Date: Thu, 2 Mar 95 11:07:39 EST Subject: Question on bulkhead installation People; Got a question on the installation of the landing gear builkheads and the lower firewall: The instructions say to install the rear LG bulkhead in the fuselage sides "in a similar manner" to the technique used for the F22, Inst. Panel, and Seatback Bulkhead. That involved floxing in place and a 2 BID layup over the joints. The manual does not talk about a 2 BID layup for either of the LG bulkheads or the lower firewall. Do I only flox these three in place, and wait for the overall BID and/or UNI layups in these area in later chapters, or do I put a 2 BID strip on them as with the other bulkheads? Also, the front LG bulkhead gets a 3 UNI and a 6 UNI layup front and back - I assume (given the orientations that this is only to tie the upper and lower halves together, and that I don't need to overlap the fuselage sides with these layups. Am I correct? Thanks. -- Marc J. Zeitlin E-Mail: marcz@an.hp.com Date: Fri, 3 Mar 1995 00:45:06 -0500 From: Ewestland@aol.com Subject: Re: bulkhead layup question Marc, I could not remember exactly how I did it, so I went down in the basement and looked over my fuselage. While I may have taped the rear bulkheads, if I did, they are buried under a billion plies of glass. Just flox them until the reinforcing lay-ups, but if it would help you to sleep better at night, tape-em! You probably know this, but when taping, do the two plies on wax paper or saran wrap, cut to width and then press into place. Peel away the wax paper and then peel ply. Aluminum foil is used by some because of possible wax contamination, but that is probably over kill. I also had a little warpage in my fire wall - plywood does this, but I'll have the chance to suck it back in when I mount the main spar. When you run into stuff like this and you don't want to stop for the day, feel free to give me a call. I keep school teacher hours. Home is 206-742-6798 and work is 360-653-0850, ext. 119. Take care, Eric Date: Fri, 3 Mar 95 10:52:25 EST Subject: Re: bulkhead layup question Eric; >I could not remember exactly how I did it, so I went down in the basement and >looked over my fuselage. While I may have taped the rear bulkheads, if I >did, they are buried under a billion plies of glass. Just flox them until >the reinforcing lay-ups, but if it would help you to sleep better at night, >tape-em! That's sort of what I figured. A billion looks about right. :-). >...... You probably know this, but when taping, do the two plies on wax >paper or saran wrap, cut to width and then press into place. Peel away the >wax paper and then peel ply. Aluminum foil is used by some because of >possible wax contamination, but that is probably over kill. I had never tried this taping method; I used it for the first time for the SB bulkhead and Instrument panel. I'm not sure I like it more than the manual unroll and brush method.... I'll have to think about it. >When you run into stuff like this and you don't want to stop for the day, >feel free to give me a call. I keep school teacher hours. Home is >206-742-6798 and work is 360-653-0850, ext. 119. Well, I sincerely appreciate the offer. I usually try to get my questions together a couple of days before I need the answer (I won't be doing the LG bulkhead layups until tomorrow) but if I ever need on the spot answers, I'll give you a ring! What do you teach? (and to whom?). -- Marc J. Zeitlin E-Mail: marcz@an.hp.com Date: Sat, 4 Mar 1995 23:32:03 -0500 From: Ewestland@aol.com Subject: Re: bulkhead layup question Subj: Re: bulkhead layup question Date: Fri, Mar 3, 1995 11:54 AM EDT From: marcz@hpwarhw.an.hp.com X-From: marcz@hpwarhw.an.hp.com (Marc J. Zeitlin) Eric; >I could not remember exactly how I did it, so I went down in the basement and >looked over my fuselage. While I may have taped the rear bulkheads, if I >did, they are buried under a billion plies of glass. Just flox them until >the reinforcing lay-ups, but if it would help you to sleep better at night, >tape-em! That's sort of what I figured. A billion looks about right. :-). >...... You probably know this, but when taping, do the two plies on wax >paper or saran wrap, cut to width and then press into place. Peel away the >wax paper and then peel ply. Aluminum foil is used by some because of >possible wax contamination, but that is probably over kill. I had never tried this taping method; I used it for the first time for the SB bulkhead and Instrument panel. I'm not sure I like it more than the manual unroll and brush method.... I'll have to think about it. >When you run into stuff like