure, but wasn't one of the later updates to use a 2" flap actuator in place of the 4" flap actuator? Fritz do not archive ----- Original Message ----- From: meltonoso To: zenith601-list@matronics.com Sent: Tuesday, October 27, 2009 8:53 AM Subject: Zenith601-List: 601 nose gear From Alan Melton (meltonoso@cox.net). Our airplane likewise landed nose heavy, resulting in excessive wear on the plastic block through which the strut runs, and ultimately warping of the firewall. Our solution, which so far seems to be working very well, is to use no more than half flaps and a 60 knot airspeed on final. The result is much less nose drop on landing. ________________________________ Message 6 _____________________________________ Time: 06:32:20 AM PST US Subject: Zenith601-List: Re: 601 nose gear From: "mhubel" As a lot of 601s are flying with minimal problem, I don't think there will be a major engineering change coming. I did however observe a tendency to land with the nose too low initially. I noted that the trim tab could not trim out all forces on final with full flaps. I did two things. I changed the angle of the stabilizer from zero to 1 degree nose up which is the center of the range in the drawings. Secondly and more significantly, I added a spring on the elevator control cable to compensate for the weight of the elevator. With the trim tab not having to lift the weight of the elevator, it then had enough range to trim with full flaps. This makes it much easier to land with a proper nose high position and reduces the chance you will stress on the nose wheel .. While I don't have carefully measured landing numbers yet, this results is a lot of runway ahead. -------- Mark Hubelbank N708HU CH601XL Jabiru 3300 Rotec TBI 40 carb Sensenich ground adj prop. 28 hr TAF Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269639#269639 ________________________________ Message 7 _____________________________________ Time: 06:33:26 AM PST US Subject: Zenith601-List: Re: Nose wheel fork failure From: "Gig Giacona" Thruster87 wrote: > It would be nice to come up with a mod to strengthen the fork to side loading especially for sealed runways which is not as forgiving as grass strips.My confidence in the design of the fork has been dented, and as such would appreciate if anyone else has any ideas for improvements or arguments to leave it as is, considering the number flying.Cheers T87 I may have missed it in a previous post, but did you have the fork doubler in place? -------- W.R. "Gig" Giacona 601XL Under Construction See my progress at www.peoamerica.net/N601WR Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269640#269640 ________________________________ Message 8 _____________________________________ Time: 06:39:25 AM PST US From: "Craig Payne" Subject: RE: Zenith601-List: Re: 601 nose gear/ flap actuator No, the travel on the old actuator with the exposed microswitches was under 2 inches as I recall. Of course they might have redesigned the arm on the flap torque tube. But I don't think the angle of travel of the flaps changed on the plans. The reason for the new actuator was the cost of the old unit. -- Craig From: owner-zenith601-list-server@matronics.com [mailto:owner-zenith601-list-server@matronics.com] On Behalf Of fritz Sent: Tuesday, October 27, 2009 7:06 AM Subject: Zenith601-List: Re: 601 nose gear/ flap actuator Not sure, but wasn't one of the later updates to use a 2" flap actuator in place of the 4" flap actuator? Fritz do not archive ----- Original Message ----- From: meltonoso Sent: Tuesday, October 27, 2009 8:53 AM Subject: Zenith601-List: 601 nose gear >From Alan Melton (meltonoso@cox.net). Our airplane likewise landed nose heavy, resulting in excessive wear on the plastic block through which the strut runs, and ultimately warping of the firewall. Our solution, which so far seems to be working very well, is to use no more than half flaps and a 60 knot airspeed on final. The result is much less nose drop on landing. href="http://www.matronics.com/Navigator?Zenith601-List">http://www.matronic s.com/Navigator?Zenith601-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c ________________________________ Message 9 _____________________________________ Time: 07:56:17 AM PST US From: "KARL POLIFKA" Subject: Re: Zenith601-List: 601 nose gear It really has little effect, assuming a properly planned approach. We operate off a 3000' runway and I normally turn off halfway down. This isn't a STOL aircraft so I would consider that acceptable performance. Karl ----- Original Message ----- From: Paul Mulwitz To: zenith601-list@matronics.com Sent: Tuesday, October 27, 2009 9:00 AM Subject: Re: Zenith601-List: 601 nose gear That sounds great for solving the crash-down nose gear problem on landing. However, I wonder what such a high speed with limited flaps does to the landing distance over an obstacle or just the required runway length with or without an obstacle on the landing approach. Paul XL awaiting (STILL) engineering changes At 05:53 AM 10/27/2009, you wrote: From Alan Melton (meltonoso@cox.net). Our airplane likewise landed nose heavy, resulting in excessive wear on the plastic block through which the strut runs, and ultimately warping of the firewall. Our solution, which so far seems to be working very well, is to use no more than half flaps and a 60 knot airspeed on final. The result is much less nose drop on landing. ________________________________ Message 10 ____________________________________ Time: 08:20:41 AM PST US From: Paul Mulwitz Subject: Re: Zenith601-List: Re: 601 nose gear I wonder if you and I are on the same planet. The designer of the CH601XL, Chris Heintz, has reduced the maximum