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Thread: Building the EX3 - Tips & Hints

  1. #11
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    #3 rib bracing is pretty straight forward in the manual EXCEPT YOU SHOULD NOT DO IT ALL NOW!

    These are just used to keep that rib from pulling/bowing out when you shrink the fabric.

    Later, after you have installed all the leading edge skins, you will install the fuel tanks and they won't fit in the fuel bays without having to flex the #1 and #3 double ribs out a little to get them in past the cap strips. So if you do this now but you will need to remove the screws from the braces into the spar web later when you install the fuel tanks and then re-secure them so for now, let's not install the ends of the braces that screw into the front and rear spar.

    For now......we will have to install the rib ends of the braces now so we can access the little nuts that go on the inside of the fuel tanks bay (inboard side of the #3 double rib) but you can easily later install the screws from the outboard end of the braces into the spar web (or just drill the hole and start the screws now).

    THE MANUAL IS WRONG WHERE IT SAYS IN RED NOT TO INSTALL IT ONTO THE RIB. You WILL install it on the rib now because you will not be able to do it after the fuel tank is in. For NOW, do NOT install the screw into the SPAR and DO install it at the rib.

    The #2 rib false rib is also pretty self explanatory. The position of the rib is with the cutouts facing UP and slide it forward or back until the fabric rivet holes on the bottom line up with the hole when using a straight edge from ribs #3 and #4.

    NOTE that Fig 68 says "holes align with other center ribs" but if you look at Section AF-AF it shows that 2.25" of the false rib should extend from the inside of the rear spar to the end of the rib. If you do this, the holes will not align..... so the Figure and Sections are in conflict. I think it's important to align the fabric rivet holes for the final look but it will shorten the amount of rib into the tail rib by about .63" which I don't think matters at all structurally. I think they changed the rib or didn't calculate correctly when doing the Section drawing. So I'm centering the rivet holes and installing the cherrymax rivets into the nose and tail ribs as shown but ignoring the 2.25" measurement in AF.

    After you line up the holes on the bottom, just place a mark on the false rib and then install the meth, clamp it and then install the rivets as shown.

    Note that there is a difference in how the holes are drilled when looking down into the cutouts in the false spar. When you have it correct you will notice that if you are looking down from the top, into the front cutout (the one closest to the front spar) that the hole drilled in the bottom of the cut-out will be more aft of the center of the cutout and the hole in the bottom of the aft (rear spar) cut-out will be more in the very center of the cutout.

    So if you install the false spar, put the end with the hole in the center of the cutout in the aft position. If you align the fabric rivet holes on the bottom of the false spar with the other center ribs on the bottom, you will see that the most aft edge of the cutout will be 2.71" from the false spar.

    (Here you are looking down onto the false spar with the nose ribs to the right side. You can see from the digital compass that it is 2.71" from the aft edge of the front spar to the most aft edge of the cutout. In this position, all the bottom holes should line up with the rest of the ribs.)

    So to summarize it again:

    The #2 false rib has pre-drilled fabric rivet holes in the bottom. According to Fig. 51 (bottom right side) it says "hole spacing to align with center ribs". So in Star Trek terms.....this is the "prime directive".

    So, go to the #4 center rib (I use #4 because it's the first rib pre-drilled by the factory since we have to drill the fabric holes in the bottom of the #3 double rib. If you have already matched the holes in the #3 double rib to the others correctly, then you can use it)......on the bottom and you can hold up the #2 false rib right along beside it and you will see that only 1 end of the false rib bottom fabric rivet holes will align with the holes pre-drilled in all the center ribs already (just like they are in the #2 false rib). If you try and turn it the other way the holes will not match up at all.

    You will see here in this photo that on this #4 center rib, the first hole back from the front spar ....and the 2nd hole aft is 2.4" and the distance between that hole and the 3rd hole is 3.4", etc.


    Now if you look at the #2 false rib, one end ONLY has the pre-drilled hole with this exact same spacing and it is as I described in the post. See the photo below and you will see the spacing is the same as the rest of the center ribs on the bottom.


    So.....THE FALSE RIB HAS TO BE INSTALLED IN THIS POSITION with the end with the shortest distance of 2.4" between the first 2 holes ....towards the nose ribs. There is no other way.

    If you install it this way, you will see that looking from above, this forward end of the false spar is the one with the hole offset from the center of the front cut-out area and the hole that is centered in the cut-out area will be on the aft end.

    You slide the false rib back and forth until you have the bottom fabric holes in alignment with the other center ribs and then install the rivets connecting it to the nose and tail ribs per the "sections AF-AF and AE-AE) and that's it. No other way to do it correctly.

    Flap False Spars

    I added a short Youtube video here at this link about this

    Once I get the false spar on I take some 2x4 blocks and put them on the sawhorses under the spars to raise it all up so that the flap false spar; nose ribs, tail ribs, etc. won't rest on the sawhorse. Just be sure you put them under all 4 corners including your 1" block on the outboard rear spar until you have all your skins on the leading edge.



    An easy way to drill through the flap false spar (and this also works for the nose ribs into the leading edge skins) is to FIRST take a sharpie and make a good line down the center of the tail ribs ON BOTH THE TOP AND BOTTOM (and nose ribs) before putting the false spar (and later leading edge skins) in place. The holes in the flap false spar are pre-drilled, so to be sure you are drilling down into the center of the tail rib, just move it back and forth until you see the line you marked in the hole and then hold it in place as you drill through it and install the SS rivet.


