ORIGINAL: TAUMULLER
So now I have confused myself... larger diam prop will draw more amps and watts right?
In effect YES...
But remember that the reason you are not seeing the expected draw, may NOT be due to the motor and ESC.
With that prop you should see more draw, so it is likely that your battery packs are not up to the task.
Get a parallel battery adaptor. They are relatively cheap.
Hook two of your packs together to the adaptor, then to the ESC. This effectively turns them into one much more powerful pack of the same voltage.
e.g. if you are using 4000mAh 14.8v packs, with the adaptor they become one 8000mAh 14.8v pack.
Then try your test again with the watt meter.
If the watt level goes UP ( which I suspect it will ) your packs are to blame, and you may need to fly with two packs at a time in parallel.
ORIGINAL: TAUMULLER
So if I go to a smaller prop it will draw less amps and watts.. but it will spin faster right?
Correct up to a point.
People often forget or do not understand that our 3 phase brushless motors are effectively ALWAYS trying to turn at maximum RPM.
All the ESC does is to reduce the electrical pulse width to keep the RPMs under control.
At full throttle the ESC should have the pulse width as wide as possible, permitting the motor to get maximum energy.
Hopefull the current delivered is enough to get the prop up to 80% of the planes rated KV measure.
So if you input 10v on a 1000KV motor, your motor SHOULD spin at around 8000 RPM at full throttle.
Why not a full 10000 RPM?
Because that other 20% is our effective "reserve" that kicks in when the prop "unloads".
So even with a smaller prop, there is an effective limit on the RPM's.
I wouldn't go crazy worrying about RPMs. Instead target that watt and amp draw figures.
Those will help you the most getting things set up.
Also remember that you are measuring CONTINUOUS current, while the specs give you BURST current.
Max burst current only occurs when the battery is freshly charged, and the plane is pointed straight up, while the engine is at low idle, and you quickly run the throttle up full.
At that point in time the batteries deliver FULL voltage, ( hence your burst current ) and then drop off VERY quickly.
But your best test is to do the parallel hookup I mentioned before.