Jump to content

Davidz90

Eurobricks Knights
 View Profile  See their activity

  • Posts

    591

  • Joined

  • Last visited

 Content Type 

Everything posted by Davidz90

  1. Davidz90
    The real rotor cover is a stroke of genius!
  2. Davidz90
    8. Mini table clock A miniature table clock with seconds and minutes hands. Features Arnfield escapement which separates the pendulum from the varying torque of pullback motor, giving excellent accuracy and stability. Running time is 100 minutes (although after 90 minutes, random stoppages do occur). Full pullback motor range (8 revolutions) would give about 6.5 hours, but torque is either too low or too high. Accuracy: about 5 seconds per hour. The pendulum is very light and hard to regulate (basically needs adjustment after any shock or simply moving the clock) but after its set, it keeps the rate. Forum topic: https://www.eurobricks.com/forum/index.php?/forums/topic/158188-tc13-micro-clock/
  3. Davidz90
    I think that the semi-random arrangement is very cool. Some additional mechanism, such a chime, would fit this perfectly!
  4. Davidz90
    Thanks!! Update: This is my final entry - now with two hands. Due to additional load, I had to revert to smaller gear ratio, with about 100 minutes of running time. Accuracy is about 5 seconds per hour.
  5. Davidz90
    Probably yes. I'm planning to add minutes hand (hours hand seems a bit pointless with ~3 hour working time) and then I'll see how much spare power I have for bigger hands (we're talking about microwatts here ).
  6. Davidz90
    Turns out, small lego tires was all I needed. All thanks to the pendulum suspension - with simple axle this would be totally unworkable. Additionally, I could increase the gear ratio between pullback motor and clock, potentially pushing the authonomy to 3 hours - but now I have to work out some small reliability problems.
  7. Davidz90
    Thanks! I'll see what I can do to substitute the nuts. Unfortunately, I don't have heavy brick, but the metal parts are not that heavy after all - its just a matter of fitting the weight in the lower part of the pendulum - there is not much space there.
  8. Davidz90
    The extension of deadline gave me enough time to tinker with pullback-powered clock. This is not meant to be a direct competition to the awesome clock by Didumos69, rather just a little exercise in efficiency - there are no hands except a tiny seconds hand, pendulum is very light etc. The current authonomy is 90-100 minutes. Are 3rd party metal nuts used in pendulum ok for an entry?
  9. Davidz90
    Excellent shaping! Cramming all the functions in such a narrow fuselage must have been very hard. How well do these thin wings hold? There seems to be quite a bit of bending in second photo.
  10. Davidz90
    This one looks great! Another stiff solution is to use single line of beams, but connect them with plates: connection by David_Z1, on Flickr
  11. Davidz90
    Awesome! 18 minutes is a very respectable authonomy.
  12. Davidz90
    Nice one! The sliding, windup motor powered part is supposed to shoot the bolt directly or move the limbs?
  13. Davidz90
    Wow, really impressive! Several of my projects are gravity powered clocks, and so far I was afraid of going past 3kg - now I see that with proper reinforcements, much more can be achieved without brick damage. Thanks
  14. Davidz90
    Great job! Indeed, lego clocks are very sensitive mechanisms. You may consider counterweighting the hands, so that there is no difference in moving up and down. Reduced pendulum amplitude needs reduced torque to work - 1/2 amplitude means 1/4 of power, so that probably pullback-escapement ratio would need to be increased 4x, for 4x autonomy. Of course, it would work only with light clock hands. Shorter pendulum = faster clock. If You want to make lego seconds equal to real seconds, some means to precisely control the pendulum length would be needed
  15. Davidz90
    Definitely. Ideally, a very heavy pendulum (like 1 kg or more) on a low loss suspension (for example, knife edge) gives the best accuracy. Low swing angle is also beneficial and cuts on the power demand. I have noticed that in Your new video, there is still rubberband on the pendulum axle - I believe it is unnecesary - gravity only should suffice.
  16. Davidz90
    Wow, nice one! If You can make it work with pendulum, go for it. The "oscillating mass" solution has a serious drawback that the period strongly depends on driving force, which is not constant with pullback. I have used the escapement from the "mini clock" above multiple times, it is very robust. However, for a long running time, escape wheel with many teeth is beneficial. For example, this one: should work pretty well with pullback and it gives a very constant impulse to the pendulum, for extra accuracy. BTW Merry Christmas :)
  17. Davidz90
    The klann linkage seems to have more up/down movement compared to jansen, which could lead to excessive power demand. Jansen linkage + lots of legs gives the best stability. Another, more complicated option would be a mechanism where only one leg moves at a given time and the walker stands on the remaining ones. like Star Wars AT-AT (from 0:20):
  18. Davidz90
    Wow, the fan has quite an impressive performance! I guess this one: https://www.bricklink.com/v2/catalog/catalogitem.page?P=89509&name=Propeller 1 Blade 14L with Two Pin Holes and Four Axles&category=[Propeller]#T=C&C=1 could be even more efficient.
  19. Davidz90
    Nicely done! How it keeps the track tension? Is the track exactly the same length when folded and unfolded?
  20. Davidz90
    Sorry, I don't have instructions and don't really have enough time to make them. However, most of my models are very open-framed, with pretty much everything visible. That said, some escapements really need some trial and error and fine manual adjustments to start working properly. For example, my last big clock is constructed around this escapement: which is super easy to make, with around 20 pieces. The rest is easy - just a long drivetrain with 1:625 ratio, the clock shape is not critical as long as structure is sturdy.
  21. Davidz90
    And now something different, watch escapement with a tourbillon :D
  22. Davidz90
    Waiting for a vide too... unbelievable model worm gears... soo many worm gears...
  23. Davidz90
    Wow, that is a really creative idea! Aren't there any issues with lightbulb heat?
  24. Davidz90
    Yet another clock. This time, with heavy, long pendulum, allowing for much better accuracy. Running time is 48 hours - this one is quite power hungry!
  25. Davidz90
    41 km/h... wow, really unbelievable! The 3200 rpm on wheels is a feat on its own - I'm surprised that centrifugal forces are not pulling the tire out of the rim.
×
×
  • Create New...