Kites have a wing and a kite line (line), or sometimes more than
one line. Kite systems may have more than one kite and more than one kite
line.
Successful kiting in particular kite applications
depends in large part on the kite line's specifications and handling. The
integrity of kite lines is affected by wear, reeling, contact with
chemicals, loss of strength from knottings, ultraviolet rays of the sun,
repeated cycles of use, and damaging actions during use. There are
historically classic specifications of kite lines. Kite lines for small toy
kites differ greatly from kite lines used for kite tugs that pull commercial
cargo ships across the ocean. Sport kites using kite lines two or three or
four lines at a time have a need for very low stretch. Single-line
recreation kite lines may do well with stretchy kite lines. Kite fighting
kites' main tether lines have sharp glass particles bonded to the line. Kite
lines misused or abused can cause injury to persons and property. Kite lines
vary in pricing and availability. Repair of a particular line has its own
arts. Reeling, handling, and storage methods differ for lines depending on
the
kite applications. Kite lines terminate at the kite's wing/bridle at one
end and at some
kite mooring at the other end; the mooring is to some object anchor that
provides the tug or tension against the resultant of the lift and drag
forces of the kite; the anchor is always powered by something even if that
something is the Earth's moving surface relative to the air for air kites; a
running human kite operator is the source of human powering.
Kite-line parameters
Depending on the kite application and kite
system needs, selecting a kite line will consider one or more of the
following parameters: availability, base material, color, density, mass per
length, size, manufacturer's reports, serial number or product number,
diameter, cross-section shape, tensile strength new, aged tensile strength,
resistance damage from chemicals, defects, safety factor, resistance to
damage from solar radiation (UV stabilization), electrical conductivity,
optical conductivity, heat conductivity, moisture intake from water (via
humidity, rain, contact with liquid water), buoyancy in water, abrasion
resistance, nature of manufacturer's line joins, feel, degradation from
knotting, terminal methods, elasticity, structure, signal transmission
capacity, visibility to radar, performance over time, maintenance actions,
effect on performance from hours of use, drag, negative lift, auxiliary line
uses, performance when being reeled under tension, performance when tensed
line touches itself, action upon breaking, memory, veil, sleeving,
inspectability, surface finish, reaction to heat and cold, taper (as
wanted), flexibility, reeling behavior, breaking strength, critical
diameter, reliability, test-results portfolio, visibility, twist,
plasticity, safety, price. Toy kites sold with a manufacturer's selected
line makes the decision easy; the decision is more challenging for custom
kite applications. The design and handling of the piano-wire kite line for
the high-altitude meteorological observations (1749–1933) was a keen
engineering process.[1][2][3][4][5][6][7][8]
Kite
lines for children's toy kites
To avoid burns and cuts, kite lines for children toy kites are frequently
soft fuzzy cotton twine.
Kite lines
for sport control kites
Lack of stretch or stable line length for
control authority is an advantage of special control lines. Melting point is
considered when controlling a kite for kite fighting; lower cost cotton line
can melt a crossed expensive synthetic line.
Kite lines Dyeing kite lines for show and control line management can
occur at a line factory or by a user.[9]
Kite
lines for high altitude attempts
Historically, high altitude kite flights were
made by atmospheric scientists and meteorologists in the late 19th to early
20th centuries. Routine flights around the world were made using steel wire
with single kites and kite trains. The highest recorded flight was made by a
German meteorological station at Lindenberg in 1919. It is reported that the
top kite reached 31,955 ft above the launch point. The line was over 20 km
of high tensile steel piano wire with a breaking strength varying between
134 and 225 kg.[10]
In 2000 the single-line single-kite altitude world record for kiting was
made using a kite line of woven Kevlar line 3/32 inch in diameter at 270
pound breaking-strength. The kite was described by Richard Synergy in his
account of the flight, as employing an angle of attack device to limit line
tension to 100 lbs. This gives a safety factor of almost 3 to 1 if the
breaking strength of this line is 270 lb.[11]
More recent high altitude kite flights by Robert Moore and his team in
Australia[12]
have been made using Dyneema, a braided Ultra High Molecular Weight
Polyethylene (UHMWPE) line, and the identically structured line, Spectra.
