Su-30 V4 “Hovering Parkjet”

Discussion in 'Scratchbuilding!' started by RCPowers, May 15, 2014.

  1. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Things didn't go exactly as planned today after upgrading the power system in my modified Su-30 V4 in search of the elusive 100 mph with a quad racing motor on 4S :)


    Although I mentioned in the video I might downsize a bit, I decided to keep it at a 24.5" wingspan which is about 84% of stock since I did see a bit of torque roll with the newer, more power motor. If I made the plane smaller, I assume the torque roll would be even more of an issue and might rob me of a bit of speed.

    98.8 mph is almost 2 mph more than the top speed I saw with the previous power system on 4S, so we are not far off :) I'll be using the proper locking prop nut that comes with quad motors to hopefully keep the prop more secure from the torque the GepRC motor cranks on 4S.

    New set of plans already back from the printer, time to start cutting some more foam. Think I'll go with a different paint scheme, as much as I like this one, it seems to be a bit jinxed for me;).

    Please watch this space for more updates in the coming days and weeks :)

    Cheers,

    Scott
     
  2. XDmToter

    XDmToter Ace Pilot

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    That's too bad. :oops:

    I was really looking forward to your video of the GepRC on 4S.

    Happy re-building!
     
  3. e3_Scott

    e3_Scott Top Gun

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    I already have the GepRC setup in another plane, hope to get some 4S video footage in the next day or two, won't be quite as fast as it would have been in this plane, but I'll have a better idea how the motor and ESC hold up over a few flights pushing it hard on 4S.

    Cheers,

    Scott
     
  4. I think I might need to order one of those Gep motors.
     
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  5. 98.8 could be out either way , heck how accurate is the gps just by itself, you possibly could be over 100 already.
     
  6. e3_Scott

    e3_Scott Top Gun

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    GepRC motor is currently under restocking at Banggood in the 2750 kv, with no published date of it being available. I did find it currently available at Gear Best, they would want to charge me a bit of shipping to Canada, the prices work out about the same as getting it from Banggood. Here is the Gear Best link https://www.gearbest.com/motor/pp_1496940.html?wid=1433363

    Cheers,

    Scott
     
  7. I stole the last one, tried to order 2 and it said only 1 left. :)
     
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  8. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Parts cut out and gear ready to be turned into "speed build" V2 after V1 met it's untimely demise :(
    2018-05-27 10.19.39.jpg
    Brand new GepRC motor just received a couple days ago in the mail, hoping to see if 100 mph with a quad racing motor in a park jet is achievable :)
    2018-05-27 10.13.46.jpg
    Everything is essentially the same as V1, I didn't trim quite as much off the ventral fins, on V1 I had trimmed off 1 cm, this time only about 6mm, hoping this might help a little bit with the torque roll I saw in my short flight with the GepRC on 4S where it got to 98.8 mph:)
    2018-05-27 08.20.01.jpg
    Since I like this size and think it will be a great size for just about any quad racing motor I have for some good fun, I decided this time to make some templates for the elevon (just kept the one from V1), the nacelles where I trim off a bunch at the back to accommodate the shorter quad motor, the wing leading edge and LERX since I trim off the canards and I made a template of the KF that I sized myself including the rudder servo cutout. Even though small, it still seems pretty stable in winds up to about 10 mph, so that suits the majority of my flying conditions.
    2018-05-27 10.13.37.jpg
    Hopefully this will make future builds a little quicker as I don't have to do a lot of measuring and math before cutting out the parts, simply lay these templates on the 84% plans, trace them and get cutting foam:)

    Cheers,

    Scott
     
  9. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Project update on my quest to break 100 mph with a quad motor equipped park jet:) V2 air frame complete, just waiting on some gear and some color.
    2018-06-06 10.31.54.jpg
    My plan for a "color scheme" will be a very simple, light one (magic marker) to keep the weight down and hopefully (touch wood) make it last longer. Every plane prior to this that I have "painted" with magic marker has lasted forever!:)

    Another update will be coming when it is ready to fly. :)

    Cheers,

    Scott
     
  10. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Ready to "slip the surly bonds of earth" in my continuing quest to break 100 mph with a park jet using a quad racing motor setup:)
    2018-06-07 12.33.58.jpg

    2018-06-07 12.34.20.jpg

    Video I shot discussing the slight differences between this plane and V1.


    So hopefully I have the prop nut nice and tight this time and this plane will last a little longer to see if I can't reach the 100 mph mark, not far to go, saw 98.8 mph already before V1 met it's demise.

    Quick build summary.

    Built at 84% of stock to get approximately a 24.5"/622 mm wingspan, canards removed, elevons reshaped and made smaller to help reduce drag, using KF4 airfoils.

    More details on the other mods made and build details can be viewed in this playlist on my YouTube channel that also includes the video above.


    Wing plate and fuselage are built with Dollar Tree foam/Adams Readi board (DTF) paper removed from the fuselage and wing plate ahead of the trailing edge of the KF4 airfoils. Behind the KF the paper is left on for strength and treated with oil based Minwax to keep it waterproof. The nacelles, vertical stabs and elevons are made with Depron.

    Components.