this and you don't want to stop for the day, >feel free to give me a call. I keep school teacher hours. Home is >206-742-6798 and work is 360-653-0850, ext. 119. Well, I sincerely appreciate the offer. I usually try to get my questions together a couple of days before I need the answer (I won't be doing the LG bulkhead layups until tomorrow) but if I ever need on the spot answers, I'll give you a ring! What do you teach? (and to whom?). ############################################################## Hey Marc, I found this letter after all, I guess AOL stores them in their post office for a while. The wax paper/saran wrap taping method works well because you can do most of your squeegeeing prior to placing the tape. Lay out your dimensions on the wax paper with a felt pen, then turn the wax paper over so the ink does not transfer to the glass. Wet out the glass on the wax paper, squeegee well, then cut into strips. Brush a little epoxy on the joint, press the glass into place with the wax paper and use your fingers to push out any air. Peel away the wax paper and peel ply. It's cool. Works super with BID, OK with UNI depending on the shape it gets applied to. I teach jr. high math although in my 17 years, I taught 10 years of industrial arts. Some years are good, some awful, this one has been excellent. While I am ready for a change sometime in the next five years, getting my placement file updated would take away from epoxy mixing time, so I'll probably stay at it for a while longer:-) Eric Date: Mon, 6 Mar 1995 08:01:30 -0800 From: gbowen@ix.netcom.com (Gordon Bowen) Subject: Re: Question on bulkhead installation You wrote: >the joints. The manual does not talk about a 2 BID layup for either of the >LG bulkheads or the lower firewall. Do I only flox these three in place, >and wait for the overall BID and/or UNI layups in these area in later >chapters, or do I put a 2 BID strip on them as with the other bulkheads? Marc, they're several situations in the book that don't cover extra lay-ups or its confusing. I did the two plies of BID over the flox, attaching the bulkhead to the side panels. You'll add a lot more plies of BID to this area later. >Also, the front LG bulkhead gets a 3 UNI and a 6 UNI layup front and back - >I assume (given the orientations that this is only to tie the upper and >lower halves together, and that I don't need to overlap the fuselage sides I think you're correct. Anyway I did not lap the UNI on the side panels. The bulkhead was floxed and BID attached Best of luck, Gordon Date: Mon, 6 Mar 95 17:16:51 EST Subject: sheet metal warning - Chapter 6 People; I'd like to warn those of you who have yet to get to Chapter 6 - I had a bad experience with the flat sheet aluminum used for the Fuel Selector Valve Mount. I laid out the outline and the holes, cut and drilled everything, and then tried to bend the aluminum on the bend lines. It promptly cracked and broke. I swore. I came into work, got another piece of aluminum, did everything over again, and bent it up just fine. I hypothesize that the aluminum I got from Wicks was 6061-T6 (which is pretty hard, and doesn't like to bend small radii). The material I got from work was 5052 - H3 (I believe) which is what we use for all our bent sheet metal parts. I've got two recommendations - either make sure that you get something softer from Wicks, or else bend the sheet stock with an internal radius larger than ~3/32" (bend it around a tube or rod, rather than over the edge of a vise or with a finger brake). Did anyone else have this problem? -- Marc J. Zeitlin E-Mail: marcz@an.hp.com Date: Mon, 6 Mar 1995 21:17:08 -0500 (EST) From: pathways Subject: Re: sheet metal warning - Chapter 6 Marc, It took 3 tries at the fuel selector bracket before I got one without a crack. This was one of my greatest frustrations to date. I ended up bending it around the stock of a drill bit. If you think this is frustrating, wait until you glass around the Naca scoop and try to get the glass to stay in the "joggle". ...Marty Kansky N321CZ Date: Mon, 6 Mar 1995 23:55:31 -0500 From: Ewestland@aol.com Subject: Re: sheet metal warning - Chapter 6 Yep. It took me a turn or two to get it without cracks. Went with a generous radius, found out later it really didn't matter as the part is almost completely hidden anyways. Eric From: Marc J. Zeitlin Subject: sheet metal & common sump Date: Tue, 7 Mar 95 13:04:38 EST Sid writes: >Yes, I broke the first one also. I used a steel tube to bend the next one >around. Sound to me as if EVERYONE has had this problem - Nat should really spec a different material. >Now, I've gone