    OK. So here is the order of what to do:

    - First, install the big FLAPS FALSE SPAR. Fit it into position, clamp the turned down edge part that goes into the fuel bay so that the bottom of the lip is flush with the bottom of the spar there. The outboard tab goes on top of the machined rib/hanger and should be flush with it.

    - Line up the pre-drilled holes with the tail rib centerlines we marked. Drill the very top row of the holes (up closest to the fuel bay) and install those SS rivets. Then move down towards the outside of the false spar and drill and rivet the next row of holes....then go UNDER the tail ribs and install the first, most outboard holes and then the last holes on the bottom of the tail ribs.

    - (See Fig. W70) Square the machined flap/aileron hanger again to be sure it's square and then match drill the 2 holes in tab that is on the BOTTOM of that hanger and install the 2 HDW-CR3213-4-2 rivets through the pre-drilled holes into the machined hangar. Just look at the pre-drilled holes in the parts to see where they go. The pre-drilled always go to the outside so you can match drill through them.

    - NEXT drill a single hole from the topside of the hanger through it and through the false spar tab that is there in that little triangle area and install an SS42D rivet from the topside. The tab of the spar goes inside that triangle area and on the bottom side of it.

    - NEXT, we will install the inboard aileron hangar and fit it per the manual. The lip/tab on top of that spar will go under the tab there from the flap false spar. DON'T DRILL OR INSTALL THIS TOP 2 TABS DOWN YET UNTIL AFTER YOU HAVE INSTALLED THE OUTBOARD AILERON FALSE SPAR because you will be moving it back and forth getting it to fit properly out at the end hanger. This is on Page 31.7 DON'T DO IT YET!

    - Set the outboard aileron false spar with the tab with the pre-drilled hole that is on the inboard end, over the top of the other inboard aileron spar and line up the inboard edge of the machined hanger. Pay attention here to the pre-drilled holes on each end and make sure any of those tabs and ends are on the TOP of other false spar parts. So for example, looking at the OUTBOARD AILERON FALSE SPARE, on the INBOARD END of it, you will notice the TOP tab will go on TOP of the INBOARD FALSE SPAR (it has the pre-drilled hole) but on the bottom tab at that same location, you will notice it will go on the INSIDE or UNDER the tab end there on the INBOARD FALSE SPAR.

    - Put the 3 fixtures in place on the 3 hangars per the manual.

    - Follow the manual on Pages 31.5-31.7 and drill #6 & #7 rib and then go back to where the INBOARD AILERON FALSE SPAR overlaps the FLAP FALSE SPAR and install the rivets shown in W73 on page 31.10. Page 31.9 shows the Marson puller. You don't really need it (as I said, it won't pull cherrymax rivets anyway) as you can use your modified (ground down) puller. These rivets ARE NOT HARD LIKE CHERRYMAX RIVETS ARE. You are using all pop rivets here, so you don't have to have the tip of the rivet puller perfect to pull these rivets. Note that in 2 places you are using the longer HDW-97525 pop rivet into the hanger.

    - Then follow the manual and drill #8 rib holes and then go back and put in the rest of the rivets on the side and bottom of the tail ribs. I just install the rivets. I don't put in clecos and then go back later. Also, you can go ahead and rivet the intermediate tail ribs there between ribs 6, 7 & 8.

    (This is a photo of the outboard aileron false spar for the left wing where it overlaps the inboard aileron false spar. You can see it goes on top of the inboard false spar. The latest one I got had a pre-drilled hole in that outboard one. As the manual says, the FLAP false spar outboard end at the hangar will go ON TOP of the inboard end of the inboard aileron false spar.)

    On Page 31.14 and W74, it shows the Aileron Hanger Brackets. This is showing the left wing so the XC31404-002 part goes on the right (inboard) side and the -001 goes on the left (outboard) side. Just be sure you have the 51-1/8" from the flap/aileron hanger (outboard edge) to the center of the slot in the end of the hanger before drilling the center holes. Note that the HEADS of the rivets go on the OUTBOARD side. (note the figure shows the heads on the inboard side but that is wrong and the RED sentence above notes that.

    (This is looking downwards on the back side of the aileron false spar. The nut is to the outboard side and note the brackets have the ends with the shortest distance from the bolt holes goes downward)

    The manual is pretty good for the remainder.

    Here is a figure showing where you need to drill a 1/2" hole through the bottom of the flap false spar. This is a view from the bottom looking up at the rear spar between ribs 4 & 5. You can see the location you need to mark and drill a pilot hole with a #30 and then a step drill to get the 1/2" hole. This is so that you can pull that drag wire out that goes from the outboard rear to inboard front spar in the fuel tank bay. You can look through the hole after you drill it and see that the wire will now pass through the hole in the back of the tail rib as well as the hole you just drilled. You'll need to remove that wire when you install the fuel tank and this hole lets you do that. This is now in the manual around page 161, Section 34 on Finalizing the False Spars.



    When drilling the holes from the flap false spar and all the leading edge skins later .... into the spar (I am referring to the lip of the flap false spar and later nose skins that overlap the top of the spars and have to be match drilled and riveted in the spar), you need to be sure you are not drilling into the spar "bulb".


