{"id":15742,"date":"2025-04-25T10:35:30","date_gmt":"2025-04-25T08:35:30","guid":{"rendered":"https:\/\/stefly.aero\/?post_type=product&p=15742"},"modified":"2026-11-09T08:13:43","modified_gmt":"2026-11-09T07:13:43","slug":"larus-standalone","status":"publish","type":"product","link":"https:\/\/stefly.aero\/en\/product\/larus-standalone\/","title":{"rendered":"LARUS Stand-Alone Variometer"},"content":{"rendered":"
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LARUS Stand-Alone Variometer<\/h1><\/div><\/div>\n\n\n\n\n\n
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\"Stefan<\/span><\/div>\n\n

Stefan Langer<\/p>\n

Three-time World Champion, No. 1 in the IGC World Ranking (as of 09\/2026). Flies LARUS in his AS 33 Me and his LS3, in training, in competitions and when traveling by glider.<\/span><\/p>\n<\/div><\/div>\n<\/div>\n\n

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Why I fly with LARUS<\/h2>\n

\u201cThe most important thing in gliding is knowing what\u2019s happening to the air I\u2019m flying through right now.\u201d<\/p>\n

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FLYING LINES<\/h3>\n

\u201cThe fast, direct vario helps me fly lines very efficiently. The feedback loop is much faster: I can feel out where the air is rising or sinking. Especially at high wing loading and in gliders that give you little feedback from thermals, it\u2019s a game changer.\u201d<\/p><\/div>\n

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SPEED TO FLY<\/h3>\n

\u201cFor speed to fly, the key is knowing when to slow down and when to speed up. Filtering out horizontal gusts minimizes errors, and speeding up at the right moment saves valuable energy.\u201d<\/p><\/div>\n

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CLIMBING<\/h3>\n

\u201cThanks to its short filter time, the centering aid works with very little delay. It shows me which way I need to shift my circle, so I can find even small, narrow thermal cores.\u201d<\/p><\/div>\n

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WIND IN THE MOUNTAINS<\/h3>\n

\u201cEspecially in the mountains, the highly precise live wind is a big help for seeing which slope is working. It\u2019s also a gain in safety: I notice much sooner when I\u2019m flying into the lee.\u201d<\/p><\/div>\n

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ONE NEEDLE<\/h3>\n

\u201cAlso important: there\u2019s only one vario needle, one clear display that I trust.\u201d<\/p><\/div>\n<\/div><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n

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Measure, don\u2019t estimate<\/h2>\n

That is the philosophy behind LARUS. GNSS provides position, altitude and ground speed in three dimensions. The inertial measurement unit (IMU) measures acceleration, rotation rate and magnetic field, while the pressure sensors measure static and dynamic pressure. Dedicated algorithms in the sensor box combine all of this into vario, wind and attitude.<\/p>\n

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Vario<\/h3>\n
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A Kalman filter combines GNSS altitude, GNSS velocity and the IMU\u2019s vertical acceleration, with no delay and without pressure readings. LARUS derives total energy compensation from GNSS ground speed and the averaged horizontal wind, so short horizontal gusts are largely filtered out.<\/p>\n

Kalman filter combining GNSS and IMU \u00b7 Vertical speed accuracy approx. 2.5 cm\/s (Competition) or approx. 5 cm\/s (Essential)<\/p>\n<\/div>\n<\/div>\n

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Wind<\/h3>\n
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LARUS determines the wind from the three-dimensional difference between ground speed and airspeed. It provides both live wind and average wind, in straight flight as well as in circles. \"Competition\" measures heading with two GNSS antennas, so wind direction and strength remain accurate even on long straight glides under cloud streets. \"Essential\" determines heading from GNSS and IMU while circling and automatically calibrates the magnetic compass for straight flight in the process.<\/p>\n

Straight flight: live wind 5 s, average wind 30 s (adjustable) \u00b7 Circling: last circle or entire circling phase \u00b7 Heading approx. 0.05\u00b0 (Competition) or 1\u20132\u00b0 (Essential, with proper installation)<\/p>\n<\/div>\n<\/div>\n

