Microlift glider
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Microlift Gliders are unpowered aircraft that have the ability to exploit lifting forces weaker than traditional lift. These gliders are intended for utilizing very weak atmospheric lift conditions, hardly usable for conventional sailplanes. These weak lift conditions are called microlift. The category of Microlift Glider was adopted for inclusion in the FAI Sporting Code, Section 3, Gliding, effective on October 1st, 2004. The FAI is the world air sports federation, founded in 1905, with the basic aim of furthering aeronautical and astronautical activities worldwide. A Microlift Glider was defined by the FAI as a glider with:
- maximum takeoff mass not exceeding 220 kg (486 pounds)
- maximum wing loading not exceeding 18 kg/m² (3.69 pounds/ft2)
In typical conditions, weak air motions occur with vertical components which the conventional sailplane is unable to exploit. On the other hand, a special sailplane designed for very low rate of sink and very small circling radius, may be able to exploit these feeble air motions for sustained flight and even for climbing. This is the Microlift Glider.[1][2]
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[edit] Terminology
See Glider for the definition and description of conventional gliding. Microlift gliding is a type of gliding which exploits non-traditional sources of weak lift. Of course, Microlift Gliders can exploit the traditional forms of lift.
Some terminology that has been in common use include: microthreads of lift, microstrings of lift, microsoaring, microflight, micropattern, microlandings, nap of the earth microlift, and dynamic soaring. The latter term is used to describe a flying technique used by albatrosses. Researchers and experimenters are attempting to use the same techniques as used by the albatross to gain energy/altitude.
Microlift has been officially defined by the FAI.[citation needed] The genesis of the term microlift is found in early papers written by Gary Osoba[citation needed] who described his early flights in an ultralight glider, the Carbon Dragon, designed by Jim Maupin and Irv Culver.
The FAI has developed this 2-dimensional diagram to depict the different domains for glider classes.[3] 
(Copyright, see below)
[edit] Additional required qualities
While a glider may meet the definition of a Microlift Glider, other qualities must be present for the glider to operate successfully in microlift conditions, including:
- extremely low weight
- low wing loading
- large wing span
- excellent controllability at low Reynolds numbers
- very slow thermalling speed; thus, a very small thermal circle
- a benign stall with little or no loss of altitude
- low sink rate at cruising speeds
- structure designed to accept high G loads
- very sophisticated wing design
- advanced materials and manufacturing processes
- cockpit size and gross weight to accommodate large pilots; plus, their gear
- comfortable semi-recumbent seating position for long flights
- advanced computer design and simulation tools.
- a dedicated, collaborative team of highly talented people
The industry is at the brink of achieving the total sum of these requirements in the next generation of gliders.
[edit] Existing Microlift Gliders
As of 2008, there are very few Microlift Gliders flying. The reason is two-fold: contest sailplanes are in demand and hold the promise of profit for manufacturers; and, numerous technological advances have been required to design and manufacture a true Microlift Glider.
Existing microlift Gliders can be divided into two categories: recreational gliders and high performance cross-country gliders. Recreational gliders will be characterized by gliders which are unable to penetrate strong winds due to a low maximum speed or high sink rates at higher speeds. These recreational microlift gliders will be limited to fun flights near the launch site or down-wind dashes. Conversely, the cross-country microlift gliders will exhibit a very low sink rates while flying at speeds necessary to penetrate up-wind. Below are two wings which show the evolution of the microlift wing from the early Carbon Dragon to the modern LightHawk. The first image belies the complexity of the varying airfoil design from the root to the wingtip of the Carbon Dragon. The wing was designed by Irv Culver. The second image is dramatic in its complexity, even transparent to the novice onlooker.[4] Sailplane designer Danny Howell was quoted saying "There's not a straight line on it anywhere."
[edit] External links to known Microlift Gliders
FAI has identified four gliders which meet the criteria for microlift glider. Listed in the order of their invention:
[edit] Organizations
[edit] References
== Copyright Notice == This copyright notice applies only to the diagram, FAI Defined Domains of Gliders.
FÉDÉRATION AÉRONAUTIQUE INTERNATIONALE Avenue Mon Repos 24,CH 1005 - Lausanne, Switzerland http://www.fai.org e-mail: sec@fai.org Copyright 2005 All rights reserved. Copyright in this document is owned by the Fédération Aéronautique Internationale (FAI). Any person acting on behalf of the FAI or one of its members is hereby authorised to copy, print, and distribute this document, subject to the following conditions: 1. The document may be used for information only and may not be exploited for commercial purposes. 2. Any copy of this document or portion thereof must include this copyright notice. Note that any product, process or technology described in the document may be the subject of other intellectual property rights reserved by the Fédération Aéronautique Internationale or other entities and is not licensed hereunder.
