The B-17 had a long and distinguished utilization as an air tanker in the annual battle against forest and range fires fought in the U.S. each summer and fall. By my count, a total of 23 B-17s were utilized in the years between 1960 and the early 1980s as air tankers, or ‘borate bombers’ as the media likes to call them. Of those 23, eight were lost in accidents related to the dangerous job of flying low and slow over raging infernos on the sides of mountains and canyons. Despite the loss rate that approached 35%, the use of the B-17 as an air tanker helped ensure its longevity and survival into the 21st Century.
First ‘Borate Bomber’ was a Paul Mantz TBM
According to the reliable records of the late William T. Larkins, the first free-drop of water or chemicals on a fire occurred with a Paul Mantz Air Services TBM-1C (N9494H) on September 1, 1954, near Lake Elsinore in Southern California. The subsequent years saw a growing industry that sought larger capacity air tankers, and the B-17 filled that bill quite nicely. Other larger air tankers that proved successful in the early years was the PB4Y-2 Privateer and the PBY Catalina. With less capacity and also less successful but still used were the B-25 and the A-26. A variety of other ex warplanes such as the F7F Tigercat as well as the TBM were also put to good use.
However, think 1960s and ‘borate bombers’ and the B-17 immediately comes to mind. But, what actually was the first B-17 air tanker? Well, it turns out that two operators were working on modifying B-17s and they followed parallel courses and both succeeded in developing the B-17 as air tankers in July 1960.
Not in any particular order…
B-17F N17W (42-29782)
Beginning in 1960, Abe Sellards of Phoenix, Arizona, obtained B-17F N17W (42-29782) on a lease agreement with owner Max Biegert. Biegert had much earlier modified the B-17 as crop sprayer and duster in 1954, adding a total seven tanks that were installed on the B-17F: one 300-gallon tank in the nose compartment, two 425-gallon tanks in the bomb-bay, three tanks with a total capacity of 950-gallons in the waist compartment, and two 450-gallon F-94 Starfire tip tanks carried externally on the underwing bomb shackles. Thus, the airplane could carry up to 3,100 gallons and a load of up to 20,000 pounds was authorized. Underwing spray bars spanned the trailing edge of the wing. The B-17F was used for crop dusting and was also used to spray DDT in Michigan to fight a gypsy moth infestation.
Beginning in May 1960, Abe Sellards leased the airplane from Biegert with the intention of modifying the airplane further for use as an air tanker. Though N17W retained the spray equipment, bomb bay tanks were installed in to carry water or fire retardant. The work was completed in July 1960, and the following month the airplane was inspected by the FAA and approved to carry 2,000 gallons of retardant or other liquid. However, I have not been able to locate records that indicate when it was actually first used as an operational air tanker.
As an aside, Sellards ended up buying N17W from Max Biegert the following year (1961) and formed a partnership with other operators to from Aircraft Specialties, first of Phoenix and, later, Mesa, Arizona. All the spray equipment was removed from N17W and it was subsequently used primarily as an air tanker. Aircraft Specialties was a significant operator of B-17 air tankers for the following two decades.
N17W survived its tanker years and is now displayed at the Museum of Flight at Boeing Field in Seattle as a restored B-17F and carries the name Boeing Bee.
B-17G N3703G (44-83546)
National Metals Co. of Phoenix, Arizona, purchased ex-USAF VB-17G 44-83546 from the USAF through an auction in July 1959 for the princely sum of $2,687. National Metals turned around and sold the B-17 to Fast-Way Air of Long Beach, California, six weeks later. Fast Way Air modified the B-17 to become an air tanker with the installation of two 900-gallon tanks in the bomb-bay, the work being completed in July 1960. The FAA signed off the airplane to carry 1800 gallons of retardant or liquid in the tanks. Again, no records have surfaced that state when exactly N3703G was actually first employed as an air tanker, but it presumably was sometime in the mid-summer of 1960. The following year, Fast Way added a second B-17G, N3702G (43-38635) to its tanker fleet. Fast Way operated both until 1967 when the pair was sold to TBM, Inc., another California air tanker company. N3703G was used an as air tanker through the late 1970s.
N3703G was then sold to David Tallichet and his Military Aircraft Restoration Corp., which has owned and operated it ever since. This B-17G now flies as The Movie Memphis Belle and is currently at the Palm Springs Air Museum undergoing long-term maintenance.
The upshot: both N17W and N3703G were modified and ready to go by July 1960 as heavy weight air tankers and were most likely on the fire lines shortly afterwards as the first of the 23 B-17s that eventually found use in the annual fight against forest fires.
Borate or PHOS-CHEK?
A closing note: Paul Mantz used water in his 1954 demonstration-of-concept. Later, borate (dyed bright red) developed as a fire retardant dropped in the path of a fire to ‘retard’ its spread and quickly create fire lines. Borate, however, was apparently only used for two years, circa 1960, but long enough to create the alliterative term of “borate bombers” that has followed along for seven decades. What is commonly used today is PHOS-CHEK marketed by Perimeter Solutions. A short blurb from the PHOS-CHEK website:
“The PHOS-CHEK® LC95 series of fire retardants are used for wildland fire control in forest, brush and grassland fuels. Functionally, PHOS-CHEK LC95 series fire retardants react with and alter the thermal decomposition of wildland fuels so that they do not support flaming or glowing combustion. This deprives the fire of fuel, reducing fire intensity and the rate of combustion and flame spread.“
Somehow, though, the term “PHOS-CHEK bomber” just does not have the same impact. We’ll stick with ‘air tanker’ anyway.
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