to a common sump under the main spar and a remote shut-off >valve cable actuated. I never did see the sense in having to switch >right-left all the time. Vance has a system like this and it works fine. I >have only one internal fuel fitting, the one that goes from the sump to the >bulkhead pass-through fitting. All other internal fuel lines are potted into >tanks. Sid, if you wouldn't mind making your set-up available via a description, plans, GIF files, DXF files, whatever, I'd sure appreciate it, and I'd guess everyone else would also. If you have some info on the "arm-pit" scoops vs. the NACA scoop, I'd appreciate that as well. -- Marc J. Zeitlin E-Mail: marcz@an.hp.com Date: Sun, 21 May 95 15:12:10 PDT From: "Michael Antares" Subject: Chapter 6 I have just finished chapter 6, except for corner taping and wanted to share some slight changes I made in methodolgy which I found quite helpful for those of you who haven't got that far yet. When you have finished doing all of the 3/4 inch foam build-ups on the bottom, Nat says to micro them to the bottom and then do a trial fit before glassing. then if it doesn't fit I assume you are going to have to do whatever re-work is required. Even though I had measured (and re-measured) everything very carefully, I still had a high degree of paranoia about whether everything was going to fit. There really isn't all that much room for error underneath at least the instrument panel. What I ended up doing was to fit and glue together with 5 minute epoxy all of the buildups directly on the bottom of the fuselage (being careful of course not to glue them TO the fuselage!). My original intent was to then transfer them, as one complete structure, to the 3/8 foam making up the bottom which was in the holding frame (ala Nat's recommendation, except I didn't glue the bottom to the frame, I made it a little more elaborate and simply laid the bottom in it. However, after finishing all of the buildups, I said to myself, why not just micro the buildups, now spread out over the sides and bulkheads in perfect position, and lay the bottom on them. Not seeing any reason why this shouldn't work, I did it. After cure I lifted the assembly off of the fuselage, laid it back in the frame and did the glassing. I then floxed it onto the fuselage per instructions, knowing that the positioning was going to be PERFECT, which it was. I am more than happy with the results. Not bonding the bottom to the frame, although it took a little longer to make a better frame, means not having to fill in all of the divots from pulling it off of the glue dabs. Happy building! Michael Michael Antares Software/Hardware Systems Engineering mantares@crl.com Santa Rosa, California Date: Mon, 22 May 1995 09:40:58 -0400 From: SidLloyd@aol.com Subject: Re: Chapter 6 In a message dated 95-05-21 18:14:39 EDT, mantares@crl.com writes: > Not >bonding the bottom to the frame, although it took a little longer to >make a >better frame, means not having to fill in all of the divots from >pulling it >off of the glue dabs. Good idea. I made the mistake of weighting down my frame too much when I was bonding the bottom to the fuselage. It caused the bottom to bow slightly inward which now creates real headaches in doing final fuselage fill. Sid Date: Sat, 24 Jun 1995 22:53:08 -0700 (PDT) From: Eric Westland Subject: Landing Brake Spacer There is a 2" spacer for the landing brake pulley that is part of the front seat support. It is made out of 3/8" aluminum tubing with a wall thickness of 0.065" which means the 1/4" bolt should fit through it although it may be tight. Anyways, mine didn't, so I had to ream it out tonight. It would have been easier to ream it before installing it , so check it out if you haven't installed it yet. Eric From: Lee Devlin Subject: Fuselage bottom Date: Mon, 28 Aug 95 16:12:54 MDT I am about to skin the fuselage bottom and was wondering about everyone's thoughts about this process. It looks like a very big job and I wanted to determine if everyone followed the plans. The plans call for doing the layup, letting it 'tack' for 2 to 4 hours and then flipping it over while still tacky and floxing it to the longerons and bulkheads. It then goes on to say that now would be a good time to do the corner tapes (while the fuselage is upside down) although it could be done any time within 12 hours. I've been peel plying everything and was wondering if this is a good time to use that technique to decouple each of these jobs. If I peel-plied everything then I could do the lay up one day, flox it to the fuselage the next, and corner tape the next day after