---------------------------------------------------------- Zenith-List Digest Archive --- Total Messages Posted Sat 05/05/07: 26 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:25 AM - Re: Locating engine mount holes (David Downey) 2. 06:04 AM - Re: Locating engine mount holes (Bill Naumuk) 3. 07:01 AM - Re: Locating engine mount holes (Paul Mulwitz) 4. 07:33 AM - Re: Locating engine mount holes (wade jones) 5. 07:44 AM - Re: Locating engine mount holes (Jaybannist@cs.com) 6. 07:48 AM - Re: Locating engine mount holes (Bill Naumuk) 7. 08:13 AM - Re: Locating engine mount holes (Bill Naumuk) 8. 08:13 AM - Re: Locating engine mount holes (Bill Naumuk) 9. 08:14 AM - Re: Locating engine mount holes (Bill Naumuk) 10. 08:19 AM - Re: Locating engine mount holes (kensmith@springnet1.com) 11. 08:38 AM - Re: Locating engine mount holes (Edward Moody II) 12. 08:41 AM - Firewall centerline final (Bill Naumuk) 13. 09:31 AM - Re: Locating engine mount holes (David Downey) 14. 10:00 AM - Painting Pieces on Firewall (Michael Valentine) 15. 10:10 AM - AN-3 + Drill Bit Question (Michael Valentine) 16. 10:10 AM - Re: Painting Pieces on Firewall (Craig Payne) 17. 10:19 AM - Re: AN-3 + Drill Bit Question (Craig Payne) 18. 10:21 AM - Re: Locating engine mount holes (Bill Naumuk) 19. 10:22 AM - Re: Locating engine mount holes (Bill Naumuk) 20. 10:22 AM - Re: Locating engine mount holes (Bill Naumuk) 21. 10:43 AM - Finding firewall centerline-final (Bill Naumuk) 22. 12:42 PM - Re: AN-3 + Drill Bit Question (Jim Hoak) 23. 12:44 PM - Oakland area builders/fliers (Ashcraft, Keith -AES) 24. 05:49 PM - Off topic - wanted Chinook Plus II (Robert Schoenberger) 25. 09:06 PM - Blaine Aviation Weekend (Lyle Peterson) 26. 10:29 PM - Bottom Rudder Bracket attachment (chris Sinfield) ________________________________ Message 1 _____________________________________ Time: 02:25:46 AM PST US From: David Downey Subject: Re: Zenith-List: Locating engine mount holes The fuse side mount fittings are the primary transfer points for the loads from the powerplant into the fuse. As such, as Paul points out, they control everything. When the mount is fabricated or installed, it needs to fit those locations - not those locations fit it. Keep in mind that the mount needs to fit without straining, because that is a recipe for a cracked mount somewhere down the road. Paul Mulwitz wrote: Perhaps I am getting this wrong, but I think the notion of where to put the engine mount on the firewall has nothing to do with the engine. After all, I am just a kit builder and put the holes for the engine mount on the firewall according to the plans. It seems to me the location of the firewall mounting bolts is dictated by the longerons attached to the fittings on the other side of the firewall from the engine. It is the longerons that dictate the location of these holes. Once the mounting position of the engine mount is fixed by the fuselage design, it is the problem of the engine mount designer to build a mount that fits these bolts to the engine itself..... Dave Downey Harleysville (SE) PA Zodiac 601XL/Corvair? --------------------------------- Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. ________________________________ Message 2 _____________________________________ Time: 06:04:56 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes All- From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. Since I "Slept on the problem" a possible solution is coming to me, but it would be nice if I didn't have to reinvent the wheel. Thanks. Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: Bill Naumuk To: zenith-list@matronics.com Sent: Friday, May 04, 2007 9:52 PM Subject: Zenith-List: Locating engine mount holes All- I know that this question was posted only a couple of weeks ago, but everything but the answer wound up in the archives. I just fabricated a firewall from scratch. What's the easiest and most accurate way of locating the engine mount holes? Let's make sure the answer gets in the archives this time! Bill Naumuk HDS Fuse/Corvair Townville, Pa ________________________________ Message 3 _____________________________________ Time: 07:01:19 AM PST US From: Paul Mulwitz Subject: Re: Zenith-List: Locating engine mount holes Hi Bill, Sorry if I misunderstood your problem. Perhaps you are trying to make the engine mount bolt holes before it is time to do so. It has been many months since I did this operation, so I don't really remember how it was done. I do remember it involved fitting the steel fittings at the ends of each longeron to both the firewall and longeron at the same time. Meanwhile, the skin has to fit both the longeron and the firewall flange. When all this is