[kostas]

the other issue who i want discuss is, how adjust the setting in vehicle.cfg file...and i will expain what i mean

According wikipedia.........
1. Powerplant: 2 afterburning turbojets .........so i put "jetab [engine_type]" and "2.0 [num_props]"
2. Wing area: 1,800 ft2 (170 m2) ......so "170 [wing_sur]"
3. Service ceiling: 85,000 ft .......so "25900.0 [max_altitude]" (in m)
4. Rate of climb: 197 ft/s (60 m/s).......... "60 [vario_climb]"
5. Wingspan: 55 ft 7 in (16.94 m).........."16.94 [wing_span]"

and i think that the settings who define the power and the speed of the plane are:
6. Max. takeoff weight: 172,000 lb (78,000 kg) ........ so i put "78000.00 [mass]"
7.Powerplant: 2 ? Pratt & Whitney J58-1 continuous-bleed afterburning turbojets, 34,000 lbf (151 kN) each ............. so i set [max_thrust] 151000N x 2 = 302000 Newton

but with those last 2 setting the max speed of the plane is only 1,6 Mach and no 3,3 Mach as in wikipedia

is some other value who i must add or change to have the max speed of 3,3 Mach?

in my vehicle.cfg to obtain the max speed of 3,3 Mach i change the [max_thrust] to the (amazing) value of......5000000 Newton (five million!!!!!!!! hock: )
and this value create two issue
1. if the plane take off in max thottle (100%) is going away like......... a bullet.
2. after the speed of 1.5 Mach the nose of the plane come up uncontrollably
- So during take off, throttle must non exceed the 10%
-for speed over 1,5 Mach must set the trim to the value -2.6
with that value of trim to turn the plane of 180 degrees is a loooooooooooong case

is a way to fix that issues ?