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 -

    Gave my modified Su-30 V4 that I built as a "beater" plane for winter a bit of a power upgrade a few weeks ago as an early celebration of spring arriving :)


    EDIT: If you watch on YouTube, check the video description for more info on the power setup :)

    Cheers,

    Scott
     
    Last edited: Mar 24, 2018
  2. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Working on another modified Su-30 V4 as a bit of a "speedster", but still having full controls so I can thrash it about aerobatically when the mood suits:)
    2018-05-06 08.44.14.jpg
    2018-05-06 08.44.30.jpg
    As I have been experimenting with quad racing motors for almost a year now and have some seriously fast setups especially now that I have some 4S batteries, I thought I would build this airframe to be a bit speedier than my "beater" plane that has served me well for several months:) Here is that plane with a pretty sporty quad racing motor setup on 3S.

    So this current build is even smaller, the wingspan is about 24.5"/622 mm which is an inch narrower than the plane in the video above. I probably could have gone even smaller, but then it would have made it a real chore to get the battery in and out as the electronic bay opening is already pretty narrow. I also scaled the elevons down considerably and made them look a bit more scale. Hopefully by narrowing the span of the elevons down to scale size that will also help reduce drag.

    The wing plate and fuselage are build with Dollar Tree foam (as are the KF4 airfoils) to also help reduce the frontal drag down somewhat over building with Depron or MPF. The nacelles, vertical stabilizers and elevons are made with Depron to give good longitudinal strength to the airframe without having to add any extra reinforcement.

    Just needs a little paint, motor and some rudder servos/linkages and she will be ready to "slip the surly bonds of earth".

    I started a video playlist on my YouTube channel discussing my thoughts through most of the build thus far. Once it is completely ready to fly, I will add another "table talk" video on how I think the build ended up:)


    Cheers,

    Scott
     
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  3. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    One modified Su-30 V4 ready to "slip the surly bonds of earth":) More pictures attached below. Looks fast just sitting still ;)
    2018-05-09 06.00.01.jpg
    I went with this "camo" pattern of the three colors of the Indian Flag, plane is complete with Indian Air Force markings. I had used this scheme recently on my short lived modified RCP T50 V1 and really liked it and since this Su-30 will be seeing some serious speed, I think it will be a little easier for me to see:)

    AUW with a 2200 3S battery is 530 gr/18.7 oz which is what my "mini Mig-35B" weighs, so it will be an interesting "fly off" to see which one is faster:)

    As mentioned in the previous post, wing plate and fuselage built with DTF (Adams Readi board), nacelles, vertical stabs and elevons built with Depron.

    Power setup

    EMAX RS2306 2750 kv motor https://hobbyking.com/en_us/emax-rs2306a-2750kv-black-version-motor.html

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

    ESC - HobbyWing Platinum PRO 40A https://www.banggood.com/HobbyWing-...l-p-70384.html?rmmds=myorder&cur_warehouse=CN

    I used 9 gr RC Timer nylon gear servos for the elevons http://rctimer.com/product-458.html and 5 gr RC Timer nylon gear servos for the ailerons and rudders http://rctimer.com/product-383.html

    Hope to maiden in the next couple days on 3S to get it trimmed and dialed in, I should also have a "table talk" video done before then to discuss the mods and other build details.

    Cheers,

    Scott
     

    Attached Files:

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  4. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    A short "table talk" discussing much of what is posted in the previous post. Plane and dog are the stars of the show;)


    Cheers,

    Scott
     
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  5. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    First flight session went really well:)
    2018-05-10 08.45.54.jpg
    Here is some video on 3S as I started getting things dialed in.


    I thought some more and will probably shoot a table talk video to get into the details of my post flight report, but here are some of the highlights.

    The CG ended up about 3/4" ahead of of what it is on the plan, but that seems to be normal when I remove the canards and add a little bit to the leading edge of the wing to compensate.

    The throws are currently as follows

    Pitch - 3/4" one way

    Roll - 3/8" one way in both the elevons and ailerons

    Yaw - 5/8" one way.

    I have purposely left the throws in the roll pretty conservative although it still rolls pretty smartly as I don't want it to be twitching too much as I line up for those high speed runs. :)

    Cheers,

    Scott
     
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  6. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Post flight discussion video, I also caught up on how I made some of the modifications that I hadn't talked about in previous videos in this series :)


    Cheers,

    Scott
     
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  7. That thing rocks pretty good, 4S will be a blast. What's the dimensions or space you have for the battery? I might just have to pick up one of those motors and try a light speed build. :)
     
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  8. e3_Scott

    e3_Scott Top Gun

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    Thanks Jeff:)

    Where the back of my 3S battery is located, the hatch opening is about 1 and 5/8" wide. I don't think I could get my battery back much farther, so luckily it balances well where my battery is placed.
    2018-05-11 06.58.37.jpg
    I slide the battery in at an angle at the front of where the notch for the electronics bay door is located, it is exactly the width of the battery. It is just over 1 and 1/4" wide there on my plane.
    2018-05-11 06.59.03.jpg
    2018-05-11 06.59.39.jpg
    It will depend on the foam you build with, since I built the fuselage with paperless DTF, I gained about 3mm width internally on the battery bay over building with Depron/MPF. Of course it will also depend where your CG ends up which will have an impact on where your battery goes of course. If you can get your servos as far forward as you can, it will help the battery be able to be further back where the opening is wider which should help with getting the battery in and out.

