radio control

97 Articles

Radio Control Joby Aircraft Uses Six Tiltrotors To Fly

January 29, 2022 by 3 Comments

eVTOL (Electric Vertical Take-off and Landing) craft are some of the more exciting air vehicles being developed lately. They aim to combine the maneuverability and landing benefits of helicopters with the environmental benefits of electric drive, and are often touted as the only way air taxis could ever be practical. The aircraft from Joby Aviation are some of the most advanced in this space, and [Peter Ryseck] set about building a radio-controlled model that flies in the same way.

The design is inspired by the Joby eVTOL test vehicle.

The result is mighty complex, with six tilt rotors controlled via servos for the utmost in maneuverability. These allow the vehicle to take off vertically, while allowing the rotors to tilt horizontally for better efficiency in forward flight, as seen on the Bell-Boeing V-22 Osprey.

The build uses a 3D-printed chassis which made implementing all the tilt rotor mounts and mechanisms as straightforward as possible. A Teensy flight controller is responsible for controlling the craft, running the dRehmFlight VTOL firmware. The assembled craft only weighs 320 grams including battery; an impressive achievement given the extra motors and servos used relative to a regular quadcopter build.

With some tuning, hovering flight proved relatively easy to achieve. The inner four motors are used like a traditional quadcopter in this mode, constantly varying RPM to keep the craft stable. The outer two motors are then pivoted as needed for additional control authority.

In forward flight, pitch is controlled by adjusting the angle of the central four motors. Roll is achieved by tilting the rotors on either side of the plane’s central axis, and yaw control is provided by differential thrust. In the transitional period between modes, simple interpolation is used between both modes until transition is complete.

Outdoor flight testing showed the vehicle is readily capable of graceful forward flight much like a conventional fixed wing plane. In the hover mode, it just looks like any other multirotor. Overall, it’s a great demonstration of what it takes to build a successful tilt rotor craft.

We’ve seen tilt rotor UAVs before, and they’re as cool as they are complicated to build. Video after the break.

Continue reading “Radio Control Joby Aircraft Uses Six Tiltrotors To Fly” →

Running Methanol RC Engines On Gasoline

January 22, 2022 by 33 Comments

Methanol is a popular fuel for small engines used in radio-controlled models, but comes at a higher price than gasoline. It’s also harder to source and can be a mite corrosive, too. Gasoline comes with some benefits, but running it in a methanol engine usually requires some mods. [David] and [Bert] worked together to build a mixture controller for just this purpose.

The controller uses a solenoid to control the flow of gasoline to a conventional methanol-tuned carburetor for a small RC engine, allowing it to be accurately tuned to run gasoline well across the whole RPM range. Having gone through many revisions, all documented in a big forum thread, the latest version uses a Seeduino Xiao controller and a BMP280 pressure and temperature sensor for determining the right fuel/air mixture for the conditions. A small OLED screen can optionally be fitted to help with configuration of the mixture controller.

The system has worked well in testing, with [David] and [Bert] reporting that they have “converted engines as small as 0.3 CID up to large radials with this system.” It’s a promising tool that could be handy to have in the RC modeller’s arsenal.

These tiny engines have other applications too; they can make for one crazy power drill, that’s for sure!

Ground Effect Aerodynamics On An RC Car

December 21, 2021 by 3 Comments

Ground effect aerodynamics will return to Formula 1 in a big way in the 2022 season, hopefully washing away the bad taste left in fan’s mouths after the recent controversial season decider. [Engineering After Hours] has experimented with F1 aerodynamics on RC cars before, and decided that it was time to try and implement a proper ground-effect design himself.

The aim of ground effect aerodynamics is to create a constriction for airflow between the bottom of the car and the ground underneath. This constriction accelerates the flow beneath the car, and as per Bernoulli’s principle, causes a corresponding pressure drop, sucking the car down onto the track. Viscosity also plays a role; from the car’s perspective, the road beneath the vehicle is moving backwards at some speed, pulling on the fluid thanks to the boundary layer on the ground itself. This further helps increase the strength of the effect.

