Free-Flight Testing in the Gas-Driven Two-Stage Light Gas Gun HEK-G

Abstract

The current status of free-flight testing with the gas driven two-stage light gas gun in JAXA Kakuda was reported. Modifications of the gun were followings. (1) Maximum pressure of the pump tube end section was increased from 100MPa to 200MPa, (2) Test section for 15mm gun barrel was extended from 5m to 6.5m with an additional optical windows located at the test section, (3) 4-pieces sabot for 15mm diameter gun barrel (4) High-speed video camera and high-wattage light source. (5) Newly built 72mm diameter gun barrel for 50mm diameter projectiles and (6) 2-pieces sabot for 72mm diameter gun barrel. The 15mm diameter gun barrel was going to be used for the study for aerodynamics under hypersonic condition. The 72mm diameter gun barrel was going to be used for the study on the aerodynamic instability of re-entry capsules under transonic to supersonic condition. In a test campaign with the 15mm diameter gun barrel, we have launched 5mm diameter sphere projectiles with 4-piecies sabot at a velocity at the gun barrel muzzle of 2.1km/s to 3.8km/s. We successfully observed sabot separation and projectile (5mm diameter steel sphere) release through the high-speed video camera. In a test campaign with the 72mm diameter gun barrel, we successfully conducted to launch Apollo shaped capsule projectile of 50mm diameter with 2-pieces sabot at a velocity at the gun barrel muzzle was approximately 430m/s. Our in-housed quasi-one-dimensional Navier-Stokes code was applied to determine safety operation condition of the 72mm gun barrel and to estimate projectile speed.