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Thread: Surgery on a fixed-pitch flybar...

  1. #1
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    Cool Surgery on a fixed-pitch flybar...

    Story time:

    I bought a really nice (and really cheap!) 200-250 size fixed-pitch helicopter from BangGood recently. It's the WL Toys V912. Solid unit, and stupid-cheap at under $70 (delivered) for a ready-to-fly bird including the controller. Stamped-steel construction, large tail boom, and very beefy components, so I figured this would be one I'd really enjoy. Best part is that it uses the same video camera as the V222 quad-copter that I had at FLEM back in January. The video camera just plugs right in. So I was really looking forward to flying this puppy.

    Well, when I got it in the air, I was at first amazed by it's stability, but that amazement quickly turned to dismay, as I soon learned that this thing was too damned stable for it's own good! Even with the controller on high-rate, I couldn't fly the bird into the wind, because I couldn't pitch it far enough forward. The damned flybar kept over-compensating and trying to bring it back into hover! Grrrr.....

    After flying several batteries (and having more than a few crashes caused by a lack of maneuverability), I was about to give up hope when I got an idea... Maybe I could remove some of the weight from the flybar to make it less stable? I called Ekeefe and asked his advice, to which he said, "I don't know if it will work, but if you do it and you ruin it, it's your fault!" Great...

    So this afternoon I decided to go for broke. After all, I had a complete crash kit of parts for the thing, including a replacement flybar, so what did I have to lose? So I went ahead and cut the weights off the ends of the flybar with my dremel. (Would you believe that each weight was 6 grams? That sure seemed like a lot to me...) Anyway, with nothing but the thin metal rod (no weights), I tried to fly the bird, and it was every bit as unstable as you'd imagine. Think trying to fly a collective pitch bird without a gyro and you've got a good idea. So that clearly wasn't going to work.

    But I had a couple tubes of JB-Quick epoxy, and a whole drawer full of assorted nuts and bolts, so I got to work. I found that a standard M6 nut weighs just over 1 gram, so I mixed up some epoxy and glued one nut to each end of the flybar. When the glue dried, I went over it with a second coat, which probably added another gram or so of glue to each end of the flybar. Then I gave it a test flight...

    What a difference! Now the bird flies like I expected it to! It will still hover with hands off the stick, but now I can pitch it forward and make it zoom off in no time. I can also pull back and stop it in a few feet, which is very cool.

    So here is a picture of the results of my recent flybar surgery. Granted, the JB-Quick epoxy looks ghetto as hell, but you can't argue with the results!



    For scale, the rotor diameter (tip to tip) is 15.5 inches.

    And Ed, if you're reading this, now you know what happens when you cut the weights off the flybar!

    Adam

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    Best of luck with that Adam - I'm not sure I'd want to be anywhere in the firing line of M6 bolts epoxied to the end of a fast rotating bar....

    [/tinhaton]

    How about threading the end of the bar and screwing on a few smaller nuts and then epoxy in place?


    Imagine the irony of trying to maintain laser eye safety, only to be blinded by a fast flying nut...
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    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

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    In lieu of epoxied nuts & bolts, you could grab some RC wheel collars from the local hobby shop.
    One or two per each side would probably do the trick, plus you could "tune" the flybar performance a bit by locking the collars at different locations on the flybar.
    Once you've ID'd the "sweet spot", a little loctite on the set screw should keep them in place.

    Of course, that wouldn't be near as ghetto-cool as your current mod...
    RR

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
    1979.
    Sweet.....

  4. #4
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    Just as a side note... I ordered my V222 last week along with extra batteries, rotors, larger memory card & shafts.

    So is it SELRCEM or SERCLEM?

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    Ok, so seeing as you started the topic, anyone got any suggestions for a ARTF or BNF chopper for a first timer to helis?
    I fly fixed wing slope already and have programmable 16ch transmitter, so want tsomething I can either bind and fly or just add Rx.

    At least 4 channel, but probably fixed pitch at this point.

