---------------------------------------------------------- Zenith-List Digest Archive --- Total Messages Posted Sat 07/29/06: 17 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:00 AM - Re: Firewall rivets (Noel Loveys) 2. 06:16 AM - Re: Plating Zodiac landing gear (Kelly Meiste) 3. 06:20 AM - Re: Re: Hat Stiffener Press + Pic of the day (Debo Cox) 4. 06:51 AM - Re: Weight & Balance (dfmoeller) 5. 06:59 AM - Re: Plating Zodiac landing gear (LarryMcFarland) 6. 07:07 AM - Leg Gear Plate (Tim Perkins) 7. 07:23 AM - composite gear (John Bolding) 8. 07:48 AM - Re: Firewall rivets (Edward Moody II) 9. 08:23 AM - Re: Re: Rotax 912 Tachometer Problems (Noel Loveys) 10. 09:15 AM - Re: Weight & Balance (David X) 11. 09:27 AM - Re: Re: Hat Stiffener Press (Paul Mulwitz) 12. 01:11 PM - (CH701) problems measuring 7H3-3SP (John Marzulli) 13. 04:58 PM - Re: Re: Firewall rivets () 14. 05:41 PM - Garanger (Bill Naumuk) 15. 05:43 PM - Re: Firewall rivets (LarryMcFarland) 16. 05:45 PM - Re: Garanger (Bill Naumuk) 17. 08:36 PM - Re: Garanger (Gary Boothe) ________________________________ Message 1 _____________________________________ Time: 06:00:54 AM PST US From: "Noel Loveys" Subject: RE: Zenith-List: Firewall rivets 250 yr??? Probably depends on how much humidity the plane has to endure. Dissimilar metals will live together in the absence of water/humidity. Electrolytic salts will also speed up the process. If you have to use dissimilar rivets etc. then the idea of using zinc chromate and/or sealant around the rivets as they are being pulled is a good one. Noel -----Original Message----- [mailto:owner-zenith-list-server@matronics.com] On Behalf Of Gary Gower Sent: Saturday, July 29, 2006 4:07 AM There has been some posts about this "discimilar metals" danger of corrosion... It beguin when I told the list about the SS firewall we built for my 701... I cant remember what the final results of this tread were... Probably the plane will fall apart because of corrosion in 250 years :-) :-) Just in case, to be on the safe side, I put some Zinc Chromate in a little cup and wetted each rivet in the firewall before installing and pulling, also double checked that we painted the touching parts with plenty ZC, Hope it holds the next 25 plus years I think I will be able to continue flying... :-) Saludos Gary Gower Flying from Chapala, Mexico. 701 912S 601 XL in progress... VideoFlyer@aol.com wrote: <<<<>> The firewall is steel...either galvanized or stainless. But the "L" braces and the channels are aluminum. Aren't those dissimilar metals? What's the difference between aluminum rivets in stainless steel...and stainless rivets in aluminum? Dave ________________________________ Message 2 _____________________________________ Time: 06:16:15 AM PST US From: "Kelly Meiste" Subject: Re: Zenith-List: Plating Zodiac landing gear Hi George, At my previous employer we used to have problems with hydrogen embitterment in all types of steel (CR, HR, spring/ music wire, and tool steels) after plating. We finally solved this problem by making sure the product was placed in an oven within 15 minutes after plating, and then baked for 2 hours at temp of 350 deg F. Problem solved. Kelly Meiste 601 HD with plated 6L3 main gear lower bearing supports (140 hours) ----- Original Message ----- From: George Swinford To: zenith-list@matronics.com Sent: Friday, July 28, 2006 9:37 PM Subject: Zenith-List: Plating Zodiac landing gear I remember from my days as a Boeing engineer that 4130N steel is not subject to embrittlement from plating, but I don't have access to the material and process handbooks anymore to be sure about it. Maybe someone on the list can can put their hands on this kind of information and clear the issue up. Anybody...? George Do not archive ________________________________ Message 3 _____________________________________ Time: 06:20:09 AM PST US From: Debo Cox Subject: Re: Zenith-List: Re: Hat Stiffener Press + Pic of the day Thanks guys. I'm glad the press idea sparked a little head-scratchin'. That's the really cool thing about this list. One guy finds a way to get himself out of a pickle - shares it, and gets a dozen good ideas back in the process. And you thought the internet was just good for lookin' at porn. Ron, I laughed out loud like a moron when I read about the "200lb gravity actuated stomp press" - classic. Debo Cox Nags Head, NC XL/Corvair (working on wing parts) do not archive --------------------------------- Yahoo! Music Unlimited - Access over 1 million songs.Try it free. ________________________________ Message 4 _____________________________________ Time: 06:51:34 AM PST US From: "dfmoeller" Subject: Zenith-List: Re: Weight & Balance --> Zenith-List message posted by: "dfmoeller" Excellent work. Just what I was looking for. thanks! Doug David X wrote: > My CG attached. Also attached spreadsheet to help work out CG cenarios. Rear baggage is a big problem if you have two good sized people in the plane. The