The ultimate outcome of all your expense and effort when building a new homebuilt airplane is going to be the performance delivered by the propeller attached to your engine. Choosing a propeller type and supplier can be as simple as following the recommendation of the original designer or as complex as sifting through websites and input from fellow builders. In our annual roundup of propeller companies, we'll try to update information and developments from the broad array of prop suppliers and revisit the subject of propeller design to help guide your choice.
Link to Wing Flying
If your homebuilt project is going to use a certified engine, you may feel the need to stay with an FAA-certified propeller, which limits your choices to the major U.S. manufacturers of such props'Hartzell, McCauley, Sensenich'and the foreign companies that have gained reciprocal certification, such as MT-Propeller. On the other hand, aside from perhaps shortening the Phase I flight testing period, there's no pressing reason to go with a certified propeller on your homebuilt. The non-certified propeller route offers many more options, including some Experimental-category props offered by traditional certified propeller makers. From those crossover models, your search can also lead to propeller suppliers who have no interest in offering certificated props, preferring to concentrate solely on the Experimental market.
The ultimate Experimental-category propellers are the custom-made props created for your particular engine and airframe combination. If you give custom prop builders your horsepower and speed range, they can create a special propeller just for your aircraft. In some cases this may involve a bit of tweaking to bring it right into the performance slot you desire, matching it exactly to your real-world operating regime.
Starting at the basics, a simple fixed-pitch two-blade airscrew will keep the cost down and simplify installation. Your engine may have been set up to only accept such a primitive device. A fixed-pitch propeller can be made of laminated wood, forged aluminum or composite materials with various core constructions. Fixed-pitch means you'll have to live with the performance compromise inherent in the pitch that's built into the blades. Engine rpm changes as airspeed varies unless the throttle is continually adjusted.
Propeller pitch is akin to an automotive transmission's gearing ratio: With only one 'gear,' your fixed-pitch propeller will likely be targeted more toward level cruising flight, where the airplane spends most of its time, to the detriment of takeoff and climb performance. However, there is a 'sweet spot' range for a given blade pitch within which performance deteriorates by 10% or less from an optimum pitch. Some prop builders claim their blades have the ability to flex under load to achieve some shift in pitch that gives better performance than a true fixed-pitch blade.
Experimental aircraft frequently utilize ground-adjustable propellers, with blades that can be rotated in a special hub mounting, enabling their pitch to be tuned to deliver maximum thrust at a certain airspeed. Such technology dates from the s, when adjustable steel and aluminum propellers were widely used. Once the adjustment is set, you'll have a fixed-pitch propeller until you can land and readjust the blade settings. Seldom do builders change the pitch once its proper setting is determined.
Of course, pilots would rather be able to adjust the propeller pitch in flight, leaving it in a low pitch setting for takeoff and initial climb, then dialing it toward higher pitch to keep the engine from over-revving as airspeed increases in level flight. Such in-flight adjustments usually require intermittent activation of an electric motor to precisely toggle the desired engine rpm. Some motorgliders, aka self-launching sailplanes, have three-position manually adjustable propellers that are shifted with the engine at idle, offering climb, cruise and feathered (engine off) positions. Adjustable propellers perform as fixed-pitch devices once set, so there will still be rpm changes as airspeed increases and decreases during maneuvering flight.
Naturally, more capability is always better, so the next step in complexity is to add a governor to the pitch-change mechanism, constantly varying propeller pitch during flight so engine rpm is held steady despite throttle and airspeed changes. Constant-speed propellers are complex devices and require a means of imparting the pilot's desires to the propeller, through either electricity or oil pressure delivered to the prop hub. Having more moving parts to wear out means maintenance is inevitable. Also, the extra up-front weight of the constant-speed prop and governor has to be taken into account.
Multi-engine airplanes require a means of stopping the propeller to reduce drag in the event of an in-flight engine failure, hence the feathering propeller was invented to stop a windmilling propeller from being a giant air brake. And for times when adding even more drag would be desirable, as during landing rollout, someone came up with reversing propellers, applying engine power for braking.
