The SkyAssistant variometer is a small on-board instrument which indicates the RC sailplane model's vertical speed by an audible signal. Lift is indicated by a pulsed tone with rate and frequency of the pulses depending on the climb rate. Sink is indicated by a low, continuous tone depending on the sink rate. Audible signal and voice messages about model state are transmitted by built-in radio transmitter and can be received on standard LPD or PMR receiver (European version), FRS (American version) or UHF CB (Australian version). Voice messages in all available languages can be listened on Language versions page.
Additional features of the SkyAssistant includes:
- voice announcement of glider altitude in [m] or [ft] at reach definable altitude step (default every 50m),
- voice announcement of on-board battery voltage, a message at each voltage drop of 0.1V and a voice alarm if it drops below a definable value,
- voice announcement of temperature (battery, engine or air) in [°C] or [°F] with temperature data logging,
- measurement of value and stability servo PPM signal and definable sound signal if interference is detected (works with PPM/PCM systems),
- measurement of atmospheric pressure in [Pa] or [inHg],
- triggering voice messages of measured values (altitude, voltage and temperature) by 3-way switch on RC transmitter,
- few modes of work with vario tone on/off, automatic messages on/off, periodic messages on/off activated by 3-way switch,
- user definable alarms: low voltage, high temperature, high altitude, PPM error,
- recording of all measured values into Flash memory (logging time >10h in typical conditions: 5 parameters every 200ms),
- easy firmware updating and automated actualization service,
- all logged data of RC glider flight can be downloaded and graphed for off-line analysis.
Details about functional blocks you can find in the English version of documentation.
Actual variometer pictures:
Video from flights on International Żar Mountain Picnic:
Mounting variometer in RC sailplane
RC sailplane variometer should be mounted in vertical position with pressure sensor pointing up. In this position vertical acceleration forces acting on the sensor's membrane cumulative increase variometer sensitivity. Mounting with pressure sensor pointing on one side is not recommended, because centrifugal force increase variometer readings circling in one side and decrease when circling in other side. Variometer should also be exposed on direct sunlight.
Sailplane crashes sometimes happens even to experienced gliders. Try to predict what happens with variometer when you crash. Do not mount it in front of heavy components like batteries. Until will be hit with something heavy, the SkyAssistant board can survive most crashes.
Please remember that variometer's transmitter is active source of radio frequency signal and can influence on your RC receiver, so always perform range check with new setup. Some receivers with badly designed RF input circuit can loose range in presence of variometer's RF signal. Let's imagine example situation. Variometer's transmitter has RF power 10 mW and RC transmitter has power 100 mW.
Variometer is placed in glider 10 cm from RC receiver and RC transmitter is 1 m from it. From physics we now that field strength depends from square of the distance. In above example both signals will be equal. Let's see how the relation will looks in bigger distance between modeller with transmitter and glider with receiver and variometer:
|Distance [m]||Relative RF field strength|
On distance of 1 km (nothing special for bigger glider) signal from RC transmitter is million times weaker then signal from onboard variometer. RC receivers has usually sensitivity about 100dB, so in general flying with variometer is possible, but in case of design errors in receiver it can loose signal in much shorter distance.
Dimensions: 173x56x40 mm, weight 140 g
Dimensions: 193x57x40 mm, weight 123 g (exc. bat.)
SkyAssistant variometer package
- SkyAssistant variometer in transparent heat shrink tubing,
- Mini USB cable,
- Temperature sensor on 17cm long cable (you can choose other length),
- Printed user manual in one of languages: EN, FR, NL, GR, FI, PL, DE, IT, CZ, HU, RO, RU, UA, ES, CA, LT,
- 2-color sticker with SkyAssistant logo to be sticked on your RC glider.
End of product life
After 10 years of sale and saturation of the market, the SkyAssistant has to retire. Some of critical components used in production become not available. Refreshing the project is theoretically possible but very costly, because it is device with radio transmitter and require expensive certification. The sale drop to so small level, so it can't cover the cost of refreshing this project. I decided to not to restore production.
Thank you for the cooperation.