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Thread: Building the EX3 - Tips & Hints

  1. #1
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Post Building the EX3 - Tips & Hints

    I just received my 3rd Carbon Cub kit and thought I would try and help Mitch out by giving some tips and hints of the build here for everyone to use. I first build an EX-2 ("Orange Crush") in just over 700 building hours. Then I just finished getting the first EX-3 kit certified last month just a couple weeks before this kit shipped to me. Mitch and I worked through this first build together and will continue to work towards making this kit as smooth to build as the EX2.

    I've been getting a few phone calls and private messages relating to the build and now there are several EX3 kits out there now and I think about 3 more kits are shipping out each month so there are a lot more people starting to put these great planes together. Note that I do NOT work for CubCrafters and am not being paid or given any other consideration for making these posts. I'm just a bored, retired homebuilder who enjoys doing this.

    First let me say that I'm just telling and showing you some of the things I've done and the way "I" do the builds and I don't represent that it's the proper, only or best way. As a legal disclaimer, I just want to say that you are welcome to follow along for your own entertainment purposes but it's your own responsibility to build your aircraft the proper way and according to CubCrafters and standard aircraft methods.

    I also ask that you are welcome to respond to any of these posts with further questions or clarifications but I just ask that your discussions stick to the topic of building the EX-3 kit and not wander off into other subject areas. I also ask that you do post your questions, concerns, suggestions, etc on here so everyone can see the questions and answers so we can best inform everyone interested instead of sending private messages if it's something everyone else would benefit from learning.

    I want to also suggest you read the posts "Chuck and Ryans Build Tips" They spent alot of time with great insights, hints and photos to building the EX2 and I am much appreciative of the time and effort they put forth to help us all out. Learn to use the search function on this forum and do searches related to what subject matter you are looking for and it will bring up every post that includes that search criteria. Almost every subject you have questions about has most likely already been discussed at detail here in the forum.

    If you haven't joined EAA then I suggest you do so. No only do they have great insurance rates for the members but their website is a HUGE database of information. What I particularly liked when I did my first build was the homebuilder videos. You can go here and there are hundreds of short videos they have had experts put together than will show you virtually everything you will do on your build. Such simple subject as "what is a squeeze riveter?"; "how do you solder 2 wires together", etc. Each video is just 3-5 minutes usually; to the point and very informative. No subject or question is too small for them to address. Just use that link and then do a search to find the videos about the subject you are looking for.

    Also please be sure you are getting the DROPBOX link for the EX3 manuals from Mitch. These manuals are updated by Mitch when he has something pertinent to change or add and when he updates it on his end, it's immediately updated on your end when you log on and download or view the manuals (or videos, pictures, etc). It's also nice to download to your ipad so you can read up on things when away from the computer. Ask Mitch to give you that link directly. I keep a laptop open on my workbench at all times and refer to the Dropbox version of the manual I'm working on and compare it against the paper version I got with the kit. Just read through a section of your paper manual and compare it to the online version to see if there are any changes in that section. I ONLY BUILD USING THE DROPBOX MANUALS, NOT THE PRINTED MANUALS !!!!! You can refer to the written manual if you want, but double check it against the updated Dropbox manual first.

    READ THE MANUALS COMPLETELY before starting! Most everything you need to do will be addressed in the manual AT SOME POINT. So if you have a question about when or what to do with a specific section or ahead as it will be addressed at some point.

    In Dropbox be sure and check out the CCK PICTURES file. It has LOTS AND LOTS OF DETAILED PHOTOS AND IS VERY HELPFUL!!

    DON'T PAY MUCH ATTENTION TO THE "INSPECTION SHEETS" IN THE MANUALS. I think these Inspection Sheets are used by the factory and you will see there are lots of things not done yet in the kit or maybe done and not included so if you use them, just use the items that relates ONLY to the things the manual directed you to do in that section and nothing more. SO ..... if you see something in the "INSPECTION SHEET" that was not in the section of the manual you just did... IGNORE IT.....DON'T THINK YOU ARE SUPPOSE TO DO IT YET.

    Also pay attention to the beginning of the manual where it says that if the written information conflicts with the figures/drawings shown......always go by the figures/drawings. They are engineering drawings and are most certainly the most current and correct version. ALSO, ONLY DO WHAT THE WRITTEN PORTION OF THE MANUAL INSTRUCTS YOU TO DO AND NO MORE EVEN THOUGH THE ASSOCIATED FIGURE MAY SHOW MORE THINGS DONE. If the manual only tells you to put 3 parts on a section but when you see the drawing you see a few more parts installed.....DON'T DO IT! The figure is just a figure showing the entire area and all the parts but only do what's instructed at that time. There is most likely a reason you will not put the other parts on at that time and later you will come back and finish.

    CALL MITCH. When you have a question, try your best to answer it by being sure you are checking the manual and if you just can't figure it out give him a call. Mitch is one of the most patient and knowledgeable people I have ever worked with. No question is too small or insignificant to him and he will explain it to you or refer you to where you can get the info you need.

    I have found that contact with Mitch is best like this:
    - For any parts you may be missing or need, email him the specifics including the quantity; part number; part name and why you need it.
    - Phone calls for anything else that you need help or instruction on. I don't normally email him questions unless it's an extremely short question with a short answer that isn't too detailed or complicated. Something like "Mitch, did you ship those AN960-10 Washers I needed".
    - I don't text him normally for anything unless he specifically asked me to and that is usually if he wants a photo of something I'm working on.

    Today I am starting the build by doing the left wing first. I'll make posts along the way of things which might be more difficult or clarification.

    Lastly you will need to keep a "Build Log". On the laptop which I keep on my workbench, I have this build log loaded up and I log every time I sit and build. I do NOT log time I spend reading manuals in advance, watching build videos, etc. I log only the time I'm physically building the airplane. This log will mostly likely be asked for by your FAA examiner or DAR when he comes to give you your Special Airworthiness Certificate when you are all done.

    I made this a simple Excel spreadsheet form. To use it just type in the date in a format like "june 4" and then tab over to the next section and type in the time in the format of "6:15 am"; hit tab a couple times (skip the "time out" box) and go over to the "Work Done" section and then just type in what you do during that session. When you are done for that session (even if just going to lunch or taking a break for a couple hours, etc) just go to the "time out" box and enter the time in the same format. It will then automatically calculate the amount of time in hours and minutes for that session and also total it up at the bottom for that section (like "LEFT WING") as well as keeping a running total at the very bottom of the form where it will tabulate the total time on the airplane. I attached the form here.


