Photo Info
Bell 47

Buckets & Belly Tanks

By Bob Petite

Published on: July 14, 2016
Estimated reading time 14 minutes, 34 seconds.

Now a crucial weapon in the fight against wildfires, the use of helicopters as a firefighting tool was apparent from its very early days.

While helicopters are a familiar — and reassuring — sight above wildfires today, the use of this new technology in tackling blazes in the wild was considered highly experimental when it began in the Angeles National Forest in 1945. Organized through a joint effort between the U.S. Forest Service and the U.S. Army Air Force (USAAF), the tests used Sikorsky R-4, R-5A, R-5D, and R-6 aircraft to explore the suitability of helicopters for fire control in mountainous country; while the Army and Navy had experience operating the aircraft at sea level, the helicopter’s performance at higher altitudes was a relatively unknown quantity.

Okanagan Helicopters Sikorsky S-58
An Okanagan Helicopters Sikorsky S-58 demonstrates a water drop using a tank slung underneath the fuselage. The operator originally used an internal tank that carried 270 US gallons (1,022 liters) of water or retardant. Okanagan Helicopters/Bob
Petite Collection Photo

In Canada, the helicopter made its official firefighting debut on June 16, 1946, when a prototype Bell 47 was used for reconnaissance of an active wildfire near Sudbury, Ontario, for the Ontario Department of Lands and Forests (ODLF). A month later, a USAAF Sikorsky R-5A was used on a forest fire in Alaska, completing short shuttle runs from Fairbanks to the blaze near Tanana River, carrying firefighters and their equipment.

The first recorded use of a helicopter on an active fire in the contiguous United States was on Sept. 9, 1946, when a single USAAF Sikorsky R-5A was used to map and scout a forest fire near Castaic, California, and also dropped supplies along its perimeter. The following summer — Aug. 5 1947, to be precise — two Bell 47B helicopters from Armstrong-Flint Helicopter Company were used to fight the Bryant Fire in the Angeles National Forest in California. Flown by Knute Flint and Fred Bowen, the two aircraft flew four missions within two hours of their arrival. The aircraft proved their worth in a wide variety of missions on the fire, and made such a difference to the operation that the Bryant Fire is widely seen as a watershed moment in the evolution of the use of the helicopter in fighting wildfires, marking its transition from an untested curiosity to a proven firefighting tool.

However, the Chief of Fire Control at the U.S. Forest Service — A.A. Brown — was still cautious about the unrestricted use of helicopters on fires without further research and more experience. The helicopter’s potential ability to drop water on forest fires offered a particularly promising operational use, but it was an area that had not been fully explored.

Hiller 360
Wax paper bags of water are loaded onto a platform underneath a Hiller 360. Ontario Department of Lands and Forests/Bob Petite Collection Photo

The next landmark in wildfire helicopter use was in 1954, when stakeholders from across the firefighting world — including a special project established by county, federal, state, military and private organizations — looked at new and innovative ways of addressing wildfire control problems in California. Known as Operation Fire Stop One, it looked at a variety of methods, including experimental work in developing new strategies to transport firefighters by helicopter, deploy them while hovering, lay fire hose, and use water and retardants on initial attack without landing.

Up in Canada, the Ontario Provincial Air Service purchased a Bell 47D-1 in 1953 to explore its potential to help support the ODLF in controlling fires. The helicopter was crewed by Spartan Air Services pilots (and was later sold to Spartan). The ODLF also leased a Hiller 360 from Kenting Aviation for comparison with the Bell 47.

In one program in 1954, the three-place Hiller 360 was used to drop water-filled wax paper bags from a rack under its fuselage onto a controlled forest fire. The Provincial Air Service had previously used one of its de Havilland Canada DHC-2 Beavers to drop these water-filled wax paper bags onto fires, before using roll-tanks on the floats, and then much later transitioning to water being carried in the floats for dropping on fires. The paper bag Hiller 360 project turned out to be ineffective due to the difficulty of delivering a concentrated load. The dropped bags also had an unfortunate tendency to spread embers along the fire’s edge.

