A firefighting bucket is a simple idea carried out under hard conditions: a fabric container on a line, filled from open water in seconds, emptied over the fire in about one. Everything that matters happens where nobody can reach it.

The Buitink FB series is built around that. Nineteen sizes, from 360 to 7,600 litres, for light helicopters through to heavy firefighting aircraft — and for the new generation of unmanned firefighting aircraft. Designed, welded and tested in our own works in Duiven.

What makes a Buitink bucket different

Welded, not stitched. The shell is hot-air welded with a 40 mm overlap. No needle holes where a tear can start, and no adhesive to age. Where load has to enter the fabric it is spread through sewn polyester webbing.

A frame that stays open by geometry. The mouth is held open by a folding frame: a hub with eight spokes to the rim, like an umbrella turned upside down. On lifting, the hub passes just over its dead point, so the frame stays open because of where it is, not because something holds it. Folding it is one movement.

One electrical function. The valve is held shut by a spring reel and opened by a short pulse. It then closes itself as soon as the bucket leaves the water — no crew action, no second command.

Made in Europe, and serviced by the people who built it. Annual inspection, repair, a replacement valve: the company that built the bucket does the work. No return to another continent.

How it works

1. Filling — the bucket is lowered into open water, a folding basin or a dip tank and fills through the open mouth.
2. Holding — with water in it a pawl carries the load, not the spring. Nothing is powered and nothing can drift open. Water pressure presses the valve tube against the bottom ring: the fuller the bucket, the better it seals.
3. Dumping — a short pulse, the pawl releases, the tube everts and the whole load leaves the bucket in about a second.
4. Closing — once the bucket is empty the spring wins, draws the purse strings up and the valve closes by itself.

One bucket, several loads

Payload is never the same twice: altitude, temperature, fuel and wind all move the number. A bucket that can only be filled to the brim forces the aircraft to carry whatever the bucket decides.

Every FB bucket therefore carries a circumference strap around the shell. Tightening it reduces the effective volume in steps to about 70% of nominal; the setting is made on the ground in a minute. Within that setting the pilot has a finer control: how fast the bucket is drawn up out of the water.

For firefighting drones

Heavy unmanned aircraft now lift several hundred kilograms and fly where a crew should not: at night, in smoke, close to the flame front. What they usually do not have is a cargo hook with a powered release circuit and a pilot who can see the load.

The -W version answers that: the release head carries its own battery and a wireless module, so the bucket is independent of the aircraft. Nothing has to be integrated or certified on the airframe, and the same bucket can move between machines. Where the aircraft does offer a payload bus, we make that connection.

For helicopters

The standard suspension is a four-point stainless cable set to a spreader with the release head below it, about 4.4 m from hook to bottom. Aircraft with limited tail rotor clearance take the -S version with a short suspension of about 3.9 m. The solenoid is driven from the load circuit: 28 VDC standard, 12 or 24 VDC on request.

The range

Nineteen sizes. The name is the capacity: FB followed by the nominal volume in litres. Suffixes: -S short suspension, -W wireless release. They combine: FB-360-SW.

Diameters are design values for planning and clearance checks; the final fabric contour of each size comes out of engineering.

Specifications FB-360

Tested before it flies

Every bucket is proof-loaded to twice its working load and then filled, held and dumped on our own rig. The results go in the file with the material certificates and the declaration of conformity; the serial number on the shell ties the bucket to that file for the rest of its life.

Supplied with it: CE marking and declaration of conformity, the test report of that individual bucket, material certificates, an operating manual, a maintenance and inspection manual with logbook, and a repair manual with parts list.

Maintenance, inspection and repair

Rinse after use, check the cords and the rim, look at the valve and the clamping ring, run a dry function test. The maintenance manual gives a limit value for every part and grades findings in three categories: safety, operational, monitor. We carry out the annual inspection in Duiven, with a report and a logbook entry.

A cut in the shell does not have to end the day: the repair kit contains a sealing clamp that closes a tear of up to 150 mm well enough to keep flying, plus patches for a permanent repair.

Also for your existing buckets

We also build replacement fabric shells for buckets from other manufacturers: your existing internals, suspension and head transfer into a new shell welded in Europe. Often a fraction of the price of a new bucket and with a much shorter lead time. We inspect and repair existing buckets in the same place.

A bucket matched to your aircraft?

Give us the aircraft type, the payload available and how the release is to be commanded, and we will come back with a proposal. Ask for the FB series brochure as well.