    If you are SURE you have the lip of the part (flap false spar or nose skin) that has the pre-drilled holes in them.....down flush with the bottom of the spar cap, then the pre-drilled holes will be safe to drill into the spar. You can put clamps on them like this to hold them down but check by looking or feeling with your fingers as well before you drill.


    Another option is this Avery spar tool I detailed in the first post of this thread. You just hold it on the bottom of the spar cap and then drill right through the hole in the tool. It has holes for a #40 and a #30 drill bit. You will see here that the holes in the skins/false spar are pre-drilled exactly the same so like I said, if you are sure you have the skin flush with the bottom, then the pre-drilled holes are fine and you don't have to use the tool. The earlier kits did not have pre-drilled holes so this fixture was a must.


    25 hours and 37 minutes into the wing build to this point.

    Last edited by Daveembry; 11-18-2021 at 09:27 AM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  2. #12
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Aileron False Spar


    The manual is pretty straightforward here. Just note the the aileron false spar has 2 sections. The INBOARD end of the INBOARD section (XC31034-001) (in the inboard end of the aileron false spar) goes UNDER the flap false spar piece where it meets the machined rib and .........

    the INBOARD end of the OUTBOARD part (XC31033-001) of the 2 piece aileron false spar goes OVER the OUTBOARD end of the INBOARD PART where it joins at tail rib #9 ON THE TOP OF THE WING and goes UNDER the inboard piece on the BOTTOM OF THE WING. You will notice that it has to go this way in order to match drill through the parts into the tail rib because the OUTBOARD end of that INBOARD piece is pre-drilled.

    (This photo is showing where in INBOARD part of the aileron false spars meets the outboard end of the flap false spar. The false spar is on the left.)


    (This photo is the view of the right wing, rib #9 joint and shows that the inboard end of the outboard aileron false spar goes OVER the outboard end of the inboard aileron false spar.)

    Also you do not have to bend the jointed areas as the manual states. The new aileron false spars have been altered by the factory to have a gap between them now so they won't actually nest into each other.


    Here are pictures of the ends of the wires. You will have to drill a #40 hole in bay #9 to install the short, orange ground wire for the stall warning switch. The orange wire on the end of the wing tip lights will screw onto a pre-drilled hole that is on the inboard side of the end of the spar. The manual has call-out for the screw that works. AN530-4R4

    I STRONGLY RECOMMEND DOING A CONTINUITY CHECK WITH YOUR VOLT METER BEFORE YOU INSTALL THE WIRES. You can do this anytime but it's much easier to do it before you install the wires since you can simply hold both ends of the wires in your hands and use the regular voltmeter leads now.


    (Wire for landing light is taped onto the spar just inboard of the #6 center rib.)

    (Wire for Stall Warning is taped onto the outboard side of the bay 9 intermediate rib it's in bay 9 just before rib #10)




    If you are installing a heated pitot (Gap 26 Garmin) then here is the list of “Heated Pitot” items that you should get from CC.


    In the kit there should be some wires 14 Awg in a bag. All the wires should be labeled “Pitot +” and “Pitot -“. There should be a pair of those wires that is shorter and has 2 ring terminals on the ends, one smaller than the other. This pair of wires will be used later to connect to the wires coming out of the wings and will connect to the switch on the panel.


    There should also be another pair of wires about 8! Long with no terminals on them (just bare ends) and labeled the same. These are the wires that go into the wing before cover. Just run them along with the pitot tube hoses and let 1’ extend past the end of the wing at the root and 1’ coming out at the pitot bracket area.

    Later when installing the pitot, the 2 positive wires coming out of the Gap 26 will attach to the + wire and 2 negative wires coming out of the Gap 26 will attach to the - wire. The heated pitot actually has 2 separate heated units in it so that’s why there are 2 wires - and 2 + coming out.

    Last edited by Daveembry; 11-21-2021 at 07:16 AM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  3. #13
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Finishing the false spars.

    The manual is good on this. Note that the rivet HEADS go to the OUTBOARD side when installing the brackets on the aileron hangar. This is not the normal way a rivet goes so just wanted to point that out. There will be fabric up in that aileron bay and if you do it the other way then you will have the big, back part of the rivets sticking out.



    Also note that in the manual, that you do NOT want to do that step of drilling holes, etc. for the flap aileron hanger until you have done the next step, Install Aileron False Spar. So do that before doing this step.


    If you are using the G3X with the AOA pitot tube, then you will need to install the pitot tube bracket and the green and blue pitot tubes. Look at the "EXECUTIVE GLASS" manual in Dropbox, Page 34 to see the info. The actual “Mast” part of the Garmin GAP26 AOA pitot tube you will put in your “little parts to be painted” box and will install it into the bracket here .....through an inspection hole behind the spar here after you get your wings installed and are finishing up. NOTE: Leave more of the tubing exiting the bracket than shown here to make it easier to install later when finishing up. Leaving on this much made it hard for me to install it onto the pitot. Just leave about 6" or so at the wing root and let the rest come out this bracket for now.

    Note that you will need to install a rubber grommet into the #4 & #5 center, ribs here where the 2 green and blue tubes will go through. This is also in the Executive Glass manual on Page 34. MS35489-17 and NONE were shipped with the kit for me. The manual calls for them to be a -17 but the -19's are the correct ones. The tubes will go in the back channel of the front spar until it gets past the fuel tanks and then they will go up and through these bottom grommets in #4 & #5 center ribs.

