Example: The Apogee F10
. The F10 has a total of 80Ns, putting it in the F impulse class. The Aerotech F101
has a total of 79Ns of impulse, just about the same as the F10. One would think that since the F10 and the F101 have the same total energy, they will be able to "push" up the same amount.
Here's the kicker: The F10, having 10N of average thrust (2.2lbs for 8 seconds), would not be able to lift a rocket that would fly on the F101 (23lbs of energy for about 1.0 second. If you do the math, the numbers don't exactly add up, its rocket math