takeoff weight as a result of all the problems. He has promised, through his son and president of Zenith Aircraft Company, a series of engineering changes including aileron mass balancing and control system sensitivity adjustment. I don't know how many XLs are actually flying, but all the ones I have personal contact or knowledge of are gounded. This includes my own XL, another one based in my local area, and the two XLs in California that were in commercial service before the NTSB letter was issued. I know there are a few flying, but only the most aggressive owners are still flying in the face of acknowledged design flaws. Whether this is 10 or 20 or 100 XLs still not grounded I cannot determine. If you have some accurate statistics on how many are still flying please let me know. In particular, I would like to know if any of the XLs in commercial service are available now. These are the ones a potential XL pilot could get dual time in to prepare for their own plane's first flight. Paul XL awaiting engineering changes At 06:32 AM 10/27/2009, you wrote: >As a lot of 601s are flying with minimal problem, I don't think >there will be a major engineering change coming. ________________________________ Message 11 ____________________________________ Time: 09:42:45 AM PST US From: "Doug - SportAviation" Subject: RE: Zenith601-List: Re: 601 nose gear Paul, certainly you and I aren't on the same sheet of music. You're certainly entitled to believe anything you want, but your characterization of a grounded fleet doesn't stack up to my experience. Not even a little. I continue to fly mine. And, while I've inspected it more aggressively and continually, I use the airplane often. I've had no problems, nor have I had any indications of potential problems. I'm approaching 500 hrs on the airplane. And, even though an AMD airplane, I know every rivet and bolt on it (I suppose I could say this was a good outcome from this brouhaha). This past weekend I flew down to an airport with cheap fuel. While there, two other 601XLs came in for the same reason. We had a nice gab session, looked over each others' airplanes, and then went our separate ways. It was delightful. And, this is typical -with different owners at different airports. Now, as to commercial use, that's a different story. The reduced weight renders the airplane useless for dual (unless one gives lessons of 1/2 hour or less). Besides, given the current "confused" state, one must acknowledge to anyone who wants to fly what outstanding issues there are. How many want to fly in the airplane now? The airplane has been rendered useless as a rental. No dual + no rental = no commercial use (I guess I could tow gliders). Are these justified alarms? Yet another discussion. But, CH reduced the weight and performance numbers NOT because of "acknowledged design flaws," but because of the hysteria and hand-wringing; and the need to come to a workable understanding with the FAA to PREVENT the grounding of the fleet. There will be a series of engineering changes coming (soon, I understand) which will allow those who perform them to bring the performance numbers back to where they were (and, to my thinking where they should be today). There may not be a mass-balanced aileron in the mix (as it's not required); but I can't say for sure. It wasn't in the set of things which were discussed with me. Of course, I don't see the lack of mass-balanced ailerons as an issue since the only uncontested facts on the table come from the German engineering study; and we know what that showed. Assuming, for argument, there are no aileron changes and you choose to alter your airplane's design to include LAA-type mass-balanced ailerons, you'll be explicitly going against the designer's design. That would be an interesting choice. Me? I'll make whatever changes CH states should be made to bring the performance numbers back up. After all, I own an SLSA. It's not a choice for me. If I didn't have to make changes, would I? Probably not. Ask yourself this question: what other LSA has had this level of scrutiny and actual testing? Careful not to look to the LAA activities as justification. Much of the posturing and requirements seem to be a self-reinforcing, positive feeedback phenomenon. I sincerely hope you're able to complete and fly your airplane someday. I hope you're not too angry with yourself for all the time you've lost. All the best, Doug Norman N601DN -----Original Message----- From: owner-zenith601-list-server@matronics.com [mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Paul Mulwitz Sent: Tuesday, October 27, 2009 11:20 AM Subject: Re: Zenith601-List: Re: 601 nose gear I wonder if you and I are on the same planet. The designer of the CH601XL, Chris Heintz, has reduced the maximum takeoff weight as a result of all the problems. He has promised, through his son and president of Zenith Aircraft Company, a series of engineering changes including aileron mass balancing and control system sensitivity adjustment. I don't know how many XLs are actually flying, but all the ones I have personal contact or knowledge of are gounded. This includes my own XL, another one based in my local area, and the two XLs in California that were in commercial service before the NTSB letter was issued. I know there are a few flying, but only the most aggressive owners are still flying in the face of acknowledged design flaws. Whether this is 10 or 20 or 100 XLs still not grounded I cannot determine. If you have some accurate statistics on how many are still flying please let me know. In particular, I would like to know if any of the XLs in commercial service are available now. These are the ones a potential