---------------------------------------------------------- Zenith601-List Digest Archive --- Total Messages Posted Sat 10/31/09: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:52 AM - Re: rear spar reinforcement (Jim Belcher) 2. 07:11 AM - Re: Additional NTSB Documents (Sabrina) 3. 09:01 AM - Re: Additional NTSB Documents (dougsire) 4. 09:17 AM - Re: Re: Additional NTSB Documents (Paul Mulwitz) 5. 09:54 AM - XL rear spar (jaybannist@cs.com) 6. 10:43 AM - Re: XL rear spar (Terry Turnquist) 7. 10:49 AM - Re: XL rear spar (Jim Belcher) 8. 11:25 AM - Re: Additional NTSB Documents (Sabrina) 9. 11:42 AM - Re: XL rear spar (jaybannist@cs.com) 10. 12:23 PM - Re: XL rear spar (Jim Belcher) 11. 02:52 PM - Re: 601 nose gear (Thruster87) 12. 03:26 PM - Complete 601XL kit for sale. (Walter Carey) 13. 03:55 PM - Re: Re: 601 nose gear (Greg Cox) 14. 04:10 PM - Re: 601 nose gear (Ron Lendon) 15. 07:50 PM - Re: 601 nose gear (Thruster87) ________________________________ Message 1 _____________________________________ Time: 06:52:48 AM PST US From: Jim Belcher Subject: Re: Zenith601-List: rear spar reinforcement I find this a much more logical thing to do than any of the things espoused by the LAA. It actually fixes something that might be a problem (I think it is a problem, but that's an opinion, and should be considered such). On Friday 30 October 2009 18:11, paul baker wrote: > After looking at the pictures of the wing failures, I am glad > I made a simple reinforcement of the rear spar where the > pushrod goes through the spar.The hole is rather large and > is very close to the bottom spar cap. I have flown 100 hrs > so far this year and I always fly within the limitations of the > airplane. After 61 years of flying I find It is best to read the > book and do what it says.You can find the attachment at > > http:/members.cox.net/n601ge/drawings/rearspar.html > > It is well written and very easy to do. > > paul baker cfi -- ============================================ 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 2 _____________________________________ Time: 07:11:01 AM PST US Subject: Zenith601-List: Re: Additional NTSB Documents From: "Sabrina" Looking back on it, an easy fix would be to purchase flap hinges that are about a foot longer than the flaps, using the forward portion of the outboard last foot of the flap hinge to reinforce the lower rear spar cap, discarding the aft portion of this new flap hinge extension. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=270221#270221 ________________________________ Message 3 _____________________________________ Time: 09:01:03 AM PST US Subject: Zenith601-List: Re: Additional NTSB Documents From: "dougsire" I think the real question to be answered here is not where the compression buckling occurred, but rather why did it occur. What physical force caused this damage? Personally I think this area is in need of strengthening and some of the suggestions are very good. After seeing these photos for the first time a couple of weeks ago I had the same thought as Sabrina regarding extending both the spar side of the aileron and flap hinge so they overlap. But the compression buckling alone did not bring these aircraft down; it is just the result, or signature, of some other force. I would say that the damage either had to have been present on the ground before the aircraft took off and the pilot did not notice it (not likely), or it occurred during flight, or it occurred as it hit the ground or water. Take a closer look at the damage to the left wing in the photos of the Markermeer (Dutch) accident (pgs 2-5). In this accident, the right wing folded over the aircraft, and the left wing was relatively straight. Could this damage have occurred as it hit the water? You can see from the damage to the leading edge D cell which is crushed that it took the bulk of the impact energy, so it likely hit somewhat parallel to the water. The skin on both the top and bottom of the wing is indented outward at the damage spots. Conceivably if the wing had hit the earth at the wing tip just right, it might have caused this type of buckling, but that clearly did not happen. Maybe if the wing hit the water primarily at the outboard end of the leading edge, that would have bent the outboard end of the rear spar back some and caused it. However, if it did that, we would expect