In another project, the Bell 47D-1 was equipped with water tanks on the side of its fuselage, complete with a nozzle attachment, controlled by the pilot, to spray the water. The system sounded great, but worked poorly in practice, and the project also showed that the tanks were too small to be effective.

Developing the Drops

Around this time, the U.S. Forest Service was also looking at dropping water — as well as retardant — directly on wildfires from a helicopter. They considered it to be an excellent tool for controlling spot fires and single tree lightning fires, and for supporting crews along the fire line.

Bell 47
A Bell 47 drops water on a wildfire using a newly-designed fabric tank. US Forest Service/Jeff Evans Collection Photo

Herb Shields, who worked at the U.S. Forest Service’s Arcadia Fire Equipment Development Center (later the San Dimas Technology & Development Center), developed the first helitank designed to drop water from a helicopter. The tank was made of a neoprene-coated nylon fabric capable of carrying up to 35 U.S. gallons (132 liters) of water or retardant. The tank attached to the sling release under the helicopter’s fuselage between the skids. Over the fire, the pilot pressed a button releasing the neck, sending the water cascading onto the flames. Loaded from a fire truck or portable pump, a second bag could be filled and would be ready to attach to the helicopter upon its return from the fire. Many demonstrations were carried out in 1957 showing off the helitank, which was later replaced by a version that could hold a larger volume of water or retardant.

One of the first to use the newly-designed fabric helitanks operationally was the Los Angeles County Fire Department, which had formed its helicopter unit in 1957 under the command of experienced helicopter pilot Roland Barton. The department was formed with the original intent of using its Bell 47G-2 helicopters to quickly transport men and equipment close to where wildfires started, but it soon began using the helitanks to attack the flames — over 77 helitanker drops were made on one fire in 1958 alone.

Several U.S. Marine Corps Sikorsky H-34/S-58 helicopters were tested in 1958 with experimental tanks under the fuselage for use on forest fires. (Okanagan Helicopters in British Columbia later retrofitted a Sikorsky S-58 with an internal 270-U.S. gallon/1022-liter tank and gating system under the fuselage for dropping on forest fires during 1958. However, the system was not financially practical without a contract, and the company eventually chose to use to a slung tank below the helicopter instead.)

One of the largest firefighting helicopter operations of 1959 took place in the Angeles National Forest, when over 56,000 U.S. gallons of water and retardant were dropped by a combination of helicopters and air tankers. Just a few miles to the east, two Marine H-34/S-58 helicopters with 150-U.S. gallon (568-liter) tanks were used to fight a forest fire in the San Bernardino Forest in August the same year.

metal belly tank
A fire department Bell 47 hovers over a portable tank, as water is loaded into its metal belly tank during a wildfire operation. Jeff Evans Collection Photo

During 1961 and 1962, the U.S. Forest Service’s Herb Shields worked with the Los Angeles County Fire Department to develop a fixed-mount 100-U.S. gallon (378-liter) metal drop tank for Bell 47 and other light helicopters.

The fledgling aviation unit of the Los Angeles (City) Fire Department was among the first to purchase one of the new tanks — known as the “L.A. Tank.” The department entered rotary-wing operations in 1962 under chief pilot Clarence Ritchie with a turbo-charged Bell 47G-3B helicopter. At first, the L.A. Tank’s hand-operated doors required the pilot to take his or her hands off one of the flight controls to pull a large lever in order to drop the water. This was soon replaced by an electrical release to open and close the doors — a far safer method of operation.

Bringing the bucket to the fire

In 1961, Dominion Helicopters of Ontario used its Vertol H-21 twin rotor helicopter to test a square metal bucket that carried 258 U.S. gallons (976 liters) of water suspended under the fuselage. The system used a rope to tip the bucket for filling and dumping the water, and the water source had to be at least six feet deep for the bucket to fill.

