The intent of this page is to explain how a barometric vario works, what you can expect from smartphone variometers and sensors and how you might benefit from an instant vario and why you will need a variometer for paragliding in general.

Continue reading if you want to know more about the major principles used by all including the best variometers in paragliding and how an instant vario works.

Instant Vario

An instant variometer has virtually no delay or lag in calculating the vertical climb rate (vertical speed). What you feel is what you hear. And this makes for a much more intuitive flying... ¯\_(ツ)_/¯

Small bumps in the air can be felt and heard, lifts are easily identified and in weak conditions a zero delay indication of the vario can help you stay in the air much longer. It just flies different and thermals are much easier centered.

This instant feedback can be provided by most of the current middleclass smartphones using the FusionBoost algorithm of theFlightVario instant vario. theFlightVario takes readings from all motion sensors, especially the

• accelerometer,

• gravity sensors,

• gyroscope

and last but not least the barometer and calculates a fused climb rate. Combining all these readings at rate of up to 100 times each second straightens out individual errors of each sensor and make the fused signal non delayed.

What is an instant vario

Remember, a basic vario for paragliding uses the variation in pressure to calculate the difference in altitudes and from that difference the climb rate. However, that difference in altitudes will need to happen first which is why a barometric vario, one that is based on pressure alone, will be delayed, always! It can only indicate lifts or change in altitude that already happened ¯\_(ツ)_/¯

That said, there is another variation, more instant, that can be used to calculate the change of the climb rate. And again it is about relative change rather than absolute values.

Acceleration - the instant in the vario

To understand how an instant variometer works, imagine you just got into an elevator. (Thermals can actually be seen as our elevators to cloud base.) You pushed the very last button to get to the top (cloud base), closed your eyes and now you wait for the ride to begin. What will you be able to tell from your senses...?

Now, you naturally feel once the elevator starts accelerating. In this case you are experiencing a

Positive G-Force: your climb rate is expected to increase!

which results in a higher vertical speed. The start is actually like entering a thermal.

Of course, you also feel once the elevator starts braking or more technically, decelerates. In this case you are experiencing a

Negative G-force your climb rate is expected to decrease!

which results in lower vertical speeds and ultimately no speed.

So whenever you are accelerating (positive or negative) your climb rate will change. But what is more important, you are anticipating the change in climb rate before any barometric variometer could have made that calculation from altitudes and hence changes in pressure.

gravity changing is INSTANT

But what can you tell about the climb rate from the elevator going up at constant speed, once the acceleration (and deceleration phase to be correct) is finished. Can you tell how fast you are going up, your exact climb rate? No, you can’t! Without any visual clues it is impossible. Which is why we need the barometric climb rate calculated from changes in pressure due to changes in altitude.

change of altitudes is NOT INSTANT

Now, taking the instant part from gravity and fusing it with the not so instant part from pressure is the basic idea of an instant vario. Best of both worlds, plain simple. Fusing is the hard part!