    (NOTE that in this photo I had not yet installed the GROMMET into that last #5 center rib. You have to install it first.)


    The difference is that with the EX3 that has the solid nose skins from top to bottom of the front spar, we have to install nutplates into the spar to screw the pitot tube bracket into. It has the 4 NARROW holes about 72" from the center hole of the front spar attach fitting in bay #5. There are 4 other holes drilled for nutplates already out in bay #6 but we are not going to use this. The factory mounts their ADHRS unit here and we will mount ours in the boot cowl.

    If your spar is not predrilled for the nutplates, it probably just has the 1 center hole pre-drilled like in the photos below in bay #5. Use the nutplate tool I recommended in the first post about tools and it makes it much easier to drill out the #40 holes on either side of the big holes that are pre-drilled.




    You can see here that there is a big knob in the middle that you put in the big, center hole to drill your first hole.


    After you have drilled the first hole on one side, then flip the tool over and put the big knob in the center hole again and the small knob/pin will go into the hole you just drilled. Then just drill the 2nd hole and your nut plate will fit perfect.



    The manual say to prep the landing light housings by installing the nutplates but I think they come from the factory now with the nutplates installed. You do NOT need to cut the 1/8" or so off either side of the housing to give you some room to fit it just right. (At least the ones I have had plenty of room on either side between the nose ribs.) You can use the dremel tool with cutoff blade if you do need to.

    UPDATE: 04/15/19. Mitch confirmed the factory is now shipping the housings 0.40" trimmed off so the new fixture is 7.25" in width and will require no trimming. So if your housing is 7.25" then you don't need to trim it.

    NOTE: When I cut or sand on carbon fiber, I always do it in front of a fan with the fan blowing from behind me. That keeps the carbon fiber dust blowing away from me all the time and that way I don't bother wearing a mask, gloves, etc. You may have to do both left and right light housing this way.

    Once it's trimmed, put in on the inboard side of the #6 rib (in the #5 bay.) Your wires should be coming out in that bay. Just put a strip of wide masking tape along the bottom of the nose ribs there and set it on that. You just need to hold it up in place for now as we will fit it later after installing the leading edge skins.





    I use to HATE doing these. Once I finally figured it out, it was very easy. It's hard to explain and I can't take a photo since you need both hands but I will try and explain. Note on page 47.2 and Fig. W96 that there are 2 sizes of fairlead we will use. 1 is thicker than the other (SC31065-001) and you will see that it goes in all 3 of the double ribs we did (Ribs #1,3,5) and the other is a thinner one (SC31065-003) that goes into ribs 4,6,7 & 8.

    First take the fairlead and be sure you are holding it completely through the rib so that the groove that we will be putting the snap ring into is completely visible on the side of the rib we will be putting the ring on.


    I use my left index and middle fingers on the back side to hold constant pressure on it because the secret is to be sure that groove stays completely through the rib. In this photo, the only thing I could not do (since I had to hold the camera) was to put my left thumb on the left END of the snap ring (up at the top left in the photo) and take some good pliers and hold the opposite end of the snap ring as shown.

    Be SURE that the left end that you have your thumb on is into the groove and KEEP IT THERE WITH YOUR THUMB. Then keeping constant HARD pressure from the backside and on your thumb, twist the pliers in a counter clockwise (left) direction while pushing it towards the rib. Work on getting the bottom of the ring into the groove (while keeping the end under your thumb in the groove as well). With practice, it will just snap right into the groove enough for you to turn loose of the pliers and then usually the very right, top end (the end you had the pliers on) may still stick up a little onto the fairlead but you can just use the end of the pliers to push it on over into the groove. Practice makes perfect and you will have plenty to do on the wings and on the fuselage. Good luck. I had more cussing from trying to do these I think than any other part of the build!! But now I just snap them right it will work!


    NOTE: The last kit I got already had all the nut plates installed here. (Jan, 2020)

    This consist of installing the nutplates in the bay #1 leading edge skins. I like using the pop rivets HDW-04-0981 instead of squeezing because it's easier and leave a better looking surface usually. Also, I don't use a dimpler to countersink the holes but use my microstop countersink tool instead.

    Take a fat sharpie and mark the centerline of each nose rib TOP & BOTTOM. Be sure it's in the center and very visible. Later we are going to drill holes in the skins and then look through the hole and make sure we see this sharpie line through the hole before we drill through it to install the rivets. This is like we did the tail ribs on the flap false spar.

    Last edited by Daveembry; 11-12-2021 at 07:37 AM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  4. #14
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Outboard ribs and cross brace.

    The manual is pretty straight forward here. Note in the picture how the diagonal cross brace goes through the outboard tail rib. It is riveted to the bottom of the rear spar 4.1" in from the end and this rivet is installed now. The other end of the brace will go about 3.1" in from the end of the machined rib BUT DON'T INSTALL IT NOW. It will be installed later after the tip bow is installed which can't be done until we install the leading edge skins.


    At this point I will stop on this left wing and put it into my wing stand and go ahead and start on the right wing. Then I'll come back and we'll go over installing the leading edge skins; tip bow; fuel tanks, pulleys and cables and we're done.