    If you catch me in a mistake along the way, please be sure and point it out so we can get it corrected quickly and as I said, I'm only going over things that may need clarification from the manuals or videos or more detailed explanations. However, after you have examined the manuals, videos and photos on Dropbox (LOTS of great photos of most anything is in Dropbox) then feel free to ask the questions on here and I'll try to cover it. I'm no expert on any of this but at least it's not my first rodeo.

    So here we go......

    P1020083.jpg ORANGE CRUSH EX2
    EX3.jpg N836DE EX3

    Attachment 7738
    Attached Files Attached Files
    Last edited by Daveembry; 07-21-2019 at 07:11 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  2. #2
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    The manual has a good list of tools and I think you can order the "kit" directly if you want. Aircraft Spruce and of course Amazon is a great source as well as Cleveland (who bought out Avery) Here are some links to the more common tools.

    Spar drill jig.jpg

    Spar drill jig 2.jpg

    • Dremel Tool. I use the dremel to do all my cutting on metal and carbon fiber using a metal cutoff wheel and sandpaper drums to smooth out cuts. Works great and more precise than a larger, air tool.
    • Flameless solder tool. The kit will use mostly "solder sleeves" to solder wires together. Much easier than hand soldering. It uses sleeves with solder and heat shrink all in one and you use this flameless tool to melt the solder ring inside the sleeves.

    solder gun 2.jpg


    Solder Sleeves. You will get some with the kit but this is what they look like.


    • Hemostat clamps. I have 3 sizes of these. You will be surprised how many times these come in handle to lock onto and hold things.
    • Drill bits. Beside a good set of the numbered drill bits you will also need a G; C and N letter bits. They are on Amazon as well. I also just order a package of size 30 and 40 bits and toss them when they get dull. Don't forget to get the 12" long #30 and #40 bits.
    • Hand Rivet Gun. I got a really cheap one because we are going to grind it to pieces to make it work! Put it on the grinder and grind it until you see the guts and then keep going!!





    I have a chart from Cleaveland Aircraft Tool Company that I hang on the wall here and use very often. One part has the numbered drill bit sized in decimal format so I can use my Digital Compass to check my drill bits before I use them and to compare sizes between maybe the #'d bits and the regular bit sizes. You can probably find one online to print and keep handy as you will find it handy.



    I also use lots of Denatured Alcohol. It's great for cleaning the plane and it will not interact with MEK (the ingredient in the Poly tak, brush and spray) or hurt paint or anything else in the airplane build that I am aware of and its great for getting rid of any oils, etc. on the surfaces before applying brush, spray, paint, etc.


    Also, it works great for removing any sharpie marks you have made. I just wait until I'm ready to start covering the parts and I use an air nozzle and spray everything off very good being sure to get rid on any metal shavings, rivet washers, etc etc and then go over everything with a rag and some denatured alcohol. Stay away from any silicone based lubricants like WD40. If you spray that in the garage where ANY little bit of it in the air gets on a covered surface.......problems. (fisheyed paint)
    Last edited by Daveembry; 12-13-2018 at 10:12 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  3. #3
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    • First thing to do is to lay out the spars on your saw horses and take a red/burgundy scotch bright pad and/or 320 sandpaper and be sure and go over the spar and sand/buff out any scratches no matter how minor they seem. If you can run your fingernail across it and feel it, you need to sand it out. This would be a stress point for future cracks. Then I clean the spars well using denatured alcohol.


    • Manual on Page 39, Fig. W2 has the wrong rivet numbers listed. All the "AN" numbers are in the kit as comparable "MS" numbers. For example, it lists rivets AN470AD4-8 and you should use MS20470AD4-8 and so on for the others listed.
    • Fig. W2 doesn't show the rivets for the rear spar fittings but they should be the same ones.
    • You can use your hand squeeze riveter for everything except the middle hole in the front spar jury strut attach fitting. These are not shown being installed until later on page 62 but you can put them on now. You will have to buck that one or you can use a cherrymax rivet (CR3213-4-4) instead and just pull that with your hand rivet puller (or your pneumatic one).

    3 hours 55 minutes into the build I have all attach fittings installed and tubes in place.


    Note here that instead of using castle nuts on the 2 bolts on the front spar temporarily, I just use the correct lock nuts called for but don't tighten them for now. Anywhere on the build where I need to draw attention to the fact that I have some unfinished business (like torquing these 2 nuts) I just use my blue sharpie and mark on the parts to flag me. Later just use a little denatured alcohol to remove any markings. Note that I always use torque seal on all nuts as soon as I torque them.



    I also have a method of pulling parts for the sections I'm working on. Note in this photo how I mark the manual figure. As I pull the parts, I lay them on the figure next to where they are shown and then take a yellow highlighter and mark that part number on the manual. Also note that I make a note on common parts in the manual as to where these parts are located. Like "T6" (Tote #6) next to part number in the manual and then when I know I'm going to have to pull these again (like at least for the right wing when I do it), I don't have to go search the parts list again to find out where that part is.


    If I am missing any parts I mark those parts on the figure with an orange highlighter, then I place the parts in one of the small, magnetic parts holders along with a note saying what those parts are for and what I'm waiting on. I then set it aside and after I email Mitch with the part numbers I'm missing and receive the parts. Then I just go back to that section and finish. Most of the time you can go ahead in the manual and work on other sections for a couple days until you get the parts. In this case I could not find my letter N and C drill bits and had to order a couple on Amazon so I set the parts I had pulled for the rear spar wing attach fitting aside until the bits arrive so I can pre-drill and then ream the holes and attach it. I went ahead and attached all the other fittings and tubes until the bits come in today. Amazon prime is great with the 2 day shipping.


    Just a note on parts management. I think one of the most time consuming things in the build is gathering parts needed for the section you are working on. First I'm sure to take a full inventory of all parts on the "Packing List" to be sure I've received them. I then unpack the parts and consolidate them into a few boxes.


    Attachment 7758


    You will notice the PACKING LISTS have a title on each page(s) like BOX 1, or SKP 1, etc. I then put several of them in big ziplock bags (for the smaller parts) into a box and label that box with the contents. Then when looking for a part from the manual, I first go to the packing lists and find it (it's in alphabetical order for each package on the packing lists), then I can simply go to the box/ziplock that has those parts and pull them.

    For the big TOTES, I take the inventory list that comes with them and take highlighters and run through all the pages and simply mark them by part number, grouping the starting numbers. In this picture you can see that I used a yellow highlights and marked all the HDW parts; an orange one for all the MS type parts and the blue sharpie to mark all "OTHER" misc. numbers. I don't mark the AN parts numbers because that is the vast majority of the parts on the lists.


