CoolIP index                                                          Most recent edit: Tuesday January 08, 2013

* See legal note below.


Line-Handling-for-Reeling Tutorial

A reel is a simple machine, cheap and easy to make. Complexity arises in the details of optimal kite-line handling on and off its storage reel.*

A basic requirement is that a reeling system must not damage line unduly. This is not easy when line experiences high forces. A shock-absorbing stage is common, the ordinary fishing-pole is the model for engineered "dipping booms". Fairleads are of smooth large-radius eyes, or ideally rollers in high-duty line handling. Special "chafing gear" in the form of braided sleeves, or heavier line sections, protect key wear points.

Static line load is commonly maintained on the storage reel, as in a basic winch, or if needed, a separate capstan stage commonly isolate the kite winching loads from the reel. An optimal capstan is a trade between a practical radius scale and line wear. An ideal capstan bearing surface is tough yet soft, like hard rubber. A bull-wheel is the kindest sort of capstan to high-duty line, but too bulky in many design cases.

Line is wound onto reels two basic ways. A Level-Winder is a shuttling mechanism that winds the line evenly onto the storage reel. Level-winders are common on fishing reels, yet expert fishermen often promptly remove the mechanism so they can manually wind line on, guiding with the thumb. This allows the expert lower drag in paying out line and numerous subtle advantages as the thumb acts as sensor and brake. The key secret is to wind the line on under tension with a high criss-crossing factor. This keeps the line from jamming into itself on the reel under high loads. The fisherman unconsciously increases criss-cross when spooling** on looser line. Level winders are not so flexible.

Note that a load carrying storage reel lowers its "gear ratio" usefully as the kite rises higher into more powerful wind. This is a true CVT, stone-age style. Mechanical advantage can even be varied by playing the line with the thumb on different parts of a barrel-shaped line spooling.

All this is just introduction to engineered reeling; endless refinements are possible. The most advanced AWES reeling method might be to duplicate the expert fisherman, even by a "robotic thumb", to thereby better play the kite while also maximizing line life.


* Line is also sometimes stored loose in a bag or bin. NTS/Fraunhofer opted for this method in its early prototype. Handling is simplified, but at a greater risk of a snarl, especially if the loose mass is shaken.

** Lets define spooling as the specific form that line takes wound on a storage reel.


Comment and development of this topic will be occurring here.       
All, send notes, links, drawings, papers, videos, plans, safety-critical findings, and photographs!

  • Terms and aspects:   
    • Spooling
    • CVT (continuously variable transmission)           wiki 
    • pattern of line lay on drum? Near-parallel? Criss-cross?
    • Line  stored on ground or in container using figure-of-eight lay pattern  (option of using two posts to center the parts of the "8."
    • Care for twists in lines! Spooling line onto drums or reels needs care about twists in the line. Especially when spooling new line to a working drum, one would aim to spool the line so that twists in the line are not installed; such twists will often cause unwanted troubles.
    • Are your methods spooling the line on drums the way you wish?
    • line lay
    • Avoid kinks and knots
    • Awareness of the full history of safety-critical lines.  Inspection of lines.
    • Line engineering.
    • Line Encyclopedia  (project) (LEP)
    • drum, reel,
    • capstan
    • detensioning line

  • Related links and concepts:

  • Commentary is welcome:
    • When using a bow-string launcher for an open-at-apex-of-launch kite wing or using a sling to launch such, one may consider having the line on ground in figure-of-eight flakes pattern to avoid installing twists in the line while having nearly no friction in the line-launch operation. | ImageTease | Article |  ~JoeF

*Legal Note: coolIP is hereby defined as a Creative-Commons Unported NonCommercial Share-Alike License,
so now we are integrated with the latest standard cooperative IP model, but "coolIP" remains a nice shorthand.