How much thrust is available from the Allison T-56-A-15 engine?
From Raymer's "Conceptual Aircraft Design", page 327, equation 13.15:

$$ \eta_p = \frac{TV}{P}$$

Where:


$\eta_P$ is the propeller efficiency
$T$ is the Thrust [kN]
$V$ is the True Airspeed [m/s]
$P$ is the engine power [kW]


Reverting the formula you get that the Thrust per engine is given by:

$$ T  = \frac{P \eta_p}{V}$$