Propellers are a important element of any FPV drone, and understanding the fundamentals is crucial for getting began within the interest. The fitting propellers could make your drone fly sooner, smoother, and extra effectively, whereas the improper ones may cause instability and poor efficiency. On this information, I’ll break down every little thing it is advisable to learn about FPV drone propellers and share my prime suggestions.
Propeller Suggestions
Propellers are available in varied designs and sizes, every tailor-made for particular flight types and functions. Elements like pitch, form, and materials considerably influence efficiency. After years of testing and expertise, I’ve narrowed down a few of the finest propellers for various use instances.
Finest 5″ Props
Finest 5″ Props for Sub250
Finest 7″ Props
Finest 3″ Props for Freestyle
Finest 3″ Props for Cinewhoops
Finest 3.5″ Props for Freestyle
Finest 3.5″ Props for Cinewhoops
Finest 2″ Props for Cinewhoops
Finest Tiny Whoop Props
For Tiny Whoop propeller suggestions, take a look at my suggestions right here: https://oscarliang.com/best-tiny-whoop/#31mm-Propellers-for-65mm-Whoops
How Does a Propeller Work?
Propellers (or simply “props”) generate thrust by spinning quickly, pushing air downward. Every blade has an airfoil form, making a strain distinction: decrease strain above and better strain beneath. This distinction generates carry, propelling the drone upward or ahead.
The entrance fringe of the blade known as forefront, which cuts into the air first. It splits the airflow, directing some over the curved floor (producing low strain) and a few below the flatter aspect (greater strain). The rear fringe of the blade known as Trailing Edge, the place the airflow recombines. The mixed strain distinction throughout the blade surfaces generates carry.
Enjoyable Reality: FPV drones can’t fly in area as a result of there’s no air for the propellers to maneuver.
Understanding Propeller Specs
FPV drone propellers are usually outlined by three principal dimensions: measurement, pitch, and blade rely. These are sometimes written as a set of numbers, comparable to 5x4x3 or 5040×3.
Measurement (Diameter)
The totally different propeller sizes
The primary quantity, just like the 5 in 5x4x3, represents the diameter of the propeller in inches. That is the diameter of the round space the prop creates when spinning.
- Bigger Props: Generate extra thrust because of a bigger floor space however require extra highly effective motors. In my expertise, with the appropriate FPV drone motor, bigger propeller are usually extra environment friendly.
- Smaller Props: Produce much less thrust however are simpler on the motor.
FPV drone frames are normally categorized by propeller measurement – the largest propeller they will run. You must all the time use the supposed propeller measurement in your body to maximise efficiency.
Pitch
The second quantity, such because the 4 in 5x4x3, represents the pitch of the propeller. This refers to how far the prop would theoretically transfer ahead in a single rotation if there have been no air resistance (measured in inches). It’s just like how a screw strikes by a strong materials with every flip.
- Low Pitch Props:
- Simpler to spin by the air, enabling faster RPM modifications.
- Present extra responsive management and generate much less propwash vibration.
- Requires much less motor torque and attracts much less present.
- Transfer much less air, leading to decrease thrust and prime pace.
- Excessive Pitch Props:
- Transfer extra air per rotation, creating larger thrust and permitting for greater prime speeds.
- Require extra torque to vary RPM, which may cut back responsiveness if the motor struggles to offer sufficient energy.
- Sometimes much less environment friendly than decrease pitch props.
How Many Blades?
The third quantity (e.g., the 3 in 5x4x3) signifies the variety of blades on the propeller. Frequent choices embody:
- Two-Blade Props: Recognized for effectivity and low drag, supreme for long-range flying because of decreased present draw and higher flight time.
- Three-Blade Props: Supply a stability of thrust, agility, and effectivity, the most well-liked selection for FPV drones, offering glorious grip and secure efficiency.
- 4-Blade Props (or Extra): Generate extra thrust and stability however are much less environment friendly, generally utilized in small cinewhoops for lifting heavier payloads whereas sustaining a compact type issue.