accomplished, the steel fittings will dictate where the engine mount bolt holes go on the firewall. If my memory serves correctly (something that will get you in trouble if you depend on it) one of the critical items was the forward bend in the cabin bottom skin. This had to fit around the corner on the firewall and the whole thing had to be held in place by the engine mount bolts to make it work. All in all it is a nasty Chinese puzzle to solve. My advice to you is to wait until you have all the parts in hand and are ready to make it all happen before worrying about the engine mount bolt hole locations. Best regards, Paul XL fuselage At 05:59 AM 5/5/2007, you wrote: >All- > From the responses, I can see I didn't get my point across. I > found out that the print locations will work for at least Corvair, > Jab, and Rotax installations, so that's not an issue. I know where > the holes are supposed to go, getting them there is the problem. > Every firewall (Scratchbuilt, at least) is going to deviate a > couple of mm's from print. Getting the Y axis locations isn't a > problem because you can use the flat bottom as an origin. Finding > the X axis center is more iffy. > A couple of weeks ago someone posted a method for accurately > locating the holes on a firewall and unfortunately it didn't make > it into the archives. That's what I'm looking for. > Since I "Slept on the problem" a possible solution is coming to > me, but it would be nice if I didn't have to reinvent the wheel. > Thanks. >Bill Naumuk >HDS Fuse/Corvair >Townville, Pa ________________________________ Message 4 _____________________________________ Time: 07:33:18 AM PST US From: "wade jones" Subject: Re: Zenith-List: Locating engine mount holes Hey Bill ,I went with what the plans called for.856mm across the top of the firewall. Bottom holes 15mm from bottom of firewall and 610mm between centers. This will leave you with 460mm between the top and bottom holes. Of course all this is started from the center of the firewall .All lined up to the longeron locations for a good fit Wade Jones South Texas 601XL plans building Cont. 0200 ----- Original Message ----- From: Bill Naumuk To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 7:59 AM Subject: Re: Zenith-List: Locating engine mount holes All- From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. Since I "Slept on the problem" a possible solution is coming to me, but it would be nice if I didn't have to reinvent the wheel. Thanks. Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: Bill Naumuk To: zenith-list@matronics.com Sent: Friday, May 04, 2007 9:52 PM Subject: Zenith-List: Locating engine mount holes All- I know that this question was posted only a couple of weeks ago, but everything but the answer wound up in the archives. I just fabricated a firewall from scratch. What's the easiest and most accurate way of locating the engine mount holes? Let's make sure the answer gets in the archives this time! Bill Naumuk HDS Fuse/Corvair Townville, Pa href="http://www.matronics.com/Navigator?Zenith-List">http://www.matron href="http://forums.matronics.com">http://forums.matronics.com ________________________________ Message 5 _____________________________________ Time: 07:44:46 AM PST US From: Jaybannist@cs.com Subject: Re: Zenith-List: Locating engine mount holes Bill, As I have previously posted, the recommended way to locate the holes is to drill pilot holes in the center of the forward vertical plate of the engine mount brackets. When the brackets have been properly located on the fuselage longerons, drill the firewall through the pilot holes. Then drill out the pilot holes for the bolts (which WW refers to as "studs"). William Wynne has said "It is acceptable to slightly flex the motor mount in order to get it to line up with the studs. After we weld them, the motor mounts are stress relieved so they will generally slide right on the studs. There will be a slight variation on plans built aircraft for the location of the holes, and the motor mount can accommodate this up to about 3/32"." Jay in Dallas "Bill Naumuk" wrote: >All- > From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. > A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. > Since I "Slept on the problem" a possible solution is coming to me, but it would be nice if I didn't have to reinvent the wheel. > Thanks. >Bill Naumuk >HDS Fuse/Corvair >Townville, Pa ________________________________ Message 6 _____________________________________ Time: 07:48:47 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes Paul- On the HDS you don't have a choice- all the components that are riveted to the firewall use the mount holes as origins. Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: Paul Mulwitz To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 10:00 AM Subject: Re: Zenith-List: Locating engine mount holes Hi Bill, Sorry if I misunderstood your problem. Perhaps you are trying to make the engine mount bolt holes before it is time to do so. It has been many months since I did this operation, so I don't really remember how it was done. I do remember it involved fitting the steel fittings at the ends of each longeron to both the firewall and longeron at the same time. Meanwhile, the skin has to fit both the longeron and the firewall flange. When all this is accomplished, the steel fittings will dictate where the engine mount bolt holes go on the firewall. If my memory serves correctly (something that will get you in trouble if you depend on it) one of the critical items was the forward bend in the cabin bottom skin. This had to fit around the corner on the firewall and the whole thing had to be held in place by the engine mount bolts to make it work. All in all it is a nasty Chinese puzzle to solve. My advice to you is to wait until you have all the parts in hand and are ready to make it all happen before worrying about the engine mount bolt hole locations. Best regards, Paul XL fuselage At 05:59 AM 5/5/2007, you wrote: All- From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. Since I "Slept on the problem" a possible solution is coming to me, but it would be nice if I didn't have to reinvent the wheel. Thanks. Bill Naumuk HDS Fuse/Corvair Townville, Pa ________________________________ Message 7 _____________________________________ Time: 08:13:08 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes Wade- Agreed, the plans locations work for different engine installations. do not archive Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: wade jones To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 10:32 AM Subject: Re: Zenith-List: Locating engine mount holes Hey Bill ,I went with what the plans called for.856mm across the top of the firewall. Bottom holes 15mm from bottom of firewall and 610mm between centers. This will leave you with 460mm between the top and bottom holes. Of course all this is started from the center of the firewall .All lined up to the longeron locations for a good fit Wade Jones South Texas 601XL plans building Cont. 0200 ----- Original Message ----- From: Bill Naumuk To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 7:59 AM Subject: Re: Zenith-List: Locating engine mount holes All- From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. Since I "Slept on the problem" a possible solution is coming to me, but it would be nice if I didn't have to reinvent the wheel. Thanks. Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: Bill Naumuk To: zenith-list@matronics.com Sent: Friday, May 04, 2007 9:52 PM Subject: Zenith-List: Locating engine mount holes All- I know that this question was posted only a couple of weeks ago, but everything but the answer wound up in the archives. I just fabricated a firewall from scratch. What's the easiest and most accurate way of locating the engine mount holes? Let's make sure the answer gets in the archives this time! Bill Naumuk HDS Fuse/Corvair Townville, Pa href="http://www.matronics.com/Navigator?Zenith-List">http://www.matron href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/Navigator?Zenith-List">http://www.matron href="http://forums.matronics.com">http://forums.matronics.com ________________________________ Message 8 _____________________________________ Time: 08:13:09 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes Jay- Since this is previously posted, do not archive Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: Sent: Saturday, May 05, 2007 10:44 AM Subject: Re: Zenith-List: Locating engine mount holes > > Bill, > > As I have previously posted, the recommended way to locate the holes is to > drill pilot holes in the center of the forward vertical plate of the > engine mount brackets. When the brackets have been properly located on > the fuselage longerons, drill the firewall through the pilot holes. Then > drill out the pilot holes for the bolts (which WW refers to as "studs"). > William Wynne has said "It is acceptable to slightly flex the motor mount > in order to get it to line up with the studs. After we weld them, the > motor mounts are stress relieved so they will generally slide right on the > studs. There will be a slight variation on plans built aircraft for the > location of the holes, and the motor mount can accommodate this up to > about 3/32"." > > Jay in Dallas > > > "Bill Naumuk" wrote: > >>All- >> From the responses, I can see I didn't