    Then when looking for a small parts (bolts, washers, nuts, rivets, etc) then I first go to this inventory sheet and can quickly scan the pages looking by color code first. Then when I find it, I simply go to that TOTE # (listed at the top of each page) and pull the parts.


    I got the Bogert rotators for the wings and fusehere

    I go to Home Depot or Harbor Freight (much cheaper on everything) and get some castering wheels and added them which makes it MUCH nicer as you can just push it around in the hangar/garage, etc. and when it comes time to move from the build area to the hangar, you just wheel it up into the enclosed trailer and secure.

    Note that you wonít use the rotators on the wings for the build because you have to keep a 1Ē block under the outboard, rear spar the entire time. You could put the wing onto the rotator to cover but for me itís just easier to leave them the sawhorses to build and cover. They are lightweight and easy to just flip over when covering the other side.

    Building the fuse if MUCH easier using the rotator.

    When I build my wing holding fixture, I also add some castering wheels to them as well making them easier to move around in the build area and onto the trailer, etc.

    The rotators are great for painting on both the wings and the fuse but you can only do 1 wing at a time which is OK as most paint booths arenít large enough to hold 2 anyway.

    So I build a wing on the sawhorses to the point of needing a set of wing clamps and move it to the wing dollie. Then I build the 2nd wing.......get a set of the leading edge wing clamps headed my way and then put the leading edge skins on each one and get the clamps back available for the next person that needs them so Iím not holding anyone up.

    I then cover and apply tapes on the wings on the sawhorses (or you could then put it on the rotator but note you will have to remove it from then rotator and back to saw horses during the cover process anyway, so I just cover them entirely on the saw horses).

    After both wings are covered, I then roll them up in the trailer and take to the hangar and cover them completely in some light plastic to keep any contaminates (like any silicone sprays, WD-40, oil, dirt, etc) off until ready to paint.

    Then you can mount up your fuse onto the rotator and complete the entire build (except that you will have to take the front off the rotator when you fit and build your boot cowl) and cover. Then wheel it into the trailer and right into the paint booth. After paint, wheel it back to the build area for the remainder of the build.

    For painting I use the rotator for everything. They are great for a couple of reasons. You can angle them so the paint booth lights hit the area perfect that you are spraying the paint onto and you can flip the wing over to do the opposite sides. Most of the time you will be spaying with the wings at about a 45 degree angle to get the best light.

    Secondly, as you spray the paint and if you get it just a tad too thick and it starts to sag or a slight run, just tip the rotator to either level or even in the opposite direction to get the paint back flat. With the DUHS CC paint I use, it will continue to flatten out for 24 hour it seems. So just keep a good eye on the area you just sprayed and tilt the rotator as needed. If one spot has a little sag or run, just leave the rotator so that area is level and the next day you will probably see the sag or run has flowed out.

    The rotators seem to have a good resale as well. They are heavy for shipping but they ship without the main piece of tubing which you buy locally. I would also get a thick wall tubing as well for mounting the wings as it does tend to bow down in the center with the tubing I got. I canít recall the thickness but it was the recommended thickness. I would go thicker.
    Attached Images Attached Images
    Last edited by Daveembry; 07-21-2019 at 07:35 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  4. #4
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    On Figure W7, page 58; note that you will not be installing the diagonal tube at this time. (SC31004-005). It will be done later.

    To be sure that I have the tubes all the way into the fittings on the spars, I measure the distance between the spars at each tube location. I've always found them to be within 1/32" of the same distance at each of the 5 locations with a measurement of 30-3/16".

    You will only be putting cherrymax rivets in the 2 tubes between the #8 & #9 ribs.


    Note on rivets.....cherrymax rivets are much different than a standard pop rivets. The rivets you will be installing in the ribs to spar are "pop" rivets. They are not very picky to be installed. You can angle your rivet gun slightly if you need to with no problem. However, the secret to setting good rivets using the cherrymax rivet is that you must have the material tight together and flush (no gaps, not at an angle, etc) and the most important thing is that you must have the head of the rivet gun FLUSH onto the rivet head. It will not tolerate any angle at all. The cherrymax is a much stronger rivet and has washers on the top that will pop off after you pull the rivet. If you pull it at an angle you will see that the center of the rivet is not up flush with the top of the rivet head but instead it will be broken off down further into the rivet head (kind of a hollow hole in the top). You must remove it if that happens by drilling down a small amount into the rivet head and then take a small punch and use it as a lever to take the head washer off the top of the rivet and then use a small punch and punch out the rest of the center of the rivet that is down through the material you just installed it in.

    There is good details in the manual about placement of the "double ribs" you riveted together. Just pay attention to which one of the double ribs you rivet to the pre-drilled holes in the spar (there are only 2 hole drilled in the #1, #3 and #5 double rib locations). The space between these needs to be perfect because the fuel tanks will be housed here.

    : The rivets used are the HDW-SS/SS42D which are stainless steel rivets. There are 850 shipped in the kit in an individual bag and probably listed on the last page of your tote parts lists on Tote 13. Also, 850 are not enough so if you only got 850, tell Mitch you probably need 150 or so more. THEY WON'T BE IN THAT TOTE AND THEY ARE NUMBERED DIFFERENTLY USING POLY FIBER NUMBERS ON BOTH THE TOTE PARTS LIST AND ON THE PARTS BAG. IT'S LISTED AS CCPS-04-03 ON THE PARTS BAG ITSELF BUT CCPO-04-03 ON THE PARTS LISTS.

    Also, I don't put all the bolts, nuts, etc in the holes like they say in the manual. Really no reason to do all that, just line up the holes they mention and then use 2 or 3 of your spring clamps to hold the 2 ribs together until you drill a couple holes on each end and stick a cleco or rivet in to hold it. Lots quicker. Doesn't matter which way you put the rivet head in as this is just to hold the ribs together until you get them riveted into the spars but as a general rule, all your fasteners normally will go into an airplane with the head of the bolt, rivet, etc. on the front (pointing aft) or the left side (pointing right). An exception to this for some reason is later on the fuse trim motor where they run the bolts from right to left for some reason????? They use to use the meth glue to hold the double ribs together but went to this rivet system with the EX3. The rivets go all the way around the ribs as shown on the Fig. W6 (see the little black dots spaced all the way around the ribs?)


    You will need to cut some of the rib at the rear spar to fit around the bolt heads in the rear spar wing attach fitting. The best tool for working with aluminum like this is the "nibbler".




