0 ▁to ▁ 4 0 ▁N · s ▁( new ton - seconds ). ▁Other ▁types ▁of ▁model ▁ro cket ▁mot ors ▁can ▁be ▁class ified ▁up ▁to ▁an ▁‘ H ’ , ▁which ▁is ▁up ▁to ▁ 3 2 0 ▁N · s , ▁and ▁even ▁further ▁in ▁some ▁cases . ▁Each ▁class ' s ▁upper ▁limit ▁is ▁double ▁the ▁upper ▁limit ▁of ▁the ▁previous ▁class . ▁ ▁Fig ures ▁from ▁tests ▁of ▁Est es ▁ro cket ▁mot ors ▁are ▁used ▁in ▁the ▁following ▁examples ▁of ▁ro cket ▁motor ▁performance . ▁ ▁For ▁mini ature ▁black ▁pow der ▁ro cket ▁mot ors ▁( 1 3   mm ▁diameter ), ▁the ▁maximum ▁thrust ▁is ▁between ▁ 5 ▁and ▁ 1 2 ▁N , ▁the ▁total ▁imp ulse ▁is ▁between ▁ 0 . 5 ▁and ▁ 2 . 2 ▁N · s , ▁and ▁the ▁burn ▁time ▁is ▁between ▁ 0 . 2 5 ▁and ▁ 1 ▁second . ▁For ▁Est es ▁‘ regular ▁size ’ ▁ro cket ▁mot ors ▁( 1 8   mm ▁diameter ), ▁there ▁are ▁three ▁classes : ▁A , ▁B , ▁and ▁C . ▁The ▁A ▁class ▁ 1 8   mm ▁mot ors ▁have ▁a ▁maximum ▁thrust ▁between ▁ 9 . 5 ▁and ▁ 9 . 7 5 ▁N , ▁a ▁total ▁imp ulse ▁between ▁ 2 . 1 ▁and ▁ 2 . 3 ▁N · s , ▁and ▁a ▁burn ▁time ▁between ▁ 0 . 5 ▁and ▁ 0 . 7 5 ▁seconds . ▁The ▁B ▁class