Originally Posted by Netspirit
In a twist serve, the ball obviously rises. You cannot clear the net with a completely flat or descending trajectory regardless of what serve you hit, if you are not as tall as Karlovic.
You must hit UP. The point of contact is below the balls "equator" and on the left side (for righties). This is why it is thrown behind the head and to the left - to be able to brush up on the left side of the ball.
Rod Cross disagrees with you. See please his article – Physics of the Tennis Kick Serve in http://twu.tennis-warehouse.com/lear.../kickserve.php
I made the picture from his video.
Figure 9. Slice serve - Rod Cross
Try please to find a similar video that could support your statements.