[Kingamada]

I'm new to machine designing and linear motion devices.
I want to create a linear motion device that is capable of reaching the speed of 750 Inch per second. Which would translate to 68kmh.

I wanted to use 8mm (Inch Per Revolution 0.75) self reversing ball screw attached to a dc motor that rotates at 60,000RPM, that would give me 1000rpm per second, since TPI is 0.75, I would get 750 inch per second. That was my initial idea as a beginner.

I found out that ball screws have critical speed limitation and since the length of my screw is 630mm and 8mm in diameter, my critical speed limit is around 5800rpm according to (http://www.nookindustries.com/Engine.../CriticalSpeed). Which means; I would have to create a ball screw of 8mm diameter with IPR greater than 7, to achieve my speed of about 750inch per second.

I found these two links with design of reversible screws that can deliver high speed

The video below shoes a video of self-reversing device which I think travels far per revolution: https://www.youtube.com/watch?v=rIE4frV3SBg

This second video shoes another video of fast reverse but slow forward: https://youtube.com/watch?v=O_-391UUHm0

The third video suggest about using support to act like anti-whipping so as to achieve high speed without whipping of the screw: https://www.youtube.com/watch?v=kkcV...ature=youtu.be

My Questions:

1. Is it possible to achieve that speed with screw of 8mm diameter or less?
2. What do you think about the videos?
3. Any idea or suggestion on how to go about this project?
4. Should I use a belt system?