    NOTE: We will need to get a set of the leading edge skin clamps to install the leading edge skins. CubCrafters built 22 set of these clamps for use among the builders but now they have almost all seemed to have disappeared. Mitch is shipping me 5 sets of "parts" for the clamp sets and I agreed to put them together and make them available for others to use but what everyone should do is to not ask for a set of clamps until BOTH WINGS are complete to that point and ready to install leading edge skins. Then you can spend just a few hours and get the skins installed on both wings and then ship the clamps out to someone else. PLEASE don't get these clamps and then just sit on them when there are builders out there who actually are ready for them now and can't get anyone to turn loose of a set.

    You can complete the build on the wings for everything except just installing the fuel tanks, tip bow, pulleys and cables without having the leading edge skins on. Once the first wing is finished, just move it to your wing stand you should have built. You can see here that I just put a piece of scrap metal (aluminum) in the wing stand that you can set the leading edge nose skins down in.



    You can see that with the wing stand, (with wheels on the bottom) you can just have plenty of room to move around the 2nd wing build and when you need more room, just roll it over.

    At this point I have a total of 29 hours and 40 minutes on this wing.
    Last edited by Daveembry; 06-18-2018 at 11:29 AM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  5. #15
    Senior Member
    Join Date
    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    The right wing is of course the same as the left with a couple of things.

    If you are installing the Executive Glass panel, then you will be installing the magnetometer in the outside end of the rear, right hand wing spar. Right now we are only going to assemble the bracket that will hold it. Don't install the actual magnetometer into the bracket and/or wing now as it is very sensitive and they have had problems with some getting damaged during construction, so we will install it at the very end of the build after the wings are on.

    The details are in the Executive Glass manual in dropbox on page 32 & 33. Right now we are just going to take the 2 halves of the aluminum bracket and rivet them together. Not that the half that has the shorter, lower back piece (the half that will go on the bottom) will go on the INSIDE of the other bracket (the one that will be on top).


    You will note the top bracket actually has the 3 holes in the bracket countersunk already. We will install the rivets MS20426A3-3 (NOTE: The manual has this wrong as it says MS20426A-3) See page 33, top, center figure (Section E-E figure). That figure is hard to understand and actually looks wrong unless you visualize it. Imagine you are standing BEHIND, (in the back of the wing) looking forward. This view is a "cut-away view" showing the bracket as it sits up against the back of the rear spar with the front part and side of the bracket gone. The Figure "Section D-D is easier to see it. You can see the top piece is OVER the bottom piece where it connects at the back where it attaches to the spar.

    Anyway, just squeeze those 3 rivets joining the 2 pieces at the back and then using Section D-D figure, put 2 of the MS20470A3-3 rivets on each side of the brackets as shown.



    You will see here where it mounts onto the outside of the rear spar. There are 2 pre-drilled holes in the rear spar out in the 10th bay (between Rib 10 & 11). You can just double check that the holes in your bracket lines up perfectly with the spar holes. It would be hard later to have to go in and match drill if it isn't right. The screws MS35214-27 that should be in the kit parts that came in the "pre-cover" parts.....can be used to double check. NOTE that all the hardware used in and around the magnetometer are non-ferrous (non-magnetic) materials and you should never use a screwdriver with a magnetic tip when working around the magnetometer. These screws are black, brass screws you will notice (as all of them used here will be).

    Once you've check that the holes aligned correctly, just put the bracket and hardware that goes with it in your "Finish" box as this is all we will do right now.

    We will also have to install the wiring harness for the magnetometer along the BACK, outboard side of the REAR spar per the figure on Page 32 of the Exec. Glass manual. It's best to do this per the manual and run them after installing the nose and tail ribs because you will have rivets going into that spar slot and you would have to be careful and don't get into the wire.

    The end with the connector already installed should go out on the spar at the magnetometer mounting location. The wiring harness should include the connector that you will have to put the pins into at the wing root end. You can go ahead now and install those pins into the connector according to the wiring diagram on page 33. This is a bit confusing because there may be 2 WHITE WIRES...... The WHITE WIRE that is THICKER is normally used as the JUMPER WIRE. This last harness I got they had actually made this JUMPER a white/black wire instead of just a thicker white wire. If you look closely at the wire where they are connected by the factory, you can see where they have attached a wire to the outside shield wire of the main wire coming from the magnetometer. That is the JUMPER's just connecting that outer shield from wire to wire.


    So look at the back of the black connector they sent you and you will see that the holes are numbered. You can see where I drew a picture of the connector next to the wiring diagram in the manual. It shows you where the pin holes are as you are looking into the connector and shows which wires go into which pin hole.


    Before you start, slide on the back of the black connector over all the wires and push it up out of the way. We will put this on after we put all the wires/pins in place.

    Slip 1 pin into the correct hole in the connector and push in gently until you hear and feel it snap into place. You will see there are 2 main wires coming from the magnetometer out on the wing. 1 only has 3 wires and the other has 4. Pay attention to which of the wires you use to put into the pins because each of them has a white; white/blue; white/black, etc. Here you can see I have the white wire from the "3 wire" and connecting it into the #4 pin.



    Push back up the black cover that you put on before putting the pins in black and secure with the 2 screws and small cover plate it came with and you are done. You can silicone the wires into the rear spar rear channel as well.
    Last edited by Daveembry; 04-03-2019 at 08:15 AM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  6. #16
    Senior Member ceslaw's Avatar
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    Sep 2013
    Carterville, IL

    Default Re: Building the EX3 - Tips & Hints

    Excellent summaries! Valuable resource.