There's something to be said for simplicity. Failure is unlikely to occur in an item of equipment that's not installed, and keeping extra weight off the aircraft is always desirable. Many owners would like the look of a three-blade prop, mistakenly expecting some benefit from performance enhancement. For most small homebuilts, a two-blade propeller is more efficient. Adding blades should only be done if extra horsepower needs to be harnessed; generally speaking, a tri-prop gives more starting torque for takeoff and sounds better, but it'll require masterful reengineering to offset the inherent loss of performance over a good two-blade propeller, and there's usually a weight penalty.
I recently encountered an Experimental airplane owner who wasn't satisfied with his homebuilt's 180-hp Lycoming O-360 engine, so he spent big bucks taking off the carburetor and installing an aft-mounted fuel injection system. On top of that, he replaced the fixed-pitch propeller with a constant-speed version, something never envisioned by the original kit designer, which required considerable cowling modification. One hopes he considered the effect of the added forward weight.
All airplanes are compromises, and propeller choices are part of the equation when it comes to designing for performance targets. It's always best to go with the kit supplier's propeller recommendation and use a propeller type that's been found to be correct for your engine installation.
As in past years, we've compiled the latest information on propeller suppliers. Here are our listings for .
At press time, we had received no reply to a request for an update on GT Propellers, based at Rimini in northeastern Italy. Relying on previous info, we can only quote their website: Italian propeller maker GT Propellers offers wood-core carbon-fiber props in two- to five-blade designs, in fixed, ground-adjustable and constant-speed applications. They've had a 30-year relationship with Tecnam Aircraft, using GT props in Rotax engine applications.
Now a part of a newly formed Hartzell Aviation umbrella that also includes exhaust and engine mount repair and fabrication, as well as the engine accessories division, Hartzell Propeller is the flagship component of Hartzell Aviation. In business for well over a century, Hartzell Propeller continues to develop robust propellers for Experimental aircraft.
Currently, Hartzell is featuring the Explorer, a three-blade carbon fiber prop for cross-country cruising with Lycoming 320/360/390 engines and some 540s as well. For STOL work, the Pathfinder three-blade composite-blade model works well on select Lycoming 360 and 390 engines, and for backcountry and floatplane operators Hartzell offers its Trailblazer two- or three-blade prop for certain Lycoming 360 through 580 powerplants. Hartzell's popular Blended Airfoil propeller, used on many kit airplanes for cross-country flying, is a two-blade constant-speed aluminum prop with swept-tip blades for most 360 and 390 Lycomings. For the next generation of aerobatic propellers, Hartzell offers the Talon carbon-fiber two- or three-blade propeller, usable on select AEIO-360, 540 and 580 Lycoming engines.
As a wholly owned division of Cessna Aircraft for the last 62 years, continuing as part of Textron Aviation Inc., a Textron Inc. company, McCauley has been in the aluminum-blade propeller business since . It's now focused largely on supplying original-equipment props for the Textron fleet and marketing the Blackmac brand of STC'd retrofit products. There are over 350,000 aircraft with McCauley propellers out there in service, so if you wind up with a used McCauley constant-speed prop on your project, it'll be well supported.
While of German origin, the MT-Propeller line of 'natural composite' props is supported in North America through a company-owned service center in DeLand, Florida. MT offers a wide variety of constant-speed propellers for single-engine planes as well as feathering and reversing systems for piston and turbine twins. Recent STC approvals were five-blade propellers for the King Air 300/350, three-blade props for Piper's PA-34-200 and a five-blade propeller for the turbine-conversion Cessna 206. Last September, MT-Propeller flew experimental 11-blade propellers mounted on a Piper Cheyenne.