flipping it over. This would be relatively easy to accomplish in three evenings rather than doing it in one weekend marathon session. It would also give the floor a smooth finish like the other peel-plied parts of the fuselage insides. Maybe the plans are easier to follow than they sound, but it seems applying and then peel-plying the corner tapes upside-down in a dark, confined space is pushing the 'fun' envelope of the building process. Thanks, Lee Devlin Date: Mon, 28 Aug 1995 17:52:06 -0700 (PDT) From: Eric Westland Subject: Re: Fuselage bottom This is a time consuming layup. I had a skilled helper and by the time we were done, it was getting stiff (it was a warm day). I was using RAE slow hardener. The point is, work fast if you can (get a third helper) and then you will have time to spare. Also be aware that if you put too much weight on it when you place the bottom on the fuselage, it may cause the bottom to bow. I would recommend floxing it in place before it has a chance to cure and then going in and taping it another day. Peel ply along all of the flat areas (white foam underneath) ad they will get additional layers eventually (seats, heater ducts, seatbelt reinforcements...). Heck, if you have the time, might as well peel ply the whole thing as long as it is still wet enough that you won't have to add alot of epoxy ( weight). Eric On Mon, 28 Aug 1995, Lee Devlin wrote: > I am about to skin the fuselage bottom and was wondering about > everyone's thoughts about this process. It looks like a very big job > and I wanted to determine if everyone followed the plans. The plans > call for doing the layup, letting it 'tack' for 2 to 4 hours and then > flipping it over while still tacky and floxing it to the longerons and > bulkheads. It then goes on to say that now would be a good time to do > the corner tapes (while the fuselage is upside down) although it could > be done any time within 12 hours. > > I've been peel plying everything and was wondering if this is a good > time to use that technique to decouple each of these jobs. If I > peel-plied everything then I could do the lay up one day, flox it to the > fuselage the next, and corner tape the next day after flipping it over. > This would be relatively easy to accomplish in three evenings rather > than doing it in one weekend marathon session. It would also give the > floor a smooth finish like the other peel-plied parts of the fuselage > insides. > > Maybe the plans are easier to follow than they sound, but it seems > applying and then peel-plying the corner tapes upside-down in a dark, > confined space is pushing the 'fun' envelope of the building process. > > Thanks, > > Lee Devlin > From: "Volk, Ray" Subject: RE: Fuselage bottom Date: Tue, 29 Aug 95 08:18:00 PDT Lee I completed that part of the build about 3 weeks ago and I can only relate my experience for what its worth. I too am peel plying everything as I go. Glassing the inside bottom is a rather large job with all the spacers and all, especially if your doing it yourself. I glassed the bottom, peel plying the large center areas with bigger pieces of peel ply, and using strips of peel ply tape, 2" and 4", for the intersecting interfaces. Then after more like 4 to 5 hours I pulled the interfacing tape off, floxed the edges and intersection points, flipped the bottom over on top of the sides, weighted it down, wiped off the over flow, and turned out the lights. The next day, 12 hours later, I turned the tub over and proceeded to tape all the joints. This was a fairly time consuming job, much more than I would have thought and that even when it was upright and easy to work on. There's no doubt it would have been well beyond fun if I would have tried to do it in the upside down position. I think splitting it into 3 sessions instead of 2 is also OK, I know at the time I was worried about the "chemical bond" and therefore proceeded to rip off the peel ply tape after a rather short time. The disadvantage of splitting up the work is that you should "rough up" the shinny surfaces (flox and epoxy) before continuing, but that is really not a big job. For what it's worth, Ray rvolk@space.honeywell.com From: Marc J. Zeitlin Subject: Fuselage bottom (fwd) Date: Tue, 5 Sep 95 0:29:43 EDT Lee D. Asks about doing the fuselage bottom layup in stages (a week ago :-). >Maybe the plans are easier to follow than they sound, but it seems >applying and then peel-plying the corner tapes upside-down in a dark, >confined space is pushing the 'fun' envelope of the building process. Ray V.'s response seemed perfectly reasonable, but I'll tell you that I followed