    Makes me want to build another . . . . . .

  7. #17
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    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints

    Thanks Chuck. Glad to give back a little. What you guys did with your "Chuck and Ryans Build" thread was a huge help to me and many others!

    Quote Originally Posted by ceslaw View Post
    Excellent summaries! Valuable resource.

    Makes me want to build another . . . . . .
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  8. #18
    Senior Member
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    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints

    WING - Right Wing

    Section 28. Note that the capstrip numbers are SC31054-008 for the right wing #1 rib, top capstrip; SC31054-010 for the top #3 capstrip for the right wing. These part numbers aren't shown in the manual for the right wing.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  9. #19
    Senior Member
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    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints





    While I am waiting to get some wing skin clamps, I'll start to do some covering. The best thing you can do is go on Dropbox and watch the videos Mitch has done. They are great for the tail-feathers but the wing has a couple of updates I'll go over when we do those.

    NOTE: There is not a specific video for the Elevators but it's essentially the same as the Stabilizer video except that there is actually different parts for the left and right elevator because of the "horn" (the part on the inboard end of the part that the cables will connect to). The taller/longer end of the "horn" faces UP.


    So watch the videos all the way through and then I keep a laptop computer on my workbench at all times (to log my build on my Excel builders log; to view Dropbox manuals and to watch videos on certain areas as I perform them). Just put the video on as you do the cover item and watch one little segment, pause it and perform it....then move on to the next task.

    There is also a COVER MANUAL that is good to show you how the joints go if you get confused with the video and is also good with figures showing where the tapes go and of what sizes. It also shows where to drill additional rivet holes in the wing if you are securing the fabric with rivets and not rib stitching. For the elevators for example:
    - Page 96 shows the elevator DRAIN HOLES. You will not burn these holes in (with soldering iron) until you are finished painting.
    - Page 80, Fig. C4 shows the way the fabric wraps around the straight edge and where and what size tapes go where. The 70200-12 tapes are the 2" and the -13 is the 3" tapes.

    There are a couple of general tips I've found that I like when covering I'll go over:

    • Chuck gave a great tip on ordering and using the "specimen cups". You can get them here on Amazon They are $6 for 25. Just throw the lids away as I don't use them. You can just pour a little Polytak at a time in these cups (which is better than putting alot and letting it thicken up). I just put a rag over it when I'm not using it for more than just a couple minutes to keep it from evaporating and thickening up.

    • You can just throw the cup away when you are finished or it gets too thick or gummed up......or, just leave the brush in the bottom of the cup and leave the top open. The next day the PolyTak will have turned to a solid sheet of plastic firmly attached to the paint brush. Just pull on the brush and the plastic will pull completely out of the cup attached to the brush and you can throw it away and the cup will be as good as new!

    • All the Poly Fiber systems are based on MEK (like a paint thinner). MEK is VERY FAST at evaporating, so leaving Poly-Tak (the glue/cement); Poly-Brush (the pink fabric filler); Poly-Spray (the silver UV coatings) and Poly-Tone (a topcoat color some use .... I don't) open to the air is not good because the MEK will evaporate quickly and leave it too thick. The great thing about this is that every layer you put on (tak, brush, spray, etc) will essentially "MELT" into each other because of the MEK. If you use MEK directly onto any of these coatings, they will essentially "MELT" away as well! This is good and bad.....GOOD because if you make a mistake on anything, a little MEK will get rid of the problem and you can do it over again. Also MEK is good to help SMOOTH the PolyTak glue if you get it too thick. Just take a LITTLE on a rag and run over the glued area (over the fabric) one last time and then leave it alone. It will melt down any lumps or bubbled, excess glue. Don't overdo it or you will weaken and "melt away" the area. Just as small an amount as needed to do what you want it to do.



    • Buy the cheap "Chip Brushes". Here are 36 for $12. You can clean the brushes out in MEK if you want between uses but I don't. I toss them after I'm finished every time because it seems that some of the hairs will fall out of the brush after a little while in the MEK and these hairs usually get into your work area and if you don't see them and get them out while wet, its a pain. I buy 1" brushed for working with the PolyTak and the 2" brushes for using with the PolyBrush when installing all the tapes.

    • Another good tip from Chuck is to take some plastic wrap and each time you open and pour some PolyTak from the container, put a new layer of this over the top before screwing the top on.


    • What I have found to get the best, smoothest jobs without alot of cleaning and smoothing is to NOT USE AS MUCH POLYTAK AS THEY DO IN THE VIDEOS! Poly Fiber people say NOT to put any tak OVER the fabric, only under it so that it will push up INTO the fabric and hold better. If you put it over the top of the fabric without the fabric being already filled with it from below, it will get hard IN the fabric from the top and not let any more tak come up from the bottom surface as it should. I think at the factory they are so good at it that they do it VERY QUICKLY so any glue from the bottom has either already saturated the fabric or is still wet. You will find that PolyTak sets up VERY QUICKLY (especially if its warm air around). Once you put the fabric over any tak you have just a few seconds to press the fabric into it good before it starts to harden. I've found that pulling the fabric at an angle over the surface it's gluing to as well as running a gloved hand over it very quickly works best. Then just keep going back and forth across it with pulling the fabric and smoothing with your hand.