    Motor - GepRC GR2306 2750 kv https://www.banggood.com/Geprc-GR23...p-1240972.html?rmmds=myorder&cur_warehouse=CN

    Prop - 6x3 EMP http://www.rctimer.com/?product-218.html

    ESC - HobbyWing Platinum PRO 40A with custom settings of 26.25 degrees timing and 8 KHz PWM frequency https://www.banggood.com/HobbyWing-...l-p-70384.html?rmmds=myorder&cur_warehouse=CN

    4S battery - Tattu R-Line 1550 4S 75C http://www.snhobbies.com/product_in...=9278&osCsid=52888ddbe25c97cfe50a7e8bb1c7dd7d

    Elevon servos - RC Timer 9 gr nylon gear http://rctimer.com/product-458.html

    Aileron and rudder servos - RC Timer 5 gr nylon gear http://rctimer.com/product-383.html

    As mentioned, I will start off getting it dialed in on 3S first to get the trims and balance sorted before putting the 4S battery in it and see how we end up:)

    Cheers,

    Scott
     
  11. XDmToter

    XDmToter Ace Pilot

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    Hey Scott.

    I've mentioned this around here before, but I'm not sure if you saw it.

    These two planes are virtually identical:
    [​IMG]

    They have the exact same power setup. The only difference is one of them is covered in packing tape, while the other is bare foam with a little paint on it.

    As you can imagine, the packing tape covered plane is slightly heavier. However, it also has a clear speed advantage over the bare foam plane.

    A friend of mine and I have had them up side by side, and the speed difference was so noticeable that someone asked me if I was running a 3S instead of a 2S in the packing tape covered model.

    Just goes to show how much difference a smooth surface makes versus the rough bare foam.

    Something to consider when going for Top Speed.
     
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  12. bogusbandit56

    bogusbandit56 Top Gun

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    I was thinking exactly the same thing about the slippery surface whilst lying in bed last night just before going to sleep.
     
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  13. SukhoiLover

    SukhoiLover Ace Pilot

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    :-0
     
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  14. e3_Scott

    e3_Scott Top Gun

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    Thanks for the tips, XDToter:) I'll see how the speed trials go once I get this one in the air. If I don't achieve the speed I am looking for (100 mph), I might try the packing tape on the KF4, where I left the paper on the rear of the wing, it is very smooth after treating with Minwax and using magic markers for color. The magic marker left a much smoother surface than paint does, so I'm excited to see how it goes especially being lighter than the first one.

    Cheers,

    Scott
     
  15. bogusbandit56

    bogusbandit56 Top Gun

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    I knew somebody would take it like that.
    I was being serious. I do a lot of thinking whilst lying down, hence lateral thinking:)
     
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  16. TacticalFlight

    TacticalFlight Ace Pilot

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    Yeah....take away more from the weight and it will go faster.......where do you get that from?The difference in markers or a layer of paint is so small......you bored? NO really you bored?.What you are doing to parkjets will not go anywhere.Really?...what are you doing?Buy cheap crap....put on crap.....lets go faster?I don't understand your thinking.Yeah....some don't have the money,what you are doing goes beyond the price to......crash=done.Crash = whey did the airframe not hold up?.You are doing what you are doing for you.....maybe a few.Get a grip.....and do something constructive.Someone offered you a speed increase with tape on the surface and you wanted nothing to do with him.
     
  17. XDmToter

    XDmToter Ace Pilot

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    Take it easy there TF. Applying packing tape is admittedly a lot of extra work. If it's not necessary to meet his goals then why spend the time and energy. I totally understand and agree with his response. It's not that he wanted nothing to do with me. Just that what I proposed may not be necessary to meet his specific objective.

    Did you watch the video of his crash? He explains exactly what happened and why, so the rest of us can learn from his experience.

    And if you want to talk about constructive, you should read up on the massive amount of data that Scott has given us in his other threads to help us make more informed decisions. He does a lot of testing of various components. Both cheap and not so cheap so the rest of us know what to expect from a given configuration.

    I for one am very appreciative of what he has done and continues to do for the community. His contributions are priceless.
     
  18. homey666

    homey666 Top Gun

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    Could not agree more! Now, let's get back to the fun!

    Peter
     
  19. Lgel

    Lgel Ace Pilot

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    I believe a profile wing instead of KF4 as PI latest planes would help you reach the speed you want to achieve.

    If not willing to go this far, may be, simply reducing the height of your KF4 steps should help (at speed your wing is generating a lot of unnecessary lift).

    When I compare two of my gliders, were weight is their only power (once gravity applied), my 1,8 m ws Fox at 740 gr is much faster then my 1,6 ws Phoenix 1600 at 1100 gr.
    Both have profile wings, but the fox as a much thinner profile and less cord.

    Your stabilizers, nacelles are also big drag producers, as the toe in of your vertical stab (could also be reduced may be).

    Air speed record need the average of two runs in opposite directions in the same wind conditions.

    My 2 cts, good luck with your challenge.

    Cheers.
     
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  20. e3_Scott

    e3_Scott Top Gun

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    Thanks very much for the tips, more goodies to go in the "tool box" if the current configuration does not work out :). I do have some 3mm Depron which would reduce the total thickness of the wing by about another 3mm total as the Adams readi board I am using for KF4s now is about 4.5 mm thick with the paper removed.

    Cheers,

    Scott
     
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