Both these lines are stronger and lighter than Kevlar for a given diameter.
One of the most important characteristics of line for high altitude kite
flying is small diameter and high strength to weight ratio. The greatest
barrier to high altitude kite flights is aerodynamic line drag.[13]
The use of Dyneema over an extended period has shown that it is highly
resistant to ultra violet degradation in comparison to Kevlar.[14].
Richard Crawford, a high altitude flyer from the USA, made an attempt on the
world single kite altitude record using a 220 lb test, Technora line
manufactured by Twinline. He reported that he flew a delta kite to
approximately 6,500 ft in September 2008.[15][16]
Kite
lines for specialized applications
When a
kite application does not fit a common purpose, then specialized kite
lines are used. Setting specific records under controlled conditions allows
kite operators or competitors to choose kite lines with high specificity and
without excessive safety factors.
The short kite line called the hang loop
for the free-flying kite hang gliders has received special engineering
attention; the further main kite-lines from the hang loop to the pilot's
harness are also highly specialized in design
[17].
When maximizing performance for large kites; E.
D. Archibald was the first to use piano wire for kiting.[18]
Flatland kiting hang gliders with 3000' of tow
line holding the manned hang glider kite takes special care to specify.
Protecting the kite line from ground abrasion is considered.[19]
Want to fly an
indoor kite without wind? The indoor no-wind kite operator need not
worry about line breaks causing damages to downwind property. The choice of
line can be very specialized here.
When the kite line is to be invisible, a clear translucent fine thread is
chosen.
Making kite lines visible for night flying
occurs in short-line and long line applications. Line lights is one solution
sometimes used. Lines that carry light is another. Lights on the ground
shining on stunt kites and their lines occurs.
Flying Kites at Night
Spider silk and their kite line for their "ballooning" (mechanical kiting)
Biologists began using the term "ballooning"
for spiderling mechanical kiting
[20][21].
Another spider silk for the bridge thread is frequently kited. And another
thread of the spider is used as a drag line from which spiders frequently
swing in the breeze, getting deflected before landing. Humans have used
spider silk for making kites[22].
Safety for kite lines
Fit the kite line to the
kite application; handle the line as needed to avoid hazards, accidents,
and injury to persons and property. The operator of a kite system is fully
responsible for damages done by the operation of his or her kite system;
this includes the kite line. Pre-flight plan and pre-flight the kite line;
avoid surprises. Piano wire is appropriate for certain applications, but
totally inappropriate for recreational or sport kite flying. Fishing
monofilament line is not used for most hobby, recreational, or sport power
kiting because of its stretch, breaking behavior, and thinness; avoid it
unless there is a very special application involved. Metal wire can conduct
static and current electricity; avoid metal wires unless a professional
scientific or industrial engineer approves the line for a specific purpose.
Gloves, proper reel choices, goggles, guards, tension limiters, and other
safety devices help to reduce accidents. Ability to de-power a kite's lift
and drag is a part of sound kite systems. Tensed line can act as razors.
Moving lines can cut through flesh too easily. Fatalities too often occur
from kite line abuse. Keep kite lines in good condition. Realize that knots
weaken kite line. Keep kite lines dry and clean. Log any wear and use of the
line; replace lines as needed. Choose a safety factor when designing a line
for an application. Avoid flying in the rain or stormy weather changes.[23],[24],[25],[26][27]
See also
External links
References
Posted:
Sun Nov 27, 2011 2:11 pm
Post subject: RE:
Exactly one-string paragliderDandies do glide; test them; I have. Control? Many choices depending on design and mission w/o more tethers. Reasons for #t=1? Many; look; review; mission-dependent; stay tuned for historical and potential. Speed, potential for wind-strata-differentials dynamic soaring, tether climbing and extension, stealth, novel launch and landing options, potential for transcontinental flight in one session. Note: Exploring #t=1 is not equivalent to a critique of non-#t=1 options; aim to savor things in themselves; competition for specific mission can be examined after well knowing specific systems. Your#2?:Party while growing. Attached for forum permanent file is a graphic up for discussion, as the graphic is not complete: Enlarge to see, perhaps print to paper:
