Drones are sensitive machines. The more you try to have fun with things, the higher the risk of component damage.
This is why having extra propellers is sort of part of the gig. But what if you, on the odd occasion, don’t? Perhaps the replacements are taking too long to ship. Or maybe you just want to take the DIY approach.
Well, the solution, then, is to fix your damaged propellers yourself.
It isn’t particularly a recommended practice in the community. However, there’s absolutely no harm in safely experimenting with cheap drones — as long as you know what you’re doing.
In this post, we’ll be looking at a few tried-and-tested methods you can use to put your propellers back in functioning shape. And don’t worry, they’re incredibly easy to follow.
Before we dive into the actionable information, I want to address a common misconception.
A lot of drone pilots seem to believe that propellers retain their performance provided there are no accidents. Here’s how it actually goes.
Drone propellers do, indeed, wear out over time. They discolor, and even lose their shape if they are cheaply made, through normal use. This is primarily because most drone propellers are not resistant to aging by UV rays. So, long-term exposure to strong sunlight has an effect.
In other words, collisions and hard landings aren’t the only things warranting an inspection. Propeller material becomes less stiff through prolonged use. In turn, the propellers lose consistency in creating lift.
This doesn’t mean that a slightly worn out propeller requires immediate “fixing”. But it is a sign for you to be wary of its reliability.
Let’s say a propeller does collide in a certain way, or ages enough, to bend out of shape. Is it even possible to fix it up? Here’s the answer.
Whether a bent propeller can be repaired or not depends on its type of material. Metal propellers, often used by large aircraft, can be easily repaired. On the other hand, bending plastic propellers into shape requires more caution. Excessive bends, however, cannot be treated in any case.
You may even find repairing facilities for propellers in your area. But as you may have expected, professionals don’t offer services for the smaller models used with drones.
This is because drone propellers are a lot cheaper than, for example, stainless steel propellers. Plus, there aren’t any widely acknowledged repairing methods for the services to be provided professionally.
This doesn’t, of course, mean there aren’t any working methods at all. We’ll be getting into them soon.
Now, don’t get the wrong idea. Reparation and replacement cannot be used interchangeably.
Even after a bent propeller is fully repaired, professionally or otherwise, it won’t be remotely as good as new. Metal propellers are generally damage-resistant. But once they’re forced back into shape, they have weak spots.
Plastic and carbon fiber propellers are worse in this regard as they’re more prone to shattering.
And while reparation makes a propeller usable, the overall system performance will be taking somewhat of a blow.
So, you’ve noticed your drone propeller is a bit deformed. Here’s how you can try fixing it.
You can fix a bent drone propeller by carefully bending it back into shape. The best way to do this is without removing the propellers and placing the drone on a level surface. It is extremely important to be delicate with the amount of force you use.
This process typically works for small drones and toy quadcopters. They sport softer propellers that are flexible and don’t have sharp ends.
Still, bending them repeatedly can most definitely push them past their breaking point.
Camera drones use blades with larger diameters. These propellers are more likely to crack as force is applied.
You can try using the same process of applying a little pressure on the bent portions of the propeller. Make sure you’re maintaining a perpendicular line of sight.
But if you start seeing white crease lines, it’s best to call the experiment off. These lines signify an impending breakage. I would strongly recommend not flying using propellers with cracks or crease lines.
Once your propeller does break though, you may use one of the following methods to put the blades back together.
You have a drone with a broken propeller and a mission that can’t wait. How do you fix the propeller on your own? Here are your options.
You can fix a broken drone propeller by using super glue on the broken part or making use of other damaged propellers. The parts of other propellers can be cut and connected to make one whole propeller. Similarly, you can make a foldable propeller out of two broken propellers.
Here’s something to remember: the rest of your drone’s components need to be compatible with a slightly larger propeller for these methods to work.
If the motor, for example, barely facilitated the propeller as it was, the repaired (and heavier) propeller will only lead to permanent damage.
That being said, there are a few points I recommend following for each of the methods. I’ll be assuming your broken propellers are dual-bladed to maintain consistency in the instructions.