    Pay special attention to the manual drawing for little things like the number of washers used on the NUT SIDE of the rear spar attach fitting. AN bolts have a washer machined into them, so they really don't need a washer but AN bolts with a "shoulder" need to be sure the shoulder is completely in the part (such as this rear spar wing attach fitting). So the figure calls for 2 washers and then the nut on each of the bolts and no washers under the head of the bolt. This is to be sure the entire shoulder is through the parts. Normally on lock nuts you should have no more than 3 threads out the nut and not less than 1. If you find you have more than 3 threads you can add washers up to 2 max on each side. Note that washers such as "AN960-10" and "AN960-10L" show not only the size but thickness. All washers with "L" at the end is a "half-washer" .....or 1/2 the thickness of the same washer that does not have the "L" designation at the end. So the AN960-10 is the full thickness washer and the AN960-10L is half the thickness.


    6 hours into the build at this point for me.

    Last edited by Daveembry; 03-27-2019 at 08:12 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  5. #5
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints



    When we build the wings, we want to have the aft end of the rear spar up higher than the rest of the other 3 spar ends so we can have "washout" or less angle of attack at the ends of the wings than at the wing roots so when the wing stalls, it will first stall at the wing root but still have less AOA at the aileron ends of the wings to let you have some roll control. Later when installing the wings, we will adjust the dihedral of the wings (outboard ends of the wings about 3.0" higher than they are at the fuse spar ends) and the washout by adjusting the struts. The front strut will let us raise or lower the height of the front spar to give us the 3" and the rear strut will let us raise of lower the aft spar so we can bring the outboard end upwards. That will all be covered when we install the wings but for now, we build the wing with 1" of the aft end of the rear spar raised so the rear spar reinforcement cap; drag wires and leading edge nose skins will lock it in pretty close before installing.


    Missing a few rivets or screws or whatever???? (You WILL be....) Just give Mitch a call and an email listing what you need and follow up....follow up and follow up. I have never ordered a single part from anyone.....Mitch will send you out what you need ASAP and usually by Priority as soon as you see you are short something..... CALL MITCH! and get it coming.

    DRAG WIRES. Note there are 2 sizes of drag wires. The Fig. W17 shows how they are installed. The thicker ones go in the inboard/rear spar to the outboard/front spar in the first 3 bay areas (there are 4 bay areas where the drag wires cross) and are always on the BOTTOM of the wires where they cross. So the thinner wire is always on top of the thicker wire in the first 3 bays and in the last, most outboard bay, both wires are the thinner and the one running from outboard/rear to inboard/front spar goes on top.

    The manual explains how you need to use a #9 drill bit to enlarge the hole in the spar attach fitting where the larger wires go through. I found that a bit snug so I used a #8.

    You will also have to completely drill through the strut attach fittings on the front and rear spar (between the #8 and #9 rib locations). Just start on the outside of the fitting and use the existing hole as a guide and you will be drilling all the way through fitting on the inside of the spar. It comes out where it comes out!



    When you drill through these fittings it might be easier to use the 3/16" drill first and finish it with the #8 for the larger wires. FOR THE SMALLER WIRES where it goes through the fittings there between rib #8 and #9 you can use a #20 drill bit for those smaller holes.

    When you install the washer and double nuts on the ends of the wires, just barely get them started right now. Don't even "snug them up" at this point. You want them really loose until we "trammel" or square up the bags using these drag wires later.

    You will have to remove some material from rib #8 up close to the front spar. I run the big wire in through the front spar fitting and see where it hits the rib and mark it with a sharpie. I then drill a small hole there and then run the step-drill bit through it to enlarge it; then you can run the wire through it.



    Page 80 we install the machined ribs on the rear spar. The explanation is a bit confusing so all you are going to do right now is to install them on the #5 and #12 ribs where you had previously put in the AN3-3A bolts. I use a screwdriver to hold the heads of the bolts up tight against the spar while I hold the machined rib up to the spar and get the nut started. Then you will need a 3/8" wrench on the bolt head and 1/4" socket to tighten the nut to 40 in lbs. Remember to torque seal.

    Then you are going to install 2 cherrymax rivet in each machined ribs at this point. Looking at Fig. W19 & W20 on Page 81, they only show 1 rivet being installed in these area but Mitch is updating it. You will notice above and below where the nuts are that you just installed, there are 2 pre-drilled holes going through the machined rib into the spar (from outboard to inboard). You may have to just run your #30 drill through the holes to be sure they are match drilled in case the rivet doesn't want to go in easily. NOTE: THE 2 CHERRYMAX RIVETS TO USE IN BOTH OF THE HANGERS ARE HDW-CR3213-4-3.



    I have highlighted the areas where the 2 rivets go now. IGNORE all the other info on these figures. Installing the caps on the top and bottom of the ribs will be done in a later section. DO NOT FOLLOW THE MANUAL INSTRUCTIONS ON PAGE 80 WHERE IT SAYS "DRILL A #30 HOLE AND RIVET TOP AND BOTTOM". This is referring to the 2 cherrymax rivets and are PRE-DRILLED already. Don't drill ANY holes right now!


    You can see in these photos the 2 nuts you installed on the bolts going through the spar and the rivets installed directly above and below the nuts. You can see how a properly pulled cherrymax rivet looks. Note there is no "hole" in the head of the rivet but you can clearly see that the center of the rivet is pretty much flush with the top of the head. These top rivets in these 2 machined ribs are the MOST DIFFICULT of the build but I pulled these all with my hand squeezer that I modified.





    As I discussed previously, they are not hard but you MUST try and keep the rivet gun as flush as possible against the rivet head when you pull it and pull it carefully being careful not to move the head as you squeeze the riveter. Much like pulling the trigger on a gun......careful as you squeeze the trigger so you don't jerk or "pull the shot" when it goes off.

    9 hours and 15 minutes build to this point.

    Last edited by Daveembry; 04-03-2019 at 12:37 PM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  6. #6
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Preparing/cutting nose ribs. The PRINTED manual is very specific on this BUT IT IS WRONG! There are only 2 intermediate ribs in the fuel bay.....NOT 3. Ribs 1 and 5 take the regular nose ribs; rib #2 takes the special one we cut out and that leaves only 2 intermediate ribs. Mitch has just changed the Dropbox manual to reflect this but check your printed manual to see if you have the correct one.

    Like I said, I like using a Dremel tool with the metal cutting EZLock blades.

    You should end up with 5 stacks of nose ribs when you are done. 1 for the #2 rib; 2 for the fuel bay ribs; 8 for the intermediate nose ribs (for the nose ribs that are BETWEEN the ones that attach to the center ribs); 1 trimmed special with a hole for the #8 rib and that leaves 11 nose ribs that will attach to the center ribs. So that is a total of 23 nose ribs. (Pay special attention later when installing them that the #1 nose rib is the opposite wing rib part number (ie; left wing will have a -002 nose rib on the 1st rib and the right wing will have a -001 part number nose rib on the #1 rib).