    Hmm, we can get that same heli for 56 delivered here, might just be worth a punt. Adam, would it take a bigger LiPo do you think? Something over 1000mAh perhaps for more duration?
    Last edited by norty303; 04-07-2014 at 09:36.
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    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

  6. #6
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    Quote Originally Posted by norty303 View Post
    Ok, so seeing as you started the topic, anyone got any suggestions for a ARTF or BNF chopper for a first timer to helis?
    I fly fixed wing slope already and have programmable 16ch transmitter, so want tsomething I can either bind and fly or just add Rx.

    At least 4 channel, but probably fixed pitch at this point.

    Hmm, we can get that same heli for 56 delivered here, might just be worth a punt. Adam, would it take a bigger LiPo do you think? Something over 1000mAh perhaps for more duration?
    BNF -

    Are you running a Spektrum radio?
    If so, virtually everything Blade sells is bind-n-fly with the Spektrum (and some JR) 2.4gHz radios:

    http://www.bladehelis.com/Helis/

    Any of the coaxial's are going to be pretty easy to fly, and will teach you the basics you'll need to safely get going with an indoor heli, at the cost of some performance.
    After that, try an indoor fixed pitch copter (a bit more performance, also a bit tougher to fly), then move up to a collective-pitch machine, which has all the basic control functions your going to find on a real helicopter.

    The micro-sized copters tend to be a bit "squirrely" due to their lack of mass, but are generally very durable and able to take some beginner poundings.
    Larger copters are generally more stable, at the trade-off of being less crash-worthy & more expensive to operate & repair.

    Indoor quad copters are generally INCREDIBALLY easy to fly compared to some other small indoor helicopters, and most can be setup to be very aerobatic, as well.
    The quads are great for teaching some of the "direction reversal" issues that come with flying RC aircraft, and are a lot of fun to fly ~
    In fact, they're so easy to fly, I'm not convinced they're a good trainer to prepare a person for flying a more advanced / difficult "conventional" RC helicopter!

    PC-based flight simulators - worth their weight in gold, IMHO!
    In fact, you can buy the Phoenix flight sim with a Spektrum DX-5 radio for less than $200 stateside, then use the radio to fly all but the most complex / expensive BNF Blade & Parkzone aircraft.

    BTW -

    Here is one of the BEST sites I have ever seen that covers virtually everything you would want to know about getting started with RC helicopters:
    http://www.rchelicopterfun.com/

    FWIW...

    Randy
    Last edited by Stuka; 04-07-2014 at 10:18.
    RR

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
    1979.
    Sweet.....

  7. #7
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    Quote Originally Posted by Bradfo69 View Post
    Just as a side note... I ordered my V222 last week along with extra batteries, rotors, larger memory card & shafts.

    So is it SELRCEM or SERCLEM?
    Cool - new shirt options!!

    I knew you were hooked...
    RR

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.
    1979.
    Sweet.....

  8. #8
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    Quote Originally Posted by norty303 View Post
    I'm not sure I'd want to be anywhere in the firing line of M6 bolts epoxied to the end of a fast rotating bar...
    HAHA! Good point Adam! But seriously, they're secured pretty well. JB-Quick is amazing, given half a chance to cure before you stress it. Also, the flybar is only about 6 inches long, so it doesn't see nearly as much force as the blade tips do.

    All that being said, it might be a good idea to re-work it at some point. I've actually considered taking the spare flybar I have out of the crash kit and grinding down the weights on it to match the weights of the nuts and epoxy I have now. But that's a project for another day.

    Quote Originally Posted by Stuka View Post
    In lieu of epoxied nuts & bolts, you could grab some RC wheel collars from the local hobby shop.
    Those might have a better tendency to fly off, since it would be just a set screw holding them in place.

    Quote Originally Posted by Bradfo69 View Post
    Just as a side note... I ordered my V222 last week along with extra batteries, rotors, larger memory card & shafts.
    You'll need the extra batteries, and the larger memory card is a definite plus. I doubt you'll need the extra rotors, and I'd be shocked if you ever had to replace a shaft. Those things are pretty tough. I have yet to break anything on mine, and I've watched it crash several times (both under my own control and under the control of others).

