ECEE THUNDER BUILD and TEMPLATES

Discussion in 'Rocket Boosted Gliders' started by Rktman, Jun 24, 2019.

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  1. Jun 24, 2019 #1

    Rktman

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    Eric Noguchi

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    Due to a stroke of incredibly good luck and the kindness of a fellow club member, I was gifted a still-sealed-in-its-bag Edmonds Ecee Thunder kit. This is one that's been on my bucket list for a long long time and I've always wanted to build/fly one of these impressive gliders that sadly went OOP long before I became a BAR. Unfortunately these kits are pure Unobtainium and I've never been able to find templates anywhere.

    Well, now that I'm building the original kit I thought I'd pass along some of that good fortune by making templates available. The templates are in a vector pdf file format. Note: either the Illustrator files I did the tracing in or the pdf file can be used to laser cut the pieces. (PM me if you want the Illustrator files). If you want to go old school and print the templates out to hand-cut the pieces with a hobby knife, you'll have to tile your printing because of their size, and tape the sheets together. Or take it to someplace like Kinkos to output it on their large format printers.

    Oh, and btw, if you need the build instructions, PM me with your email addy. For some reason it's too large to upload here so I'll have to send them via an ftp service.
     

    Attached Files:

  2. Jun 24, 2019 #2

    aerostadt

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  3. Jun 24, 2019 #3

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    Eric Noguchi

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    Okay, on with the build starting with the unboxing...or unbagging in this case. The ruler should give you an idea of the relative scale of the Ecee Thunder (one review indicated a 44"L x 28" wingspan [not counting the fuselage width] which sounds about right) so it's impressively BIG. I'd say it was and still is the largest free-flight balsa RG ever kitted. Even the standard scratch-built BG Valkyries—seriously large in their own right—topped out at 25"L x 11.5" wide by comparison.
    unboxing kit.JPG

    The parts are a jigsaw of interlocking tab and slot pieces. Good for strength (and necessary in the case of the wings, which are far too large to fit on standard widths of balsa sheet) but a bit confusing at first to figure out. The pieces weren’t always laid out on each balsa sheet the way they were illustrated in the instructions. The sheet was sparse on text and consisted of 4 pages of mostly drawings, a lot of which were hard to see because they were faded or blurry from being photocopied (I’ve since darkened the outlines to make it easier to see how everything fits together). Also the letters identifying each part don't correspond to the instructions because the text from the smaller 13mm Ecee seems to have been recycled for the Thunder. Oops. Guess no copy editing was done.
     
  4. Jun 24, 2019 #4

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    Eric Noguchi

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    To avoid mistakes I labeled the sheets and what edges went together once I identified everything.To avoid mistakes I labeled the sheets and what edges went together once I identified everything.
    IMG_3091.JPG

    To make sure the glue can grab tight I removed as much of the laser char as I could without throwing the edges out of square.
    IMG_3096.JPG
    IMG_3092.JPG


    I then marked the edges that would need to be glued together.
    IMG_3099.JPG
     
  5. Jun 24, 2019 #5

    Rktman

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    Eric Noguchi

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    I love this glider, though I've never built anything this large before. I know RC guys fly really huge craft and would consider the Thunder to be on the small side, but they're not rocket powered. Flying the Thunder is really going to be an experience. Speaking of, I have my doubts whether the recommended D12 will get this glider high enough to safely deploy the canard flaps. I think an AT E11 would be a safer long-burn choice.
     
  6. Jun 25, 2019 #6

    dhbarr

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    Just give it a lot of rail/rod, d12 hits 30N peak at ~0.25s, e11 hits 19N peak at ~0.4s.
     
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  7. Jun 25, 2019 #7

    Massrokit

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    The D12 works just fine. Use a four foot rod. The only problem I had with a D12 was when the nozzle popped at launch and the blow back from the deflector charred the tail feathers of the glider. Make sure the wing tips/stabs are securely glued. Never popped off in flight or landing, but in transporting such a big glider.
     
    Last edited: Jun 25, 2019
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  8. Jun 25, 2019 #8

    neil_w

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    Holy cow, that is a monster. Looks like fun!
     
  9. Jun 25, 2019 #9

    Rktman

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    Eric Noguchi

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    Appreciate the info.
     
  10. Jun 25, 2019 #10

    Rktman

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    Eric Noguchi

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    Those wingtip rudders will go on real good, shouldn't pose any problems. Will poke the edges to be glued full of pinholes then used the double-glue method to attach. Generous fillets too. Will reconsider the D12, was concerned about reviews that mentioned that motor didn't get the glider to a comfortable height before deploying the canard flaps.
     
