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Thread: World speed record with 250mm (or under) size quad

  1. #1
    Fretsaw Jedi Roboforcer X2000's Avatar
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    World speed record with 250mm (or under) size quad

    Dear fellow FPVers/builders, I set you a challenge!!!

    I set myself a goal to beat everybody on speed with a miniquad. After I read my first two lines it made me think even more whether I bit more than I can chew, but hey, at least I'll give my very best at it
    Why 250mm and not a millimeter more? Such term as "miniquad" has settled as "250 size Mini" as well, and on a bigger frame you can put 6" props to crank up the speed, but on 250mm or under comes much bigger challenge, where building knowledge & skills involved, rather than any CNC'ed frame with the right gear stuck on it.

    Let the fun begin
    As I don't want any unnecessary weight such as OSD with GPS, I'll be measurring my speed with this one:



    For more RPMs I'll be using 6s (2x 3s 1.4A) with new SunnySky 2207 2100kv motors. Did few tests on them- first one came out smoking ESC (Sunrise 30A) and the motor and it was with original Blheli fw. Second test was done with SimonK fw and without magic smoke, but still no full throttle. With various props at around 75% throttle ESC wouldn't give more RPMs and stalling (but still no smoke ). So far I have my throttle limited to 75% on 6s until I'll get lightweight 6s and high RPM capable ESCs. 4s works OK, I'll give a go with 4s as well.





    We talking here about splitting hairs, every little aspect will make a difference, no matter how small it will be, so I need to build a special frame for this project. Motors will be inverted for less airflow obstruction with cones on top, copter will be thin and sleek (centre frame only 32mm wide) with aerodynamic canopy and other madness. Frame is not gonna be unbreakable, all it has to withstand is stress in the air and a tiny bit rougher landings. That saves a lot of weight.



    That's my size, 242mm motor to motor across:



    Started installing the gear:





    Wiring finished. Checked future AUW roughly- it'll be a bit over 600gr.



    Canopy forming. Using 2mm balsa sheet I sculpted around to have a rough shape. Later I'll fill it with expandable foam so I can "sand/filler/sand/filler/sand/paint" it (another made up word )





    So much for now
    If you're a noob, copy 1:1 what somebody already flies without too much questions, you'll find the answers later.
    PatrikE: I don't see anything wrong in your dump...
    Derrick:
    you are flying it LOS... You are doing it wrong.

  2. #2
    Sr. Keyboard Cowbow chatch's Avatar
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    I'll take this challenge . I will keep it to 250mm M2M. Post your speed and I'll post mine
    Quote Originally Posted by jimmaplesong View Post
    When you're outraged at chatch, please don't quote his bullshit.

  3. #3
    Fretsaw Jedi Roboforcer X2000's Avatar
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    Yeah man, lets do this
    If you're a noob, copy 1:1 what somebody already flies without too much questions, you'll find the answers later.
    PatrikE: I don't see anything wrong in your dump...
    Derrick:
    you are flying it LOS... You are doing it wrong.

  4. #4
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    I'm in as well. I've been working on the design and build methodology for a while on this thing. I'll post something once I have some parts together. Mine is sitting at 260 though.... Does that mean I'm out on this one?

  5. #5
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    You need to put a swiveling teardrop cover on those arms. A round cross-section has an awful drag coefficient -- the swiveling teardrop will reduce the drag significantly.

  6. #6
    Fretsaw Jedi Roboforcer X2000's Avatar
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    Quote Originally Posted by xjet View Post
    You need to put a swiveling teardrop cover on those arms. A round cross-section has an awful drag coefficient -- the swiveling teardrop will reduce the drag significantly.
    I'll cover motormounts with cones, but not sure about the arms... I thought of doing so, but I'm afraid they will do more damage than good. At full speed quad is tilted more than 45deg and I have no way of telling what my tilt will be. If I'll put teardrop cover vertical than it will create a little lift and more drag than naked round tubes. Once I'll know my full speed tilt I'll consider making them covers, cheers Bruce
    If you're a noob, copy 1:1 what somebody already flies without too much questions, you'll find the answers later.
    PatrikE: I don't see anything wrong in your dump...
    Derrick:
    you are flying it LOS... You are doing it wrong.

  7. #7
    Navigator LKTRSMG's Avatar
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    awesome new build, robo!! Nice challenge... for now my 3S 250 will not be able to compete I'm afraid

    any reason you didn't go for tilted motors or am I missing something?

  8. #8
    Sr. Keyboard Cowbow chatch's Avatar
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    I have 6S working, just playing with geometry right now.

    No more than 250mm as the OP states. so that means 260 is eliminated. For example anyone with my original Spanky frame(265mm) cannot use that frame.
    Quote Originally Posted by jimmaplesong View Post
    When you're outraged at chatch, please don't quote his bullshit.

  9. #9
    Sky Pirate & FPV Outlaw SecretSpy711's Avatar
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    Robo you are always up to something! Do you ever sleep?
    youtube.com/secretspy711
    COFPV.com

  10. #10
    Sr. Keyboard Cowbow chatch's Avatar
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    Here is a special OneShot enabled simonk esc with regenerative braking enabled . 6S 2000kv. Although I was running 4S in this test.

    Do you want to make this the main 250mm speed thread or should this be your focused build thread and we make a more general one in the subforum?

    Quote Originally Posted by jimmaplesong View Post
    When you're outraged at chatch, please don't quote his bullshit.

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