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Pressure altitude and airspeed<\/h3>\n
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Static pressure provides pressure altitude and flight level, while dynamic pressure provides indicated airspeed (IAS). LARUS derives air density in real time by comparing GNSS altitude with pressure altitude, without measuring temperature or humidity. IAS and air density together give the true airspeed (TAS), which LARUS uses to calculate the wind.<\/p>\n

Static pressure: pressure altitude, flight level, air density \u00b7 Dynamic pressure: IAS \u00b7 IAS and air density: TAS<\/p>\n<\/div>\n<\/div>\n<\/div>\n

\"Karte<\/p>\n

LARUS was developed by the LARUS project team led by Prof. Dr. Klaus Sch\u00e4fer, Maximilian Betz and Winfried Simon. SteFly manufactures and distributes it under license, and the license fees secure its long-term development. Firmware updates are free of charge. All details on the sensor box \u2192<\/a><\/p>\n<\/div>\n<\/div><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n

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No corners, no wasted space<\/h2>\n

Round like the instrument cutout: the LARUS Vario Display uses the full 57 mm diameter to show information. Two concentric rotary knobs guide you through the menus, and colors distinguish short-term and long-term values for vario and wind.<\/p>\n

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Vario<\/h3>\n

Current and average climb, shown in different colors, plus the numeric value.<\/p>\n<\/div>\n

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Wind<\/h3>\n

Arrows for current and average wind, with numeric value and change.<\/p>\n<\/div>\n

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SPEED TO FLY<\/h3>\n

Symbol for speed-to-fly or vario mode and a pointer for MacCready. Toggle between modes with a vario\/speed-to-fly switch, for example on the SteFly remote stick.<\/p>\n<\/div>\n

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CENTERING AID<\/h3>\n

A thermal is never round: the centering aid shows which segment has the best climb, in either \u201cdotted\u201d or \u201cspider web\u201d display.<\/p>\n<\/div>\n

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Horizon<\/h3>\n

Additional aid under VFR, especially for setting up the mounting orientation. Can be switched off for competitions.<\/p>\n<\/div>\n<\/div>\n

Also: Battery charge level \u00b7 Audio via external loudspeaker (3.5 mm jack) \u00b7 Mounting orientation 0\u00b0 \/ 90\u00b0 \/ 180\u00b0 \/ 270\u00b0 \u00b7 Mounting with three M3 screws<\/p>\n<\/div>\n

\"LARUS<\/div>\n<\/div>\n<\/div><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n
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Essential or Competition?<\/h2>\n

Both versions share the same hardware, apart from the GNSS receivers and antennas. Every LARUS uses high-precision receivers that track four satellite systems simultaneously: GPS, GLONASS, Galileo and BeiDou. The key difference is how heading is determined. <\/span>Competition measures it with two GNSS antennas. Essential determines it from GNSS and IMU while circling and, in straight flight, uses the magnetic compass that was automatically calibrated in the process.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
<\/th>\nEssentialSingle-GNSS<\/span><\/th>\nCompetitionDual-GNSS<\/span><\/th>\n<\/tr>\n<\/thead>\n
RECOMMENDED FOR<\/th>\nTraining and relaxed cross-country flying<\/td>\nCompetitions, ambitious cross-country flying, frequent mountain flying<\/td>\n<\/tr>\n
Number of GNSS ANTENNAS<\/th>\n1<\/td>\n2<\/td>\n<\/tr>\n
GNSS RECEIVER<\/th>\nu-blox M9N, single-band<\/td>\nu-blox F9P, dual-band<\/td>\n<\/tr>\n
Heading<\/th>\nfrom GNSS and IMU while circling, in straight flight via the automatically calibrated magnetic compass<\/td>\ntwo GNSS antennas (D-GNSS)<\/td>\n<\/tr>\n
HEADING ACCURACY<\/th>\napprox. 1\u20132\u00b0 (with proper installation)<\/td>\nca. 0,05\u00b0<\/td>\n<\/tr>\n
CROSSWIND AT 200 KM\/H<\/th>\nuncertainty up to approx. 7 km\/h (at 2\u00b0)<\/td>\nuncertainty approx. 0.2 km\/h<\/td>\n<\/tr>\n
WIND IN STRAIGHT FLIGHT<\/th>\nyes, via the magnetic compass calibrated while circling<\/td>\nyes, via GNSS heading, even under long cloud streets<\/td>\n<\/tr>\n
DISTANCE FROM MAGNETIC INTERFERENCE<\/th>\nimportant: at least 20 cm from loudspeakers and magnets<\/td>\nless sensitive, which makes installation and setup easier<\/td>\n<\/tr>\n
VERTICAL SPEED ACCURACY<\/th>\napprox. 5 cm\/s<\/td>\napprox. 2.5 cm\/s<\/td>\n<\/tr>\n
HORIZONTAL SPEED ACCURACY<\/th>\napprox. 0.1 km\/h<\/td>\napprox. 0.05 km\/h<\/td>\n<\/tr>\n
WEIGHT WITH ONE VARIO DISPLAY<\/th>\n405 gSensor box with antenna 300 g + display 105 g<\/small><\/td>\n735 gSensor box with antennas 630 g + display 105 g<\/small><\/td>\n<\/tr>\n
POWER CONSUMPTION WITH ONE VARIO DISPLAY<\/th>\napprox. 205 mA at 13 VSensor box 120 mA + display 85 mA<\/small><\/td>\napprox. 235 mA at 13 VSensor box 150 mA + display 85 mA<\/small><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Two-seater: each additional Vario Display weighs 105 g and draws approx. 85 mA.<\/p>\n

