While all engines produce power the Propeller is essential to transmit this power.  A more efficient propeller will transmit more power to the air.  It would be fair to say that these recommended props are often much larger than those typically used in the USA but this helps significantly with noise reduction and therefore we will go with the larger prop.  The engines will not log down with these props, they just won't quite develop all the power they could.  Though to be fair we do overpower anyway.  Prop sizes are only slightly above US recommendations.  If your field is noise sensitive (as many are) then head for one of the large props.  These figures are merely estimates - do not take them as gospel.  They are merely a rough guide to get you started.

Note: This Chart was Hijacked from the UK.  Please note the disclaimer above!!!

2 Stroke Glow Engines

Engine Size

Ideal Prop Size

Propeller Size Range

Ideal RPM Range

0.10

7x4

7x4-6, 8x4

14000~16000

0.15

8x4

7x5-6, 8x4-6

14000~16000

0.25

9x5

9x4-6, 10x4-5

12000~15000

0.32-0.36

10x5

9x6-8, 10x5-6, 11x4-5

12000~15000

0.40

11x5

10x6-8, 11x5-7, 12x5-6

11000~12000

0.46

11x6

10x7-9, 11x6-8, 12x45-7

10000~12000

0.53

11x7

10x8-10, 11x7-9, 12x6-8

10000~11000

0.61

13x6

12x8-10, 13x6-7, 14x5-6

9500~11000

0.75

13x7

12x9-11, 13x7-8, 14x6-7

9500~10500

0.91-1.08

14x6

13x10-11, 14x6-8, 15x6-8

9000~10000

1.20-1.35

16x8

15x8-10, 16x8-10, 17x8

8500~9000

1.40-1.80

18x8

17x8-10, 18x8-10, 20x6-8

8000~9000

2.10

20x10

20x10, 22x8

8000~8500

4 Stroke Glow Engines

Engine Size

Ideal Prop Size

Propeller Size Range

Ideal RPM Range

0.26-0.30

10x6

10x5-7, 11x4-5

10000~11000

0.40-0.45

11x6

11x6-7, 12x5-6

10000~11000

0.48-0.56

11x7

11x7-8, 12x6-7, 13x5-6

10000~11000

0.63-0.72

12x7

12x7-9, 13x6-7

10000~11000

0.80-0.91

14x7

13x8-11, 14x7-9, 15x5-7

10000~11000

1.00-1.20

14x8

14x7-8, 15x6-10, 16x6-8

9000~10000

1.40-1.50

16x8

16x8-12, 17x8-10, 18x6

8500~9500

1.80-2.00

17x8

16x10-12, 17x8-10, 18x8

8000~9500

2.40

20x8

18x10-12, 20x6-8

7500~8500

2.70

20x10

20x8-12, 21x8-10

7500~8500

3.00-3.20

21x10

20x10-12, 21x8-10, 22-8

7500~8500

Gasoline Engines

Engine Size

Ideal Prop Size

Propeller Size Range

Ideal RPM Range

23-30cc

16x8

16x8-10, 17x8-10, 18x8

8500~9500

40cc

20x8

18x10-12, 19x10, 20x8-10

6500~7800

45cc

20x10

20x10-12, 21x8-10, 22x8

6000~7500

50cc

21x10

20x12, 21x10-12, 22x8-10

6000~7200

60cc

22x10

22x10-12, 24x8-10, 26x8

6000~6800

75cc

24x10

24x12, 26x10-12

6000~6500

100cc

26x10

26x10-12, 28x10

6000~6500

150cc

32x12

30x10-12, 32x10-12

5500~6000

200cc

34x11

32x12-14, 34x10-12, 36-10

5000~6000

 

Prop Blade Conversion

2 Bladed

3 Bladed

4 Bladed

10x6

9x6

---

11x8

10x8

10x6

12x8

11x8

11x6

12x10

11x10

11x8

13x10

12x10

12x8

14x8

13x8

13x6

14x10

13x10

13x8

15x8

14x8

14x6

15x10

14x10

14x8

16x10

15x10

15x8

18x10

16x10

16x8

20x10

18x10

18x8

22x10

20x10

20x8