- Jul 10, 2007
- Reaction score
- Melbourne Australia
Getting rid of the roll is a necessary step if you are trying to do a Vertical Trajectory System without using stupidly fast servos and a higher degree of difficulty in general.Consequently, my focus on the application of the technology is to try to eliminate as much roll as possible.
Similarly to a helicopter, when a rocket is spinning there is a phase shift in the rotation from where the fin provides force to where it is applied. In helicopters it can be up to nearly 90 degrees phase lag from the applied blade angle. So to affect pitch, the angle of the blades at the left-right position determines the outcome. Similarly the roll control is achieved by what the blades are set at in the fore-aft position, or thereabouts.
A rolling rocket will not exhibit such a large phase shift, but some roll-pitch coupling will happen. This would likely result in something like a dutch roll flight path. I am working on stopping the roll with my VTS to keep things simple... https://forum.ausrocketry.com/viewtopic.php?f=56&t=5324