BATES

BATES is an acronym for BAllistic Test and Evaluation System, which is a standardized system for measuring solid rocket propellant performance designed and developed by the United States Air Force Research Laboratory in 1959 through the early 1960s,^[1] used for almost forty years thereafter, and again beginning in 2010.^[2] Then through 2016. According to this reference, a single propellant grain weighing 68 to 70 pounds was used in the original AFRL BATES motor design. An AFRL BATES propellant grain is inhibited, usually by a flame resistant cartridge case, on the OD, burning only on the two outer ends and the central bore, and is dimensioned so the burning area does not change significantly (< 3% in the original BATES motor) through the burn, generating a flat-topped thrust curve (neutral burn) to minimize propellant characterization costs and simplify the data analysis.

The first official description of the BATES system was published by and available from the Defense Technical Information Center (DTIC): “Development and Evaluation of the USAF Ballistic Test Evaluation System for Solid Rocket Propellants”.^[3]

An official press release in 1964 included BATES information.^[4]

In 2016 the AIR FORCE published through DTIC an overview the included a summary of BATES use.^[5]

In modern usage, BATES often refers to a type of solid-fuel rocket motor grain geometry. A BATES grain consists of one or more cylindrical grain segments with the outer surface inhibited, but free to burn both on the segment ends and the cylindrical core. Such grains are very easy to cast, while allowing for the user to configure a progressive, regressive, or neutral thrust curve by changing various dimensions.^[6] The neutral BATES length is calculated by the equation $L={\frac {1}{2}}(3D_{g}+d_{c})$ , where $L$ is the length of the grain, $D_{g}$ is the outer diameter of the grain, and $d_{c}$ is the diameter of the core of the grain. ^[7]

References

^ Geisler, R.; Beckman, C. "The History of the BATES Motors at the Air Force Rocket Propulsion Laboratory" (PDF). AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST (1998). Archived from the original on October 9, 2012. Retrieved 16 September 2011.
^ Thuloweit, Kenji. "AFRL test marks return to 'in-house' rocket fuel development". Press Release. US Air Force. Archived from the original on 18 December 2011. Retrieved 16 September 2011.
^ Gale, Harold W. (April 1962). Development and Evaluation of the USAF Ballistic Test Evaluation System for Solid Rocket Propellants Accession Number : AD0276424: Technical documentary report : TEST GROUP (DEVELOPMENT) (6593RD) EDWARDS AFB CA (PDF) (Report). Archived from the original (PDF) on February 1, 2017. Abstract: A reproducible, accurate, ballistic evaluation system for solid propellants was developed. Particular attention centered on an accuracy level of 0.5 percent or better on specific impulse (Isp). Evaluation of new propellants by their manufacturers had resulted in a multiplicity of definitions and mathematical correction factors which obscure actual performance results and complicate qualitative comparison of competitive propellants. An industry survey determined desirable standard motor system parameters and prevailing practices. From industry, best practice such as 1,000 psi combustion pressure and 15 degree nozzle exit half-angle expanded to local ambient pressure, were adopted in the motor and system design as far as possible. Other system parameters were selected by the assigned design engineer/manager; 2Lt H. Gale. Eight months after assignment, first firing was in September, 1961. Twelve firings of two propellants were made for motor and system evaluation. All objectives were successfully achieved or exceeded. Calibration firings established the confidence level and accuracy of the system prior to evaluation of industry propellants.
^ "- YouTube". YouTube.
^ "Article title" (PDF). Archived from the original (PDF) on 2023-05-11. Retrieved 2022-06-02.
^ Nakka, Richard. "RNX Composite Propellant". Richard Experimental Rocketry. Retrieved 16 September 2011.
^ Nakka, Richard. "Rocket motor design charts". Richard Experimental Rocketry. Retrieved 30 January 2023.

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[1] Geisler, R.; Beckman, C. "The History of the BATES Motors at the Air Force Rocket Propulsion Laboratory" (PDF). AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST (1998). Archived from the original on October 9, 2012. Retrieved 16 September 2011.

[2] Thuloweit, Kenji. "AFRL test marks return to 'in-house' rocket fuel development". Press Release. US Air Force. Archived from the original on 18 December 2011. Retrieved 16 September 2011.

[3] Gale, Harold W. (April 1962). Development and Evaluation of the USAF Ballistic Test Evaluation System for Solid Rocket Propellants Accession Number : AD0276424: Technical documentary report : TEST GROUP (DEVELOPMENT) (6593RD) EDWARDS AFB CA (PDF) (Report). Archived from the original (PDF) on February 1, 2017. Abstract: A reproducible, accurate, ballistic evaluation system for solid propellants was developed. Particular attention centered on an accuracy level of 0.5 percent or better on specific impulse (Isp). Evaluation of new propellants by their manufacturers had resulted in a multiplicity of definitions and mathematical correction factors which obscure actual performance results and complicate qualitative comparison of competitive propellants. An industry survey determined desirable standard motor system parameters and prevailing practices. From industry, best practice such as 1,000 psi combustion pressure and 15 degree nozzle exit half-angle expanded to local ambient pressure, were adopted in the motor and system design as far as possible. Other system parameters were selected by the assigned design engineer/manager; 2Lt H. Gale. Eight months after assignment, first firing was in September, 1961. Twelve firings of two propellants were made for motor and system evaluation. All objectives were successfully achieved or exceeded. Calibration firings established the confidence level and accuracy of the system prior to evaluation of industry propellants.

[4] "- YouTube". YouTube.

[5] "Article title" (PDF). Archived from the original (PDF) on 2023-05-11. Retrieved 2022-06-02.

[6] Nakka, Richard. "RNX Composite Propellant". Richard Experimental Rocketry. Retrieved 16 September 2011.

[7] Nakka, Richard. "Rocket motor design charts". Richard Experimental Rocketry. Retrieved 30 January 2023.

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