Good after noon my Friends and Colleagues..
i was crawling through the postings related to the electric crafts here i found one thing...its hard to get some formula about a needed power train setup, to our crafts...hey Veterans...can some one give us a clear idea about the motor and prop set up that can be used from a light slow flier to a high 3D one...because all of us are using some thing on our crafts...for an example i found some of my friends were using big props on their crafts,while some were using high power motors with small props...and result..? disaster...

so from nice advices we can rectify this problem...Veterans...will some one guide us...?  please...

more clearly, if we are making a craft with a 40 inch wingspan, what type of prop can be used( size and pitch) and yes the motor power, along with the battery setup....please..

It all depends on the planform and the type of aircraft one wants to build.
For a wing with 40 in. span and an aspect ratio of 5:1 genarally a BLDC of around 250 W is used with a manufacturer recommended prop (9-10 in. usually).

thank you swapnil...

i guess this should solve all your queries!!

http://www.rcgroups.com/forums/showthread.php?t=1136470&highlight=beginners+guide+motor+prop+selection

cheers!

Sukrut...its too amazing..and yes sure..was looking for...from now...we won...yeeeehhaaaaaa............a million thanks for the link....hooorayyyyyy