    Cheers,

    Scott
     
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  9. That is snug in there, no Velcro required. ;)
     
  10. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    I had my latest modified RC Powers Su-30 V4 out for some more speed trials on 4S:)

    As I mentioned in the beginning segment of the video, I had hoped to see 100 mph, but that's OK, I am up to the challenge and I think by experimenting with some different props and/or motors that it should be achievable. 95.9 mph is still pretty darn fast for some foam and glue to be going:) Compared to the average top speed on 3S which was about 87.8 mph, it is an increase of 8.1 mph, so those next few mph will be a challenge to achieve, so it will definitely be fun to experiment.

    I did have to fly it a little nose heavy to keep the "zooming" down on the high speed runs, it seemed to want to zoom a bit more than my "mini Mig-35B", but I didn't really see any torque roll, so that is good:) It still felt very rock solid at top speed, very stable, even with a bit of a breeze. This is the lightest and smallest Su-30 V4 I have built and it almost feels like it is the most stable, which is a good thing as I keep trying to push the speed envelope even further.

    It is certainly an adrenaline rush even if only for about 3 minutes at a time:)

    Cheers,

    Scott
     
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  11. sirskyhi

    sirskyhi Ace Pilot

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    Very Kool!!!!!
     
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  12. e3_Scott

    e3_Scott Top Gun

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    Thank you:)

    Cheers,

    Scott
     
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  13. SukhoiLover

    SukhoiLover Ace Pilot

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    Holy oofda, Batman, that thing is smokin’ fast!

    Couple of thoughts: you may be near its speed limit because the drag rise is exponential as the speed increases, and; be cautious of control surface flutter (though balancing foam controls may not be worth the effort).

    But dang, that is fast! I wonder what the SCALE speed is?
     
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  14. e3_Scott

    e3_Scott Top Gun

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    Thanks for your input, yes it certainly covers the real estate in a hurry:)

    I may be getting close to the drag limit, but having flown park jets before where this limit has been an issue, I think this airframe is capable of a bit more speed before that limit is reached. I don't feel that the motor is laboring trying to overcome that drag limit. Currently the 6x3 prop is the only one I have that can be swung safely by this motor within the amp limit of the motor/ESC. Hopefully when I receive some 5" props with varying higher pitches, I will be able to get more thrust with either this motor or some other quad racing motors I have with which to experiment. Currently with this prop and motor, I think I have reached the performance limit of the motor and I think the airframe can still handle more speed:)

    The control surfaces are all pretty tight, having had elevon flutter years ago, the elevons on this plane are stiff, I "double taped" the elevon hinge by putting extra tape on the bottom of the hinge and there is about 1mm of play in the linkages. In my experience, one or all of these three things can lead to elevon flutter at high speed in a prop in slot park jet.

    Based on this formula I have used before found on RC Groups (post #10) https://www.rcgroups.com/forums/showthread.php?5221-how-to-figure-scale-speed which seems to make sense, my plane is 1/22.7 scale compared to the real Su-30, so if my math is anywhere near correct, the "scale" speed would be about 456 mph or to put in "airplane speak" about 396 kts.

    Cheers,

    Scott
     
    Last edited: May 15, 2018
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  15. A miniature little rocket, awesome. :)
     
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  16. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    I had these two "speedsters" at the field today:)
    IMG_20180517_090326022.jpg
    The main focus today was to collect some speed run data with the "mini Mig-35B" to compare it to what I have already collected with the modified Su-30 V4 on both 3 and 4S.

    The results were quite interesting. These two planes weigh exactly the same, are built with the same materials and are using identical motors/props/ESCs and batteries. The Mig-35B in fact has a slightly shorter wingspan and is also shorter in overall length. So today proved interesting to learn how much impact airframe shape has on top speed when you are really looking to push the speed envelope to it's maximum. Luckily, temperature and wind conditions were very similar today as they were when I collected the speed data with the modified RC Powers Su-30 V4, so I don't really think that had a significant impact on today's speeds.

    In four runs using my onboard GPS data logger on 3S, I achieved top speeds of 72.1/73.4/74.0 and 72.8 mph with the Mig-35B for an average top speed on 3S of 73.1 mph.

