https://picasaweb.google.com/111375374001884649365/DropBox?authkey=Gv1sRgCMuOnajxqdUb#5739474630405488162.
the dome structure with holes.
What if we go for a cylindrical or circular plate like structure?or a cuboid kind of structure in place of dome?

Dome structure looks OK, you will need more / bigger holes.

Motor is too small, you need something bigger. Will try and upload a picture.

ok i am waiting.

FINALLY<AFTER A SERIES OF FAILED ATTEMPTS AND TOO MUCH PAIN,i did it....it took me two long months although....(i am a beginner after all..:-P)
I made it using:
1 arduino-uno development board
2 a brushed DC motor and IC-L293D
3 A brushless motor EMAX 2822
4 A plastic geared 9gm servo motor
5 A Lithium Polymer battery pack- 3cell,20-30c,2200 mAh
6 And an ESC for brushless motor
7 two propellers ,6x3 for lifting fan and other 8x4(not sure) for thrust(linear motion)
thank u VC sir,swapnil sir,vivek sir,and roopeshkrishna sir for ur valuable suggestions and advice.m really thankful to u all.
here are the links to project's final appearance,https://picasaweb.google.com/lh/photo/5vXEkwwSEX-Io-URl3hWNqlVV2ZSTrSaGncxjV7WC7c?feat=directlink
presentation and report that i had to make as per curriculum http://www.scribd.com/doc/95579554/Amphibious-Surveillance-Hovercraft-Major-Project-Final-Year-Btech-EC-2011-12
http://www.scribd.com/doc/95579232/Amphibious-Surveillance-Hovercraft-Major-Project-Final-Year-Btech-EC-2011-12....
PROGRAM CODE IS ALSO GIVEN THERE....SO,if any beginner requires,he/she may refer to it.:-)

Congratulations!

Now I am looking forward to your second build.No calculations, no theory - just take your time and ENJOY yourself. PURE FUN!!!