Ice on leading edges of propellers?

[Zbip57]

Can a quadcopter really stall due to exceeding the angle of attack during a manoeuvre? I've never heard of an aerodynamic stall in a rotorcraft _ but stand to be corrected if others know of this.

Early DJI Phantoms were prone to aerodynamic stall when encountering Vortex Ring State. If descending straight down too quickly, the drone falls into its own downward prop wash and the props lose bite and stall. Adding more power doesn't help at that point. The proper recovery is to slide the drone forward or backward or sideways, any direction other than straight down, to move it out of that column of downwash air and out into clean air where the props can recover their bite.

Newer DJI models have firmware limits on descent rates, so that problem seems to have been cured.

Here's a classic video demonstrating what happens when a DJI Phantom gets trapped in Vortex Ring State. It fell out of control into a lake. Watch until the end to see the hilarious result of how they attempted to dry the drone.

 

[Jamesz]

Interesting. I can see icing causing a profile change leading to some blade stalling during rotation- but can that lead to a classic 'stall and fall' loss of control as in fixed wing flight?

 

[Zbip57]

Interesting. I can see icing causing a profile change leading to some blade stalling during rotation- but can that lead to a classic 'stall and fall' loss of control as in fixed wing flight?

If the ice buildup is enough to change the flow from laminar to turbulent over the surfaces of the propeller blade, then yes the blade will stall. You should get a warning though before that happens. As the blade progressively loses more lift, the flight controller tries to compensate by spinning the motors ever faster. Eventually that's all she wrote. The motors reach some finite limit to how fast they can spin and the drone will sink.

The warning will be something like, "Max Power Reached", or "Propellers spinning too fast", or "Motor error. Check propellers." Those are all warnings that the propeller blades aren't producing sufficient lift and the motors are spinning faster to compensate.

Coincidentally this video came up just today demonstrating prop icing. Note the error message at 3:35.

 

[Skydreamer]

how about spraying props with rain x deicer,it should keep props safe from ice for at least 30 min…..i think…..??

 

[shawgod]

I would be very hesitant spraying anything on the props. Even when I were to fly planes we didn't get any de-icer on the props. The prop is an air foil and anything to disrupt it is dangerous to the craft. Residue left by any chemicals could change the way the prop works.

 

[Navdeep]

What about if we use some kind of a grease on propellers before fly although it may increase some weight on propellers but ice may slide from it.

 

[Starz]

grease on propellers

Please provide pictures of your drone after this event.
(prior to cleaning off the grease that would be all over said aircraft)
TIA.

 

[FLDave]

What about if we use some kind of a grease on propellers before fly although it may increase some weight on propellers but ice may slide from it.

Or, just do as with a high performance fixed wing aircraft: add electric heating elements to the propellers to prevent ice buildup. Better yet, just don't fly in icing conditions unless the drone is capable of flying in icing conditions and the remote pilot is qualified for those conditions.

 

[GregS]

Took my older drone for a spin today and when it landed, I noticed this ice formation on the leading edges of the propellers. I did fly it into the clouds but the temperature was barely below freezing. Is there a real risk of flying like this? I didn't notice any decrease in performance.

Never fly when there is a lot of moister; fog, drizzle, low clouds, and temp at or below freezing. Temp on the ground is usually warmer than higher up. You won't always see the ice. It most likely melts when you descend. At altitude the Ice will eventually build up on your props and your drone can take on the characteristics of a rock, and fall out of the sky!

 

[Cymruflyer]

For the most part, you don't have to worry about icing. Don't listen to those talking about not flying in fog, drizzle etc. though that is not the best times to fly anyway, because they don't seem to understand icing conditions. Icing ONLY occurs when the ambient temp. is the same or relatively close to the Dew Point temp. so check weather and if these two are close, don't fly. If they are far apart, go and fly and don't worry about icing.