A major U.S. propeller maker dating back some 90 years, Sensenich started out in Pennsylvania, where it still makes its aluminum props, but it now operates as one company with two divisions, building its traditional wood fixed-pitch products and modern composite designs in Plant City, Florida. Airboat propellers are a major market for Sensenich, which explains its southern plant, and it covers the Experimental aircraft arena with ground-adjustable carbon-fiber STOL propellers. Engine installations include ULPower, Jabiru and Rotax, plus Lycoming O-320 and O-360 engines in Van's RVs, Bearhawk, RANS and Zenith STOL designs. Sensenich's latest type certificate approval is for its ground-adjustable carbon-fiber prop in 125- to 180-hp installations. An 82-inch-diameter version is STC'd for the Piper PA-18 with 180 hp.
In business since , New Zealand-based Airmaster Propellers specializes in electrically controlled constant-speed propeller systems, using composite blades from Sensenich and Whirl Wind mounted in Airmaster's own hubs. Selecting preset takeoff, climb and cruise parameters or a manual rpm setting, the pilot has full command of the propeller's operation via a panel-mounted controller. Airmaster's Martin Eskildsen pointed out that they now offer three- and four-blade propellers for Rotax 915 installations.
Based in South Africa, AXSport markets an aerobatic airplane of its own design, but also has been in the propeller business since , selling three-blade carbon-fiber electric constant-speed props for Lycomings up to 200 hp and Rotax engines up to the 915. Stainless-steel erosion strips for the leading edges are standard. A color-screen cockpit control is being developed for availability.
Arrowprop of Meeker, Oklahoma, builds custom composite propellers for light aircraft using engines of up to 100 hp. Diameters are available up to 72 inches. Focused on ultralight-type and small Experimental aircraft, Arrowprop has been in business since . Initially making wood propellers, they now only use composite technology.
Australian-based Bolly Aviation concentrates on making carbon-fiber propellers for LSAs and ultralight aircraft with up to 160 hp. They provide ground-adjustable props of two-, three- and four-blade configurations, fitted with Bolly's Dura-Tuff leading edge protection. The Optima Series 3 units are for engines with reduction drives, while the Series 5 props are designed for direct drive applications.
For nearly 50 years, Catto Propellers has been a noted propeller supplier for Experimental airplanes. Their props utilize a maple wood core encapsulated with fiberglass and carbon fiber, primarily fixed-pitch in two- and three-blade styles. However, Catto does have a constant-speed propeller suitable for the Berkut and Velocity canard aircraft and for Super Cub-type bush planes. Leading edge protection can be either a replaceable polyurethane tape or a nickel leading edge. Catto Propellers is located in Jackson, California.
Longtime maker of UltraProp propellers for trikes, powered parachutes and ultralights, Competition Aircraft, located in Hurricane, Utah, has composite ground-adjustable props in two- to six-blade configurations. They can ship immediately from hubs and blades in stock.
For true artwork, a custom-carved two-blade wood propeller is a visual treat. Alaina Lewis and her crew at Culver Props in Rolla, Missouri, can make you a propeller worthy of your replica antique homebuilt, if you're willing to wait. She reported a three- to four-month lead time when we talked, an improvement over the yearlong backlog Culver was experiencing during peak times. Much of their business is in 'wall hanger' decorative propellers, executed in beautiful laminated birch, mahogany and maple woods.
Based near Lyon in southeastern France, DUC Propellers has a North American office on the Sebring, Florida, airport. DUC offers a wide range of light aviation propeller styles in its Flash, Swirl, Windspoon and Flair designs. A Forged Carbon blade process is used for two- to five-blade props, which are ground-adjustable and available with electric or hydraulic in-flight pitch control. SportairUSA in North Little Rock, Arkansas, is a dealer for DUC as well.
E-Props Propellers, located in southeastern France, reportedly produces 45,000 propeller blades per year for Light Sport Aircraft, claiming to be the lightest propellers in the world. New this year is its Glorieuse three-blade carbon constant-speed prop with titanium leading edges, targeted for Rotax 9 series engines up to 140 hp, with a total all-up weight of 8.8 pounds. ASTM-certified E-Props are flying in 84 countries, according to company President Anne Lavrand.