wing lockers are a must in that type of scenario. > > I don't care what anyone from Zenair says the standard motor mount that you get for the 912 is flawed as far as CG is concerned. Hey, I can do the grade-school math as well as the next guy. > > To solve the problem, I had a special mount and cowling made by CZAW to move the 912 engine forward 4 additional inches from original design. The empty CG is now 12", which is so/so. It was more than 14" with the standard mount; which is awful. It aught to be more like 10 but the nose would be too long and would interfere with visibility. > > Im toying with the idea of using the composite gear; which should improve the CG and useful load at the same time. > > > > > dfmoeller wrote: > > Does anyone have a good sample (meaning realistic) of a W&B sheet for a 601XL with Rotax 912ULS? And can you scan it and send to me? I'm trying to get a sanity check on my numbers. > Read this topic online here: http://forums.matronics.com/viewtopic.php?p=50544#50544 ________________________________ Message 5 _____________________________________ Time: 06:59:34 AM PST US From: LarryMcFarland Subject: Re: Zenith-List: Plating Zodiac landing gear --> Zenith-List message posted by: LarryMcFarland George, I believe you're correct, but the weld causes metal to change just a little and the touch downs and hard braking or turning are what cause the edge of the weld to begin to crack. The hydrogen imbrittlement would act on the weld material and perhaps shorten the time between use and breakage. I believe we're getting between 100 hours and 300 hours on these gear plates when they let go. The very slight bending is a repeating action that takes a bit of time to get a crack started. It's probably worse for the heavier 601s like mine that have got a 730 lb empty weight, so I try to grease it on and not brake hard until the inertia is pretty well spent. Larry McFarland - 601HDS at www.macsmachine.com George Swinford wrote: > I remember from my days as a Boeing engineer that 4130N steel is not > subject to embrittlement from plating, but I don't have access to the > material and process handbooks anymore to be sure about it. Maybe > someone on the list can can put their hands on this kind > of information and clear the issue up. Anybody...? > > George > > Do not archive ________________________________ Message 6 _____________________________________ Time: 07:07:09 AM PST US From: "Tim Perkins" Subject: Zenith-List: Leg Gear Plate ron dewees wrote: >> Jim Pellen's 601HD >> that lost a gear leg failed at the weld, altho a thicker plate than >> our 1/8 inch may have helped, or at least encouraged the welder to >> lay a thicker bead on the joint. I used aprox 3/16" angle iron from Hi All, At least in the cases I know of (including my own on June 13, 2006), the weld itself did NOT fail (see attached). It is the gear plate (the original 1/8" plate on some HD and HDS models) which fails. It can make for a somewhat interesting, but relatively short ride. The fix suggested by my A&P, and approved by Nick, is to cut off the existing 1/8" plates just above the welds and weld new 1/4" plates onto the leg ends. Of course that's in addition to the estimated $15k in repairs needed to get my plane airworthy again. I'll also note that although we were aware of the issue (and discussed adding gussets), there was no visible sign of a problem at the annual in mid-April 2006. Thus I made the decision NOT to do anything other than inspect (as recommended). In retrospect....it was clearly not the way to go. If I were doing it again, I'd at least gusset it, or weld a new plate on, or try the sleeve-type fix somebody suggested earlier. It may be a pain...but I know the alternative quite well at this point....and it's a lot worse. It appears that the gear plate gets stressed, bends, eventually cracks and fails. Put a straightedge across the front and rear of each gear plate to check and see if there is any bend. Mine (after failure) had about a 1.0-1.5mm upward bend along the edges in the center. Not really noticeable by eye. Tim Perkins ________________________________ Message 7 _____________________________________ Time: 07:23:17 AM PST US From: "John Bolding" Subject: Zenith-List: composite gear Glass gear is not a new deal. I think all the Rutan designs use glass legs . My glasair is over 20 yrs old (my how time flies when you're having fun) and no sagging (yet) but there were a few that did due to incomplete cure at manufacture. The fix was pretty painless, few more layers of glass and put it in the sun with black plastic on the legs for a few hrs. As everyone on this list is aware, an airplane is a wheelbarrow full of compromises swimming along in tight formation. Something not mentioned yet is the MUCH worse corrosion properties of 7075t6 used on the aftermarket gear . My 701 is going on floats to be used in saltwater and Chris OKed 6061 instead of 2024 as speced in the early style gear which is used