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Need some mechanical input (Dave / Scott I KNOW you've both done this)

Discussion in 'Everything Scratchbuild (Questions & Chit-Chat)' started by Argonath, Mar 6, 2013.

  1. Argonath

    Argonath Ace Pilot

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    I saw a plane today and it got me thinking. I've decided it's a new project for me and it looks like I'll finally be throwing my hat into the VTOL ring....

    I know how to wire everything and build the planes, why do you or don't do certain things but what I have yet to do and have actually seen VERY little of is the mechanical workings to make things rotate (Like the Tilt rotors on a V-22 Osprey for example).

    On an RC plane, what method have you folks used to accomplish this and have it be reliable. Obviously if it's going to have prop-wash and motor torque being applied to the rotating mechanism, it has to be robust enough to do so without failure.

    I'm going to initially try doing this without a Gyro (I have yet to buy any) and I have some ideas on how to work without it but only trying it will tell if it'll work. I'll try to keep as detailed a build log as I can on this...

    So let's see'em boys. How do you rotate motors mechanically??
  2. poormansairforce

    poormansairforce Airman

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    Sounds like a cool project. If we could see the design or have an idea of how its laid out it would be helpful. Is it similar to an Osprey?
  3. JettaManDan

    JettaManDan Administrator

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    good solution may be Boxermad's TV motor mount.....not sure you can go from 90 degree to 180 degree..but worth a look possibly...

    what i've seen other people do it pretty simple....a tube to rotate a metal axle in secured ot either side of the motor hole...have that tube on either side of the mount....the "axle" connected to each side of the motor plate...but on one exposed side there is a servo horn glued on...so the servo can push the servo horn and rotate the axle connected to the mount...will give you a 90 degree rotation or more depending on how you set it up....make sense?

    F1 wannba gave me his Mig 1.44..and he did the same thing to make moving active canards..used a plastic tube..cut in the middle..a servo horn glued onto the axle..and each end secured to the canards....so one servo moved both canards the same direction..gave a lot of movement potential...
  4. rodrigo

    rodrigo Ace Pilot

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    Welcome to the hardcore way to fly, Argo!!
    Actually I am involved in a vtol project too but in the study stage.
    I think the mechanical part is the most simple.. .look this from Mr. FoamAndTape , again he designed another excellent aircraft.. Check this
    http://www.rcgroups.com/forums/showthread.php?t=1816216

    This guy tried all possibilities for a tilt rotor plane from flybars to complex electronics and the last is the best way for sure.
    A rotor plane need some stabilization assistance (even coax helis needs gyros).. Don't try to fly one without assistance or will crash lot of test planes.
    For this reason Im reading a lot about gyros and stabilization board and software ... this is the only way to accomplish the mission.
    Good luck

    Enviado desde mi GT-I9100 usando Tapatalk 2
    tjrrcon likes this.
  5. fishwhisperer83

    fishwhisperer83 Ace Pilot

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    The mount used for the tail of a tricopter may work really good. Strong and stable. I'm not sure about the angle it can be used to but you may be able to mod one a bit to get more throw.
  6. Maestro

    Maestro Ace Pilot

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    Maybe fixing the mount at 135 degree should be zero input.. That way only 45 degree is neede both directions..
  7. Argonath

    Argonath Ace Pilot

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  8. Argonath

    Argonath Ace Pilot

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    Actually, I think that the radio is more the problem then the plane is. From what I can tell, all VTOL configs use the Radio setup as a PLANE TX. I plan on using mine setup for Heli's to see if this makes a difference in this case. I have some parts to get (I need some bigger props then what I have) to do this and I want to ensure that my motors and ESC's are all bought at the same time making it more likely that they'll be from the same manufacturing lot. The reason I want this is because they'll likely respond in exactly (Or as close as possible to) the same manner when input is applied.
  9. Argonath

    Argonath Ace Pilot

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    This is along the lines of what I was thinking as well but I'm a visual person so in my case a picture really is worth 1000+ words. The more detailed the pictures are, the more I get from it...
  10. phoenix_md

    phoenix_md Airman

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    This is the best one I've seen.

  11. Argonath

    Argonath Ace Pilot

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    Ya, that's Foam and Tape's...
  12. rodrigo

    rodrigo Ace Pilot

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  13. Argonath

    Argonath Ace Pilot

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    I really want to do this on 2 props and not 4. 4 might as well be a quad-rotor aircraft. You can buy control board for that and it'll do the rest. Where's the fun in that?
  14. rodrigo

    rodrigo Ace Pilot

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    is not right at all... remember, the basis to keep a helo flying is because they have a stabilization trick.. no less than 1 gyro and a flybar (flybarless helos need a 3 axis estabilization unit)... the tx on heli mode can manege this things but no more (the mix of the swashplate is the most important job of the heli tx)...
    about geometry, on helis the CG is exactly above the rotor, think in a object suspended by a rope , and keep the heli on the air is like equilibrate a dish over a pole were the dish is rotating (do you remember a tipical act from chinese circus ? )... well a twin rotor aircraft needs to work like a balance but when you tilt a rotor, it breaks the equilibrium... you know the concecuences
  15. rodrigo

    rodrigo Ace Pilot

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    I had thought something similar a couple of month ago.. the quad don't like it at all because are ugly and I like planes, but when a I saw the XC-142, my point of view change a lot....


    and about stabilization units... this little planes are hard to control , here the gyros can help a lot: one, keeps the roll controlled, but pitch needs one more.., well, today a multiwii controller cost lower than two gyros and has 3 gyros on it and acelerometers and free software for endless customization . ,http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=685&productname=
    the fun is just the diference between keep in the air or crashing to the ground and you can deactivate at any time if you want more dificult
    and the last thing , the OSPREY would not fly without computer asistance
  16. Argonath

    Argonath Ace Pilot

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    I think I'm going to order myself a couple of inrunners to try this because all I have are outrunners and I see some issues with setting up the tilt mechanisms as I'd like to keep the COB below the rotation point so that it tends to pull it down when rotated down.
  17. Don't go with a bicopter- It's like trying to balance a table with 2 legs. This is where gyro stabilization is absolutely needed to sustain a hover which is what you don't want...
    Tri's seem to be the most effective. You'll still need gyro stabilization (motors will NEVER run at the exact same speed), but you won't run into further problems with oscillations. See here -> http://www.rcgroups.com/forums/showthread.php?t=1842418

    The hardest part of VTOL is working out control between the two different flight modes. How you control the plane in a hover will not be how you control the plane in FF. You'll have to assess how to effectively control both flight modes without them interfering with each other during any part of the flight. This will probably end in some sacrifices of design but it's important to remember unless you cave in and join the multiwii guys. Then it's all really simple :D

    I'd be happy to help you through this project and I'm very interested. Currently I'm finishing up a tiltrotor project that once I get working, will end up being an F-35.
  18. Argonath

    Argonath Ace Pilot

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    I'm still working on the layout right now. If I can get some free time I'm going to have a mock up and see if I can't get this to work. I have a VTOL Aircraft now that takes off from standing still to straight in the air and then transitions to forward flight. The problem is, it's not made to switchback into hover mode to land.

    It's bicopter design and absolutely has no Gyro's in it and it works which makes me think that it's possible, but it's not going to be easy.
  19. LukeWarm

    LukeWarm Top Gun

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    With a large servo. You can also buy servos that use worm gears.
  20. Bosstech76

    Bosstech76 Cadet

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    the hunter-killer
    not sure if youve seen this yet. maybee it will help with ideas
    seems to me he/s using a thrust vectoring setup. i noticed the flaps inside the turbines
    phoenix_md likes this.
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