• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.17-25
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• 2022

The pintle injector has many advantages in the key characteristics of a liquid rocket engine, such as combustion stability, combustion efficiency, and wide range of comprehensive thrust control, design and manufacture, and test fired under supercritical conditions. The pintle injector is manufactured with a rectangular, single-row orifice for thrust control and production considerations. In order to verify the combustion performance of the pintle injector and its potential as a commercial injector, the combustion characteristics were analyzed by varying the TMR (Total Momentum Ratio) and BF (Blockage Factor). The result of the hot firing test showed that the heat flux increased as TMR increased, and it confirmed that the characteristic velocity efficiency was more affected by BF than TMR. Suppose a single-row pintle injector with efficiency characteristics insensitive to changes in TMR can achieve high efficiency at low fuel differential pressure conditions. In that case, the variable pintle injector's design flexibility can be increase.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.147-153
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• 2020

Developments in aircraft require safety verification through flight testing for many hours with prototype design and production. The test evaluation step of performing flight tests was an important process that determines the success in the development of the system. In particular, safety development through flight tests in the armed flight test is important for the development of attack helicopters. In the development of attack helicopters, the evaluation period and cost related to the armed flight test are closely related to the required ammunition requirement. Therefore, this paper presents the amount of ammunition required for the military flight test between attack helicopter developments through an analysis of the AH-1 helicopter in a similar case and ADS-44-HDBK of military specification. The AH-1 can be used to calculate the ammunition demand by considering the exclusion of redundant firing tests and configuration differences. In the case of the machine gun-equipped configuration, approximately 10,500R was required, and approximately 324R was required in the case of a rocket-mounted configuration. In addition, if the armed integrated bench is used properly, it is expected to promote efficiently the flight test in the armed flight by identifying the possible risk factors with armed flight tests and excluding them.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.100-106
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• 2019

Ground and high altitude simulated combustion experiments were conducted using a liquid rocket engine with hydrogen peroxide and kerosene as the propellant. A ground and high altitude simulated combustion test facility was constructed by installing a high altitude model diffuser and TMS (Thrust Measuring System) on a vertical combustion test bench. The thrust characteristics according to altitude were investigated using the combustion test equipment. The diffuser was designed on a 1:4.8 scale to verify the characteristics of the high diffusing diffuser and starting pressure. The cold flow tests were conducted using nitrogen gas, and the performance characteristics and starting characteristics of the scale down diffuser were verified. A diffuser and TMS were installed on the vertical combustion test bench, and the thrust correction equations for the system resistance were derived. The thrust correction equations were derived from the step test and vacuum step test before the actual hot firing test. Nozzles with an operating altitude of 10km were designed. Hot firing tests were conducted to analyze the thrust characteristics according to the operating altitude changes. The actual thrust was calculated using each correction equation with the thrust value measured by the TMS.