ECEE THUNDER BUILD and TEMPLATES

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

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  1. Jul 3, 2019 #61

    Rktman

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    Eric Noguchi

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    Impressive, especially Ari's flight. The 1st one looked kinda painful though. :eek:
    Wonder what these Thunders tipped the scales at?
     
  2. Jul 4, 2019 #62

    mikec

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    Mine is 8.7 oz (bare balsa).
     
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  3. Jul 6, 2019 #63

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    Eric Noguchi

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    Thanks for that benchmark. Hopefully can get to weight mine in a few days.
     
  4. Jul 6, 2019 #64

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    Eric Noguchi

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    Fuselage sides are now on. I decided to reinforce the area that some fliers have reported has a tendency to break sometimes (I believe mostly because the small stock vent hole wasn’t enlarged. With better venting that piston would be traveling at a lower velocity and the impact would be less).

    It’s the area right at the notch in the fuselage that allows clearance for the canard flap when it swings down. It’s also the area where the piston slams into the bulkhead as well as the small balsa lever that rotates the flap downward.

    I cut 1/64” ply to strengthen that portion of the fuselage.
    fuse reinforcement.JPG

    fuse reinfd.JPG

    Almost ready to button things up!
    IMG_3583.JPG

    These leftover shapes on the ¼” balsa sheet, if you downloaded the templates and were wondering, become the nose piece after they’re laminated.
    IMG_3588.JPG
    IMG_3595.JPG
     
  5. Jul 6, 2019 #65

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    Eric Noguchi

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    Motor tube just went in.

    Just an observation: the glider is actually a fast and fairly easy build if you leave everything absolutely stock and don’t do stuff like rounding off edges, tissuing, or otherwise make any changes or “enhancements” like motor retainers, enlarging the vent hole, etc.
    IMG_3591.JPG
     
  6. Jul 8, 2019 #66

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    Eric Noguchi

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    Minor problem I was aware of from a review elsewhere: the plastic hinge tape supplied in the kit has a tendency to lift/let go. The comment I read advised using RC plane hinges, and luckily I just happen to have a supply of the larger Du-Bro variety. It’s all good though, the tape will hold the flap in alignment and the plastic hinges will ensure the flap stays attached. I’d advise anyone building an Ecee to use RC plane hinges from the start though.
    hinge-2.JPG
     
  7. Jul 8, 2019 #67

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    Eric Noguchi

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    I had to trace around the Du-bro hinge and cautiously cut through and remove the hinge material without damaging the balsa underneath. Fortunately things went pretty smoothly.
    peel tape.JPG


    I had to cut a relief for the hinge knuckle so each leaf would lay flat and be in full contact with the flap’s surface. I used a Dremel but as you can see, it didn’t cut as smooth a groove as I expected it to. Resorted to doing it manually with an X-acto blade and router tip.
    hinge groove.JPG
     
  8. Jul 9, 2019 at 1:55 AM #68

    BABAR

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  9. Jul 11, 2019 at 1:20 AM #69

    Crawf56

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    Very nice work. :)
     
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  10. Jul 11, 2019 at 2:36 PM #70

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    Eric Noguchi

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    May have to resort to this option if the nylon hinges start to loosen. For now I'm trying to minimize even small weight increases since I had to add 12.08g (about half oz) of trimming weight to get the CG where it needs to be.
     
  11. Jul 11, 2019 at 2:40 PM #71

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    Eric Noguchi

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    Thanks appreciate that. Part of the enjoyment was the build of this classic original. Will probably get some snaps of the Thunder sometime today.
     
  12. Jul 12, 2019 at 12:25 AM #72

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    Eric Noguchi

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    Epoxied the Du-bro hinges in place.
    hinges.JPG

    Ran into another hiccup when the hinge tape started buckling and pulling loose, interfering with the flap swinging freely. I’m guessing it has something to do with the geometry of the plastic hinges subtly changing the arc of the flap’s rotation a minute amount. The plastic tape didn’t like that. Had no choice but to slice the tape the full length of the joint. Oh well, works fine now but the tape is now nonfunctional.

    I think if I had to do it over again, I’d place the plastic hinges on the bottom side of the canard (i.e. on the side the flap swings toward). I think it would’ve allowed more freedom of movement and I wouldn’t have needed to mess with the hinge tape. Valuable learning misstep.

    Also for the forward top fuselage nose piece, I’d replace that 1/4” balsa with 1/8”. It felt plenty heavy and using a lighter piece would’ve shaved off most of the trimming weight needed for the aft end (12.08 grams).
     
  13. Jul 12, 2019 at 12:29 AM #73

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    Eric Noguchi

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    Done and ready for the pad.
    45”L x 27” wingspan @ 9.8 oz with expended engine casing and 0.43 oz of trimming weight inclusive. A tad on the heavy side.
    IMG_3636.JPG
    IMG_3639.JPG

    Thunder and its smaller Ecee sibling.
    IMG_3628.JPG
     
  14. Jul 12, 2019 at 12:50 AM #74

    mikec

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    FWIW, I used CA hinges on mine, which are much lighter and better centered than these. It's quite easy to cut the slits for the hinges given the thickness of the canard balsa. First item on http://www.greatplanes.com/accys/gpmq3950.php
     
  15. Jul 12, 2019 at 1:28 AM #75

    BABAR

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    Straight trails!
     
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  16. Jul 12, 2019 at 6:41 PM #76

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    Eric Noguchi

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    Always assumed references to "CA hinges" meant the usual Du-bro variety but now I understand it's a hinge designed to absorb cyanoacrylate better, so thanks for url. Will switch to these for future builds.
     
    Last edited: Jul 12, 2019 at 6:47 PM
  17. Jul 12, 2019 at 6:45 PM #77

    Rktman

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    Eric Noguchi

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    Thanks! Hoping for just that result when I get to fly this hopefully in September at a large (3,800 acre) field. If all goes well I'm also hoping to get some footage...or at least some stills.
     
  18. Jul 12, 2019 at 7:28 PM #78

    new2hpr

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    I just cut a piece of CA hinge material the size of the original tape, laid it across the joint between the fixed and moving parts, then CA'd to both. No slitting needed, as the canard only moves down. I guess it might be prettier with them hidden in a slit, but the full width hinge is beefy.
     

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