Editing Hang gliding (section)

== Instruments ==
To maximize a pilot's understanding of how the hang glider is flying, most pilots carry [[flight instruments]]. The most basic being a variometer and altimeter—often combined. Some more advanced pilots also carry airspeed indicators and radios. When flying in competition or ''cross country'', pilots often also carry maps and/or [[GPS]] units. Hang gliders do not have instrument panels as such, so all the instruments are mounted to the control frame of the glider or occasionally strapped to the pilot's forearm.

=== Variometer ===
{{main|Variometer}}
[[Image:Gleitschirmvario.jpg|right|thumb|upright|Vario-altimeter ({{Circa|1998}})]]
Gliding pilots are able to sense the [[acceleration]] forces when they first hit a thermal, but have difficulty gauging constant motion. Thus it is difficult to detect the difference between constantly rising air and constantly sinking air. A [[variometer]] is a very sensitive vertical speed indicator. The variometer indicates climb rate or sink rate with audio signals (beeps) and/or a visual display. These units are generally electronic, vary in sophistication, and often include an [[altimeter]] and an airspeed indicator. More advanced units often incorporate a [[barograph]] for recording flight data and/or a built-in GPS. The main purpose of a variometer is in helping a pilot find and stay in the 'core' of a thermal to maximize height gain, and conversely indicating when he or she is in sinking air and needs to find rising air. Variometers are sometimes capable of electronic calculations to indicate the optimal [[speed to fly]] for given conditions. The [[Paul MacCready|MacCready]] theory answers the question on how fast a pilot should cruise between thermals, given the average lift the pilot expects in the next thermal climb and the amount of lift or sink he encounters in cruise mode.<ref>{{cite web|url=http://www.modelaircraft.org/museum/bio/MacCready.pdf|title=Biography of DR. PAUL MAC CREADY|publisher=Academy of Model Aeronautics|access-date=21 August 2007|url-status=dead|archive-url=https://web.archive.org/web/20070927004606/http://www.modelaircraft.org/museum/bio/MacCready.pdf|archive-date=27 September 2007}}</ref> Some electronic variometers make the calculations automatically, allowing for factors such as the glider's theoretical performance (glide ratio), altitude, hook in weight, and wind direction.

=== Radio ===
[[Image:Aircraftradio 2790.JPG|left|thumb|upright=.5|Aircraft radio]]

Pilots sometimes use 2-way radios for training purposes, for communicating with other pilots in the air, and with their ground crew when traveling on cross-country flights.

One type of radio used are PTT ([[push-to-talk]]) handheld [[transceiver]]s, operating in VHF FM. Usually a microphone is worn on the head or incorporated in the helmet, and the PTT switch is either fixed to the outside of the helmet, or strapped to a finger. Operating a VHF band radio without an appropriate license is illegal in most countries that have regulated airwaves (including United States, Canada, Brazil, etc.), so additional information must be obtained with the national or local Hang Gliding association or with the competent radio regulatory authority.

As aircraft operating in airspace occupied by other aircraft, hang glider pilots may also use the appropriate type of radio (i.e. the aircraft [[transceiver]] into Aero Mobile Service VHF band). It can, of course, be fitted with a PTT switch to a finger and speakers inside the helmet. The use of aircraft transceivers is subject to regulations specific to the use in the air such as frequencies restrictions, but has several advantages over FM (i.e. frequency modulated) radios used in other services. First is the great range it has (without repeaters) because of its amplitude modulation (i.e. AM). Second is the ability to contact, inform and be informed directly by other aircraft pilots of their intentions thereby improving collision avoidance and increasing safety. Third is to allow greater liberty regarding distance flights in regulated airspaces, in which the aircraft radio is normally a legal requirement. Fourth is the universal emergency frequency monitored by all other users and satellites and used in case of emergency or impending emergency.

=== GPS ===
[[Global Positioning System|GPS]] (global positioning system) can be used to aid in navigation. For competitions, it is used to verify the contestant reached the required check-points.