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About colinrichardson

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  1. As one of my structures professors used to say (and make dozens of powerpoint slides that said..) "Triangles are Magic"
  2. Great model and great video. Details on the suspension will be very interesting, I'm sure.
  3. finally have the boom built and was able to load-test the firgelli actuator. I was wrong about 1 actuator being sufficient- it was juuuuuust able to raise the extended boom but sounded painful. 2 actuators twinned together work fairly well - some strain, but not excessive.
  4. I've put quite a bit of force on it with my hand and am confident that it will lift the boom throughout its entire range. The actuator has a lot of mechanical advantage when the boom it at its peak (most vertical), so I think it will be able to support a significant weight at that point.
  5. Thought I'd share the boom geometry I'm planning on implementing using a firgelli actuator:
  6. It's similarly cheap off of, a bit more expensive on
  7. I'm trying to use Brick Wizard for the first time but keep getting this error: "Unable to retrieve store information. Please try again." Has anyone else run into this?
  8. colinrichardson

    [MOC] Tandem Helicopter

    A few videos of the mechanisms I've been working on: The control combinations discussed above- one is linear-actuator based: the more compact one uses worm gears and racks: The rotors and swash-plates have been through a number of iterations and are remarkably similar to designs by some other MOCers I've seen recently. Cyclic: Collective: In Motion: Finally, a quick look at my first attempt at a control stick mechanism that outputs rotation:
  9. colinrichardson

    [MOC] Tandem Helicopter

    Very nice work - I hadn't seen it before. I've been focused on gear mechanisms for the control combinations but your lever-based system seems to be very elegant. It's going to take me a few more work sessions to install and test my current design, if it fails (too much friction etc) I'm going to give your system a try. Thanks.
  10. I started this project a few years ago but let it sit dormant. I've started it up again and figured it would be good to track its progress and start getting some feedback (though there's not much to critique yet). This is going to be a tandem helicpoter loosely based on the Chinook. I'm especially interested in mimicking the Chinook's flight controls and expect this to be the biggest challenge. The real helicopter's controls uses a sophisticated, for its time, hydraulic system to mix inputs from the throttle, stick, and pedals into outputs to the rotors so that it "feels" to the pilot that they're flying a more traditional helicopter. Though I briefly considered using pneumatics to create the control system, the lack of pressure variability made it an unappealing option. Instead, I'm working-out a mechanical gear and axle system to combine and actuate the controls. I may convert to an rc/servo system in the future, but plan on only motorizing the rotor's spin for now. The crude testbed / proof-of-concept mockup that I'm starting with. I'll upload some more images over the next few days.
  11. eBay: I've bought similar (not from this seller) and it has worked well for me.
  12. Yep - differentials are a bit counter-intuitive but were an important innovation, both in real-world machines and in lego. This article might be a bit long, but explains things well.
  13. I agree, this forum is not plagued by too many posts, and any more info on the 41999 is absolutely on topic.