From TFA: > The total system required just over half a watt of power to stay aloft. Given a total mass of 4 grams, that works out to a lift-to-power efficiency

From TFA: > The total system required just over half a watt of power to stay aloft. Given a total mass of 4 grams, that works out to a lift-to-power efficiency of 7.6 grams per watt. But a lot of that power is lost during the voltage conversion. If you focus on the motor alone, it only requires 0.14 watts, giving it a lift-to-power efficiency of over 30 grams per watt.... > But one thing they don't have to optimize is the vehicle's size since they already built a miniaturized version that's only 8 millimeters high and weighs just 9 milligrams but is able to generate a milliwatt of power that turns its propeller at over 15,000 rpm. 9mg is just the smallest version they managed to make. Based on the size of the solar panel in the video, there's plenty of room to scale to tens of grams per drone. And this is a laboratory proof of concept, not a well funded weapons prototype.