to see the aileron angled back and hitting the flap. The photo at the bottom of page 4 shows that not to be the case. There is a consistent gap between the aileron and flap. So what might be the most plausible explanation? Well, since it is well documented that flutter can occur in unbalanced ailerons, and that it could easily cause an upward and downward motion of the outboard end of the wing which could cause the damage shown (at the weakest spot on the rear spar), I would have to say that flutter is the most likely force which caused the compression damage. And of course since it is also well known that left unchecked, flutter can quickly destroy an aircraft, I dont see any explanation other than flutter as the cause. -------- Doug Sire 601XL Do Not Archive Read this topic online here: http://forums.matronics.com/viewtopic.php?p=270234#270234 ________________________________ Message 4 _____________________________________ Time: 09:17:20 AM PST US From: Paul Mulwitz Subject: Re: Zenith601-List: Re: Additional NTSB Documents Hi Sabrina, I don't get it. Why use a hinge part instead of just cutting some aluminum to reinforce the rear channel? Also, why not reinforce both sides of the rear channel - both the top and bottom? After all, the web has been essentially removed in that area. Perhaps it is the web that should get a doubler rather than the flange. Paul XL Awaiting engineering changes At 07:10 AM 10/31/2009, you wrote: >Looking back on it, an easy fix would be to purchase flap hinges >that are about a foot longer than the flaps, using the forward >portion of the outboard last foot of the flap hinge to reinforce the >lower rear spar cap, discarding the aft portion of this new flap >hinge extension. ________________________________ Message 5 _____________________________________ Time: 09:54:37 AM PST US Subject: Zenith601-List: XL rear spar From: jaybannist@cs.com Let's put this hole in the rear spar in perspective. See attached pdf. Comments?? Jay Bannister ________________________________ Message 6 _____________________________________ Time: 10:43:11 AM PST US From: Terry Turnquist Subject: Re: Zenith601-List: XL rear spar Another approach might be to use .032 instead of .025. Terry Turnquist ________________________________ From: "jaybannist@cs.com" Sent: Sat, October 31, 2009 11:53:56 AM Subject: Zenith601-List: XL rear spar Let's put this hole in the rear spar in perspective. See attached pdf. Comments?? Jay Bannister ________________________________ Message 7 _____________________________________ Time: 10:49:52 AM PST US From: Jim Belcher Subject: Re: Zenith601-List: XL rear spar I realize that castellated beams and truss structures are common in architecture, but I would not personally use either one for a spar. Someone else might. If I remember correctly, a truss uses cross members for bracing, and is trying to make the overall structure stronger. When a hole is cut in a solid piece of metal for an aircraft, I seem to recall that the loads must flow around the hole, and the hole must neither be too big, nor too close to the edge of the material for this to work as intended. If the hole in your spar came out - to scale - no bigger than your sketch, I'm glad for you. It would still be too close to the edge for my comfort. I think my spar hole for aileron pushrod access, when cut to the size shown on the plans, is proportionally bigger. I could probably go dig up the data on hole size vs material width, edge distance, etc, but I'd bet the hole in the Zenith spar (at least on my aircraft) wouldn't meet the criteria. Before my bird flies, I want to take a hard look at this. I'm not about to ground the bird, hoping for engineering changes that may or may not come, but I am going to fix anything I establisdh to my own satisfaction is wrong. Obviously, everybody is entitled to their own view. This is mine. On Saturday 31 October 2009 11:53, jaybannist@cs.com wrote: > Let's put this hole in the rear spar in perspective. See attached pdf. > Comments?? > > Jay Bannister -- ============================================ 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 8 _____________________________________ Time: 11:25:41 AM PST US Subject: Zenith601-List: Re: Additional NTSB Documents From: "Sabrina" I hope the NTSB and FAA realize that much of the fault rests with builders and pilots. I have seen aircraft where the rear spar attach area was mis-cut and patched, I have seen main spars where the bolt holes have been notched and chewed up, and now this UT plane with no primer on bare steel parts, patches over holes in the rear spar that don't completely cover the mis-cut hole. Ouch! The 38mm hole centered 20mm from the lower edge compromises the rear spar. That does not mean that it will fail, just that the designer made compromises. However, when pilots or builders add their own mistakes to design compromises, bad things can happen. We, as a group, should be working on/around these critical design compromises CH has bestowed upon us. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=270250#270250 ________________________________ Message 9 _____________________________________ Time: 11:42:52 AM PST US Subject: Re: Zenith601-List: XL rear spar From: jaybannist@cs.com Jim, I do respect your opinion. I didn't intend to start something, nor to agi tate anyone. I am obviously defending the design, but I am not an aeronaut ical engineer. However, I want to point out that structures answer to the same laws of physics, whether in a bridge, a building or an airplane. The compressive and tensile loads in a beam are primarily carried by the flan ges. The web primarily locates the flanges and resists horizontal shear, which is minimal, as evidenced by the configuration of a bar joist. That is the load you say "must flow around the hole", and it must not be close to the flange to work right. But look at how large the "holes" are and how close to the flange they are in a bar joist. Additionally, the flang es must be stabilized to resist buckling, which in this case is done by th e wing skins; and the way they are fastened, they also contribute to the compressive and tensile strength of the flanges. That is why I am not at all concerned by this hole in the rear spar. And BTW, there are many, many examples of trusses used in aircraft constru ction; especially in fuselages, but also in wing spars. My drawing of the rear spar is to scale - though not the same scale as the beam or the truss. Jay Bannister m> I realize that castellated beams and truss structures are common in architecture, but I would not personally use either one for a spar. Someon e else might. If I remember correctly, a truss uses cross members for bracing, and is tr ying to make the overall structure stronger. When a hole is cut in a solid piec e of metal for an aircraft, I seem to recall that the loads must flow around the hole, and the hole must neither be too big, nor too close to the edge of the material for this to work as intended. If the hole in your spar came out - to scale - no bigger than your sketch, I'm glad for you. It would still be too close to the edge for my comfort. I th ink my spar hole for aileron pushrod access, when cut to the size shown on the plans, is proportionally bigger. I could probably go dig up the data on hole size vs material width, edge distance, etc, but I'd bet the hole in the Zenith spar (at least on my aircraft) wouldn't meet the criteria. Before my bird flies, I want to take a hard look at this. I'm not about to ground the bird, hoping for engineerin g changes that may or may not come, but I am going to fix anything I establi sdh to my own satisfaction is wrong. Obviously, everybody is entitled to their own view. This is mine. ________________________________ Message 10 ____________________________________ Time: 12:23:21 PM PST US From: Jim Belcher Subject: Re: Zenith601-List: XL rear spar On Saturday 31 October 2009 13:39, jaybannist@cs.com wrote: > Jim, > > I do respect your opinion. I didn't intend to start something, nor to > agitate anyone. Jay, I'm neither offended nor agitated. You asked for comments; you got 'em. I feel the design is a compromise at this point, and needs some beef up. I'd love to have Chris Heintz take on this, and possibly his beef up. But barring that information, I intend to do a bit of research, and see what is allowable in this case. I suspect this exceeds the allowable. I seem to remember having some tables somewhere that address this issue. I deeply respect Chris' abilities. But he is human, and not beyond error. A problem I've sometimes seen in one-man designs is that there is no oversight, and no one verifying the design on a step by step basis. Whether that is true