| |
Iain Hendry wrote:
>
> In lugnet.org.ca.rtltoronto, Jeff Elliott writes:
>
> > All right, you made me do it:
> >
> > http://extranet.telepres.com/staff/jeffe/decagon_ring_2.jpg
>
> ::gasps::
>
> It's gorgeous[ness*]!
Thanks, Iain. :)
>
> * - if you're Bjork.
I'm not. Lucky thing, my clothes wouldn't fit if I was Bjork.
>
> > This version looks a lot more cyclone-like. I expanded it to give you
>
> Do we have an aversion to the prefix "Psy"? ;)
Nope, it just became "Cyclone" in my head and I didn't go back to look
at the name...
>
> I can give it a try, I think. My big problem now will be finding all the
> hinges, I don't think I've got so many. :(
I think it'll take 40. I can loan you some if you need 'em.
>
> > http://extranet.telepres.com/staff/jeffe/decagon_ring_assy2.jpg
>
> You are really good with this L-Draw thing!! :)
One day I sat down & figured out rotations in MLCad. After that, it's
not too bad.
> > As shown, they are 13 long, but you can loosen up the axle joiners to
> > give you a little extra length. These will likely be a little sloppy
> > until you finish the outer ring, but once you've got that it should be
> > nice and rigid.
>
> Seems to make sense. The only part I sometimes have a little doubt with is
> puting the 3-long axles wiht a stud on them between beams like that.
> Because the flange on the one end is only as thick as to sit flush with the
> beam face when it is put in one hole, if it was pressed it can loosen and
> "float around" inside the assembly. Do you know what I mean? Maybe its not
> a problem for this one, I dont know.
Oh, that's easy: If you anticipate compression, mount the stud in the
'far' beam and just slide the shaft through the near one. If you expect
tension, do the reverse. A single full bushing on the empty part of the
shaft will prevent compression. Anyway, you need to loosen it 1/2 stud
(to get 13.44), so just slide an extra 1/2 bushing on one of the 3-longs
and you're home free.
>
> I am still working on the drive head, on the real Revolution there are two
> 220 hp drives up top that swing the arm. For a model though because
> acceleration doesn't scale down nicely I have to use flywheels or something
> simliar to get a "slow" effect out of the pendulum drive (do you know what I
> mean?). I dont want to put a counterweight because that would just look awful.
>
> Iain
I'm not clear on the range of motion on the ride - I take it the head
swings back and forth, hanging from the place where the 4 legs meet, but
how far? Can it go right over the top? Or just 90 degrees each way?
Never mind, I decided to read your insightful and detailed page :P. 120
degrees each way, ok.
I'm tempted to try something with rubber bands... imagine two 6-hole
pulley wheels facing each other like discs in a transmission. Now,
attach bands between, say, 2, 3, 4, or 6 of the paired holes in the
disc. Keep 'em loose. When the motor starts, it'll begin winding the
elastics around one another, building up tension rapidly. When the
tension becomes enough to move the ride, it'll start to swing, slowly at
first, and gaining speed. Depending on the power of the motor, and
gearing, and the bands, I'm betting you could get a nice pendulum swing
by reversing the motor with the right period. The trick is to gear to
motor with just a little too little torque to actually move the ride, so
that the stored energy of the bands and the momentum of the disc head is
required to add energy to the pendulum. (I'm assuming that the ride
swings back and forth a few times to get going) I'll try it tonight
when I get home.
Best of all, a drive like that is more or less linear, so it can fit in
a package like the real ride.
Oh - one other problem you're going to run into: Period of a pendulum
doesn't scale: If your model is, say, 100 times smaller, the period
will be the square root of that, (10 times) faster. So if the Psyclone
(<- see? I spelled it properly) gets a sedate swing of about 10 seconds
(a simple, undriven 25m pendulum), your model would have an undriven
period of, um, 1s. Eek. More akin to the spin cycle in a laundry
machine...
Jeff
|
|
Message has 1 Reply:
 | | Re: Decagon?!
|
| (...) 40! Crap. I'll have to see what I've got when I get home. (...) You know, I think I've already stressed to Calum enough how tired I am of hearing people in line, when they first join the queue, and they all turn to one another and ask "Does it (...) (22 years ago, 4-Sep-02, to lugnet.org.ca.rtltoronto)
|
Message is in Reply To:
| | Re: Decagon?!
|
| (...) * - if you're Bjork. (...) Do we have an aversion to the prefix "Psy"? ;) (The machine given name is "Psyclone" and Mondial's manufacture name for this machine is "Revolution". I prefer Revolution but it is four sylabals and often it is easier (...) (22 years ago, 4-Sep-02, to lugnet.org.ca.rtltoronto)
|
10 Messages in This Thread:
  
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
This Message and its Replies on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
