Flip Flyer Question

Discussion in 'Low Power Rocketry (LPR)' started by sjh1, Aug 4, 2019.

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  1. Aug 4, 2019 #1

    sjh1

    sjh1

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    I have put together a Flip Flyer and I am considering a modification. I thought I would post it here and see what the community thinks of it. The Flip Flyer comes down in 2 pieces. One part is helicopter recovery and the nose section comes down on a small parachute. I hate trying to locate 2 pieces since I usually lose track of one. So, I was thinking of adding a kevlar cord between the body and the shock cord and drop the chute. What do you guys think?
     
  2. Aug 4, 2019 #2

    Amsterdam

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    I like it,

    There will be some issues with the line getting crossed with the helicopter blades as the model flips, but that won’t effect the blades deployment, and probably won’t hurt performance.

    The nose is going to eject up above the model, blades will flip out and point tip down to the ground, then any part attached to the blades will flip over, except the nose cone which will still be high above the rest of the rocket.

    A simple fix to that is use a length of Kevlar that won’t pass the blades when they’re deployed, but be advised short shock cords can put a lot of stress on the body tube, and whip back into rocket.
     
  3. Aug 4, 2019 #3

    GlenP

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    Sounds like a neat idea, the rotors might be able to handle the extra weight, you could do some drop testing with and without the payload/nose to see how much faster it will drop.
     
  4. Aug 4, 2019 #4

    5x7

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    I got a flip flyer after they came out and joined the copter to the nose section. The mod is just a length of kevlar string that goes through the main tube and comes out the motor mount. There is enough room in the mount to insert the engine next to the string. The kevlar string is trapped by the screw on motor retainer so it is a reversable mod. Tie the kevlar to the shock cord from the upper part. It comes down slow enough I think and has never been damaged.
     
  5. Aug 4, 2019 #5

    sjh1

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    I like your idea, I think I will try it.
     
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  6. Aug 4, 2019 #6

    BABAR

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    May want to add a fishing swivel to keep the line untwisted
     
  7. Aug 4, 2019 #7

    5x7

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    A911AEDD-1B6A-48C1-8A85-5E2AB82044FB.jpeg This is a pic of the Kevlar you can see the thickness that works well, just fold over the threads and screw on the cap.
     
  8. Aug 5, 2019 #8

    sjh1

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    OK, I did like you pictured. How long a cord did you allow out the other end.
     
  9. Aug 6, 2019 #9

    5x7

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    It's about three feet of kevlar tied to three feet of 1/8” elastic which is mounted as normal to the nose section. I could have used the kit shock cord but was probably afraid the Kevlar would cut it.
     
    Last edited: Aug 20, 2019
  10. Aug 18, 2019 #10

    Scott_650

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    I have to try this! Great idea - couldn’t be simpler.
     
  11. Aug 18, 2019 #11

    neil_w

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    Sorry for my denseness (density?) but could you show the whole thing laid out, showing exactly what is connected to what? I'm having a hard time picturing it.
     
  12. Aug 18, 2019 #12

    Scott_650

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    He ran a length of Kevlar from the motor retainer to what would usually be the chute attachment point on the upper section. Now when the ejection charge pops the rocket open instead of the upper section coming down separately on it’s chute it hangs “below” the now helicoptering lower section. The rocket boosts, coasts, ejects, opens (so the blades release), flips over with the upper section now hanging down while the helicopter section spins the whole thing to the ground. It’s hard to grasp because it’s such a simple solution to what seems to be a complicated problem :)
     
  13. Aug 19, 2019 #13

    5x7

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    I’ll try to find it in the basement and snap a pic tomorrow, but it’s just as described by scott_650 above.
     
  14. Aug 20, 2019 #14

    5x7

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    Here are the pics, three feet of thin braided Kevlar tied to three feet of 1/8” elastic. Length probably overkill. I also wrapped the cord above the motor in masking tape to protect it a bit.
     

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  15. Aug 20, 2019 #15

    neil_w

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    Ah, got it. Looks like a great solution. Thanks!
     
  16. Aug 21, 2019 #16

    5x7

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    You got me inspired, here is a video from this morning before work, it’s just a B6-4 which flies fairly low, you can see it slows down as it gets close to the ground and starts to really spin fast. On a C it’s really nice.

     
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  17. Aug 21, 2019 #17

    bibbster

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    Nice mod!
     

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