Including Extra Blades
Growing the variety of blades successfully will increase the floor space, permitting the propeller to provide extra thrust. That is just like utilizing a bigger propeller however you may match it in a smaller disk space. Nevertheless, with extra blades it requires extra torque type the motors to spin it. If the motor isn’t highly effective sufficient, it reduces responsiveness. It might probably additionally cut back your flight time considerably as a result of greater present draw.
Frequent Makes use of
For FPV drone pilots, each two and three-blade propellers are widespread choices. Most pilots choose three-blade propellers for racing and freestyle, as they’ve a extra balanced efficiency when it comes to effectivity and energy, they supply extra grip within the air as a result of additional floor space in comparison with two-blade. Alternatively, two-blade is normally extra environment friendly as they creates much less drag and draw much less present, therefore they’re extra widespread for lengthy vary builds.
There are propellers with greater than 3 blades, comparable to quad-blade, 5-blade and hex-blade propellers. Quad-blade propellers are mentioned to be nice for indoor tracks and cornering, however they’re much less environment friendly than tri-blade and spin at a decrease RPM at a given energy. Hex-blade propellers will not be beneficial for regular flight because of its excessive inefficiency, however micro cinewhoops generally use propellers with excessive blade rely to enhance energy with out sacrificing their compact type issue.
Weight
The burden of a propeller considerably impacts drone efficiency. Typically, lighter propellers supply higher efficiency because of their decrease second of inertia, permitting motors to vary RPM extra shortly. This makes your drone really feel extra responsive and nimble. Heavier propellers have extra mass on every blade and require a extra highly effective motor to spin them. This may result in greater torque loading, making the motor work tougher and probably lowering total efficiency, together with responsiveness and effectivity. Lighter props additionally work higher with a wider vary of motors as a result of they require much less torque to spin up.
The burden distribution of the blades additionally issues. With the middle of mass nearer the hub makes the prop simpler to spin and cease, bettering responsiveness. Nevertheless, meaning the tip could be the thinner and could also be extra susceptible to breaking in crashes. With the burden nearer to the tip, you’d expertise larger drag and makes it tougher to speed up or decelerate, decreasing agility.
Propeller Rotation
Propeller Course: CW and CCW
Propellers are designed to spin in a particular path: both clockwise (CW) or counter-clockwise (CCW). The one exception is 3D props, which may spin in each instructions however are utilized in area of interest purposes.
In a quadcopter, two motors spin CW and the opposite two spin CCW, so it’s essential to match the propellers to the motors based mostly on their supposed path of rotation.
Enjoyable Reality: Why Two CW and Two CCW?
You would possibly surprise why FPV drones use a mixture of clockwise and counter-clockwise propellers.
Two propellers generate CW torque, whereas the opposite two generate CCW torque, successfully canceling out the rotational forces. With out this counteraction, the drone would spin uncontrollably in the wrong way of the motors—very like a helicopter with a broken tail rotor (a state of affairs you’ve probably seen in motion pictures).
Moreover, this opposing torque can be utilized to create rotational motion for the quadcopter (aka yaw motion).
To find out the path a propeller ought to spin, take a look at its forefront (the aspect that cuts into the air) and trailing edge. The propeller’s form and curvature point out the supposed path of rotation. Some propellers are additionally labeled with CW or CCW close to the hub for simple identification.
When you mount a propeller within the improper path, it’s going to push air within the reverse manner, inflicting the drone to flip over or fail to take off.
FPV drone propellers are usually bought in packs of 4: two CW and two CCW.
Varieties of Propeller Mounting
Typical FPV drone motors use one of many three widespread mounting strategies: Prop Nuts, T-Mount, and Press Match. Every sort has its benefits and is fitted to particular drone sizes and purposes. Be sure you perceive which setup your motors use earlier than selecting up propellers to keep away from incompatibility.
Prop Nuts
Prop nuts are the most typical mounting methodology for five″ FPV drones and bigger rigs. The propeller is positioned onto a motor shaft with an M5 thread and secured with a self-locking nylon nut.
