Which type of burn motor generally produces a higher initial thrust?

A regressive burn motor produces a higher initial thrust compared to other types of motors. This type of motor burns the propellant from the outer surface inward, which allows for an increased surface area of the propellant during the early stages of the burn. As the burn progresses, the thrust may taper off, but at launch, the rapid consumption of the peripheral propellant leads to a significant surge in thrust.

In contrast, the other motor types do not exhibit the same initial thrust characteristics. Progressive burn motors generally start with a slower burn rate that increases over time, which means they do not generate the immediate high thrust associated with regressive motors. Constant burn motors maintain a steady rate of thrust throughout the burn but lack that initial thrust spike. Hybrid motors, which use a combination of solid and liquid propellants, also tend to have a more variable thrust profile and do not consistently provide higher initial thrust. This makes the regressive burn motor a preferred option for applications that require a strong initial lift-off thrust.