Driving A Big RC Car On The Ceiling

RC cars are a great way to have fun hooning around. There’s plenty of laughs to be had racing your friends in the local grocery store carpark, ideally after hours. [Ivan Miranda] wanted to go in a different direction, however – and that direction was up. (Video embedded after the break.)

There are existing toys that can pull off a wall-riding feat, but they’re normally on a fairly small scale. [Ivan] wanted to go big, and so outfitted some seriously powerful brushless fans on to his 1/8th Rattler buggy from Hobbyking. After initial failure, a smaller scale model was successfully built and tested, before it was realised the full-sized build had the propellers on backwards.

With this oversight fixed, the car was able to drive on the ceiling, albeit in the limited space between the roof beams. It was somewhat less viable on the wall, struggling to stay stuck and having issues with suspension flex.

Overall, it’s a great application of mass brushless power to fight gravity – the same principle behind the multirotors we all love so much. [Ivan]’s put the same trick to use for getting around on a skateboard, too. Video after the break.

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RC Trike Handles Great With Rear Steering

Small robotics builds with three wheels are plentiful. The most typical configuration is to have the two front wheels drive and turn the vehicle in a skid-steer configuration. The third wheel is often a simple caster. However, this isn’t the only way to go, and [markus.purtz] has put together a build that does things differently.

The build is a small, radio-controlled FPV trike. Instead of the usual skid-steer setup, the rear wheel is mounted on a pair of horizontal bearings which allows it to pivot left and right. A servo is used to control the rear wheel position, with a pair of tie rod ends used to connect the horn to the rear steering assembly. It’s not the only unconventional design choice, either – magnets are used to affix the top plate to the vehicle chassis, rather than screws or clips. For video, the user can mount either a small dedicated FPV camera, or a GoPro with the included mount.

Without any code or control details posted, we can’t be 100% sure how it all works. However, from the video, it appears that both front wheels are being driven at the same speed, with steering handled solely by the rear wheel. This is apparent when driving on a smooth surface, where the vehicle can be seen to slide when turning. While it’s unlikely this setup has many advantages over a simpler differential steering build with a caster, it does show that rear steering can be effective on its own.

It’s a build that shows off the benefits of using proper bearings and mechanical parts in a design. With today’s online marketplaces, it’s never been easier to find what you need. Parts are on Thingiverse for those interested in replicating the design. Meanwhile little FPV bots remain popular, and we’re sure we’ll continue to see them coming in. Video after the break.

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Lego Goes Underwater, With Model Submarines And Missiles

It is fun to make a toy vehicle with Lego, but it is even more fun to make one that actually works. [PeterSripol] made two Lego submarines, and you can see them in the video below. There isn’t a lot of build information, but watching the subs fire missiles and then getting destroyed by depth charges is worth something.

One of the subs is larger and uses a rudder to steer. It was apparently harder to control than the other smaller sub which used two motors thrusting opposite one another to steer. Looks like fun.

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Radio Controlled Wheelbarrows Tear Up The Track

The wheelbarrow is a trusty companion to the gardening set, helping move heavy loads to and fro. [James Bruton] has an active imagination however, deciding to build a motorized racing barrow, and challenging his friends to do the same (Youtube link, embedded below).

[James] went with a straightforward design, fitting two wheels to the rear, and powering them with brushless inrunner motors. The original front wheel was then fitted with a caster mechanism to allow the barrow to be skid steered. A pair of lithium polymer batteries provide the juice, with [James] using VESC skateboard ESCs to run the motors. The whole contraption is radio controlled, with an Arduino handling the mixing for steering duties.

The motorized barrow performed well against its competition, a propeller-powered barrow from [Tom Stanton] and a leaf-blower propelled barrow from [Ivan Miranda]. Inclement weather did cause some issues, but the trio were kind enough to treat us to a destruction derby with their racing machines.

You may be familiar with [James]’ earlier work on the openDog project. Video after the break.

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This Two-Wheeled RC Car Is Rather Quick

Radio control cars have always been fun, it’s true. With that said, it’s hard to deny that true speed was unlocked when lithium polymer batteries and brushless motors came to the fore. [Gear Down For What?] built himself a speedy RC car of his own design, and it’s only got two wheels to boot (Youtube link, embedded below).

The design is of the self-balancing type – if you’re thinking of an angry unmanned Segway with a point to prove, you’re in the ballpark. The brains of the machine come thanks to a Teensy 3.6, which runs the PID loops for balancing and control. An MPU6050 gyroscope & accelerometer provide the necessary sensing to enable the ‘bot to keep itself upright in varied conditions. Performance is impressive, with the car reaching speeds in excess of 40 MPH and managing to handle simple ramps and bumps with ease. It’s all wrapped up in a 3D printed frame which held up surprisingly well to many crashes into tripods and tarmac.

Such builds are not just fun; they’re an excellent way to learn useful control skills that can serve you well in industry and your own projects. You can pick up the finer details of control systems in a university engineering course, or you could give our primer a whirl. When you’ve whipped up your first awesome project, we’d love to hear about it. Video after the break.

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3D Printing A Lifting Body Aircraft

When you think of unconventional aircraft, flying wings have had plenty of time in the sun over the last few decades. With striking designs like the B-2 Spirit and F-117A Nighthawk on the flight line, it’s no surprise. The lifting body never really caught on, however, and it languishes in ignominy to this day. Despite their obscurity, [rctestflight] decided to 3D print a few lifting bodies for himself and take them out for a field test (YouTube video, embedded below).

Most aircraft have a body designed with low drag, and wings designed to provide lift. Lifting body aircraft focus the body design on providing that lift and often have no real wing to the design, needing only control surfaces to compliment the body. For this project, several different designs were constructed, with the craft being drop-launched from a multirotor at significant altitude. Initial tests were hamstrung by stability problems, both due to center of gravity issues and uncertain aerodynamic phenomena. The early designs were particularly prone to suddenly entering an unrecoverable flat spin. Later modifications included the addition of further stabilizers, which helped performance somewhat.

3D printing is a great way to experiment with aerodynamic phenomena, as it’s easy to create all manner of complicated geometries to tinker with. [rctestflight] has done solid work developing a basic craft, and we’d love to see the work continue with powered tests and more development. If flying wings are more your jam, though, you can 3D print those too. Video after the break.

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WiFi Controlled Plane Is Cheap Flying Fun

The world of radio controlled aircraft used to be an expensive and exclusive hobby, limited to those with the time and money to invest in difficult builds and pricey radio gear. More recently, the hobby has become more accessible, with cheap ready to fly planes available that can be flown in smaller spaces like suburban parks. [Ravi Butani] has built just such a plane, and you can even fly it with your smartphone!

An ESP8266 does double duty here as both the brains and the communication system. A custom smartphone app communicates with the plane over WiFi. Touching the screen increases the throttle, while steering is achieved through tilting the phone. There’s also monitoring of signal strength and battery level, with the phone vibrating if the plane is getting out of range or low on battery.

Flight control is via differential thrust, with power coming courtesy of two small DC motors controlled by tiny SMD MOSFETs. The plane flies remarkably well in still conditions, and the WiFi connection is stable in an open park environment. [Ravi] reports that control is possible at a range of around 70 meters using a Motorola G5S smartphone.

Despite the simplicity of the build and the low cost of the components, the final product performs admirably. It would be a great weekend project, and at the end of it, you get to go and fly your new plane! If you’re worried about keeping your batteries charged, don’t worry – there’s a solution for that. Video after the break.

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