geared prop test 2.5:1

6 inch 105g 2.53A                            41.5g/A
8 inch 180g 3.84A                            46.9g/A
10 inch 200g 3.25A 307g 5.21A         61.5g/A 58.9g/A
12 inch 200g 3.42A 420g 7.40A         58.5g/A 56.7g/A

geared prop test 3:1

motor cf2812 from giantshark.co.uk with and without homemade 3:1 gearbox

about 11.5V in battery

propeller size    current    thrust    geared down ratio    thrust to amps ratio
6 inch 3 blade     2.05        46g       3                       22.4
8 inch 2 blade     2.95       127g       3                       43.0
10 inch 2 blade    3.69       230g       3                       62.3
12 inch 2 blade    5.70       384g       3                       67.3

6 inch 3 blade      8.07      238g       1                       29.5
8 inch 2 blade     10.00      283g       1                       28.3
10 inch 2 blade    10.00      369g       1                       36.9
12 inch 2 blade    10.00      313g       1                       31.3

no prop            no throttle 0.09   half throttle approx 0.77  full throttle 1.2