Hello everyone,
I was looking forward to use the arrangement shown in fig 1. for a project.
My question is, If both motors are same and they are arranged as shown in fig 1. to balance the roll, then is there a possibility that i would get double thrust.?
and in fig 2. I think there is a possibility of getting more thrust.
so which arrangement is better.?

Looks interesting but are you making y-6 or x-8? As fig1 shows motors upside down.

Dual copter.. 

hi sajid i think the first one wont work if you use

a motor in CW direction with a CW prop the lift will be generated in upwards direction

and a motor in CCW direction with a CCW prop the lift will be generated in upwards direction too but since it is inverted the lift will be down

it should effectively cancel all your lift

please refer the picture attached

i suppose you have to flip the prop at the bottom to achieve what you stated

as for dualcopter i think my v22 osprey might qualify www.rcindia.org/self-designed-diy-and-college-projects/v22-osprey-vtol-(multi-rotor-control-board-v2-1)-build/ for your idea

Subbu

Hmm thanx for your reply.
Well i wasn't so much concerned with prop and motor orientation.
Simply put , my question is if both motor in fig.1 are rotating in such a direction with whatsoever  props, such that they cancel the roll and provide thrust in upward direction(push air downwards), will this design give me double thrust?

yes it will have double thrust. the thing is they will cancel out their own induced torque (it could be done by using your fig2 setup with counter rotating setups) but how shall you stabilize the rest of the axes.


Subbu

Good to hear that u also feel it will have double thrust coz thats what i need. 
But if we think more precisely, I dont think so.
lets use certain assumptions and an example,
let each motor is pushing air at the speed of 'x' Km\hr.
so in fig 1. arrangement,
1. M1 pushes air at speed of x km/hr.
2. M2 will also try to push the air at speed of x km\hr, however the air reaching at M2 is already at the speed of x Km\hr, so how the speed of air will increase (thereby increasing thrust) coz I dont think we can just add the thrust.

However in fig.2 the air is beign pushed at x km\hr at two points, so theres a possibility of double thrust.
But I want to use fig. 1 but don't know whether my assumption above is right or wrong.
I want it to be wrong.. 

for starters your assumption is wrong. you are combining the ideas of thrust wish capability to push air

if you observe sajid the propellers themselves are in the shape of an airfoil hence they create lift which pulls your aircraft or in this case lifts it.

the lift is generated when the propeller spins and it cuts the air

so the thrust i proportional to your lifting capacity. kindly refer to gusty bhaiya's basic aerodynamics thread you shall understand it better.

Subbu