get my point across. I found >> out that the print locations will work for at least Corvair, Jab, and >> Rotax installations, so that's not an issue. I know where the holes are >> supposed to go, getting them there is the problem. Every firewall >> (Scratchbuilt, at least) is going to deviate a couple of mm's from print. >> Getting the Y axis locations isn't a problem because you can use the flat >> bottom as an origin. Finding the X axis center is more iffy. >> A couple of weeks ago someone posted a method for accurately locating >> the holes on a firewall and unfortunately it didn't make it into the >> archives. That's what I'm looking for. >> Since I "Slept on the problem" a possible solution is coming to me, >> but it would be nice if I didn't have to reinvent the wheel. >> Thanks. >>Bill Naumuk >>HDS Fuse/Corvair >>Townville, Pa > > > ________________________________ Message 9 _____________________________________ Time: 08:14:30 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes Paul- Since I already responded to this re: HDS, do not archive Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: Paul Mulwitz To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 10:00 AM Subject: Re: Zenith-List: Locating engine mount holes Hi Bill, Sorry if I misunderstood your problem. Perhaps you are trying to make the engine mount bolt holes before it is time to do so. It has been many months since I did this operation, so I don't really remember how it was done. I do remember it involved fitting the steel fittings at the ends of each longeron to both the firewall and longeron at the same time. Meanwhile, the skin has to fit both the longeron and the firewall flange. When all this is accomplished, the steel fittings will dictate where the engine mount bolt holes go on the firewall. If my memory serves correctly (something that will get you in trouble if you depend on it) one of the critical items was the forward bend in the cabin bottom skin. This had to fit around the corner on the firewall and the whole thing had to be held in place by the engine mount bolts to make it work. All in all it is a nasty Chinese puzzle to solve. My advice to you is to wait until you have all the parts in hand and are ready to make it all happen before worrying about the engine mount bolt hole locations. Best regards, Paul XL fuselage At 05:59 AM 5/5/2007, you wrote: All- From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. Since I "Slept on the problem" a possible solution is coming to me, but it would be nice if I didn't have to reinvent the wheel. Thanks. Bill Naumuk HDS Fuse/Corvair Townville, Pa ________________________________ Message 10 ____________________________________ Time: 08:19:10 AM PST US From: "kensmith@springnet1.com" Subject: Re: Zenith-List: Locating engine mount holes You are absolutely correct in regards to the exact location of the mount attach points. Any change in the location no matter how small should always be approved from the designing engineers at Zenith. Change in location will proably require some structural change for attachment. Ken Paul Mulwitz wrote: > Perhaps I am getting this wrong, but I think the notion of where to > put the engine mount on the firewall has nothing to do with the > engine. After all, I am just a kit builder and put the holes for the > engine mount on the firewall according to the plans. > > It seems to me the location of the firewall mounting bolts is dictated > by the longerons attached to the fittings on the other side of the > firewall from the engine. It is the longerons that dictate the > location of these holes. > Once the mounting position of the engine mount is fixed by the > fuselage design, it is the problem of the engine mount designer to > build a mount that fits these bolts to the engine itself. > > Just my ideas on this subject . . . . > > Paul > XL fuselage > > ________________________________ Message 11 ____________________________________ Time: 08:38:24 AM PST US From: "Edward Moody II" Subject: Re: Zenith-List: Locating engine mount holes The longerons do indeed dictate the position of the engine mount brackets but the engine mount and its design and dimensins dictate the location of the holes. I drilled the pilot holes according to the directions (drawings and photo assembly guide) then enlarged them to the correct bolt size. Many moons later, when my FWF package arrived form Jabiru USA the mount matched up to the bolts pretty well, so I'd have to say the instructions and fabrication of the mount are in agreement. It is important to (A) locate the pilot holes accurately (of course), then (B) back drill the pilot holes to the engine mount brackets, then (C) enlarge