Pelton Turbine Development For An Air Powered Model Helicopter

[Tom Stanton] has been messing around with compressed air power for a few years now, and most of his work focused on piston engines. He likes using 2-liter soda bottles as lightweight tanks but their capacity is limited, so the nozzle can be a maximum of 1 mm in diameter if he wants to produce thrust for 30 seconds or longer using a turbine. Pelton turbines have been in use for a long time, especially for hydroelectric systems, and they use small diameter nozzles, so he decided to experiment with a pneumatic Pelton turbine. (Video, embedded below.)

Pelton wheels are water wheels with specially designed buckets to efficiently extract energy from a high-velocity jet of water. [Tom] 3D printed several geared Pelton turbines and started doing bench tests with a propeller and a load cell to gather empirical data. With the help of high-speed video of the tests, he quickly realized that the turbine efficiency is highly dependent on the load. If the load is too small or too large, the moving air will not come to a complete standstill, and energy will be wasted. [Tom] also suspected that some moving air was escaping from the bucket, so he created a version that enclosed the buckets with a ring on the outer perimeter, which increased the peak thrust output by 65%. Compared to his diaphragm air engine design, the peak thrust is higher, but the overall efficiency is less. [Tom] believes there is still room for improvement, so he plans to continue working on the Pelton turbine concept, with the hopes of building an air-powered model helicopter that can lift off. Continue reading “Pelton Turbine Development For An Air Powered Model Helicopter”

Model Hydroelectric Plant Is An Illuminating Educational Tool

There’s more than one way to light up a strip of LEDs. Have you tried building your own hydroelectric power plant to do it? Well, now you can. Replicating [Matic Markovi─Ź]’s entry into the 2020 Hackaday Prize is bound to teach you something, if not many things, about the way hydroelectric power is generated and the way the variables play into it.

In [Matic]’s model, water from an adjustable-height reservoir flows into a 3D-printed Pelton turbine. The water jet hits the turbine’s cupped fins at a 90┬░ angle, causing the assembly to spin around rapidly. This mechanical energy charges a brushless DC motor that’s connected to an Arduino Nano, which rectifies the AC from the generator and uses it to light up an RGB strip like an equalizer display that represents the power being generated.

This is easily one of the coolest educational displays we’ve ever seen. The reservoir can move up and down over a 55 cm (21.6″) range with the flick of a three-way toggle, which makes it easy to see that the higher the reservoir, the more power is generated. [Matic] has the STLs and INOs in the usual places if you want to make your own. Flow past the break for a demonstration, followed by an exploded render that gets put back together by invisible hands.

Your hydroelectric setup doesn’t need to be fancy, it just needs to work. One man’s trash can be another man’s off-grid phone charger.

Continue reading “Model Hydroelectric Plant Is An Illuminating Educational Tool”