    Last edited: Jun 25, 2019
  11. Jun 25, 2019 #11

    Rktman

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    Eric Noguchi

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    Monster fun definitely. Due to size, it's first flight should be impressive whether it launches well or lawn darts (not that I expect it to). At least it'll definitely leave an impression either way. :D
     
    Last edited: Jun 25, 2019
  12. Jun 25, 2019 #12

    new2hpr

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    Before posting the design files, did you try to get ahold of Rob Edmonds for permission to give away his design? Not to be a jerk, but Rob put out some amazing gliders, and even though he isn't selling anymore, maybe deserves some credit?

    You forgot one important piece of info on your design files. The balance point is critical, and is laser-scribed on the original.

    I was never able to get a successful flight out of my Ecee Thunder. Think ahead on motor retention, venting of ejection, etc. Mine spit the motor once, and jammed the piston once. Both resulted in "steep glides" and a lumber pile after the re-kitting.

    Good luck!
     
  13. Jun 25, 2019 #13

    Ez2cDave

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    Post #1 - Eric clearly identified it as an "Edmonds Ecee Thunder" . . . Tells you who it was by and what it is.

    If he had answered "yes", you still wouldn't really know, one way or the other, would you !

    If Rob Edmonds has a problem with it, let him post here, himself . . .

    Dave F.
     
    Last edited: Jun 25, 2019
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  14. Jun 25, 2019 #14

    Ez2cDave

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    Eric,

    It was a pleasure meeting you at the launch on Saturday . . . See you on July 20th !

    Dave F.
     
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  15. Jun 25, 2019 #15

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    Eric Noguchi

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    Just to clarify, "Monster" in this case refers to its impressive size and not a negative reference to appearance or design. I personally feel its interlocking tab and slot construction is brilliant and makes for really strong joints.
     
    Last edited: Jun 26, 2019
  16. Jun 25, 2019 #16

    Rktman

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    Eric Noguchi

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    I wasn't sure at first, but then assumed that's what that icon must've indicated. I didn't put it on the template because if you use the pdf file to get the parts laser cut, it would burn a hole the shape of the icon clear through the part.

    I mean to measure its exact location from either the fore or aft end of the glider once I get it more assembled and can pinpoint it exactly. Will post it as soon as I do.
     
    Last edited: Jun 26, 2019
  17. Jun 25, 2019 #17

    Rktman

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    Eric Noguchi

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    Made some progress today. Started in on the wings. I prefer using Sigment when gluing balsa sheets together. It’s SIG’s version of Ambroid glue, the old standby that was the go-to for RC and hand-launched glider hobbyists when it was easily available. Unlike CA, it won’t dry brittle and can be sanded cleanly. It’s also lighter and I’ve never had any problems with joints breaking. Everything around it will shred first.

    Glad I dry fit things together first. I discovered the wing pieces will slot together nicely even if you incorrectly pair pieces from the left wing with the right, or flip one piece upside down by mistake. Not out of the question when you’re in a rush trying to apply adhesive and align things before it sets while holding a camera trying to snap some pics with the other hand. The wing below doesn’t look quite right because I mistakenly flipped the lower piece end for end…and it still fit. Pretty crazy that it would.
    IMG_3103.JPG

    Below is how it should get glued together. Suggestion: anyone building the Thunder might want to not only mark which edges get glued together, but also color code which ends go together.
    IMG_3165.JPG

    Borrowing a technique from the hand-launched glider folks, I masking-taped the sections to be joined together after butting them up tightly, flipped them over, then spread them apart and put down a thin layer of adhesive. After that soaked in and dried another layer of glue goes down and the sections pressed together. The tape on the backside ensures they stay tightly in contact.
    IMG_3167.JPG

    Everything gets pressed under some heavy books to dry.
    IMG_3106.JPG
    Since the instructions don’t specify airfoiling the wings I’ll just be rounding the edges. I don’t want to chance possibly having the glider loop on launch anyway.

    Gave it a few hours to dry then used the double glue method to join the wings together. Here it is after a few hours under those heavy books. Nice, flat and straight.
    wings.JPG
     
    Last edited: Jun 25, 2019
  18. Jun 25, 2019 #18

    mikec

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    A few tips (I've flown mine many times on D12 and E9):

    1) motor retention -- it likes to spit the motor.

    2) canard hinge -- there's a lot of force exerted by the piston on the canard, the piece of Monokote trim that was shipped with the kit to hold on the canard is not really up to the task. I replaced mine with CA hinges.

    3) the sides of the fuselage where the canard attaches like to break. Doublers of some form (I used card stock) helps these stay together.

    Be warned that if it's not trimmed to turn the glider glides pretty well, and will glide out of a small recovery area.
     
