No pilot ever really questions the essential role of the propellers in drone flight. It kind of goes without saying.
But keeping them in tip-top shape isn’t easy. Drone propellers eventually deform and their costs start to add up. And that’s when pilots wonder whether it’s really worth replacing them.
The truth is, there’s a fine line between saving your hard-earned money and risking losing a much bigger investment (in your whole drone).
In this post, I’ll be explaining how to tread that very line.
We’ll be covering the signs you must look out for along with their potential effects. And in case you’re curious about things, we’ll also go into what’s technically possible.
Let’s start off with the facts. To what extent does a broken propeller affect basic flight? Here’s the answer.
Whether a drone can fly with a broken propeller depends on the full damage done to it. A drone cannot effectively lift off with a completely broken propeller. However, a drone with a broken propeller tip can still fly and potentially land safely. The total number of propellers also plays a role.
A hexacopter, for example, is a lot more stable with a broken propeller compared to a quadcopter. But just like any other drone, it won’t fly anywhere near as smoothly as it would otherwise.
Now, it’s important to not judge an idea based on the technicality of things.
It’s only okay to fly a drone with a broken propeller if the damage happens mid-flight. And even then, you should immediately be looking to make a safe landing.
In my opinion, a propeller can be classed as too damaged when its leading edges are imperfect. That’s when the broken propeller would disrupt the airflow created and, more importantly, when the drone would lose its ability to fly properly.
Drones are designed to make specific movements like ascending and turning. And if a component fails, (most) drones are not programmed to appropriately respond to commands in light of the failure.
So, a drone with a broken propeller can typically not be operated effectively as it would start to spin uncontrollably.
Say the propeller is complete in terms of its shape, but one of the blades is cracked. What should you expect then? Take a look.
You can technically fly a drone with a cracked propeller. In fact, drone pilots, who forget to inspect their drones, often fly with one without noticing. However, it is never a good idea to do so as the crack can very quickly expand to the hub, leading to the propeller breaking mid-flight.
The point is this: it is safer than attempting to fly a drone with a broken propeller.
Pilots who fly toy drones often use scotch tape on their cracked propellers. This does the job since toy drones don’t particularly revolve around performance.
In general, however, not making a replacement is a terrible idea. The looming danger of cracked propellers is not worth the risk of losing a camera drone.
At the same time, pilots who take the chance anyway also risk legal trouble through third-party injury and property damage.
In reality, you really shouldn’t let your propellers wear down until they break. The change needs to happen much sooner. Here are some cues you can wait for.
You should replace your drone propeller when you spot any sort of damage or notice a change in shape, noise, or color. Similarly, you should change the propeller set if the drone doesn’t feel as responsive as before.
The immediate cause for concern is contact. It’s important to note that a collision doesn’t need to be severe. Flying into small branches of trees, for example, can have more of an effect than you might think.
We’ve already talked about fully noticeable damage. Plus, changing a propeller with missing chunks is kind of a no-brainer. Let’s expand on the other, often overlooked, signs.
Sometimes, the damage isn’t really visible. This is why it’s also important to feel for damage.
Propellers have a carefully constructed, twisted design that is used to efficiently produce lift in drone flight. Over time, drone propellers can lose their shape (even without accidents) and affect performance.
I recommend inspecting the propellers before every flight by running a finger over the full length of the blades. It’s a great way to find out whether your propeller is disfigured and needs changing.
Every pilot knows how a new drone feels. The fine control and flight smoothness are so much fun to experience.
Drones gradually lose their responsiveness as you start to rack up the flight hours. The good news, however, is that you definitely do not need a new drone just to get back to that feeling.
Replacing, or upgrading, the propeller set is very likely to give your drone the added agility you’re looking for. A fresh set is always more stiff. In turn, there’s far less of a delay in the execution of commands.
This one’s pretty straightforward.
Propellers sound different when they spin due to their characteristics. In fact, a lot of pilots can tell their drones apart from a flock of other drones from the noise alone.
If your drone suddenly sounds louder or is making unusual noises, it’s best to replace its propellers with a new set.
You may handle your propellers with the utmost care but sometimes they can simply be past their best before date. And discoloration is a sign of exactly that.
Propellers lose their color over time as sun rays continue to hit their surface. But the real issue here isn’t related to aesthetics, it’s more about durability.
