plz tell me the amount of thrust needed for a plane that is 450 gms m a beginner plz help
Welcome to the forum :)
Such questions have been answered many times before, just searching for the word "thrust" gives multiple threads, like this :
http://www.rcindia.org/electric-power/which-power-system-would-you-suggest/
Please spend at least an hour searching and reading, and if you still have doubts, please ask. The more you read, the more money you save !
In addition what type of plane you plan to make also matters about the power system..... Pusher or puller .... Acrobatics or simple glider.....etc
For a beginner plane..the motor wattage is 50 to 75 watts per pound..approx.500g.