T-Mount
In T-Mount setups, the propeller is secured to the motor bell utilizing two small M2 screws. The motor shaft, usually 1mm or 1.5mm in diameter, helps middle the prop. The light-weight design is right for smaller, much less highly effective drones. It provides a safe match with out requiring massive threaded shafts or nuts. This mounting is widespread in small 2″ to 4″ FPV drones.
Press Match
In press-fit mounting, the propeller is pushed onto the motor shaft utilizing friction to carry it in place. Motor shafts are usually 1mm or 1.5mm in diameter. No screws or nuts are wanted, decreasing weight and makes altering propeller easy. Nevertheless, propellers might fly off if the motors spin too quick, or in collisions. That is widespread in toothpicks (ultralight) drones and tiny whoops.
Materials
FPV propellers are usually comprised of sturdy plastic, particularly polycarbonate. This materials is light-weight, versatile, and resilient, permitting propellers to bend or warp in crashes with out breaking simply. It’s a great selection for the calls for of FPV drones.
There are additionally propellers comprised of carbon fiber or wooden, which supply elevated stiffness and precision. Nevertheless, these are typically utilized in planes or bigger multirotors that aren’t supposed to crash, as they’re dearer and inclined to wreck.
Persist with plastic props—they’re reasonably priced, simple to interchange, and well-suited for many flying types.
The way to Set up Propellers?
Right here’s a step-by-step information to correctly putting in propellers in your FPV drone:
1. Test Motor Orientation
By default, Betaflight expects the motors to spin in particular instructions, as proven within the diagram beneath (you too can discover this diagram within the Motors tab in Betaflight Configurator).
- Set up CW props on the front-left and rear-right motors.
- Set up CCW props on the front-right and rear-left motors.
Professional Tip: To make it simpler to recollect, all entrance props spin towards the FPV digicam, whereas rear props spin towards the again of the drone.
2. Establish the High and Backside of the Propeller
- The prime aspect of the propeller is usually shiny or shiny, and close to the hub, it could function extruded textual content just like the mannequin or measurement numbers.
- The backside aspect usually has a matte end.
Ensure the shiny/textual content aspect faces up when putting in the propellers. If the props are mounted the other way up, the drone’s efficiency can be severely decreased—or it’d flip over once you attempt to take off.
3. Match Propellers to Motors
Guarantee CW propellers are mounted on CW motors, and CCW props are mounted on CCW motors. Incorrect set up may cause the drone to flip over when taking off.
4. Safe the Props
Connect the props securely utilizing the supplied screws, lock nuts, or different fasteners. Free props can fly off mid-flight, resulting in a crash.
5. Double-Test Set up
Spin every propeller by hand to verify it’s put in within the appropriate orientation. When spinning, every prop ought to push air downward.
Understanding Props In and Props Out
FPV drones will be configured in two methods: props in or props out, relying on the path the propellers spin. The default configuration in Betaflight is props in, and when you reverse the instructions of all 4 propellers, it’s props out.
This configuration impacts airflow and the way particles is thrown away from the drone. You’ll be able to study extra about the advantages and trade-offs of every configuration in my detailed information: https://oscarliang.com/reversed-motor-prop-rotation-quadcopter/
Pusher Configuration
The pusher configuration is widespread in Cinewhoops, the place the motors are mounted the other way up, and the propellers “push” air upward as a substitute of pulling it down.
This configuration does not have an effect on how props are mounted. You continue to comply with the identical guidelines for matching CW and CCW props with the proper motors based mostly on their rotation path.
The way to Select Propellers
FPV drone sizes are usually categorized by the utmost propeller measurement that can be utilized in that body. The preferred FPV drone measurement might be 5-inch because of its versatility, as it may be used for racing, freestyle, cinematic and lengthy vary. It might probably comfortably carry a full-size GoPro digicam, thus it’s typically used for capturing cinematic photographs as properly. The 7-inch builds are extra fitted to long-range flights as a result of it will possibly carry a a lot bigger battery and the bigger 7″ propellers are sometimes extra environment friendly that smaller 5″. I gained’t go into an excessive amount of element right here, you may study all of the totally different drone sizes on this put up.