Further west, Okanagan Helicopter pilot Jim Grady and Henry Stevenson of Stevenson Machinery Ltd. developed a 54-U.S. gallon (204-liter) drum for transporting water to forest fires using a Hiller 12-E. It took several years in the early 1960s for the team to perfect the product, which was called the Monzoon Bucket. Carried by a cargo hook, the bucket was easily filled while hovering over a water source. Later, the bottom hatch was activated by a solenoid to release the water. Over 300 Monzoon Bucket conversion kits were eventually sold across Canada, the U.S., and Australia.

Vertol H-21
A Vertol H-21, owned by Dominion Helicopters in Ontario, tests a square metal bucket for firefighting during 1961. It could hold up to 258 US gallons (976 liters) of water or retardant. Bob Petite Collection Photo

South of the border, the California Department of Forestry experimented with the Bowles Bag, a neoprene tank that carried 80 to 100 U.S. gallons (303 to 378 liters). It attached to the landing skid frame and was used with light helicopters.

During 1963, various attempts were made to develop a firefighting tank for use on the turbine Bell 204B. Starting with an internal 360-U.S. gallon (1,363-liter) tank that discharged water from both sides of the aircraft, the U.S. Forest Service and the Los Angeles County Fire Department worked in partnership again to develop a 400-U.S. gallon (1,514-liter) external fixed helitank that was perfected around 1967.

With the introduction of the turbine-powered Bell JetRanger, Hughes 500, and Fairchild Hiller FH-1100 in 1967 — and their increased altitude performance — helicopters were now capable of transporting even larger water bucket loads to fires. The Boeing Vertol 107-ll also demonstrated its capability as a firefighting aircraft around this time, using an enormous 800-U.S. gallon (3,028-liter) helibucket.

An indication of a new era for the tanks themselves could be seen north of the border in 1970. The Ontario Department of Lands and Forests and Ontario Provincial Air Service had developed a refined folding fire-bombing tank for the Bell 47G-4. With an aluminum frame and fabric body, the tank could be folded and retracted automatically when not required. The opening was one foot (0.3 meters) wide by three feet (0.9 meters) long for discharging the 90 U.S. gallons (340 liters) of water it carried. Uniquely, the tank could be filled by two electric pumps while hovering over a water source.

Quasar Helicopters Hughes 500C
A Quasar Helicopters Hughes 500C with a Hawkins and Powers water buoy dip tank sits ready for fire action. Bob Petite Photo

Numerous companies were in the business of manufacturing helibuckets made out of aluminum, fiberglass, polyurethane or fabric in the 1970s. Either collapsible or rigid, they ranged in size from 54 U.S. gallons (204 liters) to over 110 U.S. gallons (420 liters). Names such as Chadwick, Hawkins & Powers, Sims, and Griffith were common. The Alberta Forest Service in Canada designed a 360-U.S. gallon (1,363-liter) aluminum monsoon tank with Associated Helicopters to be used with Associated’s Bell 204B and Bell 212.

Helicopter belly tanks and helibuckets came a long way in just two decades. Fast-forward to today, ever-larger helicopters are equipped with new types of helibuckets and tanks with self-loading systems, and improved constant flow tanks that can add foam systems to the water. Names like SEI Industries, Simplex Fire Attack Systems, and Isolair Helicopter Systems — along with others — specialize in developing firefighting tanks and helibuckets for extinguishing wildfires.

These aircraft play a crucial role in helping wildfire organizations catch fires when they are small, or to extinguish hot spots along the fire perimeter. And the role they play is one that can only be accomplished with the unique capability of rotary-wing aircraft.

Leave a comment

Your email address will not be published. Required fields are marked *

Notice a spelling mistake or typo?

Click on the button below to send an email to our team and we will get to it as soon as possible.

Report an error or typo

Have a story idea you would like to suggest?

Click on the button below to send an email to our team and we will get to it as soon as possible.

Suggest a story