Two Stroke Engines
| Engine Size | Starting Prop | Alternate Props |
| .049 |
6x3 |
5-1/4x4, 5-1/2x4, 6x3-1/2, 6x4, 7x3 |
| .09 | 7x4 | 7x3, 7x4-1/2, 7x5 |
| .15 | 8x4 | 8x5, 8x6, 9x4 |
| .19 - .25 | 9x4 | 8x5, 8x6, 9x5 |
| .20 - .30 | 9x6 | 9x7, 9-1/2x6, 10x5 |
| .35 - .36 | 10x6 | 9x7, 10x5, 11x4 |
| .40 | 10x6 | 9x8, 11x5 |
| .45 | 10x7 | 10x6, 11x5, 11x6, 12x4 |
| .50 | 11x6 | 10x8, 11x7, 12x4, 12x5 |
| .60-.61 | 11x7 | 11x7-1/2, 11x7-3/4, 11x8, 12x6 |
| .70 | 12x6 | 11x8, 12x8, 13x6, 14x4 |
| .78 - .80 | 13x6 | 12x8, 14x4, 14x5 |
| .90 - .91 | 14x6 | 13x8, 15x6, 16x5 |
| 1.08 | 16x6 | 15x8, 18x5 |
| 1.20 | 16x8 | 16x10, 18x5, 18x6 |
| 1.50 | 18x6 | 18x8, 20x6 |
| 1.80 | 18x8 | 18x10, 20x6, 20x8, 22x6 |
| 2.00 | 20x8 | 18x10, 20x6, 20x10, 22x6 |
Four Stroke Engines
| Engine Size | Starting Prop | Alternate Props |
| .20 - .21 | 9x6 | 9x5, 10x5 |
| .40 | 11x6 | 10x6, 10x7, 11x4, 11x5, 11x7, 11x 7-1/2, 12x4, 12x5 |
| .45 - .48 | 11x6 | 10x6, 10x7, 10x8, 11x7, 11x7-1/2, 12x4, 12x5, 12x6 |
| .60 - .65 | 12x6 | 11x7-1/2, 11x7-3/4, 11x8, 12x8, 13x5, 13x6, 14x5, 14x6 |
| .80 | 13x6 | 12x8, 13x8, 14x4, 14x6 |
| .90 | 14x6 | 13x6, 14x8, 15x6, 16x6 |
| 1.20 | 16x6 | 14x8, 15x6, 15x8, 16x8, 17x6, 18x5, 18x6 |
| 1.60 | 18x6 | 15x6, 15x8, 16x8, 18x6, 18x8, 20x6 |
| 2.40 | 18x10 | 18x12, 20x8, 20x10 |
| 2.70 | 20x8 | 18x10, 18x12, 20x10 |
| 3.00 | 20x10 | 18x12, 20x10 |
Remember...
Install the prop
with the curved side of the blade facing forward and tighten the prop nut
or bolt with the proper size wrench.
Recheck the tightness
of the nut or bolt often, especially on wood props which tend to compress
and loosen more often.
When starting
the engine, keep spectators at a safe distance clear of the model and out
of the path of the propellor.
Keep hands away
from the prop as much as possible. Use an electric starter or if
you're going to start by hand use a chicken stick.
Keep face and
body out of prop arc as engine is started and run.
Never throw anything
into the prop to stop the engine. Pinch off the engine's fuel supply.
Make all adjustments
from behind the prop except on pusher installations.
Discard any prop
with nicks, scratches, splits, cracks or any other sign of damage.
Never attempt to repair, alter or bend a prop.
Don't run an engine
in areas of loose gravel, sand or grass as the prop can throw such materials
into your face and eyes.
Keep loose clothing,
shirt sleeves and other such items away from the prop and avoid carrying
items that can fall into the prop such as pens, screwdrivers, etc when
starting the engine.
Be sure to keep
the glow driver wire out of the prop path.
If a spinner is
used, make sure the prop cutouts clear the propellor blades.