Propellers are a essential element of any FPV drone, and understanding the fundamentals is important for getting began within the pastime. The best propellers could make your drone fly quicker, smoother, and extra effectively, whereas the flawed ones may cause instability and poor efficiency. On this information, I’ll break down every thing you want to learn about FPV drone propellers and share my high suggestions.
Propeller Suggestions
Propellers are available in varied designs and sizes, every tailor-made for particular flight types and functions. Components like pitch, form, and materials considerably affect efficiency. After years of testing and expertise, I’ve narrowed down a number of the finest propellers for various use circumstances.
Greatest 5″ Props
Greatest 5″ Props for Sub250
Greatest 7″ Props
Greatest 3″ Props for Freestyle
Greatest 3″ Props for Cinewhoops
Greatest 3.5″ Props for Freestyle
Greatest 3.5″ Props for Cinewhoops
Greatest 2″ Props for Cinewhoops
Greatest Tiny Whoop Props
For Tiny Whoop propeller suggestions, try 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 stress distinction: decrease stress above and better stress beneath. This distinction generates elevate, propelling the drone upward or ahead.
The entrance fringe of the blade is named vanguard, which cuts into the air first. It splits the airflow, directing some over the curved floor (producing low stress) and a few below the flatter facet (larger stress). The rear fringe of the blade is named Trailing Edge, the place the airflow recombines. The mixed stress distinction throughout the blade surfaces generates elevate.
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 sometimes outlined by three important dimensions: measurement, pitch, and blade depend. These are sometimes written as a set of numbers, corresponding to 5x4x3 or 5040×3.
Dimension (Diameter)
The completely 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 attributable to a bigger floor space however require extra highly effective motors. In my expertise, with the precise FPV drone motor, bigger propeller are typically 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’ll run. It’s best to at all times use the meant 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 stable 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 high pace.
- Excessive Pitch Props:
- Transfer extra air per rotation, creating better thrust and permitting for larger high speeds.
- Require extra torque to vary RPM, which might cut back responsiveness if the motor struggles to supply sufficient energy.
- Usually 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. Widespread choices embody:
- Two-Blade Props: Identified for effectivity and low drag, supreme for long-range flying attributable to lowered present draw and higher flight time.
- Three-Blade Props: Supply a stability of thrust, agility, and effectivity, the preferred alternative for FPV drones, offering glorious grip and steady 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
Rising 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 possibly can match it in a smaller disk space. Nonetheless, with further blades it requires extra torque type the motors to spin it. If the motor isn’t highly effective sufficient, it reduces responsiveness. It may well additionally cut back your flight time considerably as a result of larger present draw.
Widespread Makes use of
For FPV drone pilots, each two and three-blade propellers are well-liked choices. Most pilots favor three-blade propellers for racing and freestyle, as they’ve a extra balanced efficiency by way of effectivity and energy, they supply extra grip within the air as a result of additional floor space in comparison with two-blade. Then again, two-blade is normally extra environment friendly as they creates much less drag and draw much less present, therefore they’re extra well-liked for lengthy vary builds.
There are propellers with greater than 3 blades, corresponding to quad-blade, 5-blade and hex-blade propellers. Quad-blade propellers are stated 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 aren’t really helpful for regular flight attributable to its excessive inefficiency, however micro cinewhoops generally use propellers with excessive blade depend to enhance energy with out sacrificing their compact type issue.
Weight
The burden of a propeller considerably impacts drone efficiency. Typically, lighter propellers provide higher efficiency attributable to 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 could result in larger torque loading, making the motor work tougher and probably reducing 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. Nonetheless, which means the tip can be the thinner and could also be extra vulnerable to breaking in crashes. With the load nearer to the tip, you’d expertise better drag and makes it tougher to speed up or decelerate, decreasing agility.
Propeller Rotation
Propeller Path: CW and CCW
Propellers are designed to spin in a particular route: both clockwise (CW) or counter-clockwise (CCW). The one exception is 3D props, which might 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 meant route 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 situation 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 route a propeller ought to spin, have a look at its vanguard (the facet that cuts into the air) and trailing edge. The propeller’s form and curvature point out the meant route of rotation. Some propellers are additionally labeled with CW or CCW close to the hub for simple identification.
If you happen to mount a propeller within the flawed route, it should push air within the reverse manner, inflicting the drone to flip over or fail to take off.
FPV drone propellers are sometimes offered in packs of 4: two CW and two CCW.
Varieties of Propeller Mounting
Typical FPV drone motors use one of many three frequent mounting strategies: Prop Nuts, T-Mount, and Press Match. Every kind has its benefits and is suited to particular drone sizes and purposes. Be sure to perceive which setup your motors use earlier than choosing up propellers to keep away from incompatibility.
Prop Nuts
Prop nuts are the most typical mounting technique 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, sometimes 1mm or 1.5mm in diameter, helps middle the prop. The light-weight design is right for smaller, much less highly effective drones. It affords a safe match with out requiring massive threaded shafts or nuts. This mounting is well-liked 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 sometimes 1mm or 1.5mm in diameter. No screws or nuts are wanted, decreasing weight and makes altering propeller easy. Nonetheless, propellers might fly off if the motors spin too quick, or in collisions. That is well-liked in toothpicks (ultralight) drones and tiny whoops.
Materials
FPV propellers are sometimes created from 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 really perfect alternative for the calls for of FPV drones.
There are additionally propellers created from carbon fiber or wooden, which provide elevated stiffness and precision. Nonetheless, these are usually utilized in planes or bigger multirotors that aren’t meant to crash, as they’re dearer and inclined to wreck.
Follow plastic props—they’re inexpensive, simple to interchange, and well-suited for many flying types.