XL pilot could get dual time in to prepare for their own plane's first flight. Paul XL awaiting engineering changes At 06:32 AM 10/27/2009, you wrote: >As a lot of 601s are flying with minimal problem, I don't think >there will be a major engineering change coming. ________________________________ Message 12 ____________________________________ Time: 10:09:15 AM PST US From: Paul Mulwitz Subject: RE: Zenith601-List: Re: 601 nose gear Hi Doug, Thank you for your reasoned and reasonable post on the XL issues. I agree with virtually all you said - at least on the level of fact vs. fiction. I am happy for you. You have chosen to fly your plane, and I support you in the freedom to make that choice. I know there are lots of folks who have made the other decision and I support them on their choices too. There are no guarantees in this world, and we all need to decide for ourselves how much risk we want to live with. Zero risk is not a possibility in real life. The only differences between your situation and mine are the builder of the plane (me vs. AMD) and the final decision on how to deal with the vague questions and equally vague answers available today. I am not concerned with my "Loss of time" with my XL. I never had a specific schedule for completion and flight of my plane. The only issue in my mind is whether or not I will ever get to fly it. I am comfortable with the current situation (although getting a bit impatient) and I can live with either outcome. I have already started building my next plane. It is a scratch build project on a Wittman Buttercup. Its performance is very similar to the Zodiac XL (as you might expect with a maximum LSA) but there are no kits available. I need to weld up a fuselage from steel tubes and complete the plane with fabric and much the same sort of instruments and controls as the Zodiac. If I reach the point where I need avionics, engine, and other stuff that can be moved from the Zodiac to the Buttercup then I will decide whether to do that or buy new stuff. That decision is probably many years away. I hope I live that long. I also have another plane to fly whenever I want. It is a Tecnam Echo Super Deluxe that I leased last Spring for one year. I had hoped this would be long enough to get past the Zodiac engineering impasse but now I am not sure. If necessary I can obtain another plane or take some other steps to have something available for my flying. Just because I have completed a Zodiac doesn't mean I have to ground myself because I grounded the Zodiac. I wish you the best of luck in your flying and other endeavors. Paul XL awaiting engineering changes. At 09:33 AM 10/27/2009, you wrote: >Paul, certainly you and I aren't on the same sheet of music. You're >certainly entitled to believe anything you want, but your characterization >of a grounded fleet doesn't stack up to my experience. Not even a little. > >I continue to fly mine. And, while I've inspected it more aggressively and >continually, I use the airplane often. I've had no problems, nor have I had >any indications of potential problems. I'm approaching 500 hrs on the >airplane. And, even though an AMD airplane, I know every rivet and bolt on >it (I suppose I could say this was a good outcome from this brouhaha). > >This past weekend I flew down to an airport with cheap fuel. While there, >two other 601XLs came in for the same reason. We had a nice gab session, >looked over each others' airplanes, and then went our separate ways. It was >delightful. And, this is typical -with different owners at different >airports. > >Now, as to commercial use, that's a different story. The reduced weight >renders the airplane useless for dual (unless one gives lessons of 1/2 hour >or less). Besides, given the current "confused" state, one must acknowledge >to anyone who wants to fly what outstanding issues there are. How many want >to fly in the airplane now? The airplane has been rendered useless as a >rental. No dual + no rental = no commercial use (I guess I could tow >gliders). > >Are these justified alarms? Yet another discussion. But, CH reduced the >weight and performance numbers NOT because of "acknowledged design flaws," >but because of the hysteria and hand-wringing; and the need to come to a >workable understanding with the FAA to PREVENT the grounding of the fleet. > >There will be a series of engineering changes coming (soon, I understand) >which will allow those who perform them to bring the performance numbers >back to where they were (and, to my thinking where they should be today). >There may not be a mass-balanced aileron in the mix (as it's not required); >but I can't say for sure. It wasn't in the set of things which were >discussed with me. Of course, I don't see the lack of mass-balanced ailerons >as an issue since the only uncontested facts on the table come from the >German engineering study; and we know what that showed. Assuming, for >argument, there are no aileron changes and you choose to alter your >airplane's design to include LAA-type mass-balanced ailerons, you'll be >explicitly going against the designer's design. That would be an interesting >choice. Me? I'll make whatever changes CH states should be made to bring the >performance numbers back up. After all, I own an SLSA. It's not a choice for >me. If I didn't have to make changes, would I? Probably not. > >Ask yourself this question: what other LSA has had this level of scrutiny >and actual testing? Careful not to look to the LAA activities as >justification. Much of the posturing and requirements seem to be a >self-reinforcing, positive feeedback phenomenon. > >I sincerely hope you're able to complete and fly your airplane someday. I >hope you're not too angry with yourself for all the time you've lost. > >All the best, >Doug Norman >N601DN ________________________________ Message 13 ____________________________________ Time: 11:37:24 AM PST US From: "KARL POLIFKA" Subject: Re: Zenith601-List: Re: 601 nose gear Paul, This is pretty silly. There appear to be very few who share your opinions and I would suspect, but do not know, that very few have stopped flying the XL because of an overinflated one-size-fits-all report that was, rightfully, ignored by the FAA. The verbiage in that NTSB report was, itself, highly suspect (observers on the ground seeing aileron flutter in an aircraft at pattern altitude, and so forth. What nonsense). Every airplane has design characteristics that any competent pilot needs to learn and work around to fly any airplane successfully -- and correctly. The adverse yaw characteristics of the F-4 are an example -- potentially fatal if ignored, so you don't ignore than design aspect. I have seen far too many posts on this forum from people who deliberately exceed various design limits. That is flat dumb. The pilot adapts to the airplane, not the other way around. If adaptation is not feasible, then it is a bad airplane. The XL is not a bad airplane. I would suspect that most or all of the Zenith changes in aircraft limitations are inspired by lawyers, not engineers. There are things you simply should not do with this design. The nose whack-down phenomena is an example. Yes, it is a design weakness -- so you work around it. You, BTW, don't let the nose touch down in a cocked position -- something which should be pretty obvious. That is not a design weakness, per se, it's a pilot weakness. Our airplane flies just fine. We have had no problems, other than those I have previously noted. We have always flown within limits, including the original design limits. It is probably possible to do Mach 1 in the XL -- after you rip the wings off in a 90 degree full power dive from 10 grand. There won't be much left, but it is not a design flaw. Maybe you should sell your kit as is and move on to something else. Karl ----- Original Message ----- From: Paul Mulwitz To: zenith601-list@matronics.com Sent: Tuesday, October 27, 2009 11:19 AM Subject: Re: Zenith601-List: Re: 601 nose gear I wonder if you and I are on the same planet. The designer of the CH601XL, Chris Heintz, has reduced the maximum takeoff weight as a result of all the problems. He has promised, through his son and president of Zenith Aircraft Company, a series of engineering changes including aileron mass balancing and control system sensitivity adjustment. I don't know how many XLs are actually flying, but all the ones I have personal contact or knowledge of are gounded. This includes my own XL, another one based in my local area, and the two XLs in California that were in commercial service before the NTSB letter was issued. I know there are a few flying, but only the most aggressive owners are still flying in the face of acknowledged design flaws. Whether this is 10 or 20 or 100 XLs still not grounded I cannot determine. If you have some accurate statistics on how many are still flying please let me know. In particular, I would like to know if any of the XLs in commercial service are available now. These are the ones a potential XL pilot could get dual time in to prepare for their own plane's first flight. Paul XL awaiting engineering changes At 06:32 AM 10/27/2009, you wrote: >As a lot of 601s are flying with minimal problem, I don't think >there will be a major engineering change coming. ________________________________ Message 14 ____________________________________ Time: 12:15:10 PM PST US From: Rick Lindstrom Subject: Re: Zenith601-List: Re: 601 nose gear I agree, Karl. Paul's choice of verbiage "...crash-down nose gear problem on landing" is unfortunate, and inaccurate as well. (Sometimes I think he chooses his words just to raise my blood pressure!) But you have to remember that he's yet to fly his 601XL, so his supporting data is not coming from personal experience. Yes, the nose wheel comes down immediately after the mains plant in a full stall landing with full flaps, especially if you have a heavier engine and have placed the main gear aft instead of forward on the gear legs (which I have). The airplane really wants to keep flying, all the way down to about 45 mph, so when the wing finally runs out of lift, there's not much air going across the elevator to help keep the nose up. This is great for STOL performance and short strips, but we usually don't need to operate at this end of the flight envelope on a regular basis unless we have a REALLY short runway. Personally, I keep a bit of power in all the way down final to touchdown, thereby reducing the sink rate. I'll still make the first turn-off, even with a bit more airspeed on final and partial flaps. Pulling power ALL the way off, deploying full flaps, and holding the airplane off of the runway to the bitter end WILL result in a firm arrival. But as you've correctly pointed out, this can be addressed in a variety of ways, all involving landing technique. Rick Lindstrom ZenVair N42KP -----Original Message----- >From: KARL POLIFKA >Sent: Oct 27, 2009 1:35 PM >To: zenith601-list@matronics.com >Subject: Re: Zenith601-List: Re: 601 nose gear > >Paul, > >This is pretty silly. > >There appear to be very few who share your opinions and I would suspect, but do not know, that very few have stopped flying the XL because of an overinflated one-size-fits-all report that was, rightfully, ignored by the FAA. The verbiage in that NTSB report was, itself, highly suspect (observers on the ground seeing