Drone Hopper, a Spanish startup, is developing drones that could be used for dropping water or fire retardant on wildfires. Their Wild Hopper model would carry up to 160 gallons (600 L.) which is almost double the capacity of a Bell 206 helicopter.
The company has designed several models. One of the earliest is seen in the photo at the top of this article. I can imagine that if someone saw one, or 15 to 20 of those saucer-shaped devices flying through the sky in formation, they might be thinking — UFO.
The video below, uploaded September 16, 2016, apparently shows the small early model.
This next video, uploaded November 17, 2018, features the later Wild Hopper model with a tall visible water tank presumably holding 160 gallons, according to information on the company’s website.
The rotorcraft’s electric motors are driven by batteries which also power a device to electronically convert the water to a mist through what the company calls a nebulization process. The downward thrust of the rotors drives the mist at high speed toward the ground. While a water mist could more evenly wet the vegetation, any significant wind or strong convection off the fire might blow the water off target.
The aircraft has a thermal camera which could make nighttime water drops more accurate.