Reviving this old thread because these settings:
[launch_assistance]
launch_bar_pivot = 4.41,0.00,-3.5
launch_bar_lug = 10.6, 0.0, -9.50
don't funtion as these should. The aircraft detaches from the launch bar before you can activate the catapult. Has anyone here a working setup?

Cees
I tested his A-1H with the CIMOGT LEX model with the following launch mod for the cat (P3D4.5, but should be OK in FSX / FSX-SE):
[launch_assistance]
launch_bar_pivot = 4.41,0.00,-3.5
launch_bar_lug = 10.6, 0.0, -9.50
I think the BIG problem with breaking loose from the cat is actually running up the power in the "jam accel" mode like you would do with a jet. If you do I think the plane tends to lift the tail slightly and the invisible holdback drops loose, sheds the invisible bridle, and so you get a deck launch before firing the cat
Try easing the power up slowly, so that the plane does not seem to be moving forward on the cat. Then launch - should work.
Some other info for the A-1H/A-1J that I use in the aircraft.cfg file and for CV ops -- (The H and J models are essentially identical for FS purposes)
[WEIGHT_AND_BALANCE]//From NATOPS Manual
//EMPTY Wt 13328.0 equipped
//Max Cat: 25000 (can be 25,800 with a buddy store)
//Max Trap: 18000: (15,600 recommended)
//Max Field landing 21000
//Max Field Takeoff: 25000
CV approach: 90 KIAS in groove (full flaps, no speed brakes), no live ordnance or partial drop fuel (full center or wing drops allowable).
Don't forget, this is prop, not a jet, so you need to take a "high dip" and throttle cut approaching the ramp; cut, drop the nose slightly then ease nose up to a three point attitude to arrestment.
Let me know how it goes ---