here or not, I cannot say. But I wonder. ============================================ 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 11 ____________________________________ Time: 02:52:30 PM PST US Subject: Zenith601-List: Re: 601 nose gear From: "Thruster87" My original nose leg measured 0.080" wall thickness [come with the kit in 10/2007] which bent due to nose fork collapse.Received a new leg and it measures 0.060" wall thickness which corresponds to the drawings specifications on the plans.Does anyone know if there was an up date of the nose leg wall thickness ???? Cheers T87 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=270269#270269 ________________________________ Message 12 ____________________________________ Time: 03:26:01 PM PST US From: Walter Carey Subject: Zenith601-List: Complete 601XL kit for sale. If anyone is interested or knows of someone thinking of buying a 601 kit, t he following is for sale: - Complete 601XL kit, including-aux 12 gal fuel tanks (48 gal total), landi ng/nav/strobe lights, ect. Wings 90 %,-flaps 100%, ailerons 100%, empenna ge 100%, fuselage 25% complete. Built to plans.-Workmanship rated "excell ent" on both EAA Technical Advisor visits, and "excellent" by NAAA (Nationa l Aircraft Appraisers Association)-appraiser in-Jun -09.- - $10,000 firm. Contact Walt Carey at 937-426-8095 or at www.careywf@sbcgloba l.net. Located Dayton, Ohio. ________________________________ Message 13 ____________________________________ Time: 03:55:44 PM PST US From: "Greg Cox" Subject: RE: Zenith601-List: Re: 601 nose gear There is a complete listing of the drawing updates on the ZAC site in builders resources. http://www.zenithair.com?zodiac/xl/xl-up-drawings.html I have attached the last 2 update lists. Regards, Greg Cox Zenith Zodiac CH650, VH-ZDC Sydney, Australia (Cecil Hills) -----Original Message----- From: owner-zenith601-list-server@matronics.com [mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Thruster87 Sent: Sunday, 1 November 2009 8:50 AM Subject: Zenith601-List: Re: 601 nose gear My original nose leg measured 0.080" wall thickness [come with the kit in 10/2007] which bent due to nose fork collapse.Received a new leg and it measures 0.060" wall thickness which corresponds to the drawings specifications on the plans.Does anyone know if there was an up date of the nose leg wall thickness ???? Cheers T87 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=270269#270269 ________________________________ Message 14 ____________________________________ Time: 04:10:56 PM PST US Subject: Zenith601-List: Re: 601 nose gear From: "Ron Lendon" My prints and a crosscheck to the builders website confirms the XL 6-G-1-1 Nose Gear Leg is 2" O.D. X .065" wall 4130N round seamless tubing. 6-G-1 01/08 NOSE GEAR STRUT ASSEMBLY 1. Spacers have been lengthened to 33.4mm for proper fit inside the bearing seal. 2. Drain hole added to the bottom plate of Nose Gear Leg 6G1-1 also added to Wheel Fork 6G1-2 and Fork Doubler 6G1-5. 3. plate welded to the top of 6G1-2 nose gear leg with 2 nuts welded to it has been removed. -------- Ron Lendon, Clinton Township, MI WW Corvair with Roy's Garage 5th bearing Zodiac XL, ScrapBuilder ;-) http://www.mykitlog.com/rlendon Corvair Engine Prints: http://home.comcast.net/~rlendon/site/ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=270279#270279 ________________________________ Message 15 ____________________________________ Time: 07:50:05 PM PST US Subject: Zenith601-List: Re: 601 nose gear From: "Thruster87" Ron Lendon wrote: > My prints and a crosscheck to the builders website confirms the XL 6-G-1-1 Nose Gear Leg is 2" O.D. X .065" wall 4130N round seamless tubing. > > > 6-G-1 01/08 NOSE GEAR STRUT ASSEMBLY > 1. Spacers have been lengthened to 33.4mm for proper fit inside the bearing > seal. > 2. Drain hole added to the bottom plate of Nose Gear Leg 6G1-1 also added > to Wheel Fork 6G1-2 and Fork Doubler 6G1-5. > 3. plate welded to the top of 6G1-2 nose gear leg with 2 nuts welded to it has > been removed. What does it mean??? also added to Wheel Fork 6G1-2 and Fork Doubler 6G1-5. statement number 2 Cheers Read this topic online here: http://forums.matronics.com/viewtopic.php?p=270309#270309 ------------------------------------------------------------------------------------- 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.