British Columbia-based GSC systems uses clear eastern maple to craft its propellers for ultralights, trikes and PPCs, in two- and three-blade styles. The Tech II and Tech III props are all ground-adjustable, with individually replaceable blades in case of damage. An inlaid leading edge is optional. Downsized GSC propellers are even showing up on drones, representing a new market for the company.
Hercules Propellers' Rubert Wassey makes fine laminated-beechwood propellers at Stroud, in south-central England. Replica props for antique airplanes and warbirds are a specialty, keeping these vintage birds airworthy. Each Hercules propeller is custom CNC machined for a specific application, incorporating a 'Hercuthane' leading edge shield. When visiting their website, don't forget to click on the expanded contact port in the upper left corner. It's well worth browsing.
Even though it did not respond to our inquiries, the Hoffman Propeller firm in Germany is known to make excellent wooden/composite propellers for a wide variety of aircraft.
The Ivoprop is long known for its electrically actuated internal cam, giving the pilot the ability to change pitch in flight to optimize performance in different phases of flight. The carbon graphite fiber construction allows twisting action of imbedded rods in the blades, giving the pilot the ability to manage engine rpm as desired. Ivoprop's Medium series can handle up to 150 hp, with the Magnum series carrying up to 700 hp. Stainless-steel leading edges provide erosion protection.
Started 50 years ago making wood propellers, Kiev props are currently using autoclaved composite blades mounted in ground and in-flight adjustable hubs. Understandably, the terrible wartime conditions in Ukraine have taken a toll on shipments of both raw materials and finished product, but the Kiev factory is operating and propellers are being made, we were told. Ted Bryant at KievProps America in Cambridge, Maryland, the importer for all of the Americas, says they were stocked up in late and were able to ship from inventory up through July . His large orders were being filled and product was being received when we talked in November . All 12 workers at the plant in Ukraine were safely back from military duty and making propellers.
Kiev Props are designed for reduction-drive engine installations only, from 40 to 200 hp, using two- to six-blade styles. Blades are rated for an eight-year service life, with no hour limit, and hubs are rated for 15 years.
Located in the suburban Chicago area at Yorkville, Illinois, Performance Propellers has a 35-year history of making custom two- and three-blade wood propellers. One of its specialties is making props for Verner radial engine installations. Each propeller is created for a specific customer need and tweaked as needed for optimum performance. Business at Performance Props was booming, we were told, with lead times of up to a year, so it's best to place your order early in the project.
Primarily supplying prepreg carbon fiber propellers for ultralights, trikes and powered parachutes, Powerfin is located in Hurricane, Utah. It has two- to five-blade hubs to serve installations of up to 160 hp, offering optional custom blade colors. The low inertia of the Powerfin props helps prolong reduction gearbox life, according to the company.
The PowerMax propeller is built by TL Ultralight, builders of the Sirius, Sparker, Stream and Sting European ultralight aircraft in the Czech Republic. A three-blade carbon fiber propeller that's in-flight adjustable, fitted to Rotax 9-series engines, the PowerMax is represented by SportairUSA in Little Rock, Arkansas, which also distributes TL airplanes.
A Polish company that's been in the propeller business since , Peszke makes a B-Line three-blade carbon-fiber propeller with blades mounted in an aluminum hub, suitable for up to 160 hp, according to company literature. Other products are folding motorglider props and lightweight props for trikes, gyros and ultralights. Owner Jerzy Peszke is seeking a U.S. distributor.
Lonnie Prince reports a 10-month backlog in his order book, still making his trademark P-Tip wood/composite propellers at his plant in Whitehouse, Ohio. The P-Tip's small winglet tip design adds effective blade length without sonic stress, and Prince's scimitar-shape props reportedly can twist to change pitch with altered airspeed. A special elliptical-tip blade design for Hummel VW engine installations is also a popular Prince Aircraft propeller product.
From one of the great names in custom wood propeller building, we received the following response when we contacted Ed Sterba: 'I have ended my propeller business this past May, after 42 years. It's been a great business, with great customers. Just about props, all handmade. Thanks for carrying my listing all these years.' What a great legacy!
