One of the problems you can run into with trees that reach out and grab planes is sometimes you can't see where it went.

Or, if you fly near tall grass or thick woods and the like. You can see where the plane went down and still have trouble finding it.

I lost a plane recently. Then I learned about plane locators that emit a sound to help you find your plane in the woods, corn field, back yards, top of houses, or whatever is near your flying field.

Here is a review of an Emergency Locator Beacon that illustrates its value (this site is somewhat unreliable)
http://webhome.idirect.com/~arrowmfg...s/elb-revi.htm

Here are examples of locators for 72 MHZ flight systems.
Postings I have read say you can hear them for about 50-100 feet. Some have internal batteries, others don't work if the the flight battery becomes disconnected.
http://www.hobbico.com/accys/hcap0335.html
http://www.rcelectronics.bravepages.com/Locator.html
http://www.customelectronics.co.uk/lma.htm

For really long distances - measured in miles
http://www.texastimers.com/helpful_h.../wal_cover.htm

For some of the low cost, ready to fly planes, like the Firebird, e-gull, or my Aerobird, these locators are either too expensive or there is no place to plug them. I found an answer. I ordered
a pair of these: http://www.keyringer.com

Works great on my Aerobird.

They look like a small clicker for your car door locks. You click one of a pair which sends out a chirp that the second one hears and answers. I tested them to about 150 feet. Here are photos of a test mount on an Aerobird. I typically put it on top of the wing under the rubberbands.
http://www.shutterfly.com/osi.jsp?i=...21b33b641c4516