The Blade Nano CP S is a popular heli for beginners. It’s lightweight, which helps keep damage to it or to anything else at a minimum. It’s also cheap and won’t break the bank if you do need to replace a part. (In contrast, a high-end servo for large helis cost more than double the entire CP S!) That being said, there are some 3rd-party upgrades you can purchase to help improve the Nano CP S durability and flight characteristics.
Aluminum swashplate
Microheli swashplate 
Rakon Heli (RKH) swashplate
One complaint about the CP S is that one of the bearings in the stock plastic swashplate pops out if you crash too much. What happens is that the thin plastic surrounding and holding the bearing develops a crack, which loosens its grip on the bearing. Often you can pop the bearing back in, but if the crack gets too big, it simply won’t stay put.
Enter the aluminum swashplate. There are two companies I know of that make such an upgrade: MicroHeli and Rakon Heli. I personally own the MicroHeli version with anti-rotation guide and love it. I hear the Rakon swashplate is just as good. Either way, you’ll find these CNC aluminum swashplates can take a beating. I’ve had exactly zero issues with mine since installing. And I crash a lot while learning new moves.
If you’re going to get one upgrade to the Nano, let the aluminum swashplate be it.
Higher capacity batteries
The stock E-Flite 150 mAh batteries are sufficient if you just want to hover upright at low head speed. (As long as their the 45C max discharge ones.) You might notice, though, that you can actually hear the motor loosing RPM as you get closer and closer to the 4-minute mark. This loss of motor power can make doing anything other than hovering near impossible.
I found (as have many others before me) that upgrading the 1S 3.7 V lipo to something with greater mAh capacity helps keep the motor running at its intended speed for essentially all of its 4-minute flight. The ones I use are Tattu 220 mAh 45C. It’s the increase in capacity (220 mAh) that makes the most difference. Not only will your Nano’s head speed stay constant for most of the Nano’s flight, its ability to do steep climb (full positive collective) will be greatly improved due to the higher max discharge rate (9.9 amps vs 6.75 amps). So much so, in fact, that I actually fly at lower throttle settings that I would with the stock lipos.
Be warned, though! Even though the increased capacity will allow you to fly longer (7+ minutes!), you shouldn’t do so. Reports say that the little stock brushed motors need some cooling off time between runs. Don’t fly for more than 4 minutes. Your motors will thank you, and so will your batteries.