Repeated attempts to contact Sterna Aircraft, makers of carbon-fiber ground-adjustable propellers for light aircraft in Zephyrhills, Florida, have drawn no response, although the website remains active.
(see Competition Aircraft)
In business since , the folks at Warp Drive in Ventura, Iowa, are still making their well-regarded ground-adjustable carbon-fiber propellers, in two- to six-blade configurations. In addition to gyrocopter, trike and PPC applications, Warp Drive propellers are also used on light sport and Experimental airplanes, ranging up to 180 hp.
Whirl Wind Propellers in El Cajon, California, has been making carbon-fiber props in two- and three-blade designs since , using patented closed-mold net-shape blades. Electro-formed nickel leading edge protection is standard. The 300 series three-blade constant-speed props are targeted for RV-style aircraft with O-320 to O-390 engines, weighing in at just 36 pounds. The 330 series comes in two-blade 72-inch diameter and three-blade 73-inch styles, with the three-blade prop suited for O-360 to IO-540 installations. Standard color is black carbon fiber with a clear coat, but optional white-painted blades with red tips are available.
A maker of wood and composite variable-pitch propellers in the Czech Republic, Woodcomp offers a KW-10 constant-speed propeller for engines rated from 200 to 310 hp, as well as a ProPulse aerolastic propeller that is said to deform under load to perform like a constant-speed prop. It also has a KW-30 hydraulic variable-pitch propeller.
Photos: Paul Dye, Omar Filipovic and courtesy of the manufacturers.
Propellers are the essential component of any FPV drone as they determine the power, smoothness and responsiveness of the aircraft. These specialized airfoils attach to the motor hub and come in a variety of shapes, sizes, and blade counts. Understanding the basics of propellers is crucial for optimizing the performance of your quadcopter.
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Propellers are designed for different purposes, the pitch, shape and material all play a part in performance and flight characteristics. Here I will share what I think are the best propellers that you should get.
I've tried all major propeller brands and found HQ props to be one of the smoothest and easiest to tune. They seem to be more balanced and cause less vibration than others. I've also had better luck with triblades than twinblades when it comes to achieving smoothness.
Best 5' Props
Best All-Rounder
The 'smoothness' of the prop plays a big part in how well the drone flies, and how much we can push PID and filters in tuning. Propellers that produce less vibration will inherently have an advantage in that regard. The weight distribution of the blade and overall weight of the whole prop also matters, the easier it is to spin up and slow down, the faster it is to change RPM, which translates into faster response of the drone and better 'propwash' handling.
I love the HQ 5×4.3×3 for its linear throttle response, which gives me very precise control through the whole throttle range. The responsiveness and grip are just awesome, the quad feels snappy and connected to the sticks.
Get the HQ 5×4.3×3 from:
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Best for Racing
For a good racing prop, responsiveness and thrust output play a big part. To be responsive, the prop should be relatively light weight, and the weight distribution of the blade has to be optimized in order for RPM to change quickly.
The Gemfan Hurricane is a great performer in the high end of your throttle, lots of punch and very smooth, but perhaps slightly less precise in the lower end. They have reinforced hub and meant to take a beating around the race course. Bent props? Just bend it back and keep flying!
Get the Gemfan Hurricane -3 from:
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Best for Cinematic
If you prioritise smoothness and efficiency over raw power, these props are for you. The HQ 5.1×2.5×3 is an extremely efficient props based on my static thrust tests, and the prop wash handling is second to none.
Get the HQ 5.1×2.5×3 from:
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Most Durable
Not necessarily the best propellers in terms of performance, but they are cheap, durable and offers decent performance, it's good enough for daily practice and bashing around.
Get the Cyclone from:
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Best 5' Props for Sub250
Exceptionally efficient for sub250 5inch
Great option for 5' class that is under 250g (e.g. paired with and motors).
Product Page:
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Versatile Option with Decent Performance
Designed for sub250 5' long range, well matched to motors. Supports both T-mount and standard 5mm prop nuts.
