Skilled pilots have no fear as they put on their goggles, pick up their controller, and whizz through the air with their FPV drone, reacting to the live video transmission in their goggles to avoid obstacles and punch through gaps. Racing these drones has become quite a competitive sport. Expert drone pilots fly their high-end quadcopters through 3D courses at very high speeds. The Drone Racing League or DRL is steadily gaining popularity due to its high-speed nature.
The DRL makes all the pilots use the same drone in each race. The drones they design are high-speed demons that are also extremely agile. One of their drones, the RacerX, set the Guinness World Record for the fastest multirotor drone at 165.3 MPH. That was accomplished in July 2017. The drone ran with the following equipment.
Battery – 10s battery (two 5s batteries in series)
Motors – T80 2407 2500 kV motors
ESCs – Bee Rotor 80A ESCs
Antenna – Lumenier AXII
More build info for a closely related RacerX on Rotorbuilds here.
TOP Speed With The ARX-R
Since then, the record has been broken! Ryan Lademann from Quad Star Drones is a mechanical engineer who likes to fly fast FPV drones. From his website, you can see the banner, “Home of the Fastest Quadcopters on the Planet; A Site dedicated to The Advancement of Multirotor Frames”. His drone, the ARX-R, holds the highest speed ever achieved by a multirotor drone at 203.3 MPH.
Ryan, being a mechanical engineer, dived very deep into the physics of flight and speed with this drone. He analyzed closely Propeller RPM & Pitch, Thrust, Forces of Flight, Center of Thrust & Gravity, Drag, Air Drag & Cross Sections, and all the equations for speed that relate these. If you’d like to learn more about the details of his physics behind it, check out this section of his website….https://quadstardrones.com/drone-physics/
Notice the camera angle on the ARX-R? This allows the drone to tilt forward further and allow the pilot to still see forward and not just see the ground! It is crazy how fast this thing propels itself through the air. It accomplished this feat with the following equipment.
Battery – Tattu 1300 95C 6s
Motors – Cobra 2207 2450 kVs
ESCs – Spedix 30A
Antenna – Lumenier AXII
You might notice a big difference in the DRL rig to Ryan’s drone with the size of the Battery. The DRL rig ran 10s power to the drone whereas the ARX-R ran with 6s power. Ryan answers this difference in an interview answer. See below.
Prop tip speed: …NASA had very little success with their supersonic propeller program and dropped it. This is why I always said 5s is enough, but I’m also using 6s as a “safety” factor. Once tips hit transonic speeds (around Mach 0.8) required torque literally jumps through the roof. That’s why 10s did nothing for the DRL rig except [to] burn up ESC’s: all those amps mostly turned into heat and gave a very minimal gain in RPM.https://www.getfpv.com/learn/fpv-news/fpv-multirotor-speed-record/
Factors That Affect How Fast A Drone Can fly
Drag is a speed killer. It is applied to drones in the form of air resistance and goes against the direction the drone is moving. Let’s get just a little geeky and take a look at the basic equation here…
The drag coefficient is usually determined experimentally and is a little more complex. If you want more detail on it, open a new tab, put your reading glasses on, and google away. Anyways, if we rearrange it and think about it, the max velocity is dependent upon the coefficient of drag and the reference area. These are two factors we have control over in our FPV drone build
Reducing the reference area or cross-sectional area refers to making the “footprint” of the drone that is flying through the air smaller. Now this area only refers to area perpendicular to movement. Normal FPV drone frames are built flat. As they angle forwards their cross-sectional area increases the more they angle forwards.
FPV Drones built simply for straight speed can be built on an angle so that as the drone tilts forward to a certain point their cross-sectional area is not as big.
It can be reduced by making the frame arms not as wide and the main body thinner. Essentially just trying to reduce the cross-sectional area.
The coefficient of drag can be reduced by making the drone more aerodynamic. This gets complicated real fast. Basically, changes that will allow the air to flow over the drone and not get hung up or get turbulent are what we want. This would include making sure the drone frame is smooth with no sharp edges. Avoiding any situation where air could get caught up and not released behind the drone. This would include large flat arms that could potentially “catch” air when they are angled forwards.
There are a lot varying factors in gaining more thrust. The biggest one is most likely the propellers/props. Props can have 2 or more blades, different weights, different pitches, different diameters and different materials.
