My latest Ball-Bearing No-Snag Self-Aligning Turnaround Pulley

[rogerflies]

I just finished machining this today.

The stainless braided hose is normally used for connecting to a water heater. It's got just the right flexibility to allow the pulley to move around without being floppy, and the crimped end fitting can be used in the swivel for the self-aligning fitting. It takes the place of the rubber hose I was using.

The problem with the rubber hose was that it had a built-in curve that caused too much drag where it rotated in the swivel fitting. Using the stainless braided hose reduces the drag significantly, and I really don't need a 4" pulley wheel to develop the torque necessary to make it self-aligning. However, I like the big wheel, since it's easy on the line and doesn't have to spin as fast as a smaller wheel. Plus, I've still got a few more pieces of the red Delrin that I don't want to waste.

I'm trying to figure a way to hide the crimped end of the cable assembly that sticks out the back of the stake adapter. It's got to come through to transfer the tension load to the adapter, but it doesn't look as clean as I would like.

Roger

[MyMassMail]

Good evening,

Please check your email NOT PM for two from me, one personal and one pdf suggestion.

Looking forward to hearing from you,

Richard

Edit... Almost forgot, excellent design with the low mass wheel, hopefully should start/stop in a flash without getting grooved by the line.

[schrederman]

I guess the only thing I don't understand is... why you didn't make one for me...

Jack Womack

[Jim Frahm]

Let me know if you need someone to do a build thread. :D Or how about additional testing. ;) How about just let me know when I can get my hands on one?

Looks like a nice piece of work,

Jim

[OVSS Boss]

Beautiful piece, but the little threaded stud and plastic handle is what you attach this to the ground rod with? That looks suspect to me for the tension invovled in these things. How do you keep your GR end sized correctly when you drive it in the ground with a hammer, is there any flairing of the end you hammer?

Marc

[rogerflies]

The stake is a 32" piece of 3/4" threaded rod with most of the threads machined off. There's about an inch of threads left at the top end, and the screw on the little knob catches the stake just below those treads. There's plenty of grip to keep the adapter from sliding off the stake.

The threads are also cut away on the very top of the stake to make room for the inevitable mushroom. It takes a LOT of hammering to get back to the 3/4" diameter, and a minute or two on the lathe takes care of it when the time comes.

Besides the flashy appearance, the red Delrin wheel is low in weight and VERY easy to machine. I've used it on several pulleys, and there's been almost no wear from contact with the line. I got the piece of 4" diameter rod on eBay several years ago. I paid a good bit for it, but it was money well spent.

The stainless braided hose has a 3/8" ID on the end fitting and 1/2" on the other part, so there's not much room inside for cable hardware.

What I need is a roller swaging machine to put a threaded end fitting on with. It's only $4500. :eek: I think I'll use it for a while like it is.

Roger

[cosmicpossum]

Very nice, very clean! Well done. One question; looking at it with my ol' "farmer's eye", would the locking knob be better suited on the other side, since that's opposite from the pull? (Does that sentence make sense to anyone but me?)

[rogerflies]

The screw on the front pulls the adapter in the same direction that the tension pulls it. It'll work OK either way, but I think having it in the front puts less stress on the screw.

Roger

[V1VrV2]

How do you keep your GR end sized correctly when you drive it in the ground with a hammer, is there any flairing of the end you hammer?

Marc

I use a Copper hammer to drive my stakes in to avoid the flare. Use something softer than the stake and no problema. :)

[V1VrV2]

Nice work Roger! :rolleyes:

Here's a turnaround I built as well. Self alaigning and 2-1/2" pulley made from Phenolic material just like in the big Boeings for their aircraft cable control pulleys. Dual ball bearing and Smoooooth... :cool: Rises and falls on a tandem harness for line overfly snag avoidance and tilts for x-wind launches to virtually all anges. Euros made this design, I just made my own! Simple and effective.

[rogerflies]

That's pretty sturdy, and it appears to be nicely made. I'm not a big fan of letting the TA lie on the ground, though. It's probably OK on a flat grassy field, but I fly from a field that's got a lot of dirt showing where I put the TA. Having the TA on a stake and the winch on the tailgate of my pickup gets the line off the ground completely when there's tension on it.

I figured out how to get rid of the crimped end of the cable sticking out on the back of the stake adapter. I put a long loop on each end of the cable, then slipped it through the hose. There's just enough room for the crimps and cable to go through the end fitting on the hose. The two loops go around a piece of tubing in the fitting at the back of the pulley assembly, and the loop at the other end goes around the tube that goes over the stake. That puts the tension load directly on the stake, so there's no load on the adapter itself. I can put shims between the cable and the tube to take up any slack before I put epoxy there to lock everything in place.

Roger