ORIGINAL: bigedmustafa
Almost every computer radio on the face of the Earth has a built in flight timer and most will trigger an alarm at a pre-set time interval to warn you when to land.
Heh. I dunno about that. Most of the current models, perhaps, but not the low-end models and not most of the older models.
Where I work, we got little belt-clip timers that might work well. Where would you find them? Office supply catalogs? Perhaps sporting goods stores? They'd probably clip onto a transmitter pretty easily. Or you get one without a clip, and glue it to something you can clip onto your transmitter.