    In four runs on 4S, I achieved top speeds of 83.9/82.6/84.2 and 85.8 mph for an average of 84.1 mph.

    With the Su-30 V4, average top speed on 3S is 87.8 mph and on 4S is 95.9 mph, so not even really close. So I suppose that pains me a little as I helped design and test the Mig-35B and it is a pretty quick plane, but not compared to the modified Su-30 V4, so I give all credit where credit is due to RC Powers:)

    So I took several comparison photos of the two airframes to give me a better idea what was going on. Nose on profile, the Su-30 is considerably smaller/sleeker right from the nose.
    IMG_20180517_090352160.jpg
    You can see even more detail here how sleek the fuselage and LERX (leading edge root extension) are on the Su-30 compared to the Mig-35 in this top down view.
    IMG_20180517_090424647.jpg
    Side on full length of the planes nose to nose.
    IMG_20180517_093641034.jpg
    More of a close up of the nose/canopy areas of each plane. I think it is easy to see how much smaller and sleeker the nose is on the Su-30 V4, as well the canopy is more blended into the fuselage on the Su-30 where as it sticks up from the fuselage on the Mig-35B.
    IMG_20180517_093654707.jpg
    The Mig-35B is one of the most stable planes I have ever flown in my entire park jet career, however at this size and and speed, it again is not as stable as the modified Su-30 V4. After having flown the Su-30 on 4S, today I noticed even more the tendency of the Mig-35B to torque roll on 4S and still zoom once in awhile even though I flew it a bit more nose heavy today than I did in the previous session on 4S. This didn't normally happen right as I hammered the throttle, but would come on as the prop/motor wound out to full power. It was manageable, but I would also assume that this would be robbing some speed. In comparison, the Su-30 gets locked in and stays locked in throughout the speed run, so I would assume less airspeed is wasted in zooming and torque roll.

    In the back end, they both have the "toed in" vertical stabilizers, a ground breaking design addition that RC Powers introduced to park jets with the Mig-29 V3 that helps a lot with yaw stability at speed and in turns in my experience. I know that will probably be very hard for you to see in this picture, but here is it anyway:)
    IMG_20180517_095235181.jpg
    I think the ventral fins on the Su-30 are helping a lot with reducing torque roll, perhaps as I experiment with some 5" props the torque roll might be reduced on the Mig-35B, but I don't think that will make up for 10+ mph speed difference if they both have the same power setup:)
    IMG_20180517_095210119.jpg
    So lots was learned today, moving forward it will be interesting to see how much more speed I can push out of the modified Su-30 V4 experimenting with some different props and quad racing motors on 4S. The mini Mig-35B is certainly very quick and I think will be home to one of the faster quad racing motor/prop combos on 3S moving forward:)

    I didn't shoot any new video today, but for comparison purposes, here are the videos I shot of both planes within the last week or so on 4S.

    Mig-35B

    Modified Su-30 V4


    Cheers,

    Scott
     
    Last edited: May 17, 2018
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  17. What are you using for the gps tracker Scott?
     
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  18. e3_Scott

    e3_Scott Top Gun

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    I'm using this old Voltron GPS datalogger V2.0 by Velocity RC. It used to be available from Grayson Hobby, but I don't think it is available any longer anywhere except maybe used on Ebay or something like that.
    2018-05-17 13.09.48.jpg
    They are now up to V3 which is about the same price I paid for mine about 6 yrs ago http://www.velocity-rc.com/cgi-bin/vrc/prod/manager.cgi?action=show&pid=82

    Hobby King sells one very similar for about half the price https://hobbyking.com/en_us/quanum-gps-logger-v2-with-backlit-lcd-display-neo-6-u-blox.html, but it is almost never in stock.

    Mine simply plugs into an extra port on my receiver for power, then you just have to let it lock onto the satellites, and set it up to start logging as you fly, so it is easy to move from plane to plane. Mine only collects top speed, avg speed, total distance flown and maximum altitude, and is not always terribly accurate which is why I like to collect data from three or four flights and only use the speeds from the ones that are the closest together and most consistent. Also, I have to remember to look at the data collected on that flight before disconnecting the battery or it will be lost or default to the last data I actually looked at.

    Cheers,

    Scott
     
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  19. Thanks,
    Yes the HK one is half the price but no stock, I didn't read all the specs but the HK said it is 58g so you are doing good speed carrying that extra weight.
     
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  20. e3_Scott

    e3_Scott Top Gun

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    That is probably shipping weight with packaging, etc, although it does look a lot chunkier than mine, you might be able to take that plastic casing off and replace it with clear shrink wrap to save considerable weight. My data logger weighs 9 gr ready to go in the plane.

    Cheers,

    Scott
     
    Last edited: May 17, 2018
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