Negative Kites
negative-lifting kites, stable down-going kites  [File start date: January 21, 2014]
"inverted kiting"   "upside-down kiting"
that fly negatively stably passively with low wing loading with substantial negative lift

• Motivations and applications
• Solutions, plans, specifications
• Discussion: Stable Down-going Kites (11012) and its following posted messages.
• Mass/|negative lift|  ratio kept low.  |negative lift| is the absolute value of the negative lift of the kited wing. Have low-mass give substantial stable down-going flying of the wing.   
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• Baptiste Labat reminds us below that the matters in FFAWE include negative kiting.
• We are recalling the trolling of objects in water where the powered upper hull tows a negative-kiting wing (paravane) down deep in the water. Included in such space are the deep diving fishing lures and trawling-net-gate-opening paravanes..
• An effective easy experimental "tower" is a flying kite system; then from the main tether place negative-kiting experiments with their dedicated branching tether. Note that historical kite trees or branching trains have positive-lifting sub-kites from main tethers, whereas here we are in focus on branches that negative kite stably, passively, and with low wing loading and substantial negative lift.  We know well looping wings and spinning wings; but what is far less explored are strongly negative-lifting wings that stay downing. The mixed media of air and water has been a continuing exploration as Baptiste Labat reminds us.   Yet to be in visual portfolio are air-only negative kite plans and videos; the transient negative kiting of stunt kites and circling or looping kites is a category of itself and set aside a bit from the focus of stable-station-keeping negative kites where the station is fixed at points say from 3 o'clock to 9 o'clock on a 12 hr-clock face. Say, choose 6 o'clock; have a strongly negative lifting single-tethered kite wing fly staying near that station stably and passively.    Plans and video are sought. Analysis as researchers may produce will be featured.    Patents are robust for paravanes that dive down; but as yet patents are nearly quiet on air-only matters in focus in this folder. Kiting literature has not shown much on the matter either, as the giant thrust is to fly positively-lifting wings upward!

~~ Baptiste Labat                                January 22, 2014

[[Ed:  cerf-volant (thèse d’Emmanuel du Pontavice)   Related: https://www.polytechnique.edu/accueil/actualites/publications/les-empreintes-de-sous-marins-294226.kjsp        We recall the winners of The 2011 Wayne German Award for Kite Energy  where negative kiting is involved in some of their works, especially the negative kiting of paravanes.  Machine translated phrase to "propulsion kite" ( thesis of Emmanuel Pontavice ) (note sent to Emmanuel in his online form on Jan. 22, 2014. Labat is also contacting him. ]]

• Investigation of Negative Lifting Surfaces Attached to an Open-Wheel Racing Car Configuration
• When on a high bridge, envision the wind window expanding from the quarter-spherical shell to a full semi-spherical shell. Instead of flying a kite to the zenith, set the kite's wing to fly stably and emphatically to the anti-zenithal pole. We seek passive formats of bridling and shape that will stably fly to the anti-zenithal region of a semi-spherical wind window. Keep the mass cost low compared to the negative lift being effected.
• One motivation in kite energy regards tailing of lifting wings with negative kites as tails.  Veer fully downward stably and passively.  
• Also, the full circle of stable-station veering may be explored.  Different than looping wings, the wing is to stay veering in just one station of the wind-window full circle.
• It is common and easy to fly stunt kites downward, but not so easy to stably fix the system to the downward direction.
• Kitists are used to using gravity in their designs for upgoing-wings kited.  In "inverted kiting" or "negative kiting" when stability is wanted for downward direction, especially when stability is sought and low-mass costing is wanted, then gravity plays a different role.
• http://en.wikipedia.org/wiki/Tailplane    But note, most common tailplanes with negative lift are fixed rigidly, not flying on tether as kites.
• downward-lifting  is "negative lifting"
• Flip-wing rotating opposite to normal flip-wing kiting. Reverse the S  and have bottom going downwind to effect a negative-lifting resultant. How to stabilize the rotation direction and the wing attitude?
• Reflex in flying-wing hang glider is integrated with the wing, not tethered behind the wing. Our topic here is about detaching the "reflex" and flying the "reflex" stably at the end of a tether, thus a stable negative kite system.
• Horizontal stabilizers on many common rigid aircraft frequently have the stabilizer flying with downloading; but again such stabilizer is integrated rigidly with the aircraft fuselage.  Differently, our topic hereon would look towards tethered downloaders, especially with low mass per negative lift.
• DIVERGENT SINKER SINK http://www.vedette.it/ecoing5.htm
• Paravane:  US1320804  (A)   Trolling Line Sinker
• http://www.pescastore.it/catalogo/product_info.php?products_id=7301
• Notice the stark absence of air kites that fly negatively stably passively from high anchor points (bridge, tower, balloon, conventional kite tether,
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Conventional simple kite systems have the main tethers doing negative kiting; the lift is negative and the drag is positive; the L/D for the tether is negative.   Differently, a string hanging from the tail of a simple kite will be operating in "positive kiting" mode.  Explorations into specialized non-conventional tethers encompasses a subset of "lifting tether" that kite positively by result of being designed to be essentially a chain of positively-lifting wings.