When you're using helicopters to dump water on forest fires, it goes without saying that the faster you can obtain and deliver water from lakes or other sources, the better. Most currently-used systems are able to gather H2O at rates ranging from 1,700 to 4,000 liters (450 to 1,056 US gal) per minute, which is fairly impressive. A new system developed by Spanish firm Inventec, however, is claimed to be capable of sucking up 1,000 L (264 gal) in just five seconds – that scales up to a rate of 12,000 L (3,170 gal) per minute. What's more, it's also said to be safer.
Although some aspects of the prototype system are being kept under wraps, we've been told that it incorporates a dangling spherical tank that's connected by hose to a vacuum pump installed in the helicopter. By contrast, some other systems have a smaller pump built into the tank/"bucket" itself, or they use a snorkel-type hose to suck water into a tank attached to the underside of the helicopter.
Additionally, many setups require the tank to be submerged for filling, and then towed forward through the water. Because the Inventec tank only needs to have its bottom-located intake port submerged, however, it can be used in bodies of water no deeper than 25 cm (9.8 in) – plus, it doesn't need to be moved laterally when filling. This means that the helicopter isn't limited to accessing bodies of water that are deep and wide-open.
Once the tank is full, it can be quickly flown to the site of a fire with no leakage occurring en route. Upon getting there, it disgorges its contents onto the flames from the air, at a rate controlled by the helicopter crew. Conversely, however, it can also be lowered to the ground and untethered from the aircraft. Ground-based firefighters can then either attach a hose to it and spray the water on flames directly (the tank remains pressurized), or use it to refill their own personal water-spraying packs. Because of this functionality, Inventec is suggesting that the system could also be used for delivering drinking water to disaster sites or other locations that lack potable water.
Finally, when the empty tank is being flown back for refilling, its design allows pilots to travel at relatively high speed without any chance of it drifting up into the tail rotor – with some existing systems, there is reportedly a risk of this occurring.
An Inventec representative tells us that the company is currently in negotiations with industrial partners, that are interested in manufacturing and marketing the technology. Pool tests of the system can be seen in videos posted on the company website, which is linked below.