Foam F-35 Learns To Hover

July 15, 2021 by Tom Nardi 2 Comments

With cheap RC hardware, powerful motors, and high-capacity battery packs, getting something to fly has never been easier. It also helps that, whether you’re into fixed-wing craft or multirotors, there’s plenty of information and prior art floating around online that you can use to jumpstart your own build. But when it comes to homebrew vertical take-off and landing (VTOL) planes, things are a bit trickier.

Luckily for us, [Nicholas Rehm] has made all the plans and information necessary to duplicate his incredible RC F-35 available for anyone who wants to experiment with these relatively niche fliers. Even if it was a standard park flier, the build would be worth a close look thanks to the vectored thrust motors that give it phenomenal maneuverability and a top speed in the neighboorhood of 120 KPH (80 MPH). But with the flick of a switch, the plane transitions into a tricopter-like flight mode that allows it to land and takeoff vertically.

How does it work? The downward facing motor just behind the “cockpit” lifts up the front of the foam flier and tilts left and right to provide yaw control, while the two motors on the back tilt down to lift up the rear of the aircraft. Aviation buffs in the audience may recognize this as being fairly close to how the actual F-35B hovers, although on the real jet fighter, downward thrust under the wings is generated by redirected turbine exhaust rather than dedicated motors, and yaw control is provided by swiveling the engine’s nozzle rather than the front lift fan.

Getting the plane to takeoff vertically was one thing, but being able to transition from a hover into forward flight was quite another. To make this aerial transformation possible [Nicholas] actually had to write his own flight controller software, which he calls dRehmFlight. The GPLv3 code runs on the Teensy 4.0 and uses the common GY-521 MPU6050 gyroscope/accelerometer, so you don’t need to get any custom boards spun up just to give it a test ~~drive~~ flight. In the video below he walks through configuring the software for VTOL operation by defining how each control surface and motor is to respond to control input given the currently selected flight mode.

It probably won’t surprise you to hear that this isn’t the first time [Nicholas] has experimented with unusual flying machines. Last year we covered his RC Starship, which managed to stick the “belly flop” landing even before SpaceX managed to get the real life version down in one piece.

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DRehmFlight: Customizable Flight Stabilisation For Your Weird Flying Contraptions

February 15, 2021 by Danie Conradie 10 Comments

The availability of cheap and powerful RC motors and electronics has made it possible for almost anyone to build an RC flying machine. Software is usually the bigger challenge, which has led to the development of open-source packages like BetaFlight and Ardupilot. These packages are very powerful, but not easy to modify if you have unconventional requirements. [Nicholas Rehm] faced this challenge while doing his master’s degree, so he created dRehmFlight, a customizable flight controller for VTOL aircraft. Overview video after the break.

dRehmFlight runs on Teensy 4.0 with a MPU6050 or MPU9250 IMU

[Nicholas] has been building unique VTOL aircraft for close to a decade, and he specifically wanted flight stabilization software that is easy to modify and experiment with. Looking at the dRehmFlight code, we think he was successful. The main flight controller package is a single file of fewer than 1600 lines. It’s well commented and easy to figure out, even for an inexperienced programmer. A detailed PDF manual is also available, with full descriptions for all the functions and important variables, and a couple of tutorials to get you started. Libraries for interfacing with accelerometers and RC gear is also included. It runs on a 600 Mhz Teensy 4.0, and all the programming can be done from the Arduino IDE.

[Nicholas] has repeatedly demonstrated the capabilities of dRehmFlight with several unique aircraft, like the belly flopping RC Starship we covered a while ago, a VTOL quad rotor biplane, VTOL F35, and the cyclocopter seen in the header image. dRehmFlight might not have the racing drone performance of BetaFlight, or advanced autopilot features of Ardupilot, but it’s perfect for getting unconventional aircraft off the ground. Continue reading “DRehmFlight: Customizable Flight Stabilisation For Your Weird Flying Contraptions” →

A DIY Functional F-35 Is No Simple Task

April 27, 2020 by Danie Conradie 19 Comments

The advent of affordable gear for radio-controlled aircraft has made the hobby extremely accessible, but also made it possible to build some very complex flying machines on a budget, especially when combined with 3D printing. [Joel Vlashof] really likes VTOL fighter aircraft and is in the process of building a fully functional radio-controlled F-35B.