    • I try to only put glue in the areas that will not be seen or is going through the fabric any more than I have to. Try to get the glue on the inside edges when you can and when you do the end or joint of a fabric, try to keep the glue to a minimum as any excess will be seen all the way through the job and through the paint. So as you go, smooth as much as you can with your hand; with MEK on a rag and then with the iron. The IRON WILL ALWAYS SMOOTH THE GLUE....... so go over everything really good with your hobby iron on EVERY COAT YOU DO including the tak and poly brush. You can NOT iron the get it right before putting any Spray on. Get it perfect........what looks "OK" with only PolyBrush on it will look really bad as soon as you spray the PolySpray on. You can still sand it after Spray goes on if you have missed some spots or some areas where not as good as you THOUGHT they were.....but then you have to go back and fix/replace any Spray/Brush you sanded off. So to sum up, I only put as small an amount of Tak on as I need and only in areas that are unseen if possible. The glue should come up through the fabric and stick good but if you are getting alot of excess glue coming up through the fabric and you are having to do alot of smoothing, etc., just cut back the amount you are using. It doesn't take alot to do that job. You are going to put several coats of PolyBrush on over all these glued areas.....the MEK is going to MELT into each layer of tak and brush and you will end up with it all glued together into 1 solid piece of material when done.
    • When cutting using the pinking shears, always try to align the notches of the scissors with the notch already cut in the fabric. In other words, you take one cut in the fabric and then you have to open the scissors, re position them and then cut again. When you do this, before cutting the next cut....align the notches in the scissors with the last notch cut in the fabric before cutting. This will leave you with a much nicer looking cut line. If you don't do this, it will look very irregular when done.
    • Be sure your work area is VERY CLEAN. Especially don't have any oils and don't even think about spraying WD40, etc. anywhere near fabric as it's very hard to get off and will leave "fish eyes" in the paint.






    So starting to do an elevator, I'm putting on the stabilizer video from Dropbox and here I will just do a short outline of each step. The details you can get from the videos.

    When doing the tail-feathers, the reason we want to know which side is up is because we will put the joint of the fabric seams on the backside of the elevators and stabilizers on the bottom and the seam of the rudder on the right side. See the Cover Manual Page 80 for the details. (or just pay attention to the video).

    I'm only going to go over any things that might be questionable on the video here, not everything.

    • If you are using rivets and not rib stitching (like me and the factory does now), then you don't use masking tape like they show.
    • I opened my envelope and see that it is the wrong one. The elevators changed for the EX3 from the EX2 and they shipped me TC3100-003 and -004 which are for the EX2. This is one of the changes/corrections that didn't get done yet so double check your fabric for the elevators and if they are these part numbers, they are wrong I guess. The correct numbers are XC80900-ENV-R for the right one and XC80900-ENV-L for the left one. I'll do the stabilizers and rudder for now while waiting on the correct ones.


    You can see here that the wrong fabric will not go over the inboard end. It was made bigger and will have trim tabs installed on the finish.


    It doesn't matter which one you do first as both stabilizers are the same part number. The only difference will be that you will put the seam side DOWN on each side when you actually install them on the plane. It doesn't matter now. Whichever one you start with the side up first, just do the other one starting it on the other side. That way you will have 1 different one with the seam down for each side.

    Essentially, the side you start UP will end up having the seam on the BOTTOM. So start 1 with the outside of the stabilizer to the right and the next one with it on the left and that way, each one will have different seams.

    Note that you only need to put a LITTLE tak on the EDGE of the round bar when you first stretch it. Don't glob a bunch of tak on it or around the sides of the tube......just a little on the outside edge and be sure it's smooth and even and not big globs on the edges of your brush lines. This glue joint is only to tack the fabric in place until you turn it over and cut it and then glue it well to the backside of the tube. Any GLOBS of glue/tak you have here will show up later unless you do ALOT of work with the iron melting it down and trying to get it even. Also, don't worry about getting the fabric too will shrink up when we iron it. Just concentrate on getting no wrinkles in the glued edge for now.

    I much prefer using a compass for drawing my lines. It's much faster, easier and more accurate.


    Be sure and take your time and get any wrinkles out of the first glued joint before overlapping and gluing the other side as it's much easier now. Just use your hobby iron (I set it around 250 for this work) and iron out any wrinkles.

    When you are completely finished, take your iron and go around and work out any wrinkles and I also like to go to the edges of the joints and iron those edges down (the "pinked" edges where you cut the fabric edge). I do this on every coat I do......both on the fabric seams and later I do it on all the edges of all the tapes on every coat of PolyBrush I use. This is called "nibbing".

    When you use the iron, you will notice the fabric gets rough. This is from the glue you are melting. Go ahead and finish all your iron work to melt down any globs of glue or getting all the edges of the seams (pinked edges) laying nice and flat.....then after you are finished with that, take a rag and get a spot good and wet with MEK and quickly wipe it across the rough areas. Use an un-gloved hand to feel the fabric for any wrinkles or roughness. With the MEK NOT go over and over it. While it's nice and wet, rub over the area 1 quick time and STOP! Let it dry a few seconds and then run your hand over it to see if it's smooth. It dries so quickly that if you go over and over it, it will just get rougher as it partially melts the glue. The rag has to be re-wetting for each "swipe" you take as it will be dried after just a few seconds and not smooth the glue. A little practice with this and you will see it looks and feels great. I actually close my eyes one last time and run my hands over all the glue joints to be sure I'm feeling nothing but baby's butt!



