I was looking at one plane model that requires a Brushless motor 2212/10 1400kv. Now what does 2212/10 specify? Will any motor with 1400kv fit it?

Motors are specified either by the stator dimensions or by the bell dimensions ie internal dimension or outer dimension .

So 2212 means internal dimension : Dia 22 mm and height : 12 mm
The same motor is also called 2826 by some companies these dimensions are outer : Dia : 28 mm height : 26 mm ( these are the moving bells out dimensions in the case of out runner )

1400 kv = 1400 rpm/volt so for purpose of calculation we assume you use a 10 v battery the RPM the motor will run at is 14,000 ( in theory ) .

Sai

Thank you Sai! That helped a lot.

What do 10 specify in the above example?

10 specifies the number of poles the motors has i.e, Higher the number of poles, lesser your RPM is and Higher the torque so it can spin a larger propeller and give you more thrust.

Assume you have 2210/6 this means that the RPM is more, also the torque is less, it spins a smaller diameter propeller giving you speed.

Thanks Jatayu!