The F-35 series of aircraft is one of the most expensive defence project to date. The VTOL capable “B” variant is a complex machine, with total of 19 doors on the outside of the aircraft for weapons, landing gear and thrusters. The thruster on the tail can pivot 90° down for VTOL operations, using an interesting 3-bearing swivel mechanism.

[Joel] wants his model to be as close as possible to the real thing, and has integrated all these features into his build. Thrust is provided by two EDF motors, the pivoting nozzle is 3D printed and actuated by three set of small DC motors, and all 5 doors for VTOL are actuated by a single servo in the nose via a series of linkages. For tilt control, air from the main fan is channeled to the wing-tips and controlled by servo-actuated valves. A flight controller intended for use on a multi-rotor is used to help keep the plane stable while hovering. One iteration of this plane bit the dust during development, but [Joel] has done successful test flights for both hover and conventional horizontal flight. The really tricky part will be transitioning between flight modes, and [Joel] hopes to achieve that in the near future.

The real Lockheed Martin F-35 Lightning II project is controversial because of repeated budget overruns and time delays, but the engineering challenges solved in the project are themselves fascinating. The logistics of keeping these complex machines in the air are daunting, and a while back we saw Marine ground crew 3D print components that they were having trouble procuring through normal channels.

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Tilt-Rotor Plane Needs Flight Controller Hack To Get Airborne

November 6, 2018 by Dan Maloney 6 Comments

Part of the charm of quadcopters is the challenge that building and flying them presents. In need of complex sensors and computational power to just get off the ground and under tremendous stresses thanks to their massively powerful motors, they often seem only barely controlled in flight. Despite these challenges, quadcopter flight has been reduced to practice in many ways, leaving hobbyists in search of another challenge.

[Tom Stanton] is scratching his creative itch with this radio-controlled tilt-rotor airplane that presents some unique problems and opportunities. Tilt-rotor planes are, as the name implies, able to swivel their propellors and transition them from providing forward thrust to providing verticle lift. With the rotors providing lift, the aircraft is able to hover and perform vertical take-off and landing (VTOL); switched to thrust mode, wings provide the lift for horizontal flight.

[Tom]’s realization of this design seems simple – a spar running through the wing holding BLDC motors and props is swiveled through 90° by a servo to transition the aircraft. Standard control surfaces on the wings and tail take care of horizontal flight. Actually getting an off-the-shelf flight controller to deal with the transitions was tricky. [Tom] ended up adding an Arduino to intercept the PWM signals the flight controller normally sends directly to the servos and speed controls to provide the coordination needed for a smooth transition. Full details in the video below, and some test flights which show that an RC VTOL is anything but a beginner’s plane.

[Tom] is proving himself to be quite the Renaissance man these days. Between air-powered piston engines, over-balance trebuchets, and popping the perfect wheelie, he seems to have covered all the bases and done his best to keep our tip line stocked.

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Hackaday Links: October 28, 2018

October 28, 2018 by Brian Benchoff 11 Comments

Steve Jobs was actually a good designer and CEO. This is a statement that would have been met with derision in 2010, with stories of a ‘reality distortion field’. We’re coming up on a decade in the post-Jobs era, and if there’s one thing the last seven or eight years can tell us, it’s that Jobs really, really knew how to make stuff people wanted. Apart from the iPhone, OS X, and the late 90s redesign of their desktops, the most impressive thing Jobs ever did was NeXT. Now there’s book that describes the minutia of all NeXT hardware. Thanks to the Adafruit blog for pointing this one out.