    I haven't flown mine in several weeks, because I've had the camera hooked up to the V912 bird (above).

    Quote Originally Posted by norty303 View Post
    anyone got any suggestions for a BNF chopper for a first timer to helis?
    I fly fixed wing slope already and have programmable 16ch transmitter, so want tsomething I can either bind and fly or just add Rx.
    Depends on what radio you have Adam. Chances are good that you're not running the right protocol. However, if your radio supports add-on modules, you can probably buy one that will mount to your current transmitter and allow you to talk to the custom receivers in the cheaper birds from Blade, WL Toys, Hubsan, and Skyartech.

    Most of your basic beginner fixed-pitch helicopters and quads use a single-cell LiPo (3.7V) at between 150 and 500 maA. The larger bird that you see in my post above uses a 2 cell 7.4 volt LiPo that is rated for 900 maA. It came with it's own balance charger, but I already have a smart charger that can do 1 to 6 cell LiPo's, plus NiCd, NimH, and Lead-acid batteries, so I really didn't need it.

    Since you already have flight experience, I would say you could start with a fixed-pitch bird, rather than a coaxial. I used to fly RC planes 30 years ago (and never was very good at it), and yet I jumped straight into a fixed-pitch heli with no trouble at all. Coaxial birds are just boring in my opinion.

    If you want to go cheap, and you don't mind waiting for long shipping lead times, you may want to check out Banggood.com. They have some insanely low prices, and shipping is free on just about everything. For a good beginner fixed-pitch mini, I would suggest the WL Toys V911. This is the first bird I ever owned, although mine was re-branded for sale at Brookstone. Very stable heli, and lots of fun to fly indoors. Not really good for outside unless there's no wind and you keep it well below the trees, but it's easy to learn on one. You can get a complete RTF rig (including transmitter and extra batteries) for less than $40 delivered from Banggood.

    For a quad, there are two options I would suggest. If you want something really small to fly indoors, look at the Hubsan 107 series. All of them come ready to fly, including a transmitter. The 107L is just a quad. The 107C is a quad with a video camera that records to an SD card, and the 107D is a quad that sends first-person video back to the controller. I own the 107D, and while it's OK, the video quality isn't all that great. However, the 107C shoots very nice video - but you have to land and remove the SD card to watch it. All of them will hover with hands off the sticks though. (Great gyros!)

    For a larger quad that is suitable for shooting video outside, I'd go with the WL Toys V222. This is the one Brad was talking about above. It's very easy to fly, but it's also got enough power to fly several hundred feet high in light winds so you can shoot video of your neighborhood. Very cool. These units run around $70 for a complete RTF kit including the camera.

    would it take a bigger LiPo do you think? Something over 1000mAh perhaps for more duration?
    On the smaller birds you need to watch out when trying this, as the extra weight will affect the flight performance, and in some cases it won't add nearly as much flight time as you might expect because the motors have to work harder to lift the extra weight. Example: on my Hubsan 107C, I upgraded from a 230 maA battery to a 500 maA one. I picked up an extra 3 minutes of flying time, but the bird is more sluggish with the big battery. It still flies well, but I need more throttle when performing extreme maneuvers like flips and so on.

    Adam

  9. #9
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    On my phone so I'll be short and sweet.
    I use a FrSky Taranis Tx so can use most protocols via plug in modules.
    I'd like a 'proper' heli, not a coaxial. Fly bar seems ideal.
    I fly some electric soarers too so I've got all the necessary charging and balancing kit and a load of 2s LiPo in various sizes from about 1000mah up to 2200mah
    I have a few years power experience too (Wot4) but that was a few years back now.
    I think I've lost the auto response of closing the throttle from the soaring now, as I fly with flaps/spoilers/crow on the throttle stick these days
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    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

  10. #10
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    P.S. Don't worry about 'too' complex, there's not much out there more complex than a fully loaded F3F Soarer.
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    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

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