Peter Sripol’s DIY Electric Ultralight MK4

Peter Sripol really likes building gravity defying death traps. He recently flew the fourth ultralight, which he designed and built himself. For a taste of what’s going on here, the wings have aluminum tube spars and are made of hot-wire-cut styrofoam sections.

To keep the plane simple, he got rid of ailerons entirely. For roll stabilization he angled up the wings noticeably, adding dihedral. This gives the aircraft passive stability, because as it rolls to a side, the upper wing’s lift decreases and the lower wing’s lift increases, forcing the plane to correct itself. Interestingly he kept the rudder controls on pedals instead of moving it to the stick, so the stick only controls the elevator.

It is powered by a single large brushless electric motor borrowed from the OpenPPG project. On the first test he used a two-bladed propeller, with a small pitch angle which required full throttle to keep flying. It can be compared to driving a car only in first gear. By moving to a three bladed propeller with a higher pitch angle, and increasing the length of the wings for more lift, [Peter] was able to cruise comfortably at about 30 MPH or 48 km/h.

Although this aircraft definitely performed better than [Peter]’s previous ultralight builds, piloting something like this isn’t for the faint of heart. Although he does extensive weight-loading and thrust testing before taking to the air, adding tail weight to piloted aircraft by simply taping a water bottle to the tail just felt wrong. But we aren’t aviation experts, so we won’t pass final judgement.

Let’s Take A Closer Look At This Robotic Airship

It’s not a balloon, however shiny its exterior may seem. This miniature indoor robotic airship created by the University of Auckland mechanical engineering research group [New Dexterity] is an asymmetric system experimenting with the possibilities of an open-source helium-based airship.

Why a helium airship, as opposed to a fixed wing aircraft? The group wanted to experiment with the advantages of lighter-than-air (LTA) travel, namely the higher mobility and looser path planning constraints. Furthermore, LTA airships have a less obstructed field of vision and fewer locomotion issues. While unmanned aerial vehicles (UAV) may be capable of hovering in one place, their lift is generated by rotor thrust, which drains their batteries quickly in the order of minutes. LTA airships can hover for longer periods of time.

The design was created for educational and research purposes, focusing on the financial feasibility of manufacturing the platform, the environmental impact of the materials, and the helium loss through the balloon-like envelope. By measuring these parameters, the researchers are able to study the effects of circumstances such as the cost of indoor commercial balloons and the mechanical properties of balloon materials.

The airship gondola was designed and 3D printed in a modular fashion, then attached to the envelope with Velcro. The placement with respect to the horizontal symmetry of the gondola was done for flight stability, with several configurations tested for the side rotor angle.

The group open-sourced their CAD files and ROS interface for controlling the airship. They primarily use off-the-shelf components such as Raspberry Pi boards, propellers, a DC single brushed motor driver carrier, and LiPo batteries for a total cost of $90 for the platform, with an addition $20 for the balloon and initial helium filling. The price is comparable to the cost of indoor blimps like the Blimpduino 2.0.

You can check out the completed airship below, where the team demonstrates its path following capabilities based on a carrot chasing path finding algorithm. And if you’re interested in learning more about the gotchas of building lighter-than-air vehicles, check out [Sophi Kravitz’s] blimp talk from Hackaday Belgrade.

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Here’s Your Flying Car

We’ve seen quadrocopters galore over the past few years. We’ve never seen one big enough to lift a person until now.

[Thomas], [Stephan], and [Alexander] of e-volo have been working on a gigantic, human-lifting multicopter for a few years now. A few days ago, their prototype took to the air carrying a fully human pilot. There aren’t a whole lot of details on their build, but from what we can tell the flight was powered entirely by batteries.

The test vehicle looks to be a study in minimalism. The landing gear looks to be a repurposed yoga ball, and the chassis is just four pieces of aluminum tube welded into a cross. The the power plant for the prototype is four brushless motors in each quadrant of the vehicle. That’s right – there are 16 motors spinning around the pilot.

This isn’t the first time we’ve seen a build based on Doctor Robotniks designs. Earlier this year, some guy in China built a very nice deathtrap an octocopter. The e-volo team definitely has the leg up in safety considerations – they have actual design and engineering studies

The good news is the e-volo team wants to improve their prototype and sell it to the masses. The bad news for Americans is the FAA hasn’t taken too kindly to electric flying machines. The team is working on a hybrid drive version, and as long as the weight is kept down, we can always get an ultralight cert.

Check out the video of some 16-blade hovering action after the break.