    This is how they should look.


    I like to use 3 files. 1 regular wide, flat file. 1 round file and 1 that has 3 small, flat sides.


    Use the file(s) to remove any sharp edges from the cuts you just made. This is to keep from cutting yourself mostly and perhaps fabric on the couple of nose ribs that are not wrapped in the leading edge skins on the bottom. The EX3 skins are going to wrap around the entire nose ribs from top of the spar to the bottom of the spar except for a couple on the outboard end.

    Section 14 on page 85 I do not do at all. Here the idea is to just install a couple of nose ribs on the 1st & 12th rib just so it will hold a stringline above the spar when you square or trammel the wing in the next step. The most important to be square is the rear spar so I just put a couple of blocks on the front spar the same as I do on the rear spar and do not install any nose ribs. They will just be in the way and you will probably bump into them around while working on the next sections.




    However, when you do install them pay special attention to Fig W26. You will notice that the nose rib #1 is for the part number/nose ribs for the OPPOSITE WING! So if you are building the left wing first it will be a nose rib ending with part number "-002" and all the rest will be ending in "-001". You should know that most of the parts in the kit end with the "-001" for part on the left side and "-002" are for the right side. Parts that aren't specific to only 1 specific side will end in "-001" as well. In other words, if there are 2 parts that are identical and used on both the left and the right wing, it will end in "-001".

    You will also note on page 86 where it refers to using the nibbler to cut a piece of the rib out, on the previous post I showed how I didn't do that but instead used the drag wire to mark the location and then drilled a hole in the rib. On the EX3 the drag wire is more centered in the "meat" of the #8 rib and if you nibble it from the edge it will weaken the rib so refer to the previous post on here about that.


    Squaring) THE WINGS

    Trammeling the wing is actually simple but hard to understand the first time. I wrote an easy to understand piece about how to do it and Mitch printed it in the manual on Page 92 and 93. I think it's pretty self explanatory and if you follow it you should have no problem. One small change (since it was written for the EX2 and the EX3 is a little different with the drag wires) is the next to last paragraph on Page 93 where it says "You only need to measure 1 of the small wires in the last 2 bays (the 2 outboard bays that only have small wires).....". In the EX2 the last 2 bays had only small wires but in the EX3, they added the larger wire to the 3rd bay so now, only the last, outboard bay has 2 small wires. In any case, you only need to measure the pull weight on 1 of the small wires in each of the 4 don't have to do both wires.

    also, here is a link to a previous thread on trammeling where I posted the original info on squaring the wing.

    Note that in the first bay (where you are wanting to square the#2 tube to the front and rear spars) you will be tightening the BIG WIRE out where it comes out of the front spar and you will tighten the SMALL WIRE where it comes out on the rear spar. In all subsequent bays I only tighten BOTH WIRES from the rear spar side. In the information I stated that what I do is just start by tightening all the wires (except that first BIG WIRE) on the front spar at about 1" in from the end of the wire. It isn't critical, they just want at least 1" of exposed wire past the nuts. Tighten them up and from now on for bays 2, 3 & 4 you will just work on tightening from the rear spar.

    Also we will be pulling on the small wire in each bay with the fishing scales in the center, where it crosses the big wire. Mark a sharpie mark 1/2" on the big wire from where the small wire crosses it. We will pull the small wire with the scales from the place the wires cross and you want to pull it to your 1/2" mark and have 13-15 lbs. Don't make these 1/2" marks until you have a full turn or so of tightening on each wire so the slack is taken out. So once the front and rear spars are in line with both stringlines, hand tighten the nuts on each of the wires in the bay you are working on; then turn each side a 1/2 turn or so back and forth on each side until they are pretty tight.....THEN place your 1/2" mark on the big wire. In the first bay you are watching that the spars are square with the #2 tube. In bays 2, 3 & 4 you are simply making sure the spars stay in line with the stringlines as you tighten the nuts.


    While you have your sharpie out, I place a mark anywhere towards the rear spar end of EACH WIRE on the top. The reason for this is that when you start tightening the wires, you want to be sure as you turn the nut that the wire itself isn't turning so I put a small vice on each wire so I can hold the wire and I can look at the mark on the wire to be sure it isn't turning while I tighten the nut.



    When finished just tighten up the 2nd set nut on each wire (except for the 2 wires coming out by the #1 rib which we are going to remove later to install the fuel tanks) and put on torque seal. Cut off excess wire (leave at least 5 threads past the 2nd set nut on each one) on all the wires coming out the rear spars and the 1 big one on the front spar. DON'T CUT THE WIRES COMING OUT BY THE #1 RIB.

    Next take your digital calipers and measure to see exactly the amount of wire sticking out of the 2 wires coming out by the #1 rib on the front and rear spar and mark the measurement in sharpie on the spar web. When we install the fuel tanks, we will take these 2 wires out by removing the nuts on the ends of these 2 wires and pull the wires out the spar and then after the fuel tanks are in place, they will be slid through the fuel tanks and back into position. Since we can't remeasure the amount of tension on the wires, we will simply reinstall the nuts and tighten until the wire ends are exactly the same distance that they are now and that will make the tension the same.




    I have 11 hours and 15 minutes to this point in the wing build.

    Last edited by Daveembry; 03-24-2019 at 10:41 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  7. #7
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    OK. We are going to essentially re-write Section 19 & 20 on Pages 100-105. It's a bit confusing in the manual so I'll try to make it easy (ier).

    First layout the rear spar reinforcement SC31601-003 (see manual for part numbers) as shown in Fig. W32. Don't clamp it into place yet. Just let the inboard end be at the outboard side of rib #6 for now. Note that it doesn't matter which end goes on inboard or outboard side as long as the first, INBOARD hole (end closest to the wing root) is on the OUTBOARD side of the rear false spar (see the figure).

    So the inboard end hole should be on the outboard side of the rear spar.

    Now count down (beginning on that inboard first hole) the holes from inboard to outboard and take your sharpie and draw a circle around hole #23 and #24.

    As you read in the manual, hole #23 is the hole that will be used by the PULLEY BRACKET to align the hole in it with this #23 hole.

    Assemble the pulley as shown in W34 without cotter pins (you will have to take this apart again when you rig your aileron cables when you are finishing the plane). You can see in the photo here the hole #23 on the reinforcement cap and the pulley bracket.



    So set the assembled pulley bracket on top of the reinforcement like shown in the photo here and align hole #23 on the reinforcement with the hole in the bracket and just clamp it there on the edge for now. You will note that the pulley bracket is wider on one side and that wider side will go on the inboard side of the spar (so the angled part slants towards the OUTBOARD end). Hole #23 will be the OUTBOARD hole.