aileron flutter in an aircraft at pattern altitude, and so forth. What nonsense). > >Every airplane has design characteristics that any competent pilot needs to learn and work around to fly any airplane successfully -- and correctly. The adverse yaw characteristics of the F-4 are an example -- potentially fatal if ignored, so you don't ignore than design aspect. I have seen far too many posts on this forum from people who deliberately exceed various design limits. That is flat dumb. The pilot adapts to the airplane, not the other way around. If adaptation is not feasible, then it is a bad airplane. The XL is not a bad airplane. > >I would suspect that most or all of the Zenith changes in aircraft limitations are inspired by lawyers, not engineers. There are things you simply should not do with this design. The nose whack-down phenomena is an example. Yes, it is a design weakness -- so you work around it. You, BTW, don't let the nose touch down in a cocked position -- something which should be pretty obvious. That is not a design weakness, per se, it's a pilot weakness. > >Our airplane flies just fine. We have had no problems, other than those I have previously noted. We have always flown within limits, including the original design limits. It is probably possible to do Mach 1 in the XL -- after you rip the wings off in a 90 degree full power dive from 10 grand. There won't be much left, but it is not a design flaw. > >Maybe you should sell your kit as is and move on to something else. > >Karl > > > ----- Original Message ----- > From: Paul Mulwitz > To: zenith601-list@matronics.com > Sent: Tuesday, October 27, 2009 11:19 AM > Subject: Re: Zenith601-List: Re: 601 nose gear > > > > I wonder if you and I are on the same planet. > > The designer of the CH601XL, Chris Heintz, has reduced the maximum > takeoff weight as a result of all the problems. He has promised, > through his son and president of Zenith Aircraft Company, a series of > engineering changes including aileron mass balancing and control > system sensitivity adjustment. > > I don't know how many XLs are actually flying, but all the ones I > have personal contact or knowledge of are gounded. This includes my > own XL, another one based in my local area, and the two XLs in > California that were in commercial service before the NTSB letter was > issued. I know there are a few flying, but only the most aggressive > owners are still flying in the face of acknowledged design > flaws. Whether this is 10 or 20 or 100 XLs still not grounded I > cannot determine. If you have some accurate statistics on how many > are still flying please let me know. In particular, I would like to > know if any of the XLs in commercial service are available > now. These are the ones a potential XL pilot could get dual time in > to prepare for their own plane's first flight. > > Paul > XL awaiting engineering changes > > > > ________________________________ Message 15 ____________________________________ Time: 12:15:49 PM PST US From: Terry Turnquist Subject: Re: Zenith601-List: Re: 601 nose gear Gentlemen, let's look at this from strictly a pragmatic viewpoint. All one has to do in the aviation community is mention the 601XL and you'll get a raised eyebrow or an expression of condolences. Whether or not this is justified is strictly a matter of opinion at this point. However, the fact is that the airplane has an undesirable reputation which is not doing any of us any good. When CH releases a "fix" for the perceived problem I intend to make those changes so as to help salvage what will otherwise be a very unhappy financial outcome not to mention years of labor. Then if someone mentions it again I can say "That problems been fixed". Hopefully at some point the bad reputation will be forgotten. Best wishes Terry ________________________________ From: KARL POLIFKA Sent: Tue, October 27, 2009 12:35:33 PM Subject: Re: Zenith601-List: Re: 601 nose gear Paul, This is pretty silly. There appear to be very few who share your opinions and I would suspect, but do not know, that very few have stopped flying the XL because of an overinflated one-size-fits-all report that was, rightfully, ignored by the FAA. The verbiage in that NTSB report was, itself, highly suspect (observers on the ground seeing aileron flutter in an aircraft at pattern altitude, and so forth. What nonsense). Every airplane has design characteristics that any competent pilot needs to learn and work around to fly any airplane successfully -- and correctly. The adverse yaw characteristics of the F-4 are an example -- potentially fatal if ignored, so you don't ignore than design aspect. I have seen far too many posts on this forum from people who deliberately exceed various design limits. That is flat dumb. The pilot adapts to the airplane, not the other way around. If adaptation is not feasible, then it is a bad airplane. The XL is not a bad airplane. I would suspect that most or all of the Zenith changes in aircraft limitations are inspired by lawyers, not engineers. There are things you simply should not do with this design. The nose whack-down phenomena is an example. Yes, it is a design weakness -- so you work around it. You, BTW, don't let the nose touch down in a cocked position -- something which should be pretty obvious. That is not a design weakness, per se, it's a pilot weakness. Our airplane flies just fine. We have had no problems, other than those I have previously noted. We have always flown within limits, including the original design limits. It is probably possible to do Mach 1 in the XL -- after you rip the wings off in a 90 degree full power dive from 10 grand. There won't be much left, but it is