Algodoo

To make a good flames of your engines. First make a circle that is as the size of the flame you want. make all details(density,friction, etc) of the circle to minimum.
Add a center hinge, Place several tracers on the circle. Change the color, then make it rotate fast. Add the circle to the boosters of your engine... If you still can't understand, check my X-71 scene...

Okay I like the new ones but the white tracers are a little annoying. Mind if you make those tracers rotate just as what you do for the Orange flames....
10/10 for the great textures.