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Propeller Chart

The most difficult choice in Rc boating is picking the perfect prop!

Propellers come in many different materials, listed from softest to hardest are Plastic, Aluminum, Carbon Fiber, Beryllium Copper, and Stainless Steel. The best performance will be from a perfectly balanced and sharpened Beryllium Copper or Stainless Steel prop. You’ll notice the the bellow pictures of the Beryllium Copper & Stainless steel props are very dull, that’s because these props come as castings and need to be filed, sharpened & balanced. See How to Balance and Sharpen Article for more information. For the best “bang for the buck” and no work balancing & sharpening, look at the Graupner Carbon Filler Propellers. They are great for Sport running. 

When searching for the perfect prop we need to balance three important factors, Top Speed, heat buildup in Batteries, Motor & ESC (electronic speed control), and the ability for the hull to get up on plane.  Most Electric kit boats come with props that will work in a wide range of applications. Changing to the right prop with a kit boat will almost always yield a performance increase. Always start out with a smaller prop and work up to the optimum size. Never put to large of a prop an electric boat first. This will lead to burnt up ESC, Motor or Batteries. Bigger is not better in every case, this is particularly true in high RPM motors. To run at their best efficiency they need to spin fast. Too large of a prop will not allow the prop to reach its best RPM efficiency range and will cause heat build-up in the ESC, Motor, or Batteries. On the first run with the new prop, run it at full speed for twenty to thirty seconds, observe how quickly the boat got on plane and the top speed, the pull the boat out of the water and to test for heat, have an adult give the motor the 5-second test. Which is, hold your finger on the motor for 5 seconds. If its so hot you can’t hold it for 5 seconds, it’s too hot. Allow to cool fully before running again! If everything is cool or warm, keep doing this test until the pack starts to dump. DO NOT RUN THE PACK TO 0% CAPACITY! This will cause lots of heat and ruin your test results. At the end of the run if things are warm but not hot swap to a larger prop. With  Nitro, running too small a prop may allow the engine to spin at to high of an RPM and blow the engine!

Things to remember

  • First move the COG (center of gravity) forward or backward to get on plane quicker. For most monos and catamarans 30% forward of the transom is a good place to start. To check the COG put your left and right finger 1/3 of the hull length forward of the transom and have the boat balance in your fingers.
  • If the boat will not come on plane, and the motor seems to be at full RPM the prop is  cavitating. You may need a larger prop with more thrust to get on plane.
  • A well balanced and sharpened prop will always spin at higher RPM allowing a higher top speed!
  • Always monitor motor or engine heat! Cooler is better. To much heat kills!
  • Different water conditions will achieve different results. When comparing test results from a different day make sure the water and wind conditions where similar!

The following Chart is from Octura’s line up of Propellers. There are other companies that offer propellers but Octura seems to have the widest range of sizes for Electrics. Most props are left hand props, except for the ones labeled with an “R” after the prop Size.

To figure out how far a particular prop will travel, we need to know the total pitch, which is the diameter x pitch.
If we take into example the first prop listed(930), 1.18″diameter X .9 pitch = 1.062″
So the total pitch of the 930 prop is 1.062 inches. Every time the prop shaft turns once the boat will move 1.062 inches. This is with no slip in a perfect world. Well it isn’t a perfect world so as a rule of thumb,

  • A Mono hull will slip 25%
  • A Catamaran of scale Hydro 20%
  • A Rigger about 15%

This is assuming that the hulls are well balanced and running free.

Click here for a Tool to make some top speed estimates!

Octura Propellers.