    If you are doing the bracket should slant towards the outboard end of the wing. The photos #114-117 on page 103 of the manual are very confusing because it is of a right wing where all the drawings are of a left wing. So the bracket is going to face the OPPOSITE of these photos for the left wing. All my photos here are of a LEFT WING.

    Next take a string and just run it from anywhere on the forward side of the wing, through the pulley in the bracket and then take the end in your hand and just hold it over the aileron hangar and then simply slide the entire reinforcement cap along with the pulley bracket you have clamped on, back and forth until that string comes out of the pulley and goes right down the center of that hangar. It should work with the inboard end just at the outboard side of rib #6 but it doesn't matter......just make the string go down the center (looking from above like this photo) and then clamp the reinforcement cap in place on either end.


    Next we are going to be sure the reinforcement strip is centered on the spar before we drill. Use the end of your digital calipers and move the strip in or out on the spar until it's centered. It should be around .160 on either side of the reinforcement that hangs over the spar.



    Use several clamps and clamp it in position and then using your drill with a drill stop on a #30 bit, drill all the holes through the top of the spar.

    Now since hole #24 in the reinforcement will be UNDER the pulley bracket, we will need to countersink it and you will see on Fig. W33 that we will be using a countersink rivet for this 1 hole only. A CR3212-4-2 will be used here. I like the countersink tool I listed in the first post, the Microstop.



    After installing this rivet we want to install the 38 CR3213-4-4 rivets in all the holes we drilled except for #23.

    After installing all 38 rivets, set the pulley bracket back on top and match drill it to hole #23 (you will need to widen the hole already in the bracket with your #30 bit) and then set it on top and stick a rivet (or cleco) in that hole #23 through the bracket and reinforcement strip.

    Then swivel the bracket on the cap strip so that the inboard (on the left for the left wing) and the outboard side (on the right for left wing) is flush with the capstrip edge on both sides. Take a straight edge and just be sure the holes in the bracket line up with the holes you already drill through the reinforcement strip and spar. That way you know you are safe to drill through the spar without hitting the bulb of the spar. Be sure they are correct and then just drill it out and install the 5 longer rivets that go here (since these have to be longer to go through the bracket and reinforcement strip). CR3213-4-5


    Also check to be sure the bracket isn't going to touch or be interfered with locating properly by one or more of the rivets already installed. If so, you can just file a little off the bracket to clear the edge of the rivet.

    That's it. 13 hours total build time so far.

    Last edited by Daveembry; 04-04-2019 at 09:18 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  8. #8
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Tail ribs. Just note that the first one that goes onto rib #1 is part number -002 which is a rib from the RIGHT WING. It is different from the rest of the tail ribs which are -001's (just like the first nose rib was from the right wing).

    You will need to cut the top of the #2 rib back from the inside edge of the spar so later the false spar lip that goes over and rivets into the fuel bay will fit. The manual actually says you can cut all the tail ribs that do not connect to a center rib like this (just the few down by the aileron hanger).


    Do NOT put the rivets in the SIDES of the tail ribs on ribs #8 & #9. Later in Section 22 you will be installing the tail rib reinforcement brackets on the joints of these 2 tail to center ribs. When you put these brackets on your will be installing 7 rivets into the sides and if you put that one on the side first, before these brackets, they will interfere with the brackets sitting flush with the center rib.

    Also, it's noted in the manual that you will NOT put any rivets for these 2 ribs into the rear spar. Just put the top and bottom rivets in where the tail ribs join the center ribs but not into the rear spar. You will see when you try to install the brackets you will need to slide and twist these tail ribs a bit to get the squeeze riveter in.

    Manual page 109, photo 126 is really not true. They use to use meth to glue the double ribs together so you had to cut the tabs off further to fit but now that we are riveting the double ribs, they will fit between the center ribs perfectly don't bother doing this step. In fact, they are much more secure if you donít cut them and push that area down between the double ribs.

    You can see here how I have modified by squeezer by cutting it down in areas as well as cutting down the edge of the dies so I can have good clearances like in the places here where we have to dimple and then set the rivets in the tail ribs to center ribs.



    Here you can see the "dimpling" dies used on the holes on the top and bottom tail to center rib connections. NOTE: Go ahead and put the top and bottom rivets in these TAIL ribs (tail ribs to center ribs) on the #8 & #9 but not the side ones as we are going to do that in the next section when we install the rib reinforcements which will rivet in from the sides. Also right now, DO NOT install any of the SS rivets into the spar for the rear center and tail ribs. You will see why in Section 22 when we have to install the reinforcement brackets. To make room to get in and squeeze the side rivets for these brackets, we will need more room so by not installing the rivets, we can slide the center and tail ribs out away from the cross tubes to give us room to work. The manual says "the #8 rib may be moved inboard 2" in the rear to clear the rear strut attach fittings", this is what it's referring to. You can "Temporarily" move it over to work on the can't really MOVE IT OVER 2" permanently.

    Also note that the manual doesnít say anything about needing to install the same rivets on the tail to center ribs on the bottom side of the wing. The figure only shows the top but you also have to do the bottom.


    These modifications make it so that you can get the squeezer up close to the ribs (under the top of the rib) like here.


    I drill and install all the top and top/side rivets first before drilling the bottoms so everything stays lined up. Note that when you drill the top holes from the tail rib to the center ribs that you first hold the tail ribs (and later the NOSE RIBS you do the same) straight out (perpendicular.....90 deg. angle) from the rear spar before drilling the holes.

    When I'm finished installing all the top and bottoms rivets I go back with a pair of pliers and just straighten the tops of the connection points so they are more level and the edge isn't sticking up because the fabric will be laying on these areas and you don't want the edges sticking up.


    MACHINED CLIPS. Section 24, Page 113.

    This is a little confusing but really simple.

    On the BOTTOM of rib #5 put the clip SK31055-001 (NOTE: Pay attention to the part numbers because there is an ďSCĒ and an ďSKĒ with the same number) and SC31055-001 on the top like the pictures show in the manual.

    ON THE TOP CAP ONLY, drill 2 #40 holes up at the top towards the inboard side of the spar on the clip, dimple and install the MS20426AD3-3 rivets. Just center these holes on the parts you are drilling into (the ends of the double center ribs) and keep an edge distance of 2 times the width of the rivet.

    The top aft, outboard hole and rivet that goes into the machined rib will be installed later after the capstrip is installed. You can drill the hole now 0.25" up from the outboard edge of the clip but don't install the rivet now. You can also drill the hole in the center of the cap right over the spar. This is for a fabric rivet later.


