One of the fields where I fly also has corn. Very nasty stuff. I don't know if it's because it's feed corn (as opposed to human corn), but the rows are not very straight and there are tons of weeds. Basically, when you're in it, you have no idea where you are and you can only see about 6 feet in any direction. It once took me and three others more than 1/2 an hour to find my plane. The other side of the corn field is a swamp. So, all my planes have plane finders.

One nice thing about plane finders is some also double as battery checkers. If you ever hear the plane finder cheep-cheep as you fly by, you can bring the plane down because the battery is low.

I've used both the Hobbico "Air Alert", and another called "Sound Security (http://www.jchobbies.com/hotstuf.htm). Both are fine. I think the Air Alert is a little less expensive, but I like the Sound Security because it just plugs into a spare receiver channel, whereas the AirAlert plugs in between the receiver and the throttle servo. Either one is well worth the cost if you fly at a field where it can be hard to find your plane.

By the way, in all of my crashes, the battery has stayed connected.