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Hrafn

Eurobricks Knights
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Everything posted by Hrafn

  1. Hrafn
    Here is a purely mechanical proof of concept, which works no matter which way the motor is turning. The motor is attached to the red liftarm (Bricksafe cropped the picture). The motor remains on all the time, but when the output axle (with the lime connector and 20z gear) is blocked, the differential housing is blocked as well, and the orange gear selector disengages the red clutch plate from the gray clutch gear. The dark gray 2L liftarm is blocked from rotating more than 90 degrees either way, and acts as a manual switch to re-engage the output axle when desired. Construction notes: The clutch plate is on a smooth 2L axle joiner, not a ridged one. Obviously you would need a rigid structure- this just shows the positions of the parts. And the orange gear selector tends to rotate slightly even when the output isn’t blocked, so it needs some friction or a rubber band or spring to resist that tendency.
  2. Hrafn
    For a pure PF solution, connect the motor to one side of a differential, and the PF switch to the other. Drive your mechanism from the differential housing. When your mechanism reaches its limit, the motor will drive the switch, turning itself off. https://bricksafe.com/files/Hrafn/technic-misc/trim.5D0469E9-E870-4EB2-8010-7C0F3476E099.MOV Note that this isn’t a 100% solution since it only drives your mechanism in one direction.
  3. Hrafn
    This site has strict limits on file size. To upload photos, set up an account on Flickr or BrickSafe and link to the photos from here.
  4. Hrafn
    Great stuff! Is the front suspension based on the TC18 Porsche by @Limga?
  5. Hrafn
    This is really great. Thanks for sharing the suspension details, it is a very clean build in this scale. As for terminology, TC18 is a little cryptic, but specific; I have seen it called mid-scale as well. I too wold like a common term for it as I am working in this scale as well.
  6. Hrafn
    Such clean bodywork! I would love to see a video or gif of it moving.
  7. Hrafn
    I hear you. Maybe if the two parts directly under the headlights were white instead of black?
  8. Hrafn
    Making excellent progress! The one thin I am not sure about is the grill - the bit with the Bionicle teeth reminds me of longhorn cattle, which doesn’t fit the rest of the car IMO. Can you maybe flip that portion upside down?
  9. Hrafn
    😂 I hear you on that! As soon as I post something I invariably realize the flaws with it.
  10. Hrafn
    Thank you for providing and updating all of these tools, and letting people know about the updates. I have found the wheel tool especially helpful.
  11. Hrafn
    The bodywork looks so good! I like the linkage holding the hatch in the up position- it is a nice little touch.
  12. Hrafn
    Thanks for getting the pics to work. I would use 1:8.4 scale, because a model with wheels that are too small will look odd; the reverse is not true, as slightly oversized wheels usually look ok.
  13. Hrafn
    Your images did not upload.
  14. Hrafn
    I was experimenting with the 14 tooth gears because when using 2 gears, if the gears have a number of teeth divisible by 4, you get an angle between thee input and output shafts (15 degrees if using 12z gears.). With a servo, this is undesirable because when the servo is in a neutral position, the steering shaft is not. The 14z gears can be oriented to avoid this issue. I ended up finding a compact solution using the PF-M and Sheepo’s recommended return to center steering solution; it works well in isolation but I haven’t tested it integrated with the rest of the vehicle yet. The steering doesn’t _have_ to go in the glovebox, but I wanted to see if I could make it work so that there was room for a full interior. At this scale a servo would be too large to really look like a center console.
  15. Hrafn
    The bodywork looks good! It has strong kei car vibes to me, a little reminiscent of the Autozam AZ-1 crossed with a Miata.
  16. Hrafn
    In the Technic gear lineup, there are the old 14-tooth gears, which I have used precisely for this reason.
  17. Hrafn
    Good point. Also, getting the car to go straight would be difficult. Maybe I just need a different RTC mechanism that requires less power to overcome, so when the PF-M stalls, the stall current isn’t too great. Maybe the one that uses two 2x4 L-shaped liftarms. A servo solution would be even better if someone can figure out how to make it compact enough.
  18. Hrafn
    @That_LEGO_Guywhat is the red part in the front suspension?
  19. Hrafn
    I am working on the steering motor configuration for a 15-wide vehicle (13 wide not including the doors). The vehicle is very fast so I wanted return to center steering. I also wanted the steering motor assembly to fit more or less in the dashboard/glove compartment area. My first design uses a PF-M motor and a hockey spring; it works very well but since it relies on stalling the motor, it drains a lot of current that could be going to the drive motor. Front view: Back view: The second design uses a servo, but the four bar linkage takes up a lot of space, and the linkage sometimes jams: So now I am thinking about abandoning return to center steering, maybe using a design like this (obviously this is just a proof of concept): Any thoughts or suggestions? Thanks!
  20. Hrafn
    @Thierry-GearsManiacthat could be useful when angular position is important in a gear train - for example, I was working on a steering mechanism with two 12z teeth meshing, which led to an unwanted 15 degree offset.
  21. Hrafn
    I have broken a number of 12z single bevel gears recently. A PF-M motor powered by a BuWizz on Ludicrous speed will break orthogonal 12z gears if geared down 12/20, but not (so far) if geared down 14/20. Would either of these parts be more robust than 12z single bevels? I assume so but don’t want to break my single copy of either during testing. https://www.bricklink.com/v2/catalog/catalogitem.page?P=45360#T=C&C=12 https://www.bricklink.com/v2/catalog/catalogitem.page?P=46217c01#T=C&C=12 Is one stronger than the other?
  22. Hrafn
    Wasn’t there some speculation that the new 12z and 20z are meant to slide on an axle easily, like the red 8z that was released years ago? If so, making them beveled would be pointless since using a gear in a 90 degree mesh means you can’t also have it slide on its axle freely.
  23. Hrafn
    I hope you can! I have a variant of your brilliant front suspension sitting on my table. Yours is easily the best driven independent front suspension design I have seen at this scale.
  24. Hrafn
    @Limga did you ever finish this project?
  25. Hrafn
    I am impressed by how small you managed to make the virtual pivot point steering system!
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