This is a real simple question but i need to know..................

Some what like helis.  Forward motion requires the craft to be tilted forward a bit (head a bit down, tail a bit up)... and so on. 

Their natural movement is up or down, but if you place it in a slightly tilted angle, then "up" becomes "movement in that direction" etc.

But how does the it get tilted plz.......explain all of it admin.....

By controlling the speed of the appropriate motors. 

"Search" is your friend   See the details on the right side of this attachment.

http://www.rcindia.org/self-designed-diy-and-college-projects/quad-rotor/?action=dlattach;attach=68

Sumedha, shoot off a PM to Ashta Sir, his design is much simpler and he will eagerly help you with all inputs.

VC bhai - Being able to search and locate information is an ultimate gift   Of course, anything unclear after that needs to be discussed, but we should do everything possible to encourage searching.  It will not only help with RC, but it helps in every walk of life !

I just felt that Sumedha had posed a question / query as a rank newbie, a curious, wide eyed,  newcomer. Ashta Sir has been extremely patient with me and has gone out of his way to answer my inane queries and educate me. His humility and eagerness to help one and all has helped me grow in this hobby. I just added my 2 pennies / billion dollar worth of advice so that others may benefit from his vast knowledge and expertise. Not everyone has the patience or the inclination to turn into a search engine!

No offence meant to anyone. My apologies if any offence has been taken or transgression has been inferred.

Thanks a lot vc sir ..... I have pm'ed astha sir ...hope he helps.....

No offense taken at all... but I do strongly believe this may not be the optimal path... due to :

1.  It is always better to "not give a person some fish, instead teach him how to fish".

2.  Basic information related to the question is already provided, and it is easy to connect the dots ("when one motor runs faster than the other, obviously the craft tilts").  Any further explanation/discussion over PMs may end up being much more difficult than doing it in person or via the phone.  On a general topic like this, not sure if it is worth putting someone like Ashta bhai (who is extremely patient) on the line   It is better to have all discussions open on the forum itself, so multiple people can respond.

I see so many people who have tagged themselves as "beginners" dig up useful nuggets of information from the web and adding to the collective knowledge of all of us !  Not everything online is accurate/perfect... but being aware of the possibilities is certainly a good thing.

Sir, I shall let this one slide.