Ok, for more flaps, go down to the very bottom of the Aircraft.cfg file, in the HS121 Trident 2 and change it to look like this
[Flaps.0]
type= 2
span-outboard= 0.900
extending-time= 15.000
system_type= 1
damaging-speed= 330.000
blowout-speed= 350.000
lift_scalar= 1.200
drag_scalar= 0.000
pitch_scalar= 0.100
flaps-position.0= 0.000, 0.000
flaps-position.1= 10.000, 0.000
[Flaps.1]
type= 1
span-outboard= 0.500
extending-time= 15.000
system_type= 1
damaging-speed= 270.000
blowout-speed= 300.000
lift_scalar= 0.800
drag_scalar= 0.050
pitch_scalar= 0.100
flaps-position.0= 3.000, 0.000
flaps-position.1= 5.000, 0.000
flaps-position.2= 10.000, 0.000
flaps-position.3= 16.000, 0.000
flaps-position.4= 23.000, 0.000
flaps-position.5= 28.000, 0.000
flaps-position.6= 45.000, 0.000
Next, for more oomph, do this
[jet_engine]
thrust_scalar=1.000
change it to this
[jet_engine]
thrust_scalar=1.500
Try that, and if that doesnt work, increase it more, but keep in mind that it's a multiple, so being that each engine generates 11960lbs of thrust, they will now generate 17940lbs each, so bear in mind weight and whatnot. The reason I didn't just up the overall engine thrust in Lbs, because doing this will increase the amout of gas burned, thus fricking up the fuel burn data and maximum range of the plane