The pitch of the propeller is more important than the size. A 5040 propeller (5 inch prop with a pitch of 4 inches) will theoretically move 4 inches forwards for every rotation the prop makes. A 4 inch prop with a pitch of 4.5 inches (4045) will theoretically move 4.5 inches forward for every rotation of the prop. In short, a larger pitch will improve the top speed, however with a cut to the acceleration.
One might think that bigger and more blades produces more thrust. However, the increased prop surface area and prop weight adds a lot more load on the motor. This increases the torque requirement on the motor which generally decreases the top speed of it. It can add higher acceleration but not necessarily top speed. Also this increase in torque demands a higher amp draw which then results in the voltage sagging and less RPMs. It then relies heavier on the battery requirements.
It’s all connected! The prop selection drives the motor selection, which drives the ESC selection and ultimately the power source or battery selection!
3. Weight & Balance
Another factor that can have an impact on the drone speed is the drone weight. Just like cars, the heavier the car, the lower the maximum speed. The same rule applies to almost every moving machine.
The less the motors and props have to fight gravity the better! A lighter drone can then put more of its energy into moving forward through the air.
However, I also titled this section Balance. Ideally you want your center of gravity to line up with your center of thrust. If they don’t quite line up you will create a moment and it will require additional force to keep level. For a drone think about what would happen if you mounted the battery to much on the left side of the frame. As you fly forwards you would constantly be having to correct the roll towards the right. If it was in self-level mode the motors on the lefts side would be working double time.
Fine-tuning this balance can allow you to achieve higher speeds because you will be able to get all the motors as close to 100% as possible. If the center of thrust and gravity are even a centimeter off it can result in some motors only pushing 96% to correct the imbalance.
That sums up the top three factors that affect the top speed of an FPV drone. Needless to say FPV drones can reach some crazy speeds. But, what about a consumer drone that can shoot good video and can be ordered off the shelf?
Top Speed Of Consumer Drones
But what about the top speed of a DJI drone I can go buy tomorrow? Building a FPV Speed demon can allow for crazy speeds, but how fast can my camera drone go? Check out the following table of DJI Drone speeds.
|Phantom 3 Standard/4K/Advanced/Pro||35 MPH|
|Phantom 4 Advanced/Pro/V2.0||45 MPH|
|Mavic Pro||40 MPH|
|Mavic 2 Pro/Zoom||45 MPH|
|Mavic Air||42.5 MPH|
|Mavic Air 2||45 MPH|
|Mavic Mini||29 MPH|
|Inspire 1||50 MPH|
|Inspire 2||58 MPH|
|Matrice 200 & 300 series||51 MPH|
Fastest Off-The-Shelf FPV drones
If you are looking for a fast FPV drone that you don’t have to build, check out the list below that describes some of the fastest FPV racing drones. It gives you an idea of the standard FPV speeds compared with consumer drones (above).
Diatone GT200 2017 – 99mph
This bird is a combo of easy setup, flight dynamics and great performance. The GT200 weighs just 554 grams, offers a thrust of 1661g/motor that can allow the drone to fly at a top speed of 99mph.
The GT200 features Edge 2306 2450kv powerful motors, Gemfan 5-inch propellers, SP2 40CH video sender, PDB, HS1177 600TVL Sony camera, Fury F3 flight controller, and 30A BLHeli S ESCs.
Speedy Gonzalas: 145mph
In 2017, Patrick Gaborik, the pilot, and builder, achieved an insane speed of 145 mph recorded by the onboard GPS. Although some people raised questions about the speed meter accuracy, the official measuring equipment confirmed the speed.
Speedy Gonzalas features a 53g U180X frame along with Emax 2306 2750kv motors. So, the drone can produce a thrust of 6.75kg using a 6S battery. With the max weight of 570g, the bird can fly at a speed of 145mph. The 6S battery can produce so much power that it can melt down the solder on the electrical board.
Fastest FPV Racing Bird: DRL Racer X: 164 mph
I already mentioned this one at the beginning of the article due to all the hype but I will summarize it again here. On 13th July 2017, a Guinness World Record official watched the DRL Racer X attempting a record high speed. However, to set the record and get a mention in the record books, Racer X had to take part in a 100m race competition.
The Racer X touched an average maximum speed of 165.3 mph. The top speed was 179.3mph. This is how the Racer X became the fastest FPV racing drone. Ryan Gury and a team of other engineers opted for a monster powertrain for the drone and 580 motors. This produced a thrust of 7.55 kg using a battery pack of two 5S Tattu R-line.
