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    Depron Dynamite build

    Hi guys, so this is my first post on daddyhobby doing a build of a DLG that uses a KF airfoil called the Depron Dynamite. http://www.rcgroups.com/forums/showthread.php?t=614246
    this is my first DLG and im not very good at scratch building so please pardon any rookie mistakes i make

    first i printed out the plans, cut them out, pinned them to the foam then roughly cut them outClick image for larger version

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    then i taped the identical pieces together to sand the ends straight (in the end i found out that i didnt sand them well enough)
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    i followed someone's build on RCGroups and used a scarf joint to make the dihedral

    so i drew lines on a piece of masking tape then taped it onto the carbon strip (im using a 5mm carbon strip but after finishing the wing, it doesnt feel as stiff as i hoped it would be)
    i also cut another shorter piece to sort of reinforce the main spar (as you can see the reinforcing piece is like equal on both sides so i had to cut that)
    then i stuck the spar onto a piece of masking tape to glue them in place
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    next i cut a piece of balsa about the shape of the bend and made a jig out of pins to make sure that it was glued in place accurately. i also used the pins to hold the balsa in place while gluing. i felt like some acupuncturist doing this.
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    then i put some packing tape onto the edge of the wing piece to glue on the carbon spar. i thought that with the packing tape, i would be able to apply pressure to the carbon spar while maintaining the flatness of the bottom of the wing.
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    to glue the LE of the wing on, i used masking tape instead, making sure that they are in tension so that the foam lines up straight. then i pre-taped the top piece on so that it hinges. this way i can just apply glue then fold it into place. i then used whatever heavy object i can find on my table to hold it on.
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    then i figured i could just use masking tape to hold the other wing pieces in place while gluing so i just taped it together with some masking tape. followed by the tail pieces.
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    as of now, im still wondering how to strengthen the tail pieces, attach the vertical stabilizer (im thinking of doing it like how some people do it on the quick flick 2 but im not gonna have rudder to trim it out) and also how to make the pod. if anyone has any ideas please do share. thanks!


    #2
    Good to see some scratch building activities here.
    You may want to watch the weight of your DLG. If possible, you may also want to consider using balsa build-up wing instead of using the foam wings.
    The foam wings may not be able to offer the stiffness as well as build-up balsa structure.

    Coming back to your question on strengthening the tail pieces, I used Carbon fiber tow with CA. The bottom part of the vertical stab was covered with light glass cloth with CA.
    Detailed here:


    Let us know how your DLG fly when completed.

    Good build!

    MS

    Comment


      #3
      agree with msc on the balsa wing instead. it's doesn't matter if you are not very good on your first build, at least you try and will improve as you go on. keep up the good work.

      Comment


        #4
        @msc yea im worried about the weight as well. doug, the guy who design this used 6mm foam and he managed to get 4.2 oz. not sure if he used magic or i did something wrong >< a balsa wing seems rather complicated to build for me leh. im also wondering if i should CA a thin strip of balsa right below the step to stiffen it up or would the weight not be worth the stiffness
        carbon fiber tow... would a thin carbon spar or carbon strip do the job...?
        sure! thanks man!

        @aeromodelling thanks for the encouragement!

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          #5
          Save as much weight as possible on the tail. Balance is really important and you wouldnt want to end up putting weight into the nose. try to save any weight as far as possible...even if it seems unnecessary. my previous few scratch build dlgs turn out to be a flying brick. (maybe not quite a brick...but you get what i mean) How many servos you intend to use in this? for strengthening the wing, try epoxy very thin pieces of carbon strip on the top and bottom surface of the wing. Nice attempt in building a dlg! must let us all know how this one flies! Cheers~

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            #6
            @janson you made me wonder if i could do with just one horizontal support for the vertical fin... lol im using 2 5g for ailerons and a 9g, maybe a 5g, for the elevator. thanks man!

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              #7
              Sorry, i dun quite get what you mean for the first part... so it will be just bank and yank huh? It will work but when flying slow with flaps down, ailerons becomes rather ineffective and i tend to use rudder alot more.

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                #8
                @Janson would a carbon spar coming out from the boom (like what you did on one of your builds) be enough to strengthen the vertical fin? yup bank and yank. in that case do you use the flaps often?

                @msc erm, may i know where you got the carbon fiber tow from? is it expensive?

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                  #9
                  that one depends....i suggest you go for a thicker tube. maybe 1cm? at the end where it joins with the vert stab, lay a very thin piece of fiber glass over the join. but, cut a slot into the tube to fit in the vert stab insted\ad of using carbon strips...its okay on its own, but when i kicked the plane(by accident) the tail is shaking away...best is dun use that carbon strip method. unless its a small model.
                  I use flaps to slow down and to improve lift when flying...bank and yank is okay for a start. When you progress on, you will realise that you will need rudder alot.

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                    #10
                    Originally posted by YongChun View Post
                    @Janson would a carbon spar coming out from the boom (like what you did on one of your builds) be enough to strengthen the vertical fin? yup bank and yank. in that case do you use the flaps often?

                    @msc erm, may i know where you got the carbon fiber tow from? is it expensive?

                    I got the carbon fiber tow from NTC at Fook Hai. Can't remember the cost, but I think it is less than $10.
                    You will be surprise how much stiffer after you applied the CF tow on both sides of the tail fin. I used CA over the CF tow, and press it with transparent mylar. The surface will not stick to the mylar and will be very smooth after the instant cure.
                    Make sure you do not apply too much CA!

                    MS

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                      #11
                      @janson alamak. i got 6mm carbon tube liao leh >< been very busy these few days so no time build okay ill try out bank and yank first then see how it goes!

                      @msc i just went there on saturday and they said they dont have it anymore

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                        #12
                        Have you try Sing Hobby for the carbon tow?
                        Share the joy of flying . . .

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                          #13
                          Yea I tried but they didn't have as well :/ I think I'll just fiberglass the whole tail?

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                            #14
                            For the tail, 3mm balsa works fine.

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                              #15
                              Saw NTC had some carbon tow on their shelves today. Price around $10...

                              oh yeah, It was not called carbon tow.... I think it was called carbon tape... just ask for carbon tape... the "chinese' storekeeper will know it.


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