Day: November 24, 2024

Modular Multi-Rotor Flies Up To Two Hours

November 24, 2024 by 3 Comments

Flight time remains the Achilles’ heel of electric multi-rotor drones, with even high-end commercial units struggling to stay airborne for an hour. Enter Modovolo, a startup that’s shattered this limitation with their modular drone system achieving flights exceeding two hours.

The secret? Lightweight modular “lift pods” inspired by bicycle wheels using tensioned lines similar to spokes. The lines suspend the hub and rotor within a duct. It’s all much lighter than of traditional rigid framing. The pods can be configured into quad-, hex-, or octocopter arrangements, featuring large 671 mm propellers. Despite their size, the quad configuration weighs a mere 3.5 kg with batteries installed. From the demo-day video, it appears the frame, hub, and propeller are all FDM 3D printed. The internal structure of the propeller looks very similar to other 3D-printed RC aircraft.

The propulsion system operates at just 1000 RPM – far slower than conventional drones. The custom propellers feature internal ring gears driven by small brushless motors through a ~20:1 reduction. This design allows each motor to hover at a mere 60 W, enabling the use of high-density lithium-ion cells typically unsuitable for drone applications. The rest of the electronics are off-the-shelf, with the flight controller running ArduPilot. Due to the unconventional powertrain and large size, the PID tuning was very challenging.

We like the fact this drone doesn’t require fancy materials or electronics, it just uses existing tech creatively. The combination of extended flight times, rapid charging, and modular construction opens new possibilities for applications like surveying, delivery, and emergency response where endurance is critical.

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Hacking The Soil To Combat Desertification

November 24, 2024 by No comments

While the Sahara Desert is an important ecosystem in its own right, its human neighbors in the Sahel would like it to stop encroaching on their environment. [Andrew Millison] took a look at how the people in the region are using “half moons” and zai pits to fight desertification.

With assistance from the World Food Program, people in Niger and all throughout the Sahel have been working on restoring damaged landscapes using traditional techniques that capture water during the rainy season to restore the local aquifer. The water goes to plants which provide forage during the 9 drier months of the year.

The main trick is using pits and contouring of the soil to catch rain as it falls. Give the ground time to absorb the water instead of letting it run off. Not only does this restore the aquifers, it also reduces flooding during during the intense rain events in the area. With the water constrained, plants have time to develop, and a virtuous cycle of growth and water retention allows people to have a more pleasant microclimate as well as enhanced food security. In the last five years, 500,000 people in Niger no longer need long-term food assistance as a result of these resiliency projects.

If this seems familiar, we previously covered the Great Green Wall at a more macro level. While we’re restoring the environment with green infrastructure, can we plant a trillion trees?

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