hello to all the members of the forum.my question is how can we calculate the thrust in grams when we are known to some of the constants like the amps and watt drawn by the motor and a specific prop. or we can say by the variables that are there on the watt meter as i am using a watt meter but still unable to calculate the thrust power of a particular motor at a specific prop.any help will be highly appreciated.

This should be a starting point.

http://www.rcindia.org/electric-planes/estimate-electric-motor-and-prop-combo-calculate-thrust-watts-flight-time-etc/

Hi all dont know how to calculate thrust required fly plane
anybody having idea
plz help 

Please search

Look at the first page of results when I just searched for "calculate thrust" and "measure thrust" :

http://www.rcindia.org/search2?search=calculate+thrust

http://www.rcindia.org/search2?search=measure+thrust

Merged.

The starting point in understanding thrust is these thread, which is part of the Gems.  They talk about wattage and thrust :

http://www.rcindia.org/electric-power/amp-rating-and-motor-size/

http://www.rcindia.org/electric-power/understanding-electric-power-systems/

Another one :

http://www.rcindia.org/electric-power/a-basic-guide-to-electric-flight/