them to size, preferably firewall and bracket at the same time. If you err, make sure the error places the bolt hole slightly farther from the base of the bracket rather than closer to it. If the hole is too close to the bottom of the bracket it clashes with the AN3 bolts which attach the bracket to the longeron. Dred ----- Original Message ----- From: Paul Mulwitz To: zenith-list@matronics.com Sent: Friday, May 04, 2007 11:39 PM Subject: Re: Zenith-List: Locating engine mount holes Perhaps I am getting this wrong, but I think the notion of where to put the engine mount on the firewall has nothing to do with the engine. After all, I am just a kit builder and put the holes for the engine mount on the firewall according to the plans. It seems to me the location of the firewall mounting bolts is dictated by the longerons attached to the fittings on the other side of the firewall from the engine. It is the longerons that dictate the location of these holes. Once the mounting position of the engine mount is fixed by the fuselage design, it is the problem of the engine mount designer to build a mount that fits these bolts to the engine itself. Just my ideas on this subject . . . . Paul XL fuselage ________________________________ Message 12 ____________________________________ Time: 08:41:44 AM PST US From: "Bill Naumuk" Subject: Zenith-List: Firewall centerline final All- Putting together the best of the list's comments and ideas, my plan of action is: 1. Ignore the tooling holes as location references. 2. Concentrate on the outside contact edges of the firewall and the flat bottom flange. Think about it. Eventually, those will dictate the perimeter of the fuse and consequently the centerline. Dr. "Painless" Dred is right on going to the widest point in the X axis. So, what I'm going to do is box the firewall in with 2x4's screwed down to my bench. Start by using the flat bottom flange as the primary origin. Next I'll square one of the perpendicular pieces, then the other, contacting the widest point in the X axis. Finally, a short piece at the top of the firewall to keep everything from moving while I make my Sharpie marks. I'm going out to the garanger and start laying things out. If someone comes up with a flaw in my logic I'll be back in to check comments before drilling metal. Bill Naumuk HDS Fuse/Corvair Townville, Pa ________________________________ Message 13 ____________________________________ Time: 09:31:17 AM PST US From: David Downey Subject: Re: Zenith-List: Locating engine mount holes on April 11 I posted this - maybe it is what you were remembering? While not the easiest way it is a very accurate way to determine the "average" centerline of an irregular shaped piece with supposed symmetry: one way to achieve a near "average" centerline: Cut out a cardboard pattern that will fit precisely inside the flanges of the firewall blank from bend radius tangent to bend radius tangent. Perhaps some odd shaped holes in the cardboard near the edges that can be traced with a sharpie for matching positioning later? Mark or cut the existing "tooling holes" holes in the cardboard from the firewall Then turn over the cardboard and re-trim to fit as well as possible. Trace the odd shaped hole in the cardboard on the firewall with a sharpie again to allow repositioning later. Re-mark or cut the hole locations in the cardboard. Find the center between each set of holes in the cardboard and drill a 1/16" pilot hole in the cardboard there. Replace the cardboard in the firewall and position with that set of alignment marks. Make a sharpie mark through the 1/16" holes in the cardboard. Flip the cardboard and repeat. Remove the cardboard. Find the center between each pair of pilot hole markings: there is the centerline. Note that you can do this even if there are no pilot holes to transfer from the part. The greater the distance between the 1/16" pilot holes in the cardboard, the greater the precision of this technique to find the center of a non symmetrical part. Bill Naumuk wrote: All- From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. Dave Downey Harleysville (SE) PA Zodiac 601XL/Corvair? --------------------------------- Looking for earth-friendly autos? Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center. ________________________________ Message 14 ____________________________________ Time: 10:00:10 AM PST US From: "Michael Valentine" Subject: Zenith-List: Painting Pieces on Firewall I know there was recently discussion about painting the firewall. That is NOT my question! I want to know about painting all of the aluminum pieces attached to the firewall. I have been using the Dupli-Color self-etching primer from the auto parts store. It ends up with a slight matte finish - green. Should I paint over the top of it before I rivet the pieces to the firewall or after? Do I need to paint over the primer at all? Finally, if I paint now can I just use some simple rattle-can paint from the auto parts store as well? (I may paint the plane myself later, but I obviously don't have that paint or equipment yet.) And one last question - is galvanization a surface treatment? If I scratch up the firewall a bit (as in deburring with a file), am I inviting problems? Thanks, Michael in NH ________________________________ Message 15 ____________________________________ Time: 10:10:12 AM PST US From: "Michael Valentine" Subject: Zenith-List: AN-3 + Drill Bit Question Are #12 and 3/16 drill bits equivalent? I had been using 3/16 for all my bolt holes and nut plates, but a while back on the rear fuse the guide (I think) mentioned a #12 - I think it was an AN-3 bolt. Anyway, I thought it would be easiest to just ask before it comes up for me again! If the plans call for an AN-3, which drill bit do you pull out? Thanks, Michael in NH ________________________________ Message 16 ____________________________________ Time: 10:10:48 AM PST US From: "Craig Payne" Subject: RE: Zenith-List: Painting Pieces on Firewall I'll only address the last question: yes, galvanizing is basically hot-dip electroplating zinc onto steel. http://en.wikipedia.org/wiki/Galvanize -- Craig ________________________________ Message 17 ____________________________________ Time: 10:19:37 AM PST US From: "Craig Payne" Subject: RE: Zenith-List: AN-3 + Drill Bit Question http://www.patchn.com/drillsizesnumbered.htm http://www.thedirtforum.com/conversions.htm 3/16 = 0.1875. #12 = 0.1890 or about a 0.8% difference -- Craig ________________________________ Message 18 ____________________________________ Time: 10:21:53 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes See final do not archive Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: kensmith@springnet1.com To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 11:18 AM Subject: Re: Zenith-List: Locating engine mount holes You are absolutely correct in regards to the exact location of the mount attach points. Any change in the location no matter how small should always be approved from the designing engineers at Zenith. Change in location will proably require some structural change for attachment. Ken Paul Mulwitz wrote: Perhaps I am getting this wrong, but I think the notion of where to put the engine mount on the firewall has nothing to do with the engine. After all, I am just a kit builder and put the holes for the engine mount on the firewall according to the plans. It seems to me the location of the firewall mounting bolts is dictated by the longerons attached to the fittings on the other side of the firewall from the engine. It is the longerons that dictate the location of these holes. Once the mounting position of the engine mount is fixed by the fuselage design, it is the problem of the engine mount designer to build a mount that fits these bolts to the engine itself. Just my ideas on this subject . . . . Paul XL fuselage ________________________________ Message 19 ____________________________________ Time: 10:22:09 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes See final do not archive Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: Edward Moody II To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 11:37 AM Subject: Re: Zenith-List: Locating engine mount holes The longerons do indeed dictate the position of the engine mount brackets but the engine mount and its design and dimensins dictate the location of the holes. I drilled the pilot holes according to the directions (drawings and photo assembly guide) then enlarged them to the correct bolt size. Many moons later, when my FWF package arrived form Jabiru USA the mount matched up to the bolts pretty well, so I'd have to say the instructions and fabrication of the mount are in agreement. It is important to (A) locate the pilot holes accurately (of course), then (B) back drill the pilot holes to the engine mount brackets, then (C) enlarge them to size, preferably firewall and bracket at the same time. If you err, make sure the error places the bolt hole slightly farther from the base of the bracket rather than closer to it. If the hole is too close to the bottom of the bracket it clashes with the AN3 bolts which attach the bracket to the longeron. Dred ----- Original Message ----- From: Paul Mulwitz To: zenith-list@matronics.com Sent: Friday, May 04, 2007 11:39 PM Subject: Re: Zenith-List: Locating engine mount holes Perhaps I am getting this wrong, but I think