not a design flaw. Maybe you should sell your kit as is and move on to something else. Karl ----- Original Message ----- >From: Paul Mulwitz >To: zenith601-list@matronics.com >Sent: Tuesday, October 27, 2009 11:19 > AM >Subject: Re: Zenith601-List: Re: 601 nose > gear > > >I wonder if you and I are > on the same planet. > >The designer of the CH601XL, Chris Heintz, has > reduced the maximum >takeoff weight as a result of all the problems. > He has promised, >through his son and president of Zenith Aircraft Company, > a series of >engineering changes including aileron mass balancing and > control >system sensitivity adjustment. > >I don't know how many XLs > are actually flying, but all the ones I >have personal contact or knowledge > of are gounded. This includes my >own XL, another one based in my > local area, and the two XLs in >California that were in commercial service > before the NTSB letter was >issued. I know there are a few flying, > but only the most aggressive >owners are still flying in the face of > acknowledged design >flaws. Whether this is 10 or 20 or 100 XLs still > not grounded I >cannot determine. If you have some accurate > statistics on how many >are still flying please let me know. In > particular, I would like to >know if any of the XLs in commercial service > are available >now. These are the ones a potential XL pilot could get > dual time in >to prepare for their own plane's first > flight. > >Paul >XL awaiting engineering changes > > >At 06:32 AM > 10/27/2009, you wrote: >>As a lot of 601s are flying with minimal > problem, I don't think >>there will be a major engineering change > nbsp; >Features >Chat, > http://www.matnbsp; >via the Web > href="http://forums.matronics.com">http://forums.matronics.com >_p; >generous > bsp; > href="http://www.matronics.com/contribution">http://www.matronics.com/c================ > > ________________________________ Message 16 ____________________________________ Time: 12:23:15 PM PST US From: Jim Belcher Subject: Re: Zenith601-List: Re: 601 nose gear On Tuesday 27 October 2009 12:35, KARL POLIFKA wrote: > Paul, > > This is pretty silly. > > There appear to be very few who share your opinions and I would suspect, > but do not know, that very few have stopped flying the XL because of an > overinflated one-size-fits-all report that was, rightfully, ignored by the > FAA. The verbiage in that NTSB report was, itself, highly suspect > (observers on the ground seeing aileron flutter in an aircraft at pattern > altitude, and so forth. What nonsense). I agree. Paul has the distinction of being the only person on this list whose posts hit a filter in my local server, and go straight to the trash. The only way I see them is if someone replies to them, and quotes them in the reply. I probably should not say that, but this whole theme of some mysterious problem that requires we all ground our aircraft appears to be misinformed, and I for one don't care to see further posts on the subject. The simplest way is to filter out anyone who continually harps on that theme. Paul, or anyone else, is free to filter me in a similar manner. If Zenith knew of a problem, I think we would have seen the fix long ago. We might see something so that it can be said a fix was offered to allow the performance quoted to be returned to the previously quoted numbers, but I seriously doubt (personal opinion again) it actually corrects anything. My 25 cents worth, with the usual reminder that 25 cents won't buy what it once would. -- ============================================ Do not archive. ============================================ Jim B Belcher BS, MS Physics, Math, Computer Science A&P/IA Retired aerospace technical manager Mathematics and alcohol do not mix. Do not drink and derive. ============================================ ________________________________ Message 17 ____________________________________ Time: 12:26:04 PM PST US From: Jim Belcher Subject: Re: Zenith601-List: Re: 601 nose gear On Tuesday 27 October 2009 14:15, Terry Turnquist wrote: > > Gentlemen, let's look at this from strictly a pragmatic viewpoint. All one > has to do in the aviation community is mention the 601XL and you'll get a > raised eyebrow or an expression of condolences. Whether or not this is > justified is strictly a matter of opinion at this point. However, the fact > is that the airplane has an undesirable reputation which is not doing any > of us any good. When CH releases a "fix" for the perceived problem I intend > to make those changes so as to help salvage what will otherwise be a very > unhappy financial outcome not to mention years of labor. Then if someone > mentions it again I can say "That problems been fixed". Hopefully at some > point the bad reputation will be forgotten. Terry, when I started flying, the Globe Swift had a really bad reputation, and sold very cheaply. This was due to the early Swifts being underpowered (85hp) and having accidents as a result. But that problem has been gone for years, people have forgotten about it, and Swifts sell at a premium. I'm not convinced there is anything wrong with the XL design. But once the accident reports stop for a while, whatever the cause, I think people forget there was ever supposed to vbe a problem, and things will go back to normal. ============================================ Do not archive. ============================================ Jim B Belcher BS, MS Physics, Math, Computer Science A&P/IA Retired aerospace technical manager Mathematics and alcohol do not mix. Do not drink and derive. ============================================ ________________________________ Message 18 ____________________________________ Time: 