Taking a crack at the original question--
From “Mechanics and Thermodynamics of Propulsion” by Hill & Peterson, for air-breathing engines,
Equation 6-6 T = me * ve
where T = thrust, me = mass flow rate at the exhaust, and ve = exhaust velocity
and neglecting the terms having to do with the incoming air velocity which, if considered, would reduce the thrust, also neglecting the mass of the fuel component and assuming the flow is subsonic:
On the basis of 9 hp per lb/min of air consumed, at 100 hp mass flow rate would be 11.11 lb/min
Exhaust air density at an assumed 200 F Rho = 2.7(P/T) = 2.7 ( 14.7/(460+200)) = 0.060 lb/cuft
Volume flow rate = mass rate/density = me/rho = 185 cuft/min
Assuming 1.75” diameter tailpipe, flow area = 0.0167 sqft
Flow velocity, ve = V/A = 185/.0167 = 11,062 ft/min = 184 ft/sec
Then, T = me*ve = 11.11* 11,062 = 122,906 lb-ft/min^2 = 1.06 lbf
So, it would appear there’s not much thrust to be had there.