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The Vortex's Oscillating Fairlead - OLaF!


A feature of the Vortex that I am sure goes over-looked by the untrained eye is our Oscillating Ladder Fairlead (aka OLaF).  It is an in-house engineered solution that simply isn't available anywhere else.

The boom-style fairlead isn't a new concept - the idea is to have a stable, stationary point out in front of the drum that is rock-solid centered on the drum so the line naturally "level-winds" on the drum.  It is much like how a bobbin on a sewing machine gets wound on nice and even for those sewing enthusiasts out there.

The problem lies when the drum gets too wide....the wider the drum, the longer the last point of contact needs to be.  Some say the length of the boom needs to be at least 20x the width of the drum.  So, on a portable winch, it makes it almost impossible to have one long enough and stable enough to stay centered on the drum. 

We tried this "natural" path and it didn't work.  The result is the line will naturally pile up on one side of the drum (the downwind side) when towing the glider in.  Sure it gets stacked on rather tight due to the tow pressures but the problem lies when you go to pull that rope back off when:

  • you pull the line back out to launch
  • while on downwind on a step tow
  • using the winch as a payout winch

Here is a video on how quick it can go bad.  The video is only 1.5seconds long but slowed down to six seconds.  The pilot released before he felt the impact.  It took about one hour to fix the enjoyment!

The known industry solution is to implement a "mechanical fairlead" - some sort of mechanical solution to guide the towline back-and-forth on the drum as the winch reels in the rope.  The problem is that these solutions are a very complicated solution that often wears out your rope and expensive to engineer and produce.  They are also rather heavy and we wanted to keep the Vortex's weight to a minimum as it is meant to be a portable winch.

This set us back at least six months in our Vortex development timeline as we wanted something much more reliable than the natural boom.  Also, our non-mechanical boom solution was an 8' boom...not very portable.

We were already in the process of developing our next-generation digital controller so we were able to use a simplified version of our embedded controller and Vortex OS and were able to use those brains to drive our OLaF! 

Since the main Vortex motor controller strictly focuses on keeping a constant tension on the tow line, it doesn't control the winches speed/rpms.  We added two proximity sensors on the hub to calculate the rpms of the winch and that also allows us to control the rate at which the fairlead oscillates.  To lay the rope down flat, it has to spend less time at the edges or the rope would pile up - so when the fairlead gets to edge, it quickly changes direction!

How it works is there is this off-centered disc (black nylon one in the pic) that rotates on a small stepper-motor and as the winch pulls in - and with the rpm sensor, the faster the winch spins, the faster the motor goes.

You can see the black disc turning around the stainless disc in this video of towing in operation:


The other side of the fairlead is a fixed point that allows the arm to just pivot back and forth.

What makes it even cooler is when we answer people's question "how is that little arm & tiny motor strong enough to move a rope back and forth that has upwards of 300lbs of line tension on it?!?" actually doesn't move the rope!  The point at where the towline exits the roller fairlead (also unique to other PG electric winches out there) doesn't move while the line is being pulled in.  The arm moves in one direction and we have some nice slick flange bearings on the trailer hitch which forces the middle of the winch (where the fairlead is attached) to 'bend' in the opposite direction.  This causes the winch to "wig-wag" back and forth while the line is being pulled in.  It is hard to even take a video of this in action as it is very subtle - with the 4' boom, it only has to move back and forth about one inch!

The result...a nice "tight stack" of rope that is ready to come off the winch perfectly whether it is rope revival between tows or while a tow is in progress (payout or step-towing).

This is just one of our innovations that makes our electric winch unique in the hang gliding and paragliding industries...and its embedded electronics (not Android based!) and Vortex Operating System allows us to build and add many more cool features in the future!

See more info on the Vortex including pricing here and read the FAQs here

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