Product Page:
AliExpress: https://s.click.aliexpress.com/e/_DDlqcI1
GetFPV: https://oscarliang.com/product-oe2l
RDQ: https://oscarliang.com/product-58rm
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Best 7' Props
Best All Rounder
Hands down the best 7' props I've flown, responsive, low vibration, decent thrust output.
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For Heavy Lifters
A decent alternative to the HQ DP, a great choice for cinelifters.
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GetFPV: https://oscarliang.com/product-zl0g
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For Long Range
Great props for long range builds. Works well on smaller motors.
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GetFPV: https://oscarliang.com/product-vqeh
Amazon: https://amzn.to/3nmZFvW
Want more information on uav propeller manufacturers? Feel free to contact us.
Best 3' Props for Freestyle
Ideal props for power and speed.
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Balanced Performance.
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Best 3' Props for Cinewhoops
Ideal for power and lifting heavy.
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For low noise (without lifting a GoPro).
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Best 3.5' Props for Freestyle
Ideal for power and speed.
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All rounder for freestyle builds.
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Best 3.5' Props for Cinewhoops
HQ DT90MMx3
Ideal for power and lifting heavy.
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Relatively low power for cinewhoops, but one of the quietest. If you intend to carry a GoPro, it's better to pick the DT90MMX3.
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Amazon: https://amzn.to/4e5kd1H
What's A Propeller?
Propellers, also known as props, are the unsung heroes of an FPV drone. They play a crucial role in generating thrust that lifts the quad off the ground and enables it to move in different directions. However, many drone pilots often overlook the importance of choosing the right propellers, leading to issues such as increased noise, reduced flight time, or even motor failure.
In this tutorial, we provide a comprehensive guide to the different factors that affect the performance of FPV drone propellers, including pitch, shape, and the number of blades. Whether you're a beginner or an experienced pilot, this guide will help you understand how to choose the right propellers for your quadcopter, enhancing your flying experience. Learn everything you need to know about propellers and take your FPV drone flying to new heights.
Propeller Directions
Propellers are designed to spin in either a clockwise (CW) or counter-clockwise (CCW) direction. In a quadcopter, two motors spin CW and the other two spin CCW, so it's important to match the propellers to the motors based on their intended direction of rotation.
On an FPV drone, the off-center placement of the propellers produces both thrust and rotation around the center of the drone. To counteract this rotation, it's necessary to use two CW and two CCW props.
When purchasing propellers, they usually come in pairs of CW and CCW.
To generate downward thrust for the drone to take off, the propellers should spin in a way that allows the leading edge to cut through the air first, with the air then escaping through the trailing edge. You can easily determine the direction of a prop by identifying its leading edge, which is often labelled as either CW or CCW on the blade.'
How to Mount Propellers?
By default, Betaflight expects the motors to spin as shown in the diagram below. This means that you should install the CW prop on the motors at the top left and bottom right.
Pro tip: To make it easier to remember, just note that all front props spin into the FPV camera, while the rear props spin into the rear of the quadcopter.
There are three types of propeller mounting in FPV drone motors: M5 threaded shaft, T-mount, and press fit.
M5 threaded shaft (5mm) is the most common in 5' FPV drones (and larger rigs). The propeller is attached to a shaft with an M5 thread at the end and screwed tight with a self-locking nut (also known as a 'nylon nut'). There are often spikes on the motor bell, which dig into the propeller and hold it in place.
In the T-Mount, the propeller is attached to a 1mm or 1.5mm thick motor shaft, secured by two M2 screws onto the top of the motor bell. This mounting is popular in less powerful 2', 3', and 4' FPV drones.
Press-fit (or friction fit) is popular in small FPV drones such as tiny whoops and toothpicks because this mounting is extremely light weight. These drones are relatively low-powered, so the props are unlikely to fly off even in crashes.
Propeller Size
Propeller size is given in imperial inches (1' = 2.54 cm).