Thrust
Thrust is measured in grams. On your drone to hover, the propeller wants to provide no less than 1 gram of thrust for each gram that your drone weighs. To carry out stunts, and even simply to take off or fly ahead, your drone wants greater than 1 gram of thrust per gram of weight.
Propellers produce extra thrust after they spin sooner and fewer after they spin slower. The pace of the drone additionally impacts the quantity of thrust produced. Some props carry out properly when the drone is stationary, however not so properly throughout a cruise, whereas others carry out properly at excessive speeds however poorly when hovering. You desire a prop that balances these elements and might create an excellent quantity of thrust at totally different speeds.
To search out the perfect prop to your drone, lookup motor thrust exams to see what prop measurement work finest along with your motor. Take into account that props carry out wildly in a different way when strapped to a thrust stand in a static setting in comparison with after they’re really flying by shifting air. Props can produce 20-30% much less thrust within the air than on the bottom.
To precisely assess prop efficiency, it must be examined on the pace your drone usually flies at. Nevertheless, few individuals have entry to wind tunnels for this sort of testing. So, take efficiency exams with a grain of salt as they will not be an correct illustration of real-world use.
Smoothness
Within the interest, individuals typically use the time period “smoothness” to explain the standard of a motor or propeller. It’s not one thing that may be measured quantitatively, however extra of a sense that pilots have. In my expertise, decrease pitch props are usually smoother as a result of the motor can change RPM extra simply and shortly. This permits the drone to reply sooner to appropriate errors and reduces one thing known as “prop wash”.
Velocity
A propeller that creates a lot of thrust with excessive pitch doesn’t essentially make a drone sooner than a decrease pitch propeller that generates much less thrust. Because the propeller’s pace will increase (which is measured in rotation per minute – RPM), so does the drag, requiring extra torque from the motor to show.
The theoretical most pace of an plane will be calculated utilizing the equation:
Max Velocity (in inch per second) = Max RPM * Propeller's Pitch / 60
In actual life, elements comparable to air resistance, head wind, and angle of assault and many others can all have an effect on a drone’s pace.
Thrust impacts acceleration and angle of assault, whereas RPM impacts prime pace. To attain the perfect pace to your FPV drone, you want a stability between thrust and RPM.
Are Bigger Props Higher?
1. Responsiveness: A bigger prop means the next second of inertia, resulting in decreased responsiveness. That is notably noticeable when utilizing motors that usually drive 5-inch props just like the 2207 measurement. On these motors, a 7-inch and even 6-inch prop can be much less agile in responding to fast, sharp management inputs in comparison with a 5-inch prop. You will want an even bigger motors to compensate however it’s going to add weights and requires extra highly effective battery and electronics.
2. Thrust and Effectivity: Bigger props generate extra thrust, making them extra environment friendly – they will carry extra weight, even with the identical motor. The elevated effectivity means you get extra thrust for a similar energy or the identical thrust at a decrease energy requirement.
3. Vibration: As you enhance prop measurement, anticipate extra vibration. That is amplified by bigger, much less stiff frames.
4. High Velocity and Prop Wash Dealing with: Bigger props are inclined to have a decrease prime pace however higher prop wash dealing with. Nevertheless, they’re typically extra environment friendly, able to sustaining greater speeds over longer durations.
Angle of Assault
The angle of assault refers back to the angle at which air meets the propeller blades throughout flight, and this could considerably affect the effectivity of your propellers based mostly in your drone’s perspective and pace.
Hovering and Low-Velocity Flight
When a drone is hovering, the airflow is primarily vertical, and the propeller blades depend on their pitch to generate thrust. A decrease pitch propeller is mostly extra environment friendly on this state of affairs, because it strikes air easily with out requiring excessive torque. For instance, if the pitch is just too excessive (e.g., near 90 levels), the propeller finally ends up “slapping” the air moderately than effectively displacing it, leading to wasted power and decreased thrust.