the notion of where to put the engine mount on the firewall has nothing to do with the engine. After all, I am just a kit builder and put the holes for the engine mount on the firewall according to the plans. It seems to me the location of the firewall mounting bolts is dictated by the longerons attached to the fittings on the other side of the firewall from the engine. It is the longerons that dictate the location of these holes. Once the mounting position of the engine mount is fixed by the fuselage design, it is the problem of the engine mount designer to build a mount that fits these bolts to the engine itself. Just my ideas on this subject . . . . Paul XL fuselage ________________________________ Message 20 ____________________________________ Time: 10:22:53 AM PST US From: "Bill Naumuk" Subject: Re: Zenith-List: Locating engine mount holes Recently archived. do not archive Bill Naumuk HDS Fuse/Corvair Townville, Pa ----- Original Message ----- From: David Downey To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 12:30 PM Subject: Re: Zenith-List: Locating engine mount holes on April 11 I posted this - maybe it is what you were remembering? While not the easiest way it is a very accurate way to determine the "average" centerline of an irregular shaped piece with supposed symmetry: one way to achieve a near "average" centerline: 1.. Cut out a cardboard pattern that will fit precisely inside the flanges of the firewall blank from bend radius tangent to bend radius tangent. Perhaps some odd shaped holes in the cardboard near the edges that can be traced with a sharpie for matching positioning later? 2.. Mark or cut the existing "tooling holes" holes in the cardboard from the firewall 3.. Then turn over the cardboard and re-trim to fit as well as possible. Trace the odd shaped hole in the cardboard on the firewall with a sharpie again to allow repositioning later. 4.. Re-mark or cut the hole locations in the cardboard. 5.. Find the center between each set of holes in the cardboard and drill a 1/16" pilot hole in the cardboard there. 6.. Replace the cardboard in the firewall and position with that set of alignment marks. Make a sharpie mark through the 1/16" holes in the cardboard. 7.. Flip the cardboard and repeat. 8.. Remove the cardboard. 9.. Find the center between each pair of pilot hole markings: there is the centerline. Note that you can do this even if there are no pilot holes to transfer from the part. The greater the distance between the 1/16" pilot holes in the cardboard, the greater the precision of this technique to find the center of a non symmetrical part. Bill Naumuk wrote: All- From the responses, I can see I didn't get my point across. I found out that the print locations will work for at least Corvair, Jab, and Rotax installations, so that's not an issue. I know where the holes are supposed to go, getting them there is the problem. Every firewall (Scratchbuilt, at least) is going to deviate a couple of mm's from print. Getting the Y axis locations isn't a problem because you can use the flat bottom as an origin. Finding the X axis center is more iffy. A couple of weeks ago someone posted a method for accurately locating the holes on a firewall and unfortunately it didn't make it into the archives. That's what I'm looking for. Dave Downey Harleysville (SE) PA Zodiac 601XL/Corvair? ------------------------------------------------------------------------- ----- Looking for earth-friendly autos? Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center. ________________________________ Message 21 ____________________________________ Time: 10:43:42 AM PST US From: "Bill Naumuk" Subject: Zenith-List: Finding firewall centerline-final All- Your eye can fool you when trying to find an edge, but you can't fool a 2x4. Attached are pictures of an idiotproof method (The idiot being me) of locating a firewall centerline to within .5mm. I didn't add text, because it should be self-explanitory. Feel free to e-mail me with any questions. The existing holes were transferred from the kit part layout and plywood forms. Scratch firewall forming isn't an exact science, which is what worried me. One look at the "Discrepancy" pictures and you'll see this wasn't a wasted effort. Good building! Bill Naumuk HDS Fuse/Corvair Townville, Pa ________________________________ Message 22 ____________________________________ Time: 12:42:29 PM PST US From: "Jim Hoak" Subject: Re: Zenith-List: AN-3 + Drill Bit Question Michael, Over the years I've followed the old idea that a loose fit will only get more loose with use and time. Use the smallest hole which will allow the bolt to be installed. If the fit is critical you can use a reamer, but