for float operation. LOW&SLOW John ________________________________ Message 8 _____________________________________ Time: 07:48:54 AM PST US From: "Edward Moody II" Subject: Re: Zenith-List: Firewall rivets I believe the accepted procedure is to prime the contacting surfaces, particularly with dissimilar metals (which includes different alloys of the same basic metal). If that is an accepted practice as is dipping rivets in Zinc Oxide or Zinc Cromate primer at the time of insertion, then I'd guess the issue was adequately covered. Anyone have other or additional ideas or hints? Ed Moody II Rayne, LA 601XL / 2nd wing The firewall is steel...either galvanized or stainless. But the "L" braces and the channels are aluminum. Aren't those dissimilar metals? What's the difference between aluminum rivets in stainless steel...and stainless rivets in aluminum? Dave ________________________________ Message 9 _____________________________________ Time: 08:23:58 AM PST US From: "Noel Loveys" Subject: RE: Zenith-List: Re: Rotax 912 Tachometer Problems --> Zenith-List message posted by: "Noel Loveys" When posting I generally forget to put in the do not archive statement. I can see how there are several posts that are either comments or observations that are not important enough to archive and the no not archive statement should be used. For the other 99% of the posts I think we can overlook the DNA Noel > -----Original Message----- > From: owner-zenith-list-server@matronics.com > [mailto:owner-zenith-list-server@matronics.com] On Behalf Of David X > Sent: Saturday, July 29, 2006 1:23 AM > To: zenith-list@matronics.com > Subject: Zenith-List: Re: Rotax 912 Tachometer Problems > > > --> Zenith-List message posted by: "David X" > > I can't speak for others, but I use "DO NOT ARCHIVE" because > of what happened to a late friend of mine who was killed in a > Zodiac. The newspapers quoted all sorts of things out of > context about him and thus maligning him, home-builds and > experimentals in general. It seems that they got the info > from an archive of this forum. > > > 321PT wrote: > > Am I missing something?? You guys have some good info on > problems, so why would you put "Do not archive" on your > messages?? Being an old fart, I am not going to be able to > remember all this info on the top of my head.? Doesn't the > DNA stop anyone from finding it later? > > Or maybe I just don't understand all this new fangled stuff. > > ? > > > -------- > Zodiac 601 XL - CZAW Built - Rotax 912S > DO NOT ARCHIVE > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=50474#50474 > > > > > > > > > > > > > > > > > > > ________________________________ Message 10 ____________________________________ Time: 09:15:17 AM PST US From: "David X" Subject: Zenith-List: Re: Weight & Balance --> Zenith-List message posted by: "David X" I've used this spreadsheet for my own calculations and I believe it to be correct, but in no way do I warranty the spreadsheet. Check the math. Use at your own risk. -------- Zodiac 601 XL - CZAW Built - Rotax 912S DO NOT ARCHIVE Read this topic online here: http://forums.matronics.com/viewtopic.php?p=50572#50572 ________________________________ Message 11 ____________________________________ Time: 09:27:43 AM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Re: Hat Stiffener Press --> Zenith-List message posted by: Paul Mulwitz From a slightly different point of view, this is also a great example of the value of the home building experience we all are going through. Along with the brilliant solution to the hat stiffener problem, we all are figuring out solutions to new problems every day. OK, the usual result is we reinvent the wheel rather than come up with something really new, but that is not a bad experience either. Now if we could only get off the mixed metal corrosion topic . . . Paul XL Fuselage do not archive >Thanks guys. I'm glad the press idea sparked a little >head-scratchin'. That's the really cool thing about this list. One >guy finds a way to get himself out of a pickle - shares it, and gets >a dozen good ideas back in the process. ________________________________ Message 12 ____________________________________ Time: 01:11:59 PM PST US From: "John Marzulli" Subject: Zenith-List: (CH701) problems measuring 7H3-3SP Has anyone had the following problem? I'm starting my elevator/stab hinges and noticed a difference between the builder's manual, the plans and the manufactured piece supplied by Zenith concerning the Center Hinge Bracket ( 7H3-3SP ). Using the plans I measured 50mm into the flange to make a mark to draw the perpendicular line. This line was off center with the bracket tip by about 2mm. The builders manual states that the line should be centered with the tip. When tried to figure out why this was and I realized that the flange was 109mm in length, not 107mm as stated in the plans. Since these measurments are enclosed by boxes on the plans, I assume they are critical, especially