Dear friends....

I am looking for an efficient motor to work with... I checked all the tiger and kd motors  and finally ended up with an cheap motor...

AX-2810Q 750KV
Here goes the link

http://www.himodel.com/electric/AX-2810Q_750KV_Outrunner_Brushless_Motor_for_Multi-rotor_Aircraft.html

The manufacturer says it delivers almost 850gms of thrust at 72 watts at a rate of 12g/w

Is that true... Anybody has experience with this motor???
If its true is this is the effecient motor in the field of multirotors???

http://www.rcgroups.com/forums/showthread.php?t=1733937
I think this would help.

@balakrishnan
Thank you sir. But I have already read all those posts... They prove that this motor can go up to 8-10g/w

I don't find even a t motor with that efficiency... Now the problem is  can it go 12g/w... I don't know the prop suggested. By the manufacturer also

And the system used buy the person in the rc groups is not that good...

In the product page it states that the motor lamination is made of 0.2mm sheets so the eddy current losses are very very less.
In the review section of same product some person states his problem of motor imbalance on first crash so we can say that motor's bearings are not very fine quality.
According to specifications at 7.4V motor may go upto 5550rpm at specified kV, if so it would give the specified thrust but no motor(except ideal) can maintain same RPM mounted with 12x6 propeller.

Great research sir... Thank you so much for telling about the eddy loss... And I also read about the imbalance and the bearing issues sir...

I am planning to buy this motor for test...
I ll test the motor with the given bearings and change bearings and ll post the data soon...

Meanwhile if anybody else has experience with this motor pls post...

 
Anyway try it and upload your results.
BTW dont call me sir we all are friends on RCI.

Efficiency very much depends upon type of model
Gliders can fly on 3500mah 3S for about 45min
And only 5min on a 3D
We have models which have thrust less than weight of models but fly like charm

What u said is very right bro...
Model with a very low wingloading like 5oz/sqft does not even requires thrust...

Airbus a380 fly's with only thrust of 30 percent of its weight...

But when it comes to rotorcrafts... The efficiency of power system alone matters...

avroto motors . have a look

Finally found the data...

Useful info 
So we can have extra long flights

I am working on a quad copter which has a payload of 1kg with more than 1 hour flight time... Almost there... Hope I ll finish within this month

Thanks you so much bro for your inputs.

But finally this motor also disqualified for the project because of its friction issues...

I guess by using gebattery and tiger motor of 100kv this could be possible... But I am looking at a solution for this under 50k

Some 18650 li-ion cells have much higher energy density than normal lipo. You want slow spinning props with high voltage power system for efficiency.

Thanks bro but they have very less c ratings.
If I want to use... Then I should make an octa and only 1kg payload....

I think it is pointless