Lift is really generated by the wings...

The smaller diameter is going to reduce the amount of THRUST the engine produces.

The prop will spin marginally faster however and with less load on the engine. The pitch determines the SPEED of the airflow created by the prop, or you can think of it as the prop slicing through the air, or effective plane AIRSPEED.

The plane may fly at the same speed after you reduce the diameter or close to it, as would have with the bigger prop, but it will be less powerful when climbing straight up. It will take longer to get up to the same airspeed though.


Anyone who flies electrics MUST, MUST, MUST get a Watt meter ASAP.

This is the only way of accurately determining what is going on with your power systems.

Your motor is rated for no more than 266 watts constant, and this figure is in part determined by the motor's thermal limit ( it's ability to deal with heat ).

A watt meter permits you to select a propeller that will keep the motor under this range.

If you ran the motor at a constant 30A, you would fry it after a minute.