This is going to be a long post with a lot of quotes...
Thanks for the reply guys. I'm thinking of using F450 frame kit version that comes with integrated PCB.
and looking for 1000kv brushless motors, Do you think that is good to start up with ? to take off all the weight I'm gonna install later, such as FPV kit, A gimbal ( not now, but maybe in future ) + SJcam or mobis cam
Generally, to get more thrust you use lower kv motors spinning larger props (sometimes even with higher LiPo cell counts). A good rule of thumb is to have twice as much thrust as the total weight of your quad. If, for example, your quad weighs 1500g, the total thrust of all 4 motors should be around 3000g. Once you estimate how much all the parts are going to weigh, you can choose the motors. Anywhere from 800-1000kv ought to work but you nee dto check the thrust data and ensure that your quad arms support the size of propellor necessary.
I don't mind to start up with 2200mAH and upgrade to 4000 or 6000mAH later in future. But Would I be able to do that with my current plan of stuff ? As mentioned above ?
This again depends on whether you have enough thrust available to lift the larger batteries. And whether your frame has enough space for a large battery. Just increasing the battery capacity will increase flight time only up to a point, after which the additional weight will be a hindrance. Also, smaller batteries will need to have a higher discharge C rating to be able to supply enough current as compared to larger batteries. For example, a 2200 mAh battery will need a 25C rating to supply 55A whereas a 6000 mAh battery will need only a 10C rating. (the formula is max. discharge current= capacity in Ah x discharge rating). Make sure that the battery is capable of discharging quite a bit more than your max estimated current to ensure it has a long life and doesn't heat up.
Not sure, what ESC should I use for 1000kv motors. ( I'm new at this ) Any ideas ?
The rule here is to check the maximum current draw of your motor and choose an ESC that is rated at least 5A higher as a safety margin. ESCs are generally made in some standard values though- 6/12/16/20/30 Amps. You will also have to choose between SimonK and BLHeli firmware.
Also, I checked on the Turnigy 9XR Transmitter and looks good to start up with.
What module would be best for this ?
The FrSky DJT with D8R telemetry capable receiver is a good choice. You could also look at Orange DSM modules. There is also a Turnigy DSSS module if you want FlySky protocol.
PS: 1. I assume we're allowed to fly at beach ? no ?
2. any recommendations for FPV kit ? Heard Boscam is pretty good but they do cost a bit though. Any alternatives ?
It should be OK as long as there are no people around. I'm not sure about the FPV kit. There are options like DAL, Eachine, Skyzone which may work for you