mainwheel... I'm not certain I'm reading you here... or to whom you are addressing...?
Anyway... the "math"... a CFM56-7B26 is "flat" rated to 26,300 lbs static thrust at sea level and a bypass ratio of 5.1. Using that bypass ratio and "assuming" the N1/N2 thrust ratio is proportional to the bypass ratio... the fan should be producing around 80% (21,040 lbs) and the core should be producing 20% (5,260 lbs) of the indicated (N1) thrust. If we also assume and use 45° angle of the reversed air in relation to the direction of travel… and assuming no parasitic losses, the “net” reverse thrust from the fan will be cosine 45° (.7) X 21.040 = 14,728. Now the core will be producing forward thrust (5260 lbs) so subtracting this will leave us with 9,468 lbs… “net” reverse thrust… or around 36%
I have never ran a B737-800 to maximum N1 in reverse thrust… but since the VBV’s are partially open in reverse thrust… to improve your core stall margin… I can guarantee that you will not reach the same N1 as if you were in TO mode…
Dag