What have you got so far? It is pretty tough to just hand you a project without you plagerizing it. You've got to show some initiative and demonstrate that you've put some thought into this already. Even a 2d sketch would be proof.
The R plane for a G8_ cycle is a return plane for rapid movements made during the automatic motions of the cycle in use, such as peck drilling, etc. Normally, the tools will be set to operate at a comfortable height above the clamps or other obstructions in the machining zone. This could be called the initial rapid plane, and is most often higher than the return plane for a drill cycle. The objective of the return plane is to provide an intermediate rapid plane that is close to the surface to be drilled, and thus avoid wasting time having the tool feeding slowly down, all the way from the initial rapid plane. The additional instruction, G98 is used to command the controller to move back to the initial rapid plane between holes, whereas G99 is used to command the controller that the return plane is to be used as a safe operating height for movements from one hole position to the next. The programmer generally will determine if the job is safe enough to allow rapid positioning at the return plane. In the case of drilling many identical holes, it can save some machine time to use the return plane, but, it could have more potential for a tool mishap should the tool hit an obstruction or even snag a mass of chips laying on the surface of the part.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)