Speaking of Apple, here’s something else that’s probably not worth your time. It’s a highly exclusive leak of upcoming Apple hardware that’s sure to change everything you know about tech. Really, it’s a floating hockey puck branded with the Apple logo. No idea what this is, but somebody is getting some sweet, sweet YouTube ad revenue from this.

A few years ago, [Tom Stanton] built an electric VTOL plane. It looked pretty much like any other foam board airplane you’d find, except there were motors on the wingtips a lá an Osprey. Now, he’s massively improving this VTOL plane. The new build features a 3D printed fuselage and 3D printed wing ribs to give this plane a proper airfoil. Despite being mostly 3D printed, this VTOL plane weighs less than half of the first version. Also, a reminder: VTOL planes (or really anything that generates lift from going forward) are the future of small unmanned aerial craft. Better get hip to this now.

Next weekend is the Hackaday Superconference, and you know we’re going to have an awesome hardware badge. It’s a badge, that’s a computer, and has a keyboard. What more could you want? How about an expansion header? Yeah, we’ve got a way to add a shift register and 8 LEDs to the badge. From there, you can do just about everything. Who’s going to bring an old parallel port printer?

Delta Clipper: A 1990s Reusable Single-Stage To Orbit Spaceship Prototype

July 19, 2018 by Steven Dufresne 51 Comments

With all the talk of SpaceX and Blue Origin sending rockets to orbit and vertically landing part or all of them back on Earth for reuse you’d think that they were the first to try it. Nothing can be further from the truth. Back in the 1990s, a small team backed by McDonnell Douglas and the US government vertically launched and landed versions of a rocket called the Delta Clipper. It didn’t go to orbit but it did perform some extraordinary feats.

Origin Of The Delta Clipper

The Delta Clipper was an unmanned demonstrator launch vehicle flown from 1993 to 1996 for testing vertical takeoff and landing (VTOL) single-stage to orbit (SSTO) technology. For anyone who watched SpaceX testing VTOL with its Grasshopper vehicle in 2012/13, the Delta Clipper’s maneuvers would look very familiar.

Initially, it was funded by the Strategic Defence Initiative Organization (SDIO). Many may remember SDI as “Star Wars”, the proposed defence system against ballistic missiles which had political traction during the 1980s up to the end of the Cold War.

Ultimately, the SDIO wanted a suborbital recoverable rocket capable of carrying a 3,000 lb payload to an altitude of 284 miles (457 km), which is around the altitude of the International Space Station. It also had to return with a soft landing to a precise location and be able to fly again in three to seven days. Part of the goal was to have a means of rapidly replacing military satellites should there be a national emergency.

The plan was to start with an “X” subscale vehicle which would demonstrate vertical takeoff and landing and do so again in three to seven days. A “Y” orbital prototype would follow that. In August 1991, McDonnell-Douglas won the contract for the “X” version and the possible future “Y” one. The following is the story of that vehicle and its amazing feats.

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Generate Random Numbers The Hard Way

December 13, 2017 by Will Sweatman 24 Comments

Your job is to create a random number generator.

Your device starts with a speaker and a membrane. On this membrane will sit a handful of small, marble-size copper balls. An audio source feeds the speaker and causes the balls to bounce to and fro. If a ball bounces high enough, it will gain the opportunity to travel down one of seven copper tubes. Optical sensors in each of the tubes detect the ball and feed data to an Ardunio Mega. When the ball reaches the end of the tube, a robotic hand will take the ball and put it back on the speaker membrane. The magic happens when we write an algorithm such that the audio output for the speaker is a function of how many balls fall down the pipes.

The above is a rough description of [::vtol::]’s art piece: kinetic random number generator. We’re pretty sure that there are easier ways to get some non-determinstic bits, but there may be none more fun to watch.

[::vtol::] is a frequent flyer here on Hackaday Airlines. Where else would you showcase your 8-bit Game Boy Photo Gun or your brainwave-activated ferrofluid monster bath? Would it shock you to find out that we’ve even covered another kinetic random number generator of his? Fun stuff!