The Axworthy
This system was originally created by Scott Axworthy. His site is HERE.
Thank you Mr. Axworthy.
There is a fair amount of info about this system on the web so I won't go over everything, just the changes I have made. Check out the links at the bottom of the page. This page is a jumble of information right now, I promise to organize and detail everything better, soon...
My setup so far. First, the drive motor. I use a 24 volt DC motor out of one of those electric scooters elderly people use to get around. I use it with a motor speed control from Bakatronics, about $25 with shipping, but it comes already assembled and able to handle a large amount of current. With that I will be able to vary the speed from a dead stop to as fast as I want. I prefer a DC motor over an AC motor for that reason and also because you can reverse speed very easily, although people who use an AC ceiling fan motor should also be able to reverse speeds with the switch mounted on most fans. Next year I will replace this DC motor with one about 1/3 the size that will weigh a lot less and will make mounting easier. Making this system easy to setup was a priority of mine. After I get the new motor I will reassign this motor to my original purpose, my electric Lake boat, but that's another story.
Below the motor is a Bow Roller. That's the rubber pulley thing you mount on the front of a boat trailer for the bow to snug up to. The black one on the left was $3 at Walmart. The one on the right is a $6 version. The bow roller is used as the drive pulley for the system. The rubber texture really grips the line well with no noticeable slippage. I was concerned about the line wearing into the pulley but so far they have little signs of wear. To connect to the motor I had to bolt on an aluminum plate 1/8 inch thick because that's all I had room for on the motor shaft. Then I added spacers and a second plate securing the pulley as you can see. I like this setup because it keeps everything compact and eliminates the need for a second chain or belt driven wheel. The picture on the right shows how I use a bow roller for a guide wheel. More on the brackets holding it below...
Below is the MX033 speed controller. It's called a pulse width modulator, (PWM). Instead of turning the voltage up or down it sends out pulses of full power. More pulses for faster, less for slower. This gives the motor more torque at slow speeds. It is made for controlling model trains. Bakatronics
Below is
another style guide wheel. It's nothing more than a bike wheel hub. For this
guide wheel I cut all the spokes from the bike wheel, took the hub and mounted
it to a 2" x 2" piece of aluminum angle with a hole drilled in both
faces. The second pic shows how this is then mounted to a second angle giving
you a bracket that can be attached to a variety of places. A garage ceiling, the
overhang of a house, even a horizontal tree branch. For dynamic testing of my
Axworthy I have pulleys and wheels mounted this way to my garage
laboratory ceiling I'm learning a lot from this and having it in the gar,
LAB-oratory beats climbing ladders after every meltdown.
The photo above and far right is the result of failed tests. I found that as long as the ghosts were very light everything worked fine. Also if the line made a sharp turn around this type pulley it held fine. But when the line made only a slight turn and the ghost weighed 8 oz or more the line would slip off the pulley. After staring at it for a long time I took it down, trimmed the angle's corners at 45 degrees, as in the first photo, and remounted it. (I realize now that the pivoting mount is a copy of an original Ax worthy design. That's me - reinventing wheels. Now I was able to pivot the pulley and the results were surprisingly good. (I should explain at this point that the line came from directly behind this pulley or in line with your line of vision, and in front of the pulley it angled slightly to the left with the line naturally passing on the right side of the pulley.) The line stayed at the top of the pulley until the ghost approached. As the ghost approached, the line would slowly move down, stopping at the top of the slight angle at the bottom of the hub. As the ghost passed the line moved back up to the opposite spot on the pulley. Now that I could pivot the pulleys, the bow rollers worked the best. They have the added ability to allow for some change in elevation from one pulley to the next. The bike hubs have a major drawback, they're noisy. Because the have a small diameter they have to spin fast and when mounted to a ceiling, the ceiling acts like a soundboard.
2 short videos.
The video is a 6 point system where the ghost flies out from behind a wall (not shown in the video), then gets up in the face of the spectators and flies back behind the wall again. It's my wife's idea. She wanted the ghost to fly out and back so fast you weren't sure what you just saw.
Here's another system. A simple 2 point incline. I will use this to have a ghost fly from a tree in my front yard, up to the window in my attic gable, turn and fly away again. I'm leaning toward having several simple systems rather than a complicated one and a 2 point system is as easy as it gets. For this version you have only to mount the pulleys on the slope you want the track to follow. The slope in this test setup was 33% or a rise of 1 foot for every three horizontal. Even a light ghost will cause the track to move slower on the uphill climb and speedup as it goes down, an effect that works well for this setup.
To make the Bow Rollers spin like pulleys I use a 4 1/2 inch x 1/4 inch bolt, enough nylon spacers to fill the inside of the roller, 2 of which are 5/8 O.D. x 1/4 inch I.D., the rest can be 1/2 O.D. x 1/4 I.D.,2 nuts and a lock washer, and a 2x2 piece of aluminum angle with a 1/4 inch hole drilled in the center of each face. Assembly goes like this, force a 5/8" O.D. nylon spacer into one end of the roller. Then starting with the bolt, slide on a washer then the roller with the nylon spacer end first. Grease or oil everything as you go. Add more 1/2" nylon spacers till you almost fill the inside of the roller, then add the second 5/8" O.D. spacer and force it into the top of the roller. One more small spacer should bring you up to the threads of the bolt, add a washer then a nut then your angle then a lock washer and second nut. Be careful tightening the nuts so that the roller still spins freely but with very little room to move up and down on the bolt. You can use the pulley as is or mount it to a second angle so it can be pivoted.
I was making a ghost out of stiffened cheesecloth when I saw one already made in the store. Since it was much better than mine I used it. Below are two more videos of a system where Axworthy Ghost meets Flying Crank Ghost . These video's are what I did for Halloween 2007. The way it worked was kids would be watching the FCG, mesmerized, then suddenly the Axworthy ghost would dart in and out. Worked pretty good and made quite a few jump. That trick would be better done with a pop-up type prop because most of the system was hidden.
Originally I had set up a simple 3 point system that flew out the 2nd story window of my house, out to a tree and then back in another window. Unfortunately, we had 20 to 30 MPH winds and I was only able to do my one garage mounted system, but there's always next year.
I'd like to hear from anyone with questions or comments. Andy
Links to some great Axworthy systems
Coming in 2008