12:51:19 PM PST US From: Paul Mulwitz Subject: Re: Zenith601-List: Re: 601 nose gear Hi Karl, I don't know where people like you get the idea I have a Zodiac XL kit. I used up my last kit part around two years ago. My plane is complete and nearly ready for certification. It has been registered for around a year. I did remove the wings last Spring to make room for a flying plane in my hangar. I don't think anyone has exact numbers of XLs that are currently grounded vs. those that are flying. We all have anecdotal information. To assume that the rest of the world has made the same decision as I or you have is just egotistical nonsense. If indeed you want me to sell my plane to you then please make an offer. Any offer under $50,000 will not be considered since that is the value of brand new engine, avionics and other stuff in my plane. Paul XL awaiting engineering changes. At 10:35 AM 10/27/2009, you wrote: >Maybe you should sell your kit as is and move on to something else. > ________________________________ Message 19 ____________________________________ Time: 02:15:58 PM PST US Subject: Zenith601-List: Re: Nose wheel fork failure From: "Thruster87" Gig Giacona wrote: > > Thruster87 wrote: > > It would be nice to come up with a mod to strengthen the fork to side loading especially for sealed runways which is not as forgiving as grass strips.My confidence in the design of the fork has been dented, and as such would appreciate if anyone else has any ideas for improvements or arguments to leave it as is, considering the number flying.Cheers T87 > > > I may have missed it in a previous post, but did you have the fork doubler in place? Hi Gig, Yes the gear was reversed and the doubler was installed.I'm now wondering if the lower bearing mod which allows smoother rotation [less friction] may have contributed?? Is the high friction an issue during flight?? I'll now properly go back to specs Cheers T87 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269710#269710 ________________________________ Message 20 ____________________________________ Time: 02:40:36 PM PST US Subject: Zenith601-List: Re: Nose wheel fork failure From: "Gig Giacona" Was the wheel bent to the left by any chance? The reason I asked is that I've seen two fast taxi accidents in my 30 years of flying where pilots tried to "hit the brakes" buy slamming down on the left rudder. -------- W.R. "Gig" Giacona 601XL Under Construction See my progress at www.peoamerica.net/N601WR Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269716#269716 ________________________________ Message 21 ____________________________________ Time: 02:42:28 PM PST US From: Subject: Re: Zenith601-List: Re: Nose wheel fork failure Gig, how about using a T-shaped outer piece? The stem of the T wouldn't need to be more than 3/4" or create too much drag, but it ought to greatly stiffen the fork to side loads. Naturally, it would need to be tapered and ground off just above the axle bolt. Paul R (Nose gear? We don' need no esteenkin' nose gear!) ----- Original Message ----- From: Thruster87 To: zenith601-list@matronics.com Sent: Tuesday, October 27, 2009 4:15 PM Subject: Zenith601-List: Re: Nose wheel fork failure > Gig Giacona wrote: > > Thruster87 wrote: > > It would be nice to come up with a mod to strengthen the fork to side loading especially for sealed runways which is not as forgiving as grass strips.My confidence in the design of the fork has been dented, and as such would appreciate if anyone else has any ideas for improvements or arguments to leave it as is, considering the number flying.Cheers T87 > > > I may have missed it in a previous post, but did you have the fork doubler in place? Hi Gig, Yes the gear was reversed and the doubler was installed.I'm now wondering if the lower bearing mod which allows smoother rotation [less friction] may have contributed?? Is the high friction an issue during flight?? I'll now properly go back to specs Cheers T87 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269710#269710 http://www.matronics.com/Navigator?Zenith601-List http://www.matronics.com/contribution ________________________________ Message 22 ____________________________________ Time: 02:50:49 PM PST US Subject: Zenith601-List: Re: Nose wheel fork failure From: "Gig Giacona" paulrod36(at)msn.com wrote: > Gig, how about using a T-shaped outer piece? The stem of the T wouldn't need to be more than 3/4" or create too much drag, but it ought to greatly stiffen the fork to side loads. Naturally, it would need to be tapered and ground off just above the axle bolt. > > Paul R (Nose gear? We don' need no esteenkin' nose gear!) > Don't ask me about redesign issues. I don't know nothin' about design. -------- W.R. "Gig" Giacona 601XL Under Construction See my progress at www.peoamerica.net/N601WR Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269721#269721 ________________________________ Message 23 ____________________________________ Time: 03:34:38 PM PST US From: "Bill Naumuk" Subject: Zenith601-List: Fw: Nose fork failure ----- Original Message ----- From: Bill Naumuk Sent: Tuesday, October 27, 2009 6:33 PM Subject: Nose fork failure All- Before you even think of mods to the Zenith nose fork, look at the Sherman tanks of the industry. Students have been beating the shit out of C-150s and C-172s for fifty years and their nose gear rarely falls off. What's the big difference? do not archive Bill Naumuk Townville, Pa. HDS N601MG/Corvair 95% ________________________________ Message 24 ____________________________________ Time: 03:53:56 PM PST US From: "Dave Austin" Subject: Re: Zenith601-List: Re: Nose wheel fork failure I cannot help wondering what piece of the a/c would have failed if the forks had not given way? Would the leg have bent, or been torn from he firewall? How many 601s have bent the fork from the hundreds flying today? Think about it, folks. Chris knows what he is doing. Dave Austin 601HDS - 912 ________________________________ Message 25 ____________________________________ Time: 04:04:58 PM PST US Subject: Zenith601-List: Re: Nose wheel fork failure From: "chris Sinfield" Dave Chris knows what he is doing. ?? Maybe Chris H knows what he is doing? My wife often says I don't know what I am doing.. But I am Chris S.. Its morning here Down Under Chris S. