Guys,
I had Paul from NQRC make me a relay switch so I could turn my ignition on and off from the transmitter. Its works fantastic, no interference and way cheaper than anything else I have found so far. Its only $25AUS ($20US), way better than a servo and microswitch which is what alot of people in my club are doing.

Here's a link:

http://pldaniels.com/rcshop/frame.php?vp=PLD-RCS-RL2A

Don't most relays have small frail conductors and springs in them? I thought they were not the best for high vibration environments... especially if the relay is conducting all the current for your ignition. That's why everyone has gone to solid state switches for ignition cut-off.

I dont know, no idea. This is my first gasser so I was looking for something better than the servo/microswitch which is what the other in my club are using. The vibration you mention may be a problem, but I wouldnt think my plane vibrates that much (plus the relay is not solid mounted to the plane). It should handle the switching current fine I think. I did some searching on here to find an estimate on the current draw of an ignition on a 50cc, got various numbers but mostly under 1 amp. The relay is good for 4 amps so should handle the current fine.
Anyone got an good/bad experiences using a relay switch?