When describing propellers, there are two types of formats:
L ' length, P ' pitch, B ' number of blades:
For example, 6×4.5×2 (also known as ×2) propellers are 6 inches long 2-blade propeller and have a pitch of 4.5 inches. Another example is 5x4x3 (also known as ×3), a 3-blade 5' propeller with a pitch of 4 inches.
You might sometimes see 'BN' at the end of the numbers, which means 'Bullnose.'
You might also see 'R' or 'C' after the size numbers, such as 5x3R. 'R' indicates the rotation of the propeller, which stands for 'reversed.' It should be mounted on a motor that spins clockwise. 'C' is the opposite and should be used with motors that spin counter-clockwise, but usually, the letter 'C' is ignored.
A propeller is said to be 'heavier' when you increase the diameter, pitch, the number of blades, or all. It takes more torque to spin a heavier prop than a lighter prop.
Propeller Length
The length of a propeller refers to the size of the disc that it creates when it spins (or the distance from one tip of a two-blade prop to the other).
Propellers generate thrust by spinning and moving air. The faster the propeller spins, the more air it can move, which generates more thrust.
Did you know? FPV drones can't fly in space because there is no air for propellers to move.
When the propeller pitch (explained below) and blade count are the same, a longer propeller can generate more thrust because it increases the surface area. This means you can accelerate faster, but it also requires more power from the same motor. However, longer propellers don't necessarily mean faster flight ' pitch is a more important factor (as explained below). Shorter propellers can spin up and slow down faster due to lower drag and momentum, which makes the drone more agile and responsive.
Propeller Pitch
Propeller Pitch refers to the distance a propeller travels during one revolution, and it's measured in inches. Essentially, it's how far the propeller would move forward if it were moving through a solid medium instead of air.
A propeller with a higher pitch moves more air with each revolution, which can create more thrust when the aircraft is traveling at high speeds. However, it also means that the propeller generates less thrust when the aircraft is not moving.
A higher pitch propeller can also create turbulence and prop wash, which can affect the performance of the aircraft. It also spins slower, which can make the aircraft less responsive. On the other hand, a lower pitch propeller is more responsive and can spin up and down faster, making it better for manoeuvrability.
Blade Count
Adding blades increases the surface area and hence creates more thrust. This is similar to making the propeller longer, except you can fit it in a smaller disk area. By increasing blade count improves grip in the air, but it also makes it less efficient and puts more strain on the motor.
For FPV drone pilots, both two and three-blade propellers are popular for racing and freestyle flying. Most pilots prefer three-blade propellers as they are a great balance between efficiency and power, they provide more grip in the air due to the extra surface area compared to two-blade. On the other hand, two-blade is usually more efficient as they creates less drag and draw less current, hence great for long range flying.
You should also consider the sound these propellers create ' when there're more blades, it lowers the RPM at a given power so it's usually quieter but it also depends on the design.
There are propellers with even more blades, such as quad-blade and hex-blade propellers. Quad-blade propellers are said to be great for indoor tracks and cornering, but they are less efficient than tri-blade and spin at a lower RPM at a given power. Hex-blade propellers are not recommended for normal flight due to its extreme inefficiency, but micro cinewhoops sometimes use these to improve their power due to the lack of space to use larger propellers.
Weight
When it comes to propellers, weight is an important factor to consider. In general, lighter propellers tend to perform better. Heavier propellers have more mass on each blade and require a more powerful motor to spin them. This can lead to higher torque loading, making the motor work harder and possibly decreasing overall performance.
Lighter propellers have less moment of inertia and can change RPM faster, making your drone feel more responsive. They also work better with a wider range of motors because they require less torque to spin up.
The weight distribution of the blades also makes a difference. Propellers with the blade's center of mass closer to the hub are better. However, this means the tip of the prop gets thinner and easier to break. If the center of mass is further away from the hub, there is more drag and the propeller is harder to speed up and slow down.
What Propellers To Use on an FPV Drone
Here is a table that shows which size propeller to use with different motors and voltages..