Ahead Flight and Excessive-Velocity Cruising
Because the drone tilts ahead to fly, the angle of assault modifications, and air begins coming into the propeller blades at an angle moderately than straight from beneath. At this level, Increased pitch propellers turn out to be more practical as a result of they’re higher suited to displacing air in ahead movement. They generate extra thrust with every rotation, making them supreme for drones that preserve excessive cruising speeds or want fast acceleration. In case your purpose is to cowl lengthy distance as a substitute of lengthy flight time, making an attempt some greater pitch props is likely to be a good suggestion.
Discovering the Optimum Setup
It’s only a generalization, it’s completely essential to experiment with totally different props to seek out the optimum setup to your particular drone setup and flight type.
Climate and Temperature
Chilly climate poses vital challenges for drones. As defined in our information “The way to fly FPV within the winter“, not solely does it negatively influence battery efficiency, however it will possibly additionally have an effect on propellers. Relying on their materials, propellers might stiffen and turn out to be brittle in chilly temperatures, growing the chance of breaking upon collision.
Influence of Altitude
Altitude can drastically have an effect on air density and, consequently, the efficiency of your FPV drone. In areas of decrease air density, comparable to excessive altitudes, you’ll expertise much less thrust from the identical motor RPM. This leads to the drone feeling extra sluggish and fewer highly effective, just like the impact of utilizing lower-pitch propellers. Due to this fact, when flying at excessive altitudes, it’s advisable to make use of higher-pitch propellers to compensate for the decreased air density.
Influence on Tuning
Altering propellers can impact your drone’s PID and filter tuning. Props of various design, measurement, pitch or blade rely may have impact on RPM, throttle/thrust linearity, vibration and many others.
Say in case you are simply swapping out the HQ 5×4.3×3 with some Gemfan Hurricane 51466, it’d most likely nonetheless be flyable, however in case you are a perfectionist you most likely need to tune your quad for a particular sort of props.
The distinction is much more pronounced once you use props of fully totally different measurement or blade rely. As an example, 2-blade propellers are inclined to have a stronger 2nd harmonics in motor noise band, whereas for 3-blade the third harmonics is normally stronger than the 2nd.
Noise Concerns
The noise and sound profile of propellers is an often-overlooked side when deciding on props to your FPV drone, however it will possibly considerably influence your flying expertise—particularly in city areas or indoor.
Elements That Have an effect on Propeller Noise:
- RPM (How Quick It Spins): Increased RPM creates higher-frequency noise, typically perceived as a loud whine. Some cinewhoop would use props with the next blade rely in an effort to cut back RPM whereas sustaining the identical thrust output, which can lead to a quieter drone at the price of effectivity.
- Propeller Design: The form, pitch, and floor space of the blades have an effect on airflow and noise. Wider or thicker blades might create a deeper sound, whereas thinner blades will be extra high-pitched. Toroidal props have a novel form that produces a softer, extra nice sound profile to the human ear. Be taught extra about them right here: https://oscarliang.com/toroidal-propellers/
- Body Design: Cinewhoops, with their ducted frames, are notably noisy as a result of manner air is pushed by the ducts at excessive RPM. Open-frame designs typically produce much less noise compared.
Ultimate Ideas
Propellers are one of many best and least expensive parts to experiment with on an FPV drone. By understanding the fundamentals of measurement, pitch, blade rely, and materials, you may select the appropriate props to match your flying type and drone setup. Don’t be afraid to strive totally different combos and see what works finest for you.
Comfortable flying!
Edit Historical past
- 2017 – tutorial created.
- 2023 – article up to date, URL shortened, up to date product hyperlinks.
- Jun 2024 – Added suggestions for extra propeller sizes.
- Sep 2024 – up to date merchandise.
- Dec 2024 – up to date information.