that isn't necessary in most cases. I saw a Midget Mustang I that had aileron flutter because of accumulated slop in the system where # 12 drill was used with AN #3 bolts. We were able to fix it by going to NAS 3 bolts and in one location using and "oversize" ( special ) bolt. A lot depends on the installation. I.E. fixed or moving joint. Snug is GOOD, slop is BAD. Jim Hoak ----- Original Message ----- From: Michael Valentine To: zenith-list@matronics.com Sent: Saturday, May 05, 2007 12:09 PM Subject: Zenith-List: AN-3 + Drill Bit Question Are #12 and 3/16 drill bits equivalent? I had been using 3/16 for all my bolt holes and nut plates, but a while back on the rear fuse the guide (I think) mentioned a #12 - I think it was an AN-3 bolt. Anyway, I thought it would be easiest to just ask before it comes up for me again! If the plans call for an AN-3, which drill bit do you pull out? Thanks, Michael in NH ________________________________ Message 23 ____________________________________ Time: 12:44:22 PM PST US Subject: Zenith-List: Oakland area builders/fliers From: "Ashcraft, Keith -AES" All (any Zenith builders/flyers), Any builders/fliers in the Oakland area (within 50miles or so)? I am here on work related travel and have tomorrow (Sunday May 6th) free. If you need a hand, let me know, or if you need an excuse to go flying let me know also. Since I worked today (Sat May 5th) I missed my chance to go to Cloverdale QualitySportPlanes Bummer!! Anyway, call me or reply back to: keith.ashcraft@itt.com or ch701builder@yahoo.com or 719-332-4364!! Thanks, Keith CH701 -- 8% scratch N 38.9947 W 105.1305 Alt. 9,100' Do Not Archive ***************************************************************** This e-mail and any files transmitted with it may be proprietary and are intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error please notify the sender. Please note that any views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of ITT Corporation. The recipient should check this e-mail and any attachments for the presence of viruses. ITT accepts no liability for any damage caused by any virus transmitted by this e-mail. ******************************************************************* ________________________________ Message 24 ____________________________________ Time: 05:49:30 PM PST US From: Robert Schoenberger Subject: Zenith-List: Off topic - wanted Chinook Plus II List . . . if any of you know of a person who has a Chinook Plus II by ASAP for sale which is located in the eastern part of the US or Canada, please contact me off list at hrs1@frontiernet.net. Thanks. Robert Schoenberger do not archive ________________________________ Message 25 ____________________________________ Time: 09:06:19 PM PST US From: "Lyle Peterson" Subject: Zenith-List: Blaine Aviation Weekend This is coming very soon but it should be a great fly-in. EAA Chapter 237 is having a fly-in pancake breakfast and lunch at Anoka County Airport in Blaine, MN on May 19th and 20th Chapter 237's Famous Pancake Breakfast with sausage and beverage runs from 7a.m. to noon and lunch of hamburgers, hot dogs and chili runs until 4p.m. There are two really great aviation museums on the airport. Golden Wings Museum has a collection of beautifully restored vintage airplanes that includes five trimotors. American Wings Air Museum has a collection of warbirds from WWII to Dessert Storm. They also have a Wright Flyer replica, an original 1911 Steco biplane plus many other exhibits. There was a Swift, an Ercoupe, a Luscombe T8-F plus a lot of other vintage airplanes, warbirds and the usual later model airplanes at last year's event. There will be a Hangar Dance Saturday evening with the Sights and Sounds of Dave Andrews Big Band. This has been a lot of fun for everyone that attended in past years. More can be found at www.eaachapter237.org Thank you, Lyle Peterson President, EAA Chapter 237 ________________________________ Message 26 ____________________________________ Time: 10:29:16 PM PST US Subject: Zenith-List: Bottom Rudder Bracket attachment From: "chris Sinfield" Hi Gang I am using the latest plans 03/06 and have a Q. On page 6-B-2 bottom LH coner , it shows a lower rudder hinge. Ths hing USED to have 2 3/16" bolts 2 A5 rivets and a tiedown bolt on it with a row of 4 X A5 rivets behind. (older plans) on my plans it shows the rivets next to the tiedown bolt as being replaced bu 2 more 3/16" bolts , but the top RH corner of that Hinge picture still shows 6 X A5 with only 4 ++++. Should there be 6 A5 rivets in the back row or 4??? is the 6 a mistake? as the 2 A5 rivets in the next row are now bolts?? Chris Down Under.. 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