Cortex 2 is One Serious 3D Printed Experimental Rocket

Rocketry is wild, and [Foaly] is sharing build and design details of the Cortex 2 mini rocket which is entirely 3D printed. Don’t let that fool you into thinking it is in any way a gimmick; the Cortex 2 is a serious piece of engineering with some fascinating development.

Cortex 1 was launched as part of C’Space, an event allowing students to launch experimental rockets. Stuffed with sensors and entirely 3D printed, Cortex 1 flew well, but the parachute failed to deploy mainly due to an imperfectly bonded assembly. The hatch was recovered, but the rocket was lost. Lessons were learned, and Cortex 2 was drafted up before the end of the event.

Some of the changes included tweaking the shape and reducing weight, and the refinements also led to reducing the number of fins from four to three. The fins for Cortex 2 are also reinforced with carbon fiber inserts and are bolted on to the main body.

Here’s an interesting details: apparently keeping the original fins would result in a rocket that was “overstable”. We didn’t really realize that was a thing. The results of overstabilizing are similar to a PID loop where gain is too high, and overcorrection results in oscillations instead of a nice stable trajectory.

Cortex 2 uses a different rocket motor from its predecessor, which led to another interesting design issue. The new motor is similar to hobby solid rocket motors where a small explosive charge at the top of the motor blows some time after the fuel is gone. This charge is meant to eject a parachute, but the Cortex 2 is not designed to use this method, and so the gasses must be vented. [Foaly] was understandably not enthusiastic about venting hot gasses through the mostly-PLA rocket body. Instead, a cylindrical cartridge was designed that both encases the motor and redirects any gasses from the explosive charge out the rear of the rocket. That cartridge was SLA printed out of what looks to us like Formlabs’ High Tempurature Resin.

Finally, to address the reasons Cortex 1 crashed, the hatch and parachute were redesigned for better reliability. A servo takes care of activating the system, and a couple of reverse-polarity magnets assist in ensuring the hatch blows clear. There’s even a small servo that takes care of retracting the launch guide.

The rocket is only half built so far, but looks absolutely fantastic and we can’t wait to see more. It’s clear [Foaly] has a lot of experience and knowledge. After all, [Foaly] did convert a Makerbot printer into a CNC circuitboard engraver.

Why No Plane Parachutes? And Other Questions.

This week I was approached with a question. Why don’t passenger aircraft have emergency parachutes? Whole plane emergency parachutes are available for light aircraft, and have been used to great effect in many light aircraft engine failures and accidents.

But the truth is that while parachutes may be effective for light aircraft, they don’t scale. There are a series of great answers on Quora which run the numbers of the size a parachute would need to be for a full size passenger jet. I recommend reading the full thread, but suffice it to say a ballpark estimate would require a million square feet (92903 square meters) of material. This clearly isn’t very feasible, and the added weight and complexity would no doubt bring its own risks.

Continue reading “Why No Plane Parachutes? And Other Questions.”

Quadcopter Beer Delivery System

One of the major design challenges when it comes to building an efficient quadcopter is weight. The idea here is that the more you can trim down the weight of the frame, motors, and circuitry, the longer the batteries will last. Or, in [dalbyman]’s case, the more beer it can carry.

[Dalbyman]’s housemate built the actual quadcopter, but then [dalbyman] got a little inebriated and decided that, while the quadcopter was exciting on its own, it would be even better with this modification. The actual device is a modified Pringles can with two servo motors on the bottom with arms that hold the beer. A parachute is attached to the beverage can and the assembly is loaded in. With a simple press of a button, the servos turn the arms and the beer falls out of the tube. Hopefully the parachute deploys and gently (and accurately) floats the beer to the thirsty person on the ground!

This project is a simple step that goes a long way towards a beer delivery system even Amazon could be proud of, and also shows off the capabilities of quadcopters in general. Perhaps the next step could be to automate the beer delivery system!

