another vote for 3450kv.
sadly the batteries doesnt hold their promises at all, you can leave that theme about current. if i would get 80a out of my 850mah packs for more than 15 seconds i would be very happy...

another input about kv, kv and voltage gives the max rpms in theory. we know given rpm values with common rotorpitches does result in a good and in longterm.
as example on 5inch we us e lower kv, as we have bigger blades they does provide more thrust on lower rpms.

the motortests are confusing, they did that motor backthan for cinamatic 3inch builds, carry alot of weight on small blades. we cant read from that specs for your 4inch, trust i our suggestion for 3450kv.

3450kv does give the right rpms for good 4inch performance, you could go for more about straightline speed. 3450kv will allow to use them from low to high pitched rotors, all should match that kv.

2800kv would match 6s, it would be equal to 4200kv on 4s about rpms - that would be on the extreme side.

2450kv is typical 5inch kv for 4s batteries.
on 4inch blades 2450kv would be equal to a 3700kv on 4s about rpms. that would work nicely on 4inch either.

as you plan to use 4s, you realy need the rpms of 3450kv :-)

the math would be: motor kv / battery voltage / rotorlenght ,-pitch,-shape

if you "drain the batteries to much" later, you could adjust acceleratiom and motor output softwarewise later. for 3450kv that wont be needed.

Yeah, if you're looking to fling a chunker around, at bare minimum have 3000kv. Mine weighs 280g AUW with 1407 3700kv motors. It'll fling like a pro athlete threw it with a half second throttle burst.

I have a Micro Apex 4” with XNova 1804 3500k motors.
 They weigh 14 grams and do have some punch.
 I think the 12 tooth 14 magnet wind lightens them up and gives them a bit more power and efficiency.
 
  Although the impulse RC apex may cost more it comes with enough accessories to make it actually less expensive.
 I’ve never heard anyone complain about how any of the Impulserc apex build or fly other than being a bit on the heavy side.
 Here’s a short video of mine flying.I go full throttle when I do climb outs for an idea of their power.
 
   
  

Thanks a lot everyone, I think I would've gone crazy without your help! In the end I decided to stick with those 2005 cause I think I'll need the extra power, and I'll do as you suggested and get the 3450KV. Right now I'm ordering all the parts... It's gonna take a while because of shipping and whatever, but I'll make sure to update this thread with some more info once I get to fly this thing. In the meantime, thanks again!

(02-Oct-2023, 09:11 PM)Rob3ddd Wrote: I have a Micro Apex 4” with XNova 1804 3500k motors.
 They weigh 14 grams and do have some punch.
 I think the 12 tooth 14 magnet wind lightens them up and gives them a bit more power and efficiency.
 
  Although the impulse RC apex may cost more it comes with enough accessories to make it actually less expensive.
 I’ve never heard anyone complain about how any of the Impulserc apex build or fly other than being a bit on the heavy side.
 Here’s a short video of mine flying.I go full throttle when I do climb outs for an idea of their power.
 
   
  

great to post a dvr :-)

it looks like there is some throttle related videonoise, dterm related noise. maybe you can improve flightperformance and video by lowering d-term. additional capacitance could maybe help either.

After building a 3" and 3.5", I had similar fears about a 5", and was thinking about building a 4" as a step on the way. I went ahead and built a 5", and have no regrets. It is no louder than my 3" -- maybe even a bit quieter. It flies much nicer than my 3". Much better hang time. Much easier to do decent power loops.

I'm starting to plan my next 5".