Discoloration shows the propellers aren’t as rigid as before. This means they’re more prone to bends, cracks, and eventually breaking apart.
Propellers only discolor when they’re really old. So, I suggest replacing them as soon as you spot a change in color.
Unlike typical camera drones, FPV drones provide a live feed to the pilot. The general rules for them about replacing propellers are the same, but you may consider one more thing.
You should replace your FPV drone propellers if they’re damaged in any shape, way, or form. This includes cracks, nicks, dents, and bends. A clear indication of needing to change propellers is an unstable live feed. The problem is typically fixed with a fresh set of propellers.
Since you can watch the transmitted video feed as you fly, performance issues are a bit easier to notice. Pilots with normal drones usually don’t notice excessive vibration until after they review their footage.
Damaged propellers can obviously cause accidents. But another thing to keep in mind is that they also cause other components to deteriorate faster.
For example, propellers can loosen with continuous use which can, in turn, damage the drone’s motor mounts and bearings.
This is why I often emphasize the importance of regularly inspecting your drone’s propellers.
A lot of drone pilots prioritize performance. So, for them, it isn’t just about safety but also minimizing negative effects as much as possible.
This part is targeted towards them. Here’s how a damaged propeller can bring down the levels of your drone flights.
A damaged drone propeller affects performance mainly by causing vibration issues. This results in a lack of speed control, meaning the change in directions would not be sharp and the flight would not feel smooth. A damaged propeller also leads to poor efficiency.
Don’t get me wrong, there are bigger causes of poor efficiency. A bad battery, for example, definitely reduces flight times.
But if the rest of your components are freshly installed, your propellers might be to blame. Propellers with scratches or missing chips simply cannot produce a consistent lift. And this can potentially lower the battery life of your drone.
This part’s sole purpose is to quench your thirst of curiosity. Needless to say, flying with one less propeller is incredibly reckless.
But is it possible? Here’s the answer based on experiments carried out by experts.
A drone cannot fly with 3 propellers if it’s designed as a quadcopter. There would be an imbalance of forces and a quadcopter generally isn’t designed to overcome such a problem. However, three propeller drones do exist in the market. They fly perfectly since they’re designed to do so.
The imbalance is related to the working of drone propellers. Since quadcopter propellers work together to cancel out torque, losing one is a blow to the drone’s functionality.
Going back to one of the introductory questions of this post, it’s a different story for hexacopters and octocopters.
These drones are a lot more powerful and losing a propeller does not affect their capability to fly. You may notice a slight drop in flight performance but, as a pilot, safely landing the drone would not feel particularly different.
A drone doesn’t always have to go down before a propeller requires replacement. Here’s how long they can generally be used.
Drone propellers generally last around 300 flight hours before they turn more fragile and terribly affect flight performances. Drone pilots, however, replace their propellers a lot sooner based on their drone models. Owners of high-end drones often make the change after 25 flight hours.
The variation in how long pilots use their drone propellers is based on the risk they’re willing to take and the performance levels they’re fine with losing out on.
Expensive drones, like the DJI Inspire 2, are used professionally for serious filmmaking. Replacing the propellers well before their breaking point ensures quality and reliability.
Having gone through all of the signs, you may still want to put a time limit on your propellers. Here’s a safe estimate.
According to DJI Support, you should replace your drone propellers once every 200 flights or 3 months. This is, however, a generic estimate. It ultimately depends on the actual amount of flight hours you have put in and the final condition of your propellers.
Similarly, aggressive pilots demand more from their drones and, hence, are forced to replace their propellers sooner.
It’s best to find a balance between preserving performance and being cost-efficient by factoring in your applications and goals.
It’s worth noting that some pilots opt to fix their drone propellers themselves. I’ve written a separate article on the various techniques used to do so.
To wrap it up, there isn’t a rule on discarding your propellers after a certain number of flight hours. It ultimately depends on their condition and how they feel (literally and figuratively in flight).
You can know if your drone propeller is bad by inspecting it closely before every flight. Propellers that are visibly deformed are always a risk. More importantly, they’re bad because the damage is reflected even in the post video edit and in the live feed if you fly FPV.
There’s no denying propellers are important components. So, if your gut is telling you to make the replacement, it’s always a good idea to trust it and not push them for the infamous one more flight.