For a long time radial aircraft engines, with their distinctive cylinder housings arranged in a circle, were a common sight on aircraft. As an experiment, [KendinYap], wanted to see if he could combine 3 small DC motors into a usable RC aircraft motor, effectively creating an electric radial engine.
The assembly consists of three “180” type brushed DC motors, mounted radially in a 3D printed casing. A 3D printed conical gear is attached to each motor shaft, which drives a single output gear and shaft mounted in the center with two bearings. The gear ratio is 3:1. A variety of propellers can be mounted using 3D printed adaptors. As a baseline, [KendinYap] tested a single motor on a scale with a 4.25-inch propeller on a scale, which produced 170 g of thrust at 21500 RPM. Once integrated into the engine housing, the three motors produced 490 g of thrust at 5700 RPM, with a larger propeller. Three independent motors and propellers should theoretically provide 510 g of thrust, so there are some mechanical losses when combining 3 of them in a single assembly. However, it should still be capable of powering a small RC plane. It’s also not impossible that a different propeller could yield better results.
While there is no doubt that it’s no match for a brushless RC motor, testing random ideas just to see if it’s possible is usually fun and an excellent learning experience. We’ve seen some crazy flyable RC power plants, including a cordless drill, a squirrel-cage blower, and a leaf blower.
[rctestflight] has built several autonomous boats, and with missions becoming longer and more challenging, he bought an inflatable kayak to serve as a dedicated rescue vessel. Instead of relying on outdated manual paddling, he built an autonomous solar-powered tugboat.
The tugboat uses a pair of molded fiberglass hulls in a catamaran configuration. The wide platform allows a pair of 100W solar panels to be mounted on top. It was [rctestflight]’s first time molding anything out of fiberglass, so there was quite a bit of trial and error going on. The mold was 3D printed in sections, aligned with dowel pins, and glued together. After the epoxy had cured, the mold halves could be split apart for easier removal of the hull.
As with most of [rctestflights] autonomous vehicles, control is handled by a Pixhawk 4 running ArduPilot/ArduRover. A pair of 76 mm brass propellers powered by brushless motors provide propulsion and differential steering. The motors get power from six LiFePO4 batteries, which charge from the solar panels via MPPT charge controllers. The hulls are covered with plywood decks with removable hatches and inspection windows. After a bit of tuning, he took the boat for a few test runs, the longest being 5.1 km with himself in tow in the kayak. At less than 5 km/h (3 mph) it’s no speedboat, but certainly looks like a relaxing ride. Many of [rctestflight]’s previous vessels were airboats to avoid getting underwater propellers tangled in weeds. It was less of an issue this time since he could just haul the tugboat close to the kayak and clear the propellers.
[rctestflights] are always entertaining and educational to watch, and this one certainly sets the standard for sea-shanty soundtracks at 13:32 in part two.
[Matt] from [DIY Perks] has made a name for himself building nice custom computing machines, and his latest triple-monitor luggable PC (video after the break) is sure to give most high-performance desktop machines a run for their money.
The large central monitor folding laptop monitors mounted vertically on either size look impressive, but only just scratches the surface of this build. Hidden behind aluminum panels are Ryzen 5950X CPU and RTX 3080 GPU with water cooling, 64 GB of RAM, and two 8 TB SSDs. A set of high-quality speaker drivers, subwoofer, and audio amps is also included. All this hardware pulls about 600 W of power from a large DC-DC converter block, which in turn receives power from either a pair of onboard AC-DC converters or a 16 V – 63 V DC source, like a battery system.
To mount everything to the back of the main monitor, [Matt] created 3D printed adaptor blocks with threaded inserts which slide under existing hooks on the back of the monitor. Aluminum angles screw to these blocks to cover the edges of the display panel, together with a large mounting plate with pre-drilled holes to mount all the components on standoffs. A set of adjustable and removable legs mount to the side of the PC. A hinged door in the back cover allows storage space for a keyboard and mouse during transport. When folded, the laptop monitors don’t fully cover the main monitor, so [Matt] created a leather cover that doubles as a cable and accessory organizer.
The Strider mechanism might look similar to Strandbeest walkers, but it lifts its feet higher, allowing it to traverse rougher terrain. [Chen]’s little 3D printed version is driven by a pair of geared N20 motors, with three legs on each side. The ESP32 camera board allows for control and an FPV video feed using WiFi, with power coming from a 14500 LiFePO4 battery. The width required by the motors, leg mechanisms, and bearings means the robot is quite wide, to the point that it could get stuck on something that’s outside the camera’s field of view. [Chen] is working to make it narrower by using continuous rotation servos and a wire drive shaft.
We’ve seen no shortage or riffs on the many-legged walkers, like the TrotBot and Strider mechanism developed by [Wade] and [Ben Vagle], and their website is an excellent resource for prospective builders.
The hacker spirit is always alive and well in post-apocalyptic fiction, as characters throw together contraptions from whatever junk they can find. While these might not always be practical or possible in reality, their primary purpose is usually to look the part. This is definitely the case for [Danny Huynh]’s post-apocalyptic animatronic creations, which look like they can slot straight into Mad Max or Fallout.
All the vehicle builds are electric, but it looks like [Danny] often includes an audio module to simulate a roaring engine. He makes extensive use of servos and linkages for character movement, with wiring and electronics carefully hidden by paint or bodywork.
[Joe] is well known for his thrust-vectoring rockets, some of which have came within a hair’s breadth of making a perfect powered landing. Previous rockets have used larger, more complex flight computers, but for this round, he wanted to go as small and minimalist as possible. Each stage of the rocket has its own tiny 16 x 17 mm flight computer and battery. The main components are a SAM21 microcontroller running Arduino firmware, an IMU for altitude and orientation sensing, and a FET to trigger the rocket motor igniter. It also has servo outputs for thrust vector control (TVC), and motor control output for the reaction wheel on the third stage for roll control. To keep it simple he omitted a way to log flight data, a decision he later regretted. Shreeek did not have a dedicated recovery system on any of the stages, instead relying on its light weight and high drag to land intact
None of the four launch attempts went as planned, with only the first two stages functioning correctly in the test with the best results. Thanks to the lack of recorded flight data, [Joe] had to rely on video footage alone to diagnose the problems after each launch. Even so, his experience diagnosing problems certainly proved its worth, with definitive improvements. However, we suspect that all his future flight computers will have data logging features included.
Controller vs keyboard and mouse is one of the never-ending battles in the world of gaming, with diehard proponents on both sides of the fence. [Tech Yesterday] has been working to create a controller that’s the best of both worlds. His latest Mouse Pro Controller V5 features an inverted mouse riding on ball bearings.
Mouse Pro Controller V1-3‘s main focus was to create the largest possible moving surface for an optical thumb mouse for precision aiming. However, [Tech Yesterday] found that one’s thumb doesn’t work well for traversing a large flat surface, but works better with a concave surface. On V4 he flipped the optical sensor around, embedding it in the controller, with a small circular “mouse pad” attached to his thumb. The concave surface was made from the diffuser of a large LED light bulb. It had slightly too much friction for [Tech Yesterday]’s liking, so he embedded an array of small ball bearings in the surface using magnets.
While this “thumb mouse” has excellent precision, it can be a bit slow when you need to make large movements, like when performing 360° no scopes for the clips. For these situations, [Tech Yesterday] embedded a thumb stick on the back of the controller to allow for fast sideways movements using his middle fingers.