the plans to the letter. You're right, upside down at 2:00 A.M. doing 2" tapes in the dark sucked. I was worried that the fuselage would not be strong enough to flip without the BID tapes (only the flox), so I figured I better do it the way I was told. In retrospect, it's hard to imagine the fuselage coming apart with a flox joint holding it together. I'd say 2 or even 3 stages should work just fine, as long as you are VERY careful to peel-ply and/or sand all the joint areas thoroughly. See you soon, Lee. -- Marc J. Zeitlin Mail Stop: MS-460 Email: marcz@an.hp.com Date: 5 Oct 1995 15:30:02 -0600 From: "Scott Mandel" Subject: Wrong Size Parts Subject: Time: 3:25 PM OFFICE MEMO Wrong Size Parts Date: 10/5/95 Since we're on the subject of wrong sized parts. I made the fuel selector bracket in chapter 6, but the screws seem to be too long. How far do you screw the screws into the nut plates? It seems like once the screw fills the threads it gets pretty tight, but the fuel valve isn't tight against the bracket. I'm afraid if I keep tightening them they'll strip the nut plate. From: Marc Zeitlin Date: Thu, 5 Oct 95 17:58:33 EDT Subject: Wrong Size Parts (fwd) Scott Mandel writes: >Since we're on the subject of wrong sized parts. I made the fuel selector >bracket in chapter 6, but the screws seem to be too long. How far do you >screw the screws into the nut plates? It seems like once the screw fills the >threads it gets pretty tight, but the fuel valve isn't tight against the >bracket. I'm afraid if I keep tightening them they'll strip the nut plate. They did seem long, but believe me, you won't strip that steel nutplate with a screwdriver and your hands. Don't know why the screws are long, though - maybe something goes in between later? Someone on a later chapter (or who has done the fuel system) can answer better. -- Marc J. Zeitlin Email: marcz@an.hp.com Date: 23 Oct 1995 09:31:38 -0600 From: "Scott Mandel" Subject: Chapter 6 Speed Brake Subject: Time: 9:26 AM OFFICE MEMO Chapter 6 Speed Brake Date: 10/23/95 I'm about to cut out my speed brake. The instructions say to use a sabre saw at a 45 degree angle. I'm thinking that sabre saw is going to make a pretty ugly cut if I've already mounted my foam on blocks. Did anyone else have a better way of doing this? I'm thinking about trying to cut the speed brake out before I mount it, but I've already glued my foam together. Boy that is one big piece of foam to move around on my work bench. Date: Mon, 23 Oct 1995 10:27:04 -0700 (PDT) From: Eric Westland Subject: Re: Chapter 6 Speed Brake I just used a 12" long stick of wood that I had a 45 degree face on (cut with table saw) and used this to hand-guide a hack saw blade. Eric On 23 Oct 1995, Scott Mandel wrote: > Subject: Time: 9:26 AM > OFFICE MEMO Chapter 6 Speed Brake Date: 10/23/95 > > I'm about to cut out my speed brake. The instructions say to use a sabre saw > at a 45 degree angle. I'm thinking that sabre saw is going to make a pretty > ugly cut if I've already mounted my foam on blocks. Did anyone else have a > better way of doing this? I'm thinking about trying to cut the speed brake > out before I mount it, but I've already glued my foam together. Boy that is > one big piece of foam to move around on my work bench. > > Date: Mon, 23 Oct 1995 18:16:54 -0400 From: RonKidd@aol.com Subject: Re: Got another question ... The 45 degree angle is not all that critical. You might find that you have to ream them slightly for clearance later on anyway. Ron Date: Mon, 04 Dec 1995 11:50:28 -0600 From: tims@enet.net (Tim Sullivan) Subject: Is my Gemoetry bad? I'm just in the process of assembling the map box/center console/vent and ran across a numbers problem. I know its trivial but the sketch for the spacers (fig 19) in ch 6 shows the box much higher and flatter than reality. I checked the dimensions over and over again. The only way I could get the dimensions along the hypotenus to work was by taking the 1.5" and 4.5" pieces and placing them inline from the 16.5" vert. spacer (near the end) and running then horz. then using the (6.5? Can't remember exact size) lower spacer for the box at the appropriate bottom box line then cutting off the inch or so of extra. Nat said that it really didn't make much of a difference as long as the opening was in the right place and there is an inch or so of clearance just above the vent box for running lines. Anyone else have this problem? Or has the epoxy finally started pickling my brain? Tim Sullivan (tims@enet.net) Phoenix, AZ | * | Cozy MK IV Builder #470 |-----(/)-----| The journey begins 8/10/95 / \ Current Status: Ch 6 o o