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Re: Air tanker American invention?

Posted by Joe Scheil on Sat Jul 05, 2003 01:22:02 AM

In reply top Air tanker American invention? posted by Olivier Lacombe on Fri Jul 04, 2003 10:26:48 PM

Oliver,

A great question, and perhaps a jointly North American operation...but here is the thumbnail.

Air Tanker History, I reference Alexander Linkewich, and Air Attack on Forest Fires. First attempts were made in 1930 using a Ford Trimotor at Felts Field in Spokane, an N3N duster operated by Red Jensen in 191 and the USFS testing a Travel Air in 197. These were all containerized drops and were largely unsuccesful. The Canadians modified a Norseman in 1944, but again were unsuucesful as the re was too little material sread from the aircraft too thinly to be effective. The next try was fused drop tanks dropped from B-29's and P-47's during 1947 in the US, and the Forest Commission of Victoria using a B-24H, Avro Lincoln and P-51's dropping 50 and 5 gallon unfused bombs. This was unsuucesful as well, though it pointed to a solution. In 1949 the Ontario Province brough water filled bags held in racks to operational use, and standardized technique by 1951. Everything continued as such until late 1953...

A DC-7 prototype jettisoned its load (1300 gal)of water ballast over Palm Springs airport. The Douglas company saw the potential for firefighting and conducted tests at Rosamond Dry lake for Los Angeles County. The first successful free fall drop of retardant was Dec 2, 1953. From that point all tankers improved or continued the free fall method of application. Tanker 1, N75081, another candidate for NASM, (She Survives!) was built at Willows, CA and led the line of free fall tankers, eventually totalling 7 aircraft that year. In 1956 the squadron dropped 83,120 gallons of water and 65,990 gallons of borate on 25 fires and credited with controlling 20. Due to some good publicity on the Inaja fire north of Los Angeles, the heroic squadron achieved results and public acclaim. The scramble began, and the same year (1956) saw the conversion of the first of 8 TBM's bought by the USFS. 1957 saw the first PBY-6A, C-82, two Trimotors in Idaho, and a different TBM with a 600 gallon system. In 1957 the Canadians switched their drop system to free fall and realized a leap in gallons per hour efficiency. From that point the future of the free fall Tanker was assured. Watching the Utah fires last week, and seeing the SEAT Dromedairs flying on the fire struggling to climb on their 9 cylinder radials in 42 C temp at 6200' DA, I thought of the gallant Stearmans and N3N's that came before...and could probably still work today.

Incidentally the Field Conversion for the PBY, the "standard" scooper Catalina, utilized doors that are the same doors that Canadair choose for the CL-215. The PBY however had a better drop pattern, and was considered the best drop footprint until the advent of the constant flow tank for retardant application. I may be biased though.

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