A vacuum-formed undertray complete with side skirts was installed on the RC car in order to generate ground effect downforce. A quick test with a leaf blower indicates the system works, and that the side skirts are a key component.

Lateral acceleration was significantly improved by around 20% in testing with the ground effects installed, though [Engineering After Hours] admits that without a wind tunnel, the results aren’t the most scientific. However, with the undertray being relatively lightweight, we suspect the aero elements are likely providing plenty of benefit without too much of a negative effect on acceleration or handling.

Check out some of the other aero experiments [Engineering After Hours] has undertaken, too. Video after the break. Continue reading “Ground Effect Aerodynamics On An RC Car” →

RC Sub Built With A Water Bottle

December 15, 2021 by 8 Comments

Submarines are one of the harder modes of transport to build in radio-controlled form. Doing so involves tangling with sealing electronics from water ingress and finding a way to control the thing underwater. It’s a challenge, but one relished by [Project Air] in his latest build.

The body of the sub was built from a drink bottle, serving as a stout container upon which could be mounted all the necessary hardware. Filling the bottle with water allowed buoyancy to be adjusted to a neutral level. Twin brushless motors were used for drive, while servos were waterproofed using a combination of rubber gaskets, olive oil, and sealing spray.

Control was via a floating 2.4 GHz receiver, as high-frequency radio signals don’t penetrate water very far. The floating box also carries an FPV transmitter to allow the sub to be piloted via video feed. Rather than using a ballast system, the sub instead dynamically dives by thrusting itself beneath the water’s surface.

Unfortunately, water sloshing around in the partially-filled drink bottle meant controlling the sub in pitch was virtually impossible. To fix this, [Project Air] filled the bottle completely, and then used some plugged syringes on the outside of the body to adjust buoyancy. The long heavy tether was also replaced with a much shorter one, and the sub became much more fun to drive around under water.

The build was actually built for a friendly contest with [DIY Perks], a fellow Youtuber whose efforts we covered recently. It also bears noting that better results can be had by using lower-frequency radio gear. Video after the break.

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Build Your Own Submarine

December 10, 2021 by 22 Comments

If you are tried of building things that fly, why not try a submarine like [DIYPerks] did? As you can see in the video below, the key is to control buoyancy, and the mechanism used is impressive. The sub has two giant syringes fore and aft to compress or decompress water. The plungers are now 3D-printed actuators that travel on a lead screw. Two high-torque motors and some batteries sandwiched in acrylic disks make up the rest. This is a big vessel — you won’t be trying this in your bathtub and maybe not even your pool unless it is a big one.

Of course, everything needs to be watertight. Instead of trying to waterproof a power switch, this sub uses a reed switch so that a nearby magnet can turn it on. Not an original idea, but we always think it is more elegant than seals and potting compounds.

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A Guide To Designing A Custom RC Controller

November 12, 2021 by 5 Comments

These days, there are tons of RC controllers out there of all shapes and sizes. However, if you want to build something with just the right amount of buttons and sticks for your application, you might want to design something yourself. That’s precisely what [Sebastian] did. 

The project actually began some time ago, with [Sebastian] sharing his process for building a custom ergonomic enclosure through the use of clay and photogrammetry, which we’ve covered before.

Inside that shapely housing, the build relies on a STM32 microcontroller, hooked up to a series of potentiometers, buttons, and a thumbstick (more potentiometers). A NRF24L01 module is used to handle the radio transmission side of things.

Overall, [Sebastian] has produced a great guide to designing a custom RC controller from the ground up, rather than simply instructing one how to replicate his own build. Armed with these skills, any maker should be able to whip up their own entirely bespoke controllers. Video after the break.

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When Benchies Fly

October 9, 2021 by 5 Comments

Most of us have printed a few benchies to test our 3D printers. The intrepid little boat has a variety of features that tax different parts of the printing process. However, the guys at [FliteTest] had a different idea. They set out in a competition to build a giant flying benchie. They aren’t quite done, but they did make some interesting progress, as you can see in the video below.

In all fairness, the benchies are not, themselves, 3D printed. Foamboard, however, is a bit more practical.  Inevitably, you can’t help but think of a flying boat when you see the results.

Continue reading “When Benchies Fly” →