    Put the SK31055-001 clip on the bottom and do the same except use a #30 bit and there will be 4 of the CR3213-4-2 Cherrymax rivets onto the back of the clip into the machined trailing edge rib. 2 will go on the inboard side of the spar going through the clip and each side of the double ribs and the other 2 will go onto the machined tail rib.


    NOTE: MITCH CONFIRMED THAT THE FIGURES ARE CORRECT SHOWING THE CR3213-4-2 BOTTOM CHERRYMAX RIVETS WHICH ARE NOT COUNTERSUNK. THIS MADE NO SENSE TO ME SINCE THE BOTTOM FABRIC WILL CONTACT THE BOTTOM AND THE 3213 RIVETS WILL LEAVE A BIG BUMP THERE BUT.....I was finally told that the reason is that the countersunk rivets are not as strong as the others and the engineers wanted more strength here.

    Use SC31055-003 caps on both top and bottom of the #12 rib. Drill #30 holes on both the top and bottom clip in 1 location going from the clip into the machined rib, countersink and install HDW-CR3212-4-2 rivets.

    Then drill 1 hole on each clip aft of the spar, on the inboard side and 2 holes in each clip, forward of the spar on the outboard side and install the 6 HDW-CR3213-4-3 rivets on the sides.

    This is rib #12 clips. Note the location of the single cherrymax rivets on the sides going into the machines tail rib and there is only 1 hole in the top and bottom of the clips and its on the machined rib side. There are no rivets from the top and bottom clips into the center ribs.

    This is a view of the outboard side of the #12 rib showing the 2 rivets that go from the sides of both the top and bottom clip into the center rib.

    16 hours and 40 minutes into the build at this point.

    Last edited by Daveembry; 04-06-2019 at 11:09 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  9. #9
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Nose Ribs.

    The manual is pretty self explanatory here. Just a note that you do NOT want to install the top or bottom rivet in the #8 rib nose rib (and remember we left it out also on the bottom of the center rib there on the front rib) because..... you will see that when you go to install the bottom rivet of the nose rib to center rib for that #8 rib that you are going to need to slide the bottom over just a little to get your squeeze riveter up into position to set the rivet because the tubes are in the way. After you install that bottom rivet in that connection, then you can install the 2 SS rivets in the #8 center and nose ribs.

    Also just pay special attention that the nose rib on the #1 rib is actually the -002 rib that normally goes on the right wing. All the rest are the -001 nose ribs.

    NOTE: I don't install the intermediate rib between center ribs #2 & 3 until after I install the false #2 rib later. This will give you more room for a couple of holes and rivets you have to install into the side of the #2 false rib. So just leave that one out for now.

    CAPSTRIP #5.
    Page 121, Section 27

    (Note: many of these changes here have been updated by Mitch. Some of the updates are still wrong, so just be aware).

    There are a few typos, figure and photo referrals here. Looking at my printed manual, the first sentence should refer to Fig. W45, not W46.

    Also note that Fig. W45 shows the rivet that goes through the capstrip, cap and machined rib is listed incorrectly. It's shown as a CR3212-4-2 but if you look at Fig. W46 it shows that rivet should actually be the longer CR3212-4-3. If you look at Dropbox however, Fig. 45 in the printed manual is actually W46 and the incorrect rivet number has been removed from W46 and is correct in Fig 47.


    NOTE: If you use the Dropbox version of the manual (as you should as there are current changes there that is different from the printed manual) it's much easier to enlarge the page and figures to read them. It's pretty hard to see these figures and small print in the manual but you can make it HUGE onscreen.

    Page 121, middle of 3rd paragraph the referral to Photo 193 is wrong. I think it should be photo 142.

    Page 122 says to install the 3 CherryMax rivets per Fig. W45 and that should also be W46.

    Page 124 refers to W45 in th first line and should be W46 also.

    -Mark and drill a #30 into the machined clip on the #5 double rib per the manual (W45) .25" from the top of the machined rib radius on the top, centered on the machined rib.

    - Get the capstrip PC31054-001 (same for left and right wing) and the end with the 2 holes in the center about 8.5" from the end and has 2 more holes centered at the very end..... goes on the aft spar end.

    There are 2 holes there pre-drilled....1 is smaller than the other. Circle it with sharpie. Measure 3.5" aft and mark the capstrip and another mark another 3.5" aft (see Fig. W46). (Note that the latest kit I got has these 2 holes already drilled out in the capstrip.)

    Drill out this smaller hole with a #30 drill bit and place the capstrip onto the double #5 rib and cleco this one you just drilled to the hole you made in the capstrip (the one .25" from the top of the machined rib). You can then drill a #30 fabric rivet hole through the capstrip into the machined clip (it would be right over the aft spar).


    - Next get a small square and square the flap/aileron hangar with the rear spar and use clamps to hold the capstrip and machined rib in place. Drill out 2 #30 holes in the 2 spots (each 3.5" from the first hole) and cleco. (Again note that the latest kit I got has these 2 holes already drilled out in the capstrip.)


    - Center the capstrip on the double rib and clamp in place. If it's off just a little, it will flex over a little as you go. Just center the first foot or so from the aft spar and get some cleco's in, then keep moving the rest of the capstrip over to the center as you go until you get to the end.

    There are 25 holes you will need to drill and cleco. Use a #30 bit for all the capstrip holes except the one you will drill into the nose rib at the very end. This one is #40 with the HDW-MS20426AD3-3 rivet. The rivets used in the other 25 holes are HDW-MS20426AD-4-4 rivets. You will have to dimple and then install the rivets.

    The front of the latest capstrip I have does not need to be trimmed. If yours is the older ones, it will be too long. Just cut it off 1" forward of the outboard edge of the front spar.

    DO NOT FOLLOW THE MANUAL HERE WHERE IT SAYS TO INSTALL ANY RIVETS. YOU WILL NEED TO REMOVE, DEBUR AND DIMPLE THE CAPSTRIP BEFORE RIVETING. I think the manual got a page of text on the wrong page. He says to install the rivets but then on the next page, it says to "Mark the capstrip in the front as shown ......."

    - If you are going to rivet your fabric on, then take a long #30 drill bit and match drill the 3 fabric holes (come up from the bottom) in the machined rib through the capstrip and also drill out the other 4th fabric hole that is the larger hole in the capstrip that is directly over the clip underneath.

    Just match drill down through the capstrip hole through the clip. There are 3 holes in the machined rib you come up through the capstrip and 1 that you drill in the center of the machined clip through the capstrip for fabric holes. If you look at the tail ribs, etc on either side of the machined tail rib, you will see where all the other rivet holes are that you will be using, so you will be putting these in to match.


