I am working on a f-22 design.
My Brushless motor is recommended to use 10" propeller.
But my design forces me to use a 6x4 prop.
Also my plane looks heavy to me..........m really afraid to fly it, though it is not completed yet!!!!!!
Please guide!!!!

Whats the weight till now? whats the material of plane? which motor?

You can use the smaller props with larger pitch, for the motors which suggest larger props, as per my knowlege. But wait for expert's opinion.
This will however increase your flying speed.

If the motor belongs to Hobbyking, just read the reviews, you will get the specifications with smaller props as well.

You'll have to change you motor, get a high kv motor; preferably a 2200kv.
I hope this is not your first plane.

Hi there... if u think ur aircraft is heavy than use the wing loading calculator..the link for wing loading calculator is @ http://adamone.rchomepage.com/design.htm#calculate

Hope this helps you and all the best for your test flight.

Cheers,
Arif

I am using Emax 1400Kv motor which produces max thrust of 1600gms.
i believe my plane wud reach max weight of 1kg. So wud it be problem if i use 6x4 prop....
and yes its my first plane!!!!!!!!

A 1400Kv motor will produce ~300 gms thrust on a 6x4 prop.