All of these powerful parts added to the weight of the drone making it weigh 800g. So, this is the heaviest FPV drone for racers.
On 10th August 2017, VXR-190 achieved an average speed of around 165.8 mph in a 100 meters race. The customized frame is made of cutting-edge materials. It has a hollow tube of carbon fiber with a nose cone.
Also, the unique design has a low drag coefficient but maintains the center of gravity, pressure and thrust. Although the drone focuses on aerodynamics the most, the frame weighs only 48 grams. On the other hand, most traditional carbon plate frames have a much higher weight.
The VXR-190 features Cobra CP 2207/2450 motors for high RPM. The Cobras offer high RPM as they don’t draw a lot of amperes unlike other motors that offer high RPM. So, the VXR-190 uses a 5S battery to achieve a speed of 165.8 mph. The combined thrust of all of the motors is 7376 grams and gives the drone a thrust-to-weight ratio of a whopping 15.4.
According to Ryan, the pilot of the drone, extra power from batteries or motors can provide only a slight amount of speed gain as the prop tips of this drone already move at supersonic speed. So, this results in huge turbulence between subsonic and subsonic airflow. So, the additional power becomes turbulence. So, higher speeds will rely on the design of the propeller.
Nytfury’s ARC 200: 75mph
In 2016, Shaun Taylor, a firefighter, quit his job to fly FPV drones as a full time pilot. Soon he emerged as an FPV Drone Racing Champion. His favorite drone is ARC 200, which has a 36 gram frame, 29 grams 2600kv Viking motors and Raptor 30A ESCs.
Shaun was a winner of the MultiGP Championship. Although the highest speed of Tylor’s ARC 200 is not known, other pilots of the drone say that the bird has the top speed of 120 km/h or 70 mph. The drone weighs just 458 grams (battery included), but the thrust to weight ratio is only 9:1.
Gemo Copter: 119mph (fastest vertical flight speed)
Owned by Dirk Brunner, the German researcher, the Gemo Copter hit a whopping speed of 189 km/h or 119 mph straight up. So, the drone had its name written in the Guinness World Records for highest ascent speed in a 100 meter ascent test.
Dirk Brunner took 20 years to made his drone so fast and powerful. According to Dirk, it was all about looking for the best combo of propellers and motors.
FAA Rules & Regulations
It is fairly common knowledge that the max height one can fly according to the FAA is 400ft above the ground level. Or 400′ above the tallest structure which one is inspecting.
However, the FAA also dictates the max speed limit for drones is 87 knots or 100 mph. You are probably thinking, well damn most of the drones talked about above are faster than that! And they are. This is hard to enforce as there are no FAA police out there with a radar gun trying to shoot your tiny drone as it whizzes by at hundred miles an hour.
There are waivers that you can file. For reason I guess you can just put you’re a speed demon? Needless to say an FPV drone flying at 120 MPH could really hurt someone if it crashed. Let’s do a sample calculation for fun!
How Much Would It Hurt To Get Hit By A FPV Drone Flying 120 MPH?
This assumes a few things and is a simple calculation for something that is quite complicated. But, using basic physics this is what we get. What are we looking at here? The equation below is showing the work that would be done on someone’s face with the Kinetic energy of a FPV drone. Work is defined as Force x Distance. Kinetic energy is 1/2 mass times velocity squared (assuming drone is traveling straight horizontally).
In a car crash calculation, the distance refers to how much the car crumples after its impact. For this calculation, I assumed a 600-gram weight drone (0.6kg), that it would crump about 5 inches or half its length (0.127m) and that it was trucking at 120 MPH (~54m/s). See calcs below.
6,888 Newtons equates to about 1548.5 lb force. That’s deadly. Not to mention the props that will hit first spinning at extremely high RPMs with sharp tips. Ouch. I guess I can see the FAA’s concern…
However, in an open field with no people and I emphasize no people, kids or anything at least you can speed peacefully with only potential harm to yourself or the trees at the edge of the field.
According to FAA rules and regulations, you can fly drones during daylight or in twilight. In other words, you can fly half an hour prior to official sunrise to half an hour post official sunset. For twilight flights, there must be proper anti-collision lighting installed.
Hope you found this article informational, interesting and happy speed flying! Stay safe out there eh!