Prop Sizing Guide
A good guide for selecting the correct prop...
Have you ever built a new plane, or installed a
different engine size and were not sure of the correct prop size to use? The following guide
lists the correct prop to start with for 2-stroke and 4-stroke engines. It also lists a range of
prop sizes you can use depending on engine rpm desired, ground clearance required, and the
acceleration or top speed you might like to acheive.
TWO STROKE
ENGINES
|
STARTING PROP |
ALTERNNATE
PROPELLORS |
ENGINE SIZE |
|
6x3 |
5.25x4, 5.5x4, 6x3.5, 6x4,
7x3 |
.049 |
|
7x4 |
7x3, 7x4.5, 7x5 |
.09 |
|
8x4 |
8x5, 8x6, 9x4 |
.15 |
|
9x4 |
8x5, 8x6, 9x5 |
.19-.25 |
|
9x6 |
9x7, 9.5x6, 10x5 |
.20-.30 |
|
10x6 |
9x7, 10x5, 11x4 |
.35-.36 |
|
10x6 |
9x8, 11x5 |
.40 |
|
10x7 |
10x6, 11x5, 11x6,
12x4 |
.45 |
|
11x6 |
10x8, 11x7, 12x4,
12x5 |
.50 |
|
11x7 |
11x7.5, 11x7.75, 11x8,
12x6 |
.60-.61 |
|
12x6 |
11x8, 12x8, 13x6,
14x4 |
.70 |
|
13x6 |
12x8, 14x4, 14x5 |
.78-.80 |
|
14x6 |
13x8, 15x6, 16x5 |
.90-.91 |
|
16x6 |
15x8, 18x5 |
1.08 |
|
16x8 |
16x10, 18x5, 18x6 |
1.20 |
|
18x6 |
18x8, 20x6 |
1.50 |
|
18x8 |
18x10, 20x6, 20x8,
22x6 |
1.80 |
|
20x8 |
18x10, 20x6, 20x10,
22x6 |
2.00 |
FOUR STROKE
ENGINES
|
STARTING PROPS |
ALTERNATE PROPELLERS |
ENGINE
SIZE |
|
9x6 |
9x5,
10x5 |
.20-.21 |
|
11x6 |
10x6, 10x7, 11x4, 11x5, 11x7, 11x7.5,
12x4, 12x5 |
.40 |
|
11x6 |
10x6, 10x7, 10x8, 11x7, 11x7.5, 12x4,
12x5, 12x6 |
.45-.48 |
|
12x6 |
11x7.5, 11x8, 12x8, 13x5, 13x6, 14x5,
14x6 |
.60-.65 |
|
13x6 |
12x8, 13x8, 14x4, 14x6 |
.80 |
|
14x6 |
13x6, 14x8, 15x6, 16x6 |
.90 |
|
16x6 |
14x8, 15x6, 15x8, 16x8, 17x6, 18x5,
18x6 |
1.20 |
|
18x6 |
15x6, 15x8, 16x8, 18x6,
20x6 |
1.60 |
|
18x10 |
18x12, 20x8, 20x10 |
2.40 |
|
20x8 |
18x10, 18x12, 20x10 |
2.70 |
|
20x10 |
18x12 |
3.00 |
|