since being off will cause problems with the elevator's movement. Is it better to use the tip center to determine the line knowing that one side of the piece was manufactured 2mm to long, possibly grinding down that side? ( my guess ) Or would it be better to use the line drawn 50mm in? ( seems like that would weaken the hinge ) Thanks, -- John Marzulli http://701Builder.blogspot.com/ ________________________________ Message 13 ____________________________________ Time: 04:58:24 PM PST US From: Subject: Re: Re: Zenith-List: Firewall rivets --> Zenith-List message posted by: I believe the accepted procedure is to prime the contacting surfaces, particularly with dissimilar metals (which includes different alloys of the same basic metal). If that is an accepted practice as is dipping rivets in Zinc Oxide or Zinc Cromate primer at the time of insertion, then I'd guess the issue was adequately covered. Anyone have other or additional ideas or hints? Ed Moody IIRayne, LA601XL / 2nd wing The firewall is steel...either galvanized or stainless. But the "L" braces and the channels are aluminum. Aren't those dissimilar metals? What's the difference between aluminum rivets in stainless steel...and stainless rivets in aluminum? Dave Dave: You have some good questions.I'm working on my firewall now.I've been wondering about the rivets we use on the firewall.The firewall is fire resistant galvanized,but the rivets securing the various braces are alum.Won't they melt if you have a fire?Also,are the rivet heads on the firewall side?Zenith says(generally)that the rivet head should go on the thinner side.A couple of the "l" angles on the back are thinner than the firewall.Hopefully we will get guidance from some of the guys that have already been down this road. Bob Haring(Zman601xl) ________________________________ Message 14 ____________________________________ Time: 05:41:39 PM PST US From: "Bill Naumuk" Subject: Zenith-List: Garanger All- The garanger's done. Two weeks behind schedule, but done. For anyone building in a basement, you have to pay the piper sooner or later . It cost me as much as the kit and 4 month's work to build my new shop. Cost without sweat equity, probably 25-30K in our area. God knows what it would be on the West Coast. Building supply prices are unreal!! Bill Naumuk 40%HDS Townville, Pa ________________________________ Message 15 ____________________________________ Time: 05:43:30 PM PST US From: LarryMcFarland Subject: Re: Zenith-List: Firewall rivets --> Zenith-List message posted by: LarryMcFarland Dave, I used aluminum rivets in a stainless firewall with aluminum skin and longerons because it's sound. The temps that would melt the rivets would otherwise melt the airframe as quickly. The surfaces were zinc chromated, but if I were to put corroding parts together, I'd rather not see it on the outside of my skins. With a header tank, its likely the heat would be greater inside anyway, eh? Strength wise, the aluminum rivets have done the job well for my 601. :-) Larry McFarland at www.macsmachine.com zman601xl@verizon.net wrote: >--> Zenith-List message posted by: > > >I believe the accepted procedure is to prime the contacting surfaces, particularly with dissimilar metals (which includes different alloys of the same basic metal). If that is an accepted practice as is dipping rivets in Zinc Oxide or Zinc Cromate primer at the time of insertion, then I'd guess the issue was adequately covered. Anyone have other or additional ideas or hints? Ed Moody IIRayne, LA601XL / 2nd wing The firewall is steel...either galvanized or stainless. But the "L" braces and the channels are aluminum. Aren't those dissimilar metals? What's the difference between aluminum rivets in stainless steel...and stainless rivets in aluminum? Dave > > > > > > > > > ________________________________ Message 16 ____________________________________ Time: 05:45:36 PM PST US From: "Bill Naumuk" Subject: Zenith-List: Re: Garanger Bill Naumuk 40%HDS Townville, Pa ----- Original Message ----- From: Bill Naumuk To: zenith list Sent: Saturday, July 29, 2006 8:40 PM Subject: Garanger All- The garanger's done. Two weeks behind schedule, but done. For anyone building in a basement, you have to pay the piper sooner or later . It cost me as much as the kit and 4 month's work to build my new shop. Cost without sweat equity, probably 25-30K in our area. God knows what it would be on the West Coast. Building supply prices are unreal!! Bill Naumuk 40%HDS Townville, Pa do not archive ________________________________ Message 17 ____________________________________ Time: 08:36:38 PM PST US From: "Gary Boothe" Subject: RE: Zenith-List: Garanger Simple shop or garage with some up-grades, over $100 per sq.ft. Gary Boothe Cool, CA 601 HDSTD, WW Conversion Tail done, working on wings.... Do Not Archive All- The garanger's done. . It cost .probably 25-30K in our area. God knows what it would be on the West Coast. . Bill Naumuk 40%HDS Townville, Pa