    - Remove the clecos and capstrip and deburr all the holes and then put the capstrip back up and cleco in place again. You can dimple all the rivet holes (but NOT the fabric holes) .

    - Measure 1" past the forward side of the front spar and cut off the rest of the capstrip and drill a #40 hole through the capstrip into the nose rib and install a MS20426AD3-3 squeeze rivet (dimple first).

    - Install the rivets after using the microstop to countersink the 3 aft hole for the cherrymax rivets through the capstrip into the machined rib. Use CherryMax CR3212-4-3 rivets are 3 in the tail end aft of the rear spar; 25 squeeze rivets into the center ribs and the 1 squeezed rivet in the nose rib.

    - Again, if you are going to use rivets in the fabric, use a long #30 drill bit again and from the bottom, match drill through the fabric holes in the top of the center ribs. It doesn't really matter which rib you use, but only use 1 rib....don't drill out the holes in both of the double ribs.

    LASTLY, this needs to be "pretty" since the fabric will be laying directly on top of these capstrips. So, I take a file and use it as a straight edge and go over the tops of all the rivets to be sure none of them are sticking up and would show through the fabric. If you find 1 high, then just file it down a bit on the top.


    Last edited by Daveembry; 04-13-2019 at 11:39 AM.
    Dave Embry
    "You only live once.....
    ..but if you do it right.....
    ....once is enough."..

  10. #10
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Rib #1 and Rib #3 Capstrip

    The manual is pretty straight forward here. A couple of things:

    - You see that the #1 capstrip is set flush with the end of the #1 tail rib, it should be flush with the inside (outboard) of the double rib and the lip on it should face down. If you get it right, the nutplate pre-drilled holes will be sitting on the inboard center double rib and the rivets will be going into the outboard double center rib.


    Rib #3 capstrip you will set so that the nutplates line up with the ones on the #1 capstrip. Just measure up to the first nutplate on the #1 and set the #3 capstrip so that it's first nutplate is the same distance forward of the rear spar. This capstrip should be centered on the double center rib and the nutplate holes should be INBOARD of the #3 rib and the rivets will be on the outboard center rib..

    If anything, you might want to cheat it just a hair towards the inboard side of the double rib. The reason is that you will be giving yourself plenty of room for the nutplates to fit under that cap/rib without hitting the center part of the center rib.



    Use the microstop to countersink all the rivet holes (except not the #20 center holes of the nut plates).


    One little trick I like to do it after drilling all the nutplate holes (the #40's on the rivet holes and #20 in the center, screw hole), I like to take my rivet squeezer and just lightly squeeze the ribs and capstrip where you drilled these holes just to push them up flush together. This will keep you from problems setting the nutplates flush with the bottom of the top of the rib and lets the rivets go all the way through the nutplates.

    After installing the nutplates be sure they "wiggle" around some to be sure you haven't pinched them when installing the rivets.

    These nutplates will be used near the end of the build when we install our tank covers but we won't match drill them until the plane is finished to allow for any movement during fabric and shrinking, etc. One thing I like to do is to keep these holes (the #20 ones in the center of the nutplates that our screws will eventually go down through) clear so after I install fabric over them later, I use an awl to punch holes through the fabric down into the nutplate. That way they are easier to find later when you have to match drill them. I do this after fabric and then again after paint. It's easier to keep them in sight now than later when the wings are installed and you are on top of a ladder, leaning over the wing trying to find these holes through everything. Later you will take a soldering iron and burn these holes completely open before installing the screws through the fuel tank covers.

    If you are riveting your fabric then you will need to drill out some holes from the bottom using a #30 bit. On the #5 double rib match drill up from the bottom through the existing holes in the tops of the ribs through the capstrip. Only drill out the holes on 1 of the double ribs, not both. I drill them through the inboard rib just because it lines up with the nose rib which is attached to that inside center rib. At the tail end it won't line up on either center rib because the machined rib is in the center of them both so the rivet line will just have to veer off to one direction or the other here.

    You will also need to drill out fabric holes in the bottom of one of the #3 double ribs. I use a long straight edge and just lay it across the holes in the #4 and #5 ribs (on the bottom) and make a mark on the bottom on the inside rib (same reason....because the nose rib attaches to the inside rib) and then just drill them out with a #30. This isn't critical, you just want it to line up with the rest of the rivet in the wing to look nice.

    #1 Bottom Capstrip

    NOTE: Dropbox has the correct info now on this section AND THE MANUAL IS WRONG. The manual says to put the end with the longest distance from the first hole towards the aft but it should actually be the shortest end. See below.

    Just look at the strip and the end that has the hole the shortest distance from the end goes towards the aft/tail rib end and should start with being where the bottom of the #1 tail rib (see photo and drawing below that I did) and the back of the tail rib intersect. You can use a small ruler to put on the back of the rib and then just slide the capstrip down until it touches the ruler.

    The strip should be centered on the #1 double rib and the last (most aft) hole should be on the INBOARD side.

    Note that some 6 holes won't be used as they do not pass through the double rib. There is 1 outboard, nose rib hole that won't be used now as it will be done later when the nose skins are installed. There are 2 inboard nose rib area holes that don't go into anything and won't be used. Then there are 2 on the inboard side of the tail rib that don't meet the rib and 1 more inboard on the double center rib area but it also does not meet the rib.

    There are 2 that will go now into the tail rib on the outboard side. So there are 27 holes in the capstrip of which 6 won'ts be used so 21 rivets should be installed. See Fig. W49 which is a bottom view looking up at the left wing. You can lay on the floor looking up at the wing and look at the drawing to see it easier.



    The figure says to use 23 rivets but in the drawing they only show 22 being shown in the drawing???? The drawing is wrong where it shows something strange on the at end of the capstrip where it overlaps the tail rib at the very end? Is looks like they added one there but I can't tell.

    I just installed 21 rivets now. I just put them in every hole that went through the double rib or tail rib but did not put any in the nose rib itself as we will later put the nose skin OVER the top of this capstrip and install a rivet through all 3 pieces (leading edge skin; capstrip and nose rib).

    This figure was not in the manual but shows where the cap strips for the top and bottom of the #1 rib start at the aft tail rib. I didn't take a fuzzy photo....this is just the way it was in my EX2 manual. The left figure is just showing that the top is flush with the outboard edge of the double rib and the bottom is centered and the right figure is showing that the top and bottom capstrips start with being flush with the point where the bottom and back ends meet (see above).


    I have a total of 20 hours and 30 minutes to this point in the wing build.

    Last edited by Daveembry; 04-13-2019 at 01:32 PM.

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