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Prop Charts For Model Airplane Engines

Prop Chart For Two – Stroke Engines

Alternate PropellorsStarting PropEngine Size
5.25×4, 5.5×4, 6×3.5, 6×4, 7×36×3.049
7×3,7×4.5,7×57×4.09
8×5,8×6,9×48×4.15
8×5,8×6,9×59×4.19 – .25
9×7,9.5×6,10×59×6.20 – .30
9×7,10×5,11×410×6.35 – .36
9×8, 11×510×6.40
10×6,11×5,11×6,12×410×7.45
10×8,11×7,12×4,12×511×6.50
11×7.5, 11×7.75, 11×8,12×611×7.60 – .61
11×8,12×8,13×6,14×412×6.70
12×8,14×4,14×513×6.78 – .80
13×8,15×6,16×514×6.90 – .91
15×8,18×516×61.08
16×10,18×5,18×616×81.20
18×8,20×618×61.50
18×10,20×6,20×8,22×618×81.80
18×10,20×6,20×10,22×620×82.00

Prop Chart For Four – Stroke Engines

Alternate PropellersStarting PropEngine Size
9×5,10×59×6.20 – .21
10×6,10×7,11×4,11×5.11×7,11×7.5,12×4,12×511×6.40
10×6,10×7,10×8,11×7,11×7.5,12×4,12×5,12×611×6.45 – .48
11×7.5,11×7.75,11×8,12×8,13×5,13×6,14×5,14×612×6.60 – .65
12×8,13×8,14×4,14×613×6.80
13×6,14×8,15×6,16×614×6.90
14×8,15×6,15×8,16×8,17×6,18×5,18×616×61.20
15×6,15×8,16×8,18×6,18×8,20×618×61.60
18×12,20×8,20×1018×102.40
18×10,18×12,20×1020×82.70
18×12,20×1020×103.00

Starting Propellor sizes are mid range pitch props that should fly just about any plane designed for that size engine. Use these first as in most cases they will be close to being the correct size. Then use trial and error to try and fine tune the maximum performance from your ship by trying the alternate props. If none work better stick with the recommended starting prop.


Below are some safety items that although seem elementary still need to be repeated regarding propellers and their use.

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