|
Bulk loaded liquid propellants are an artillery technology that was pursued at the U.S. Army Research Laboratory and U.S. Naval Weapons Center from the 1950s through the 1990s. The advantages would be simpler guns and a wider range of tactical and logistic options. Better accuracy and tactical flexibility would theoretically come from standard shells with varying propellant loads, and logistic simplification by eliminating varying powder loads. In general, BLP guns have proven to be unsafe to operate, and they have never entered service. ==Gun fuels== Several propellants were tried in various programs: One of the later (1991) successful gun fuels was a saturated solution of ammonium perchlorate in ammonia. This has a vapor pressure of one atmosphere at 20C, and generally forms a convenient liquid that is stable and possible to handle. The mixture is notable for its low burning temperature per impetus, with resulting lowered damage to expensive gun tubes and liners, or alternatively, increased firing rates. A typical impetus is 388,000 ft-lb/lb. The ammonia vapors are toxic, but the toxicity is readily apparent to ordinary people and can be handled with normal industrial precautions.〔U.S. Patent 5,060,551; 1991, Thomas L. Boggs; Jack L. Prentice; Donald F. Zurn; Claims; Patent assigned to U.S. Navy.〕 In the 1950s through 1970s, a mixture of 63% hydrazine, 32% hydrazine nitrate and 5% water was used in experimental 37mm gun firings and later in 120mm gun firings. The 32% hydrazine nitrate mixture was selected by extensive experiments to have a notably flat pressure profile, increasing gun safety.〔Knapton, John; Stobie, Irvin Elmore, Les; ARl-TR-81 A review of the Bulk-Loaded Liquid Propellant Gun Program for Possible Relevance to the Electrothermal Chemical Propulsion Program, Army Research Laboratory, March 1993; (Accessed ) 2011-7-23. Section 4.1 on the Detroit Controls Experiments, and 4.3 which both describe the hydrazine mixture as having a "notably flat pressure profile."〕 Otto Fuel II, a mixture of the low explosive propylene glycol dinitrate with a stabilizer, has also been tried in 37mm guns.〔 In 1981, the Naval Weapons Center tried a 350 round/minute cyclic bipropellant gun, using 90% nitric acid and a proprietary hydrocarbon (probably a low molecular weight alkane, like propane). High or low breech pressures could be obtained by varying the surface to volume ratio of the injector. Varying the oxidizer ratio could change performance. Ullage, the injection pressure, affected the reliability of the gun, but not its safety or operation.〔〔U.S. Patent 5,060,551; Background.〕 Another tested gun fuel is NOS-365. This is a mixture of hydroxylammonium nitrate, isopropyl ammonium nitrate and water.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bulk loaded liquid propellants」の詳細全文を読む スポンサード リンク
|