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269739#269739 ________________________________ Message 26 ____________________________________ Time: 04:32:34 PM PST US From: "Dave Austin" Subject: Re: Zenith601-List: Re: Nose wheel fork failure G'Day Chris, Pom here in Canada. My 1993 601 (not me) bent the fork rather quickly, so I fitted the doubler. But by then I'd managed to learn to keep the nosewheel off the ground until just enough elevator influence is left to lower it to the runway with NO brakes on. I was glad the fork had bent. Good lesson. Dave Austin 601HDS - 912 ________________________________ Message 27 ____________________________________ Time: 04:45:08 PM PST US From: Afterfxllc@aol.com Subject: Zenith601-List: (no subject) _http://www.youtube.com/watch?v=Ocq2UBkyzFI_ (http://www.youtube.com/watch?v=Ocq2UBkyzFI) ________________________________ Message 28 ____________________________________ Time: 04:57:33 PM PST US Subject: Zenith601-List: Re: Nose wheel fork failure From: "Thruster87" Gig Giacona wrote: > Was the wheel bent to the left by any chance? > > The reason I asked is that I've seen two fast taxi accidents in my 30 years of flying where pilots tried to "hit the brakes" buy slamming down on the left rudder. To the right,it bent from the radius at the top.Left hand side of fork rubbing the ground and the right side bent up towards the nose leg.The nose leg held on very well and it bent about 5 deg 250mm up from the base,base plate twisted about 5mm and the brunt was taken by the structure aft of the lower bearing support.Cheers T87 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269749#269749 ________________________________ Message 29 ____________________________________ Time: 07:51:07 PM PST US Subject: Zenith601-List: Jabiru USA 3300 engine mount NOT to Specs From: "Thruster87" Started the repair on the bent/cracked engine mount and during the straightening process it broke off at the lower mid point at the intersection of tubes 7 & 6.On measuring the wall thickness it came to 0.035" and the drawings called for 0.058" [6-JE-1] This is now the second engine mount supplied with the use of incorrect thickness tubing/plates.What is happening to quality control?????? Jab USA has to get rid of the person welding these mounts.Lucky or unlucky as the case may be, if it wasn't for the nose wheel collapse the bloody engine might have fallen off.Cheers T87 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269775#269775 ________________________________ Message 30 ____________________________________ Time: 07:51:29 PM PST US Subject: Re: Zenith601-List: Re: Nose wheel fork failure From: Bryan Martin Just remember to set the rudder cable tension with no weight on the nose wheel. Because the strut angles backwards at the top, tension on the rudder cables is reduced when the strut is compressed under load. > > > > Hi Gig, Yes the gear was reversed and the doubler was installed.I'm > now wondering if the lower bearing mod which allows smoother > rotation [less friction] may have contributed?? Is the high friction > an issue during flight?? I'll now properly go back to specs Cheers T87 > -- Bryan Martin N61BM, CH 601 XL, RAM Subaru, Stratus redrive. do not archive. ________________________________ Message 31 ____________________________________ Time: 09:24:14 PM PST US Subject: Zenith601-List: Re: Jabiru USA 3300 engine mount NOT to Specs From: "chuck960" How are they (Jab USA) about replacing factory defective parts? Chuck Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269787#269787 ________________________________ Message 32 ____________________________________ Time: 09:33:26 PM PST US Subject: Zenith601-List: Re: Jabiru USA 3300 engine mount NOT to Specs From: "Thruster87" chuck960 wrote: > How are they (Jab USA) about replacing factory defective parts? > Chuck The first one no problem, waiting a response for the second Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269788#269788 ________________________________ Message 33 ____________________________________ Time: 09:39:54 PM PST US From: "Craig Payne" Subject: RE: Zenith601-List: Re: Jabiru USA 3300 engine mount NOT to Specs My 3300 motor mount placed the engine at the wrong angle. They replaced it. I received an oil cooler with the threads pre-striped. They replaced that too. -- Craig -----Original Message----- From: owner-zenith601-list-server@matronics.com [mailto:owner-zenith601-list-server@matronics.com] On Behalf Of chuck960 Sent: Tuesday, October 27, 2009 10:24 PM Subject: Zenith601-List: Re: Jabiru USA 3300 engine mount NOT to Specs How are they (Jab USA) about replacing factory defective parts? Chuck Read this topic online here: http://forums.matronics.com/viewtopic.php?p=269787#269787 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message zenith601-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Zenith601-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/zenith601-list Browse Digests http://www.matronics.com/digest/zenith601-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.