Hi Parapente, Buzz here. There are conversion formulas, we used to grind through them when I was going to college. I haven't used them in years... So for an accurate answer, see what JetMech, and Jetlagged have posted.
For a very rough approximation, 60% of the horsepower is more or less the pounds of thrust. Of course, it makes a difference if you're at cruise speed (and altitude), or waiting at the end of a runway and hoping you have enough power to take off. (grin) Propellers are more effective at low speed - move a larger mass of air more efficiently.
Those little Bede BD
-5's with the tiny jet engine worried me - can it get up to flying speed before the end of the runway?