News

Onboard camera of choice

News | October 23, 2012

At Makani we have long seen the value of well-documented tests and have been an interested consumer of the latest robust, small-camera technology for the past six years. When the first GoPro came out we were impressed with its size and resolution, and as they continue to release new, modular accessories and better cameras, our reliance on the equipment is growing.

Our Testing Director, Paula Echeverri says, “The great thing about gopros is that, since they have good resolution and a wide field of view, we can capture a large part of the wing in a single shot. Just one video can help us confirm good behavior of the structure, the aerodynamics and several different components (motors, tether, bridles and control surfaces). For example, we have seen the extent of fuselage twist through a crosswind loop, and the locus of attached flow as the air combs the tufts over the wing. And we still have enough room for gorgeous views of the sky and the land.”

The good: the resolution, detail and contrast of GoPros makes for stunning images. We have not tried the brand-new Hero3 yet (released last Thursday), but if the improved light sensitivity of the Hero2 is an indication—it is probably worth the price tag. GoPro’s modular gear allows one to clip into old gear (eco-friendly!) or buy a replacement for just one damaged part (e.g., we like their lens kit). Battery BacPacs give us longer recording time, which is great as we conduct longer test flights.

At present our only grievance is with the wireless remote, which has limited battery life, requiring us to keep it plugged in right up until we use it. The excellent footage from the groundside gimbal we got using this method was worth the workaround, and all in all GoPro has been a great addition to our camera gear. You will see their signature fisheye view in Makani videos and press coverage for the foreseeable future.

If you are already a fan of GoPro, you might like this recent profile of the company in Popular Mechanics.

Here is a recent photo taken from the wing as we conduct a test flight over Sherman Island.

  • AWT

    A wind based energy generation device with at least one airborne element. The Makani AWT consists of a rigid wing with mounted turbines that flies in circles across the wind at 300 meters (1,000 feet) above ground level.

    Airborne Wind Turbine

    A wind based energy generation device with at least one airborne element. The Makani AWT consists of a rigid wing with mounted turbines that flies in circles across the wind at 300 meters (1,000 feet) above ground level.

    Airborne Wind Turbines

    A wind based energy generation device with at least one airborne element. The Makani AWT consists of a rigid wing with mounted turbines that flies in circles across the wind at 300 meters (1,000 feet) above ground level.

    Autonomous Controller

    An on-board computer that controls the flight path of the wing by changing the position of the control flaps.

    Avionics

    The electronic backbone of the AWT. Avionics include the sensors, actuators, controllers and communication systems that keep the wing flying on its desired path.

    Capacity factor

    The average power output divided by the name plate power output of a power plant. Capacity factor demonstrates the frequency with which a power plant is running at its name plate capacity.

    COE

    Cost of Energy or the total cost to generate energy that is fed into the grid.

    Firming Power

    The outside power generation needed to stabilize the flow of electricity to the grid when an inconsistent resource, like wind or solar, creates less electricity than needed.

    Ground Station

    The base station for the AWT, includes a winch for retrieval of the wing and storage of the tether.

    Car vs. AWT

    A typical compact car weighs about 1.2 tons and produces about 30 kW during the 10 seconds it takes to slow from 25 m/s (50 mph) to a stop. Each cubic meter (~1.2 cubic yards) of air weighs only .0012 tons and a good wind day might be traveling at 25 mph (11 m/s), so Wing 7 would have to to interact with 350 cubic meters of air (about 23 dump trucks worth) every second to extract an equal amount of power. In reality it is not as efficient to design an AWT to completely halt the air it interacts with, so we design our AWTs to exert a smaller force on an even larger body of air.

    Material efficiency

    Material efficiency refers to how much power is output in relation to the raw material needed for construction of the generator.

    Rated power

    The amount of power a plant delivers when operating at full capacity.

    Rated capacity

    The amount of power a plant delivers when operating at full capacity.

    Rotors

    The rotors capture the accelerated wind as it rushes across the wing and convert it into electrical power with small, direct drive generators. The hybrid rotors can act as propellers as well as turbines, allowing the wing to stay aloft if the wind dies.

    Turbines

    The rotors capture the accelerated wind as it rushes across the wing and convert it into electrical power with small, direct drive generators. The hybrid rotors can act as propellers as well as turbines, allowing the wing to stay aloft if the wind dies.

    Tether

    The tether is made of high strength fibers surrounding a conductive core. The tether carries the traction force of the wing and transmits the electrical power to the ground station.

    Tethered

    The tether is made of high strength fibers surrounding a conductive core. The tether carries the traction force of the wing and transmits the electrical power to the ground station.

    Usable land

    Factors that influence whether land is usable include site geography, ecology, and wind patterns, for example.