It's important to choose your propeller size first because it determines the size of the frame you can use.
The propeller size you choose also depends on the type of flying you want to do. The 5-inch propeller is the most popular because it's versatile and can be used for racing, freestyle, and even carrying a full-size GoPro camera. The 7-inch propeller is better for long-range flights because it can carry a much larger battery. You can learn about all the different drone sizes in this post, I won't repeat it here.
Here are my recommendations for 5-inch propellers..
Thrust
Thrust is measured in grams. For your drone to hover, the propeller needs to produce at least 1 gram of thrust for every gram that your drone weighs. To perform stunts, or even just to take off or fly forward, your drone needs more than 1 gram of thrust per gram of weight.
Propellers produce more thrust when they spin faster and less when they spin slower. The speed of the drone also affects the amount of thrust produced. Some props perform well when the drone is stationary, but not so well during a cruise, while others perform well at high speeds but poorly when hovering. You want a prop that balances these factors and can create a good amount of thrust at different speeds.
To find the best prop for your drone, look up motor thrust tests to see what prop size work best with your motor. Keep in mind that props perform wildly differently when strapped to a thrust stand in a static setting compared to when they're actually flying through moving air. Props can produce 20-30% less thrust in the air than on the ground.
To accurately assess prop performance, it needs to be tested at the speed your drone normally flies at. However, few people have access to wind tunnels for this type of testing. So, take performance tests with a grain of salt as they may not be an accurate representation of real-world use.
Smoothness
In the hobby, people often use the term 'smoothness' to describe the quality of a motor or propeller. It's not something that can be measured quantitatively, but more of a feeling that pilots have. In my experience, lower pitch props tend to be smoother because the motor can change RPM more easily and quickly. This allows the drone to respond faster to correct errors and reduces something called 'prop wash'.
Speed
A propeller that creates lots of thrust with high pitch doesn't necessarily make a drone faster than a lower pitch propeller that generates less thrust. As the propeller's speed increases (which is measured in rotation per minute ' RPM), so does the drag, requiring more torque from the motor to turn.
The theoretical maximum speed of an aircraft can be calculated using the equation:
Max Speed (in inch per second) = Max RPM * Propeller's Pitch / 60
In real life, factors such as air resistance, head wind, and angle of attack etc can all affect a drone's speed.
Thrust affects acceleration and angle of attack, while RPM affects top speed. To achieve the best speed for your FPV drone, you need a balance between thrust and RPM.
Are Larger Props Better?
1. Responsiveness: A larger prop means a higher moment of inertia, leading to reduced responsiveness. This is particularly noticeable when using motors that typically drive 5-inch props like the size. On these motors, a 7-inch or even 6-inch prop will be less agile in responding to quick, sharp control inputs compared to a 5-inch prop. You will need a bigger motors to compensate but it will add weights and requires more powerful battery and electronics.
2. Thrust and Efficiency: Larger props generate more thrust, making them more efficient ' they can carry more weight, even with the same motor. The increased efficiency means you get more thrust for the same power or the same thrust at a lower power requirement.
3. Vibration: As you increase prop size, expect more vibration. This is amplified by larger, less stiff frames.
4. Top Speed and Prop Wash Handling: Larger props tend to have a lower top speed but better prop wash handling. However, they are often more efficient, capable of maintaining higher speeds over longer periods.
Weather and Temperature
Cold weather poses significant challenges for drones. As explained in our guide 'How to fly FPV in the winter', not only does it negatively impact battery performance, but it can also affect propellers. Depending on their material, propellers may stiffen and become brittle in cold temperatures, increasing the likelihood of breaking upon collision.
Impact of Altitude
Altitude can drastically affect air density and, consequently, the performance of your FPV drone. In areas of lower air density, such as high altitudes, you'll experience less thrust from the same motor RPM. This results in the drone feeling more sluggish and less powerful, similar to the effect of using lower-pitch propellers. Therefore, when flying at high altitudes, it's advisable to use higher-pitch propellers to compensate for the reduced air density.
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