 

Nose Cone Parachute Deployment from a Soda Bottle, Rubber Band, and Servo

nose-cone-parachte

This piece of engineering is so simple and elegant, you’ll want to build a pretty serious water rocket just so you can try it out. It’s an automatic parachute deployment system that you build into the nose-cone of your rocket. The main portion of the build is made out of plastic soda bottles (2 liter size) to end up with a chamber to store the chute, as well as a friction joint that holds the thing together.

The video after the break shows a complete tutorial on how to build one of these. It starts by tracing out a sine-wave-like pattern on the wall of the bottle. The staggered tongues that are left after cutting along this line make up the friction joint. After gluing a cone (the blue thing) to the bottom of the bottle, it receives the parachute and is then slipped over another bottle that makes up the body of the rocket. The rubber band wraps around the outside of the chassis, holding those plastic tongues in place. The loose end of the rubber band is hooked around the horn of a servo motor, which can then be triggered remotely, or by using a sensor of your choosing. There is even a spring made out of a loop of plastic bottle — you can see it just on top of the chute in the image above.

Need a launching system that is as fancy as the parachute system? Here you go.

Continue reading “Nose Cone Parachute Deployment from a Soda Bottle, Rubber Band, and Servo”

Adding payload to an RC cessna

For just a few bucks you can add a payload to your flying toys. In this case it’s a Cessna RC plane which now has an added surprise. The first thing to be dropped was a parachute with a weight on it (for testing purposes). But there are hints of future projects that will use the same system for different purposes.

As you can see in the image above, the system depends on an additional compartment attached to the bottom of the plane. It was built from foam board to keep the weight down and connects using rare earth magnets. The bottom of the enclosure acts as the door, hinging on a servo motor with a bamboo skewer as the axle. So far the test drops have gone pretty well, but some more work needs to be done with the parachute design. It only opens about 60% of the time. We can sympathize, having had to work out some of our own parachute issues.

Don’t miss video from the plane as well as the ground after the break.

Continue reading “Adding payload to an RC cessna”

Human flight at 190 MPH with no steering

It’s been a while since we looked in on a TED talk but this one is fantastic. [Yves Rossy] is interviewed about his jet-powered flight wing at the TED conference. He designed the unit as a form of personal flight. He straps it on, jumps out of a plane, then flies across the sky until he runs out of fuel. There’s no steering mechanism; it’s more of a fixed-wing hang glider plus jet turbine engines. But the pilot can affect the direction of the wing by moving his body.

We’ve embedded the video after the break. The first five minutes are all flight footage (which you’re going to want to watch… we specifically kept the banner image vague so as not to spoil it for you). After that, you’ll enjoy the interview where details about the hardware and its operation are shared.

The wing itself is about 2 meters across, hosting four kerosene-powered turbine engines. There’s about eight minutes worth of fuel on board, which [Yves] monitors with a clock while also keeping an eye on the altimeter. Landings are courtesy of a parachute, with a second on board as a backup. If things go badly–and they have as you’ll hear in the interview–an emergency release frees the pilot from the machine.

Want to build your own? Maybe this will get you started.

Continue reading “Human flight at 190 MPH with no steering”

Wall-climbing bot does it with ease

Paraswift is a robot that can climb vertical surfaces with ease. Here you can see the robot motoring up the side of a building with a parachute packed on it’s back for use on the way down. The team that built the robot is calling it a base jumper, but after seeing them catch the falling robot in a net we’d say it’s still a bit too fragile to make that claim.

The parachute isn’t the only way for this guy to get down after a long climb. As you can see in the video after the break, it has no trouble driving in any direction on a wall. Like other wall-climbers the Paraswift is using air to stick to the surface. A vortex of air, similar to a tornado, generates a large amount of negative pressure, sucking the body of the robot to the surface it is climbing. I you’re the one who traded a good portion of your life to spend building the Paraswift we’re guessing you added the parachute to hedge your bets against a power failure.

Continue reading “Wall-climbing bot does it with ease”