Coaxial 9x47 + 10x60 Propellor, 3Cell, Benchmark

The 10x60 inch prop again suprises in a coaxial benchmark. It seems that using a prop with higher pitch on the bottom motor increases the efficiciency. Increasing is in fact not correct, I should say: It minimizes the efficiency loss.

The 9x47+10x60 setup benchmark results are ~ the same as the normal 9x47 benchmark results. 

For my Y6 project I need 225 grams of thrust per motor. That is 450grams of thrust per pair. At 450 grams of thrust there is ~10% efficiency loss between the real benchmark and the theoretical value. 

thrust (grams)	9x47 + 10x60 benchmark (watt)	9x47 + 10x60 theoretical (watt)	9x47 Coaxial benchmark (watt)	10x60 Coaxial benchmark (watt)	9x47 + 1060 Theo-Bench (%)
50	6,4	6,5	6,2	6,6	-1,6
100	12,4	11,8	9,9	12,7	4,8
150	17,7	16,7	15,6	19	5,6
200	23,7	22,8	22,2	26,5	3,8
250	30,2	28,6	29,5	33,2	5,3
300	38,5	34,7	37	41,4	9,9
350	45,9	41,3	44,8	49,9	10,0
400	54,4	48,9	53,2	56,8	10,1
450	62,4	56,3	61,5	65,6	9,8
500	71,1	63,9	71,1	72,7	10,1
550	80,1	71,1	79,7	81,7	11,2
600	89,5	79,7	89	91,4	10,9
650	99,3	88	99	100	11,4
700	107,1	96,9	107,1	109	9,5
750	115,2	104,5	117	118	9,3
800	126,6	114,3	127	125	9,7

(lower is better)