Rocket propellants with reduced smoke and high burning rates

The material-based ranges of performance and properties of 3 non-aluminized rocket propellants are presented and compared to each other. The selected formulations based on AP/HTPB, AP/PU/TMETN and AP/HMX/GAP/TMETN have roughly the same specific impulse of ISP = 2430 Ns/kg at 70:1 expansion ratio. The burning rates in the pressure range from 10-18 MPa vary from 26-33 mm/s for AP/HTPB, 52-68 mm/s for AP/PU/TMETN, and 28-39 mm/s for AP/HMX/GAP. Propellants with 58 and 20% AP contents and nitrate ester plasticizers create a much smaller secondary signature than the AP/HTPB representative contg. 86% AP. Their disadvantage, however, is the connection of high performance to a high level of energetic plasticizer. For this reason, the very fast burning propellant based on AP/PU/TMETN is endowed with a low elastic modulus and is limited to a grain configuration which isn't exposed too much to the fast and turbulent airstream. The mech. properties of the AP/HMX/GAP propellant are as good or bette r as those of the AP/HTPB propellant. The first exhibits the same performance and burn rates as the composite representative but produces only 1/5 of HCl exhaust. For this reason it is recommended for missile applications, which must have high accelerating power together with a significantly reduced plume signature and smoke prodn.