Methods to Set up Propellers?
Right here’s a step-by-step information to correctly putting in propellers in your FPV drone:
1. Examine 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 digital camera, whereas rear props spin towards the again of the drone.
2. Determine the High and Backside of the Propeller
- The high facet 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 facet sometimes has a matte end.
Be sure that the shiny/textual content facet faces up when putting in the propellers. If the props are mounted the other way up, the drone’s efficiency will probably be severely lowered—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 offered screws, lock nuts, or different fasteners. Unfastened props can fly off mid-flight, resulting in a crash.
5. Double-Examine Set up
Spin every propeller by hand to substantiate 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 route the propellers spin. The default configuration in Betaflight is props in, and if you happen to 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 may be taught 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 frequent in Cinewhoops, the place the motors are mounted the other way up, and the propellers “push” air upward as an alternative of pulling it down.
This configuration does not have an effect on how props are mounted. You continue to observe the identical guidelines for matching CW and CCW props with the proper motors based mostly on their rotation route.
Methods to Select Propellers
FPV drone sizes are sometimes categorized by the utmost propeller measurement that can be utilized in that body. The preferred FPV drone measurement might be 5-inch attributable to its versatility, as it may be used for racing, freestyle, cinematic and lengthy vary. It may well comfortably carry a full-size GoPro digital camera, thus it’s usually used for capturing cinematic photographs as nicely. The 7-inch builds are extra suited to long-range flights as a result of it might probably 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 possibly can find out about all of the completely different drone sizes on this publish.
Thrust
Thrust is measured in grams. In your drone to hover, the propeller wants to provide not 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 quicker and fewer after they spin slower. The pace of the drone additionally impacts the quantity of thrust produced. Some props carry out nicely when the drone is stationary, however not so nicely throughout a cruise, whereas others carry out nicely at excessive speeds however poorly when hovering. You desire a prop that balances these components and might create a great quantity of thrust at completely different speeds.
To seek out the most effective prop in your drone, lookup motor thrust checks to see what prop measurement work finest along with your motor. Take into account that props carry out wildly otherwise when strapped to a thrust stand in a static setting in comparison with after they’re really flying by transferring 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. Nonetheless, few individuals have entry to wind tunnels for such a testing. So, take efficiency checks with a grain of salt as they will not be an correct illustration of real-world use.
Smoothness
Within the pastime, individuals usually 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 typically smoother as a result of the motor can change RPM extra simply and shortly. This permits the drone to reply quicker to appropriate errors and reduces one thing known as “prop wash”.
Pace
A propeller that creates a number of thrust with excessive pitch doesn’t essentially make a drone quicker 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 Pace (in inch per second) = Max RPM * Propeller's Pitch / 60
In actual life, components corresponding to air resistance, head wind, and angle of assault and so on can all have an effect on a drone’s pace.
Thrust impacts acceleration and angle of assault, whereas RPM impacts high pace. To attain the most effective pace in 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 lowered responsiveness. That is significantly noticeable when utilizing motors that sometimes drive 5-inch props just like the 2207 measurement. On these motors, a 7-inch and even 6-inch prop will probably be much less agile in responding to fast, sharp management inputs in comparison with a 5-inch prop. You will want a much bigger motors to compensate however it should 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’ll 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 Pace and Prop Wash Dealing with: Bigger props are inclined to have a decrease high pace however higher prop wash dealing with. Nonetheless, they’re usually extra environment friendly, able to sustaining larger speeds over longer intervals.
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-Pace 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 situation, 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 relatively than effectively displacing it, leading to wasted vitality and lowered thrust.
Ahead Flight and Excessive-Pace Cruising
Because the drone tilts ahead to fly, the angle of assault modifications, and air begins getting into the propeller blades at an angle relatively than straight from beneath. At this level, Greater pitch propellers grow 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 keep excessive cruising speeds or want fast acceleration. In case your objective is to cowl lengthy distance as an alternative of lengthy flight time, making an attempt some larger pitch props could be a good suggestion.
Discovering the Optimum Setup
It’s only a generalization, it’s completely essential to experiment with completely different props to seek out the optimum setup in your particular drone setup and flight model.
Climate and Temperature
Chilly climate poses vital challenges for drones. As defined in our information “Methods to fly FPV within the winter“, not solely does it negatively affect battery efficiency, however it might probably additionally have an effect on propellers. Relying on their materials, propellers might stiffen and grow to be brittle in chilly temperatures, rising the chance of breaking upon collision.
Impression 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, corresponding 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 lowered air density.
Impression on Tuning
Altering propellers can impact your drone’s PID and filter tuning. Props of various design, measurement, pitch or blade depend may have impact on RPM, throttle/thrust linearity, vibration and so on.
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 kind of props.
The distinction is much more pronounced once you use props of utterly completely different measurement or blade depend. 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 Issues
The noise and sound profile of propellers is an often-overlooked side when choosing props in your FPV drone, however it might probably considerably affect your flying expertise—particularly in city areas or indoor.
Components That Have an effect on Propeller Noise:
- RPM (How Quick It Spins): Greater RPM creates higher-frequency noise, usually perceived as a loud whine. Some cinewhoop would use props with the next blade depend with a view 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 significantly noisy as a result of manner air is pushed by the ducts at excessive RPM. Open-frame designs usually produce much less noise as compared.
Ultimate Ideas
Propellers are one of many best and least expensive elements to experiment with on an FPV drone. By understanding the fundamentals of measurement, pitch, blade depend, and materials, you possibly can select the precise props to match your flying model and drone setup. Don’t be afraid to attempt completely different mixtures and see what works finest for you.
Joyful 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.