  19. Jun 26, 2019 #19

    Rktman

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    Eric Noguchi

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    Thanks mikec I have a list of "improvements" that I believe I got from one of your threads regarding your list of tips above. I have it stapled to my instruction sheet as a checkoff list to incorporate in this build. All excellent suggestions. One thing I added was to enlarge the vent hole. That tiny 1/8" opening seems far too inadequate to handle the pressure from a D or larger motor's ejection charge. It's probably the reason they tended to spit the motor.
     
  20. Jun 26, 2019 #20

    Rktman

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    Eric Noguchi

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    You as well my friend!
     
  21. Jun 26, 2019 #21

    Saluki

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    Eric would you mind giving a link to mikec list of "improvements" and thread regarding his list of tips?
     
  22. Jun 26, 2019 #22

    Ez2cDave

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    "List of Improvements" PDF below . . . Provided to me by Rktman.

    Dave F.
     

    Attached Files:

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  23. Jun 26, 2019 #23

    Saluki

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    Thanks, Dave.
     
  24. Jun 27, 2019 #24

    Rktman

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    Eric Noguchi

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    Moved on to the canard today. A piece of self-adhesive plastic serves as a hinge for the canard flap. I beveled a chamfer on the forward edge of the flap to allow it to move freely once attached to the canard’s trailing edge. Since there needs to be a tiny space between canard and flap I taped things down to make aligning the two pieces easier and more exact while applying the hinge tape. (Having received and read review suggestions to replace the tape with RC plane hinges, I want to see how this tape strip works out first. If it tears or the adhesive lets go, it’s easy enough to epoxy the RC hinges on after the fact).
    IMG_3151.JPG

    Two pieces of 1/4” hard balsa are laminated together to form the actuating arm that will rotate the flap down when the ejection charge shoves a balsa piston into it. It’s attached to the bottom of the canard flap and hangs down into the fuselage through a hole notched into it.
    IMG_3157.JPG
    IMG_3160.JPG

    The bottom fuselage piece is divided into 2 pieces (probably so it would fit in the kit packaging)? Just a guess, but as old reviews don’t mention that this was one of those areas that failed under thrust, I’m more curious than concerned. It gets double glue joints, and like the wings, any spaces left between the parts get filled and reinforced with CA just in case.
    fueselage-A and C.JPG

    Since the wings will be subject to the most boost stress and the fuse bottom actually forms the “backbone” of the glider, I’ll be tissuing these 2 areas at a minimum.
     
    Last edited: Jun 27, 2019
  25. Jun 27, 2019 #25

    Rktman

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    Eric Noguchi

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    Began my least favorite step, doping the parts after masking those areas that shouldn’t get any because they’ll be glued to other parts. This took the better part of the day since the humidity keeps things from drying quickly, even if the dope is thinned out. Had to work in the garage since the fumes are really horrendous and would quickly contaminate the whole house in minutes if I did it indoors. Even with the garage doors rolled up I still had to use a respirator to cope.

    In the meantime, because yardwork chores have piled up, I'll let things dry for a day or two before starting to tissue.
    IMG_3286.JPG
     
    Last edited: Jun 27, 2019
  26. Jun 27, 2019 #26

    BABAR

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    This may be too late for you, but I remember in the instructions for all the Edmonds kits I built (and kicking myself for not making copies of fins and instructions) specific direction NOT to airfoil the surfaces, just sand them smooth and leave the flat.

    I did CC two stage, Gemini, twinsee, and one other I can’t remember now, all flew great with no airfoiling

    YMMV.
     
  27. Jun 27, 2019 #27

    Rktman

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    Eric Noguchi

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    Thanks, I remembered the same thing and didn't bother airfoiling any flight surfaces, just rounded the edges to reduce air resistance and smooth airflow a bit.
     
  28. Jun 27, 2019 #28

    mikec

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    I'm skeptical that you need to do this, I haven't had any issues with the wings being strong enough as is, at least on BP motors like the D12.
     
  29. Jun 27, 2019 #29

    Rktman

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    Eric Noguchi

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    Now that I've assembled the wings, anyone notice anything unusual about them?

    Extra bonus points if you said "no dihedral".

    I wondered about that myself at first, until I recalled that swept back wings don't necessarily require any. I don't understand the exact aerodynamic physics of why that is, though, but I found it to be an interesting factoid that makes this design that little bit more unique.
     
  30. Jun 27, 2019 #30

    Rktman

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    Eric Noguchi

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    Maybe not necessary, but just a personal preference of mine to build for strength rather than flight duration. Also adds color, so I get a surprising amount of strength and visibility at a negligible weight penalty.
     

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