    Next we will shrink the fabric and install the reinforcement tapes where the rivets will go; install the rivets and then the tapes.
    Last edited by Daveembry; 11-27-2021 at 07:28 PM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  10. #20
    Senior Member
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    Jul 2015
    Broken Arrow, OK

    Default Re: Building the EX3 - Tips & Hints


    Stabilizer Finish

    It's important to be sure you are using a good iron that holds a constant and correct temperature. Household irons won't work because they may vary too much in temperature changes with their thermostats (in other words, it may cool alot before turning back on to heat and then may go over the correct temp before shutting off). Use a good specialty iron.

    This is the SWIX iron that was shown in the Cubcrafters cover video with Mitch. This is a good iron BUT...... it will only go to 170c or 338F. Another iron that goes to 180c or 356f.

    Since we need the final ironing to go to 350, I think this iron (which is recommended by Stewart Systems) is a better pick. and will go to 356. It's the Wintersteiger Part 57-100-315.

    This is the SWIX Model T73110 used in the video.

    There is a new iron being developed that is suppose to be available in May, 2020. Supposedly it’s just for fabric and will hold a very constant temperature. The website is being developed and will be and his contact info is Steve Nussbaum; S&M Innovations LLC; 619-517-0840;

    To be sure you have the right temps, use an infrared Thermometer. Take a piece of scrap fabric and hold it TIGHTLY across the surface of the iron and shoot it in a couple of places. If the fabric isn't real tight against the iron, it won't read correctly. I stretch it tightly while shooting it.


    With the fabric, it will shrink only so much at 250 degrees and then shrink again at 350 to it's maximum. If you go HIGHER, IT WILL ACTUALLY DO THE OPPOSITE AND EXPAND!!! So be sure you have it right and don't go over 350 degrees!

    Go over it all at 250 degrees and then go to 350 degrees. This is fun to do and see all the wrinkles and slack come out. Don't worry as it will shrink out almost any amount of wrinkles! I use the smaller hobby iron to go around the edges and then the big iron on all the flat sections. STAY AWAY FROM ALL THE GLUED AREAS ! Don't melt the glue at this point because you are shrinking the fabric and it will be pulling at these seams!! Don't worry if you hear some creaking......that's normal. Also, you can not OVERSHRINK the fabric by leaving the iron on an area too long. It will only shrink so much at any temperature and you can leave the hot iron on the fabric and it won't shrink more or burn. Also don't worry if you see steam coming off the fabric at the 350 degree setting. That's normal and is just the moisture in the fabric evaporating.

    After shrinking the fabric, I next take a sharp pencil and poke a hole through the fabric in each of the pre-drilled rivet holes in the cross tubes. You should see the holes through the fabric where the hot iron outlined it. It helps to have some backlight UNDER the part. Stick a flashlight under it and you will see the holes good. You can also shade the top with your hand from overhead lights and the holes will show up better.


    Page 97 of the COVER MANUAL shows where the rivets are on the stabilizers. It is showing rib stitching but that is also the rivet locations.

    After punching holes through the fabric with a pencil, I then put a mark in the same holes using a sharpie. Make this mark right in the hole and give it lots of ink. This is so we can see the hole locations in the next steps where we have to burn holes through some reinforcement tape with the soldering iron.


    Next take a ruler and on the cross tubes that you have marked the rivet holes with the sharpie and with a pencil I mark 1" on either side of the row of rivet holes. This will give us a line that our 2" tapes will go in. I also make a little mark 1/2" on either end of each of the end holes in each row of rivet holes. This is just a mark to end our reinforcement tapes.


    Next take a long straightedge and draw the 2" wide tape lines down the line of rivet holes in each crosstube (3 rows of crosstubes) from outside edge of the stabilizer to the other outside edge.


    Cut pieces of the reinforcement tape that will go over each line of rivets down each cross-tube. It will go from 1/2" outside 1 end to the mark you make 1/2" outside the other end. Be sure the sharpie marks are centered on the reinforcement tape as you go and make them straight as you will see them after finished paint.

    Next take a hot soldering iron and you should be able to see the sharpie marks THROUGH the reinforcement tape. Touch the soldering iron tip down onto the tape and let it burn a hole through the tape and fabric right down into the hole that was pre-drilled in the stabilizer cross tube. Don't leave it there for long....just burn the hole and get out of there.


    Install the fabric rivets that came with your cover kit and pull them.

    If you use a pneumatic rivet puller, be sure and put a cloth cover over the exhaust port when pulling rivets over fabric to prevent any oil from being blown out onto your fabric!!!!


    Next take a short piece of the 2" and 3" tapes and fold in half and crease well so you can see the centerline of the tape.


    Looking at Page 80 in the COVER MANUAL you will see that all 4 ends of the stabilizer will get 3" tapes and 2" tapes will just go down the cross-tubes. On each end of the stabilizer, hold the 3" tape so that the creased center is over the center of the tube. Make marks on either side of the stabilizer where the edge of the tape is and then just take your compass and set it the same and run it down that edge. It will be different for all 4 edges because each is a little different width.



    This is the finished stabilizer ready to have the tapes installed which we will go over next.

    Last edited by Daveembry; 02-24-2020 at 06:30 AM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

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