Upgrade later? We can convert your LARUS Essential to Competition at any time. To the upgrade \u2192<\/a><\/p>\n<\/div>\n<\/div><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n

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\"LARUS
LARUS Vario Display in the AS 33 Me panel<\/figcaption><\/figure>\n
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Independent of your flight computer<\/h2>\n

LARUS Stand-Alone also works without a flight computer: its own sensor box, its own GNSS antenna(s), its own display. Your existing system stays exactly as it is. The only things shared are static, pitot and the onboard power supply.<\/p>\n

Combined with a SteFly NAV<\/a> LARUS data is put to even better use: the LARUS wind feeds into the final glide calculation, and MacCready, ballast and other settings are synchronized automatically.<\/span> The connection is made via RS232 cable or Bluetooth, and also works with other devices running XCSoar or OpenSoar as their navigation app.<\/span><\/p>\n<\/div>\n<\/div>\n

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STEP 1<\/span><\/p>\n

Mount the sensor box<\/h3>\n

The sensor box is mounted firmly in the fuselage so that it cannot move under acceleration. Any mounting orientation is possible and is stored in the configuration file. Keep at least 20 cm away from loudspeakers, magnets and moving metal parts such as control rods. Static and pitot are connected to the existing lines using T-pieces. Power is supplied with 9\u201328 V via RJ45.<\/span><\/p>\n<\/div>\n

Step 2<\/span><\/p>\n

Position the antennas<\/h3>\n

The GNSS antennas need a clear view of the sky (even while circling) and must not be shadowed by metal or carbon fibre parts. They are installed roughly level in flight attitude. On the LARUS Competition, two antennas are mounted at least 1 m apart.<\/span> In a carbon fibre fuselage, a canopy antenna, an external antenna on the fuselage spine or installation under the GRP engine bay doors are possible options.<\/span>.\u00a0<\/p>\n<\/div>\n

Step 3<\/span><\/p>\n

Install the display<\/h3>\n

The display is mounted in a free 57 mm cutout with three M3 screws and can be rotated in 90\u00b0 steps. It connects to the sensor box via CAN using a standard patch cable (RJ45), which also supplies power. In a two-seater, two displays are connected via a CAN splitter. Finally, the mounting orientation is calibrated on the display.<\/span><\/p>\n<\/div>\n<\/div>\n

You\u2019ll find manuals, drawings and 3D print files for mounts on the product pages LARUS Sensor Box<\/a> or LARUS Vario Display<\/a>.<\/p>\n<\/div>\n<\/div><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n

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Scope of delivery and technical data<\/h2>\n
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IN THE BOX<\/h3>\n