Vortex Ring State explained

One thing we absolutely want to avoid is Vortex Ring State, also known as VRS.
….uhm… What?
This means that your drone is falling out of the sky when descending, and nothing you can do about it…

VRS happens when you are descending too fast with any rotorcraft (drones, helicopters)There are many difficult explanations for this, this is the simple one.

A vortex ring state can occur when you do a vertical descent. While descending, your propellers lose the ability to produce lift because they are traveling directly through the turbulent downwash they are designed for to create.
This might sound strange, propellers are designed to create this downwash, yet this downwash can harm the drone as well.
The situation gets even worse if you have overloaded your drone with an extra camera or gimbals that don’t come with the drone. The drone might be able to lift it, but when you are running into (VRS) problems you only wish you didn’t add the extra weight.

But there are ways to avoid it, and if it can’t be avoided, there are ways to attempt to recover from it.

First, the recovery:
To recover you need to get your drone back into clean (non-turbulent) air.
To get in clean air, you need to pitch forward or move sideways to get out of the propellers downwash.
It is also good to reduce throttle input, more power is more turbulent air, less power is less turbulent air. less turbulent air is more manageable to get out of.
Sometimes the air you’re descending through can be so turbulent that you will lose complete control. This near irreversible, and will almost always result in a crash. That’s why it is so important to not get in a VRS.

How to prevent:
One golden rule it to decent SLOW! a slow descent will cause little turbulent air, this will reduce the chance getting in a VRS.
Sometimes you need to descent fast because you are running out of battery, maybe try to prevent that the next time you fly. don’t try to overrule the automatic safety measure… IF you need to descend fast, do this in a forward/backward movement, or sideways, or a combination of that.. generally everything other than straight down.


Here is a great video that shows you more about VRS.

One comment

  1. Most (or at least many) drones can’t power out of VRS (vortex ring state), because they don’t have enough power, not because that adding power aggravates the issue. VRS reduces, but doesn’t eliminate lift, and with enough power, a model (or even a full scale Skycrane (empty) or MBB-B105 (it can do loops) can power out of VRS vertically). Normally only 3d aerobatic models can power out of VRS. Short example video of such a model:


    As mentioned above, for a non-3d drone, the drone has to be moved laterally to clear the vortex rings in order to recover.

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