Thread: Axworthy Ghost Help

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Hi, I'm trying to recreate this:
http://ravenmanor.com/history/2003/20030815_02.JPG
http://ravenmanor.com/history/2005/20051022_02.JPG

Was wondering if this motor would work, perhaps you could recommend something better? :
http://www.grainger.com/Grainger/DAY...earmotor-1MBG2

The drive pulley I was looking at was this model from McMaster-Carr:
3060K17 It states that there isn't a keyway. Does that mean it doesn't have the hole for the screw? I need this to directly attach to the shaft with a screw since I don't have tools to create a hole. I also need the 2 white pulleys and the rubber belt as depicted in the picture above so if you guys could direct me to those items I would be appreciative.

Specs:
Pulley Type
Drive Pulleys
For Belt Type
V-Belt Pulleys
Pulley Design
Solid
Number of Grooves
1
System of Measurement
Inch
V-Belt Section and End Dimensions (Top Width x Height)
2L-Section - 1/4" x 1/8"
Outside Diameter
3"
Bore Type
Finished Bore
Finished Bore Pulley Style
Standard
Bore Size (ID)
5/16"
X-Dimension
27/64"
Y-Dimension
7/8"
V-Dimension (Pitch Dia.)
2.9"
Pulley Material
Nylon with Aluminum Hub
Specifications Met
Not Rated
Note
Includes a set screw. Does not include a keyway.

That pulley will work fine with the motor you have picked out. Where it indicates that the pulley includes a set screw, that is a screw in the side of the hub to lock the pulley to the motor shaft. If you look at the motor's shaft, you can see a machined flat area which is designed for the set screw to make contact there. They are perfectly compatible with one another.

As to the white pulley's, they are in fact small front bicycle wheels from a young child's learner bike (the ones that have training wheels). Hope that helps

Thanks for the help. I got another question. What would be the best way to power the AC motor? Do I need a power supply or can I directly wire it with a plug cord? I was going to buy this to go with the motor: http://www.grainger.com/Grainger/DAR...-Control-5JJ60


The rims for children's bikes have rivets causing bumps, will that affect the string line for the ghosts? Should I wrap it in some kind of rubber?

Dependent on the ratio of the pulley to bicycle wheel, you may or may not need the speed control. You can wire the motor directly to any regular 110 VAC outlet, and the easiest way is to use an outdoor rated extension cord to do so. I would hold off on purchasing a speed controller until I had everything set up, and knew for a fact that the motion was to fast.

If you use a spoked wheel, it probably won't matter as the weight of the ghost will pull the line to the lower part of the rim itself (in relation to the wheels horizontal orientation). FRP (fiberglass reinforced plastic) wheels are the type used by Raven's Manor. The minor bumps caused by the tip of the nipple for a spoke protruding slightly inside however, won't have any effect.

The majority of the reasons that Axeworthy's jump their pulleys is due to excessive weight of the ghost on the line. Scott Axeworthy solved this problem by attaching pulleys in a vertical manor to serve as guide wheels, though I've not seen but a couple of persons after he revised his design to include the use of them in theirs. Also, the "inverted J" type hanger is a necessity if you decide to use a leading guide wheel as Mr. Axeworthy did.

This is the revision Scott made to his to fix the problem caused by heavier props being flown:






http://www.scaredy-cat.com/afg.html

I find it's best to take from all of the best components of the persons that came before us, and combine them into what may end up being the best design of all. Instead of just using one particular take on how it should be done

Yeah I saw that design change but don't understand how he was able to make the ghost attach from a side position on the line in order to avoid snagging that extra support. Doesn't the line twist as it's moving through, so how can it stay horizontal and balanced? I thought the reason this worked on a real ski lift was because it's using a very rigid steel wire.

A marginal amount of twist is there always. But the weight of the ghost (prop) itself is what keeps it oriented correctly due to the J hook's design. That is why the attachment of the prop is hinged by a double eye hook to connect them. To alleviate any extra movement due to line twist. Gravity does all of the work.