This method is the simplest of the three. It’s meant for a broken propeller that has its blade separated from the hub.
You start off by applying epoxy glue to the propeller hub and reconnecting the blade. Make sure you know exactly where each side of the blade is meant to face.
Keep the propeller in place for a few minutes to allow the glue to dry. Then, coat the area with another layer of glue.
For added durability, you can use a thin piece of thread. Tightly wrap it around the hub and the base of the blade before topping it off with glue to harden the fibers.
It’s important to not use heavier thread or more glue than necessary since you’re already potentially disturbing the propeller’s balance.
This concept is pretty straightforward. However, the method requires attention to detail. It applies to propellers that are chipped or have missing chunks.
You’ll basically be using other broken propellers you may have to repair the one you need. Needless to say, they need to be identical so the parts can match.
The method involves cutting the chipped part off your propeller. At the same time, you cut an identical part from a broken propeller that has its blade intact.
You can then use some tape on one side to connect the unbroken part to your propeller and glue it together. The gaps can be filled in with chalk.
Now, it’s incredibly important to make the correct measurements as you work through this process. You can do this by aligning the propellers and marking the parts that are to be cut.
The YouTube tutorial below runs you through the entire process.
This method is ideal for pilots who have propellers with completely missing blades. You will, however, need a few extra things.
You’ll be using two propellers that have one blade each. These blades need to be different from one another so the leading edges of the blades move towards the drone when the foldable propeller is installed.
You’ll need a plastic rectangular block with three linear holes. The two propellers will need to be screwed into the holes on the left and the right.
You’ll then be using the hole in the middle as the “hub” to install the foldable propeller on its corresponding motor.
The two significant downsides of using this method are vibration and additional weight.
You’ll be losing out on performance due to the excessive vibration created and there will be a substantial weight increase that you’ll need to consider.
Still, the foldable design does provide function and allows you to make use of the otherwise useless, broken propellers.
It’s entirely possible your drone propeller starts tilting to one side after you’re done “fixing” it. Here’s how you can balance it.
You can balance a drone propeller by using repair tape on the blade that is seemingly lighter. You start off by removing the propeller from the drone and placing it in a propeller balancer. Then, you keep adding tape on one of the blades until the propeller stays horizontal and is balanced.
One thing to note is that you don’t necessarily need a propeller balancer. You may use paper bundles and a round stick (that goes through the hub). However, a balancer is much easier to use.
In case you’re coming across this issue in general, I’ve done a separate article on balancing drone propellers. It covers the topic in greater detail and breaks down other techniques you can use.
You may already know the answer to this question based on the talking points of this post. Still, here are the possible reasons.
Your drone may be flipping on takeoff due to damaged propellers as they can cause an imbalance in the thrust generated. However, a drone flip can have a multitude of other causes. These include bad motors, wrong wiring, insecure parts, and uncalibrated sensors.
The question fits into today’s topic because of the role the propellers play in flight. To put it simply, consistent flight becomes impossible when each propeller doesn’t create an equal difference in air pressure.
Thrust imbalance typically points towards one of the propellers in the set being damaged or deformed. Or, on the contrary, the propellers may just be installed the wrong way around.
Once you’re sure the propellers aren’t to blame, and the issue persists, you can safely assume the problem lies in the drone’s software or internal components.
To bring things to an end, drones aren’t programmed to fly with damaged components. They need to ultimately be fixed to allow safe operation.
Whether a drone can fly with a broken propeller depends on the damage done to it. A drone cannot lift off with a missing propeller blade. However, you can still fly a drone with scratched or slightly bent propellers. Similarly, chipped propellers, though dangerous, typically allow safe landings.
The point is this: you don’t have to throw away your broken propellers if you own a small drone or even a racing quadcopter.
They may come in handy when you least expect it. Similar to the methods I covered above, drone enthusiasts are always coming up with new ways to craft solutions themselves.
Still, the time to actually make replacements does inevitably come. I recommend keeping an eye out for signs that tell you to replace them so you never end up risking your whole drone.