Originally Posted by Cubdriver

It can be done but there is some thinking involved. In a Cessna 172 or similar airplane, define a user waypoint using using the typical way, for example in the diagram below I would define "waypoint" as 35 DME on the 90 deg. radial of ABC VORTAC. Then I would set up a hold there (G1000 does holds) and specify zero for the leg length. The flight director will do this, but the trick is placing your user defined waypoint where the orbital center you want results.

That's a tad tricky, but to locate the user waypoint properly so it results in an orbit around some nearby center, you need it to be about 2900ft radius from the desired center, and at a right angle to the radial you used. The AP will do standard rate right turns holding at the user waypoint fix, so with zero length legs it will result in a circle around your orbit point. At about 100 knots in a Skyhawk you will see about 17 deg. bank angles for standard rate, which results in a radius of 2900 ft.