Prop# Diameter Pitch Fits shaft size Plastic Al BC
930 30mm (1.18″) 0.9 x 1.18 =1.062″ 1/8″ x x
937/3 37mm (1.48″) 0.9 x 1.48 =1.332″ 1/8″ x x
955/3 55mm (2.17″) 0.9 x 2.17 =1.953″ 3/16″ x
0955/3R 55mm (2.17″) 0.9 x 2.17 =1.953″ 3/16″ x
977 77mm (3.03″) 0.9 x 3.03 =2.727″ 1/4″ x
1240 40mm (1.57″) 1.2 x 1.57 =1.884″ 3/16″ x
1240/3 40mm (1.57″) 1.2 x 1.57 =1.884″ 3/16″ x
1245 45mm (1.77″) 1.2 x 1.77 =2.124″ 3/16″ x
1250 50mm (1.97″) 1.2 x 1.97 =2.364″ 3/16″ x
1250R 50mm (1.97″) 1.2 x 1.97 =2.364″ 3/16″ x
1255 55mm (2.17″) 1.2 x 2.17 =2.604″ 3/16″ x
1270 70mm (2.76″) 1.2 x 2.76 =3.312″ 3/16″ x
1337/3 37mm (1.48″) 1.3 x 1.48 =1.924″ 3/16″ x
1427 27mm (1.07″) 1.4 x 1.07 =1.498″ 1/8″ x x
1435 35mm (1.38″) 1.4 x 1.38 =1.932″ 3/16″ x
1440 40mm (1.57″) 1.4 x 1.57 =2.198″ 3/16″ x
1445 45mm (1.77″) 1.4 x 1.77 =2.478″ 3/16″ x
1450 50mm (1.97″) 1.4 x 1.97 =2.758″ 3/16″ x x
1455 55mm (2.17″) 1.4 x 2.17 =3.038″ 3/16″ x x
1455/3 55mm (2.17″) 1.4 x 2.17 =3.038″ 3/16″ x
1457 57mm (2.24″) 1.4 x 2.24 =3.136″ 3/16″ x x
1457R 57mm (2.24″) 1.4 x 2.24 =3.136″ 3/16″ x
1457/3 57mm (2.24″) 1.4 x 2.24 =3.136″ 3/16″ x
1460 60mm (2.36″) 1.4 x 2.36 =3.304″ 3/16″ x x
1462 62mm (2.44″) 1.4 x 2.44 =3.416″ 3/16″ x x
1462R 62mm (2.44″) 1.4 x 2.44 =3.416″ 3/16″ x
1465 65mm (2.56″) 1.4 x 2.56 =3.584″ 3/16″ x x
1467 67mm (2.64″) 1.4 x 2.64 =3.696″ 1/4″ x
1470 70mm (2.76″) 1.4 x 2.76 =3.864″ 3/16″ x
1470 70mm (2.76″) 1.4 x 2.76 =3.864″ 1/4″ x
1475 75mm (2.95″) 1.4 x 2.95 =4.130″ 1/4″ x
1540 40mm (1.57″) 1.5 x 1.57 = 2.355″ 3/16″ x
1567 67mm (2.64″) 1.5 x 2.64 = 3.960″ 1/4″ x
1630 30mm (1.18″) 1.6 x 1.18 = 1.888″ 1/8″ x x
1640 40mm (1.57″) 1.6 x 1.57 = 2.512″ 3/16″ x
1650 50mm (1.97″) 1.6 x 1.97 = 3.152″ 3/16″ x
1655 55mm (2.17″) 1.6 x 2.17 = 3.472″ 3/16″ x
1657 57mm (2.24″) 1.6 x 2.24 = 3.584″ 3/16″ x
1662 62mm (2.44″) 1.6 x 2.44 = 3.904″ 3/16″ x
1667 67mm (2.64″) 1.6 x 2.64 = 4.224″ 1/4″ x
1732 32mm (1.26″) 1.7 x 1.26 = 2.142″ 1/8″ x x
1735 35mm (1.38″) 1.7 x 1.38 = 2.346″ 1/8″ x
1740 40mm (1.57″) 1.7 x 1.57 = 2.669″ 3/16″ x
1740/3 40ma (1.57″) 1.7 x 1.57 = 2.669″ 3/16″ x
1742/3 42mm (1.65″) 1.7 x 1.65 = 2.805″ 3/16″ x
1745/3 45mm (1.77″) 1.7 x 1.77 = 3.009″ 3/16″ x
1747 47mm (1.85″) 1.7 x 1.85 = 3.145″ 3/16″ x
1750 50mm (1.97″) 1.7 x 1.97 = 3.349″ 3/16″ x
1752/3 52mm (2.05″) 1.7 x 2.05 = 3.485″ 3/16″ x
1755 55mm (2.17″) 1.7 x 2.17 = 3.689″ 3/16″ x
1760 60mm (2.36″) 1.7 x 2.36 = 4.012″ 3/16″ x
1860 60mm (2.36″) 1.8 x 2.36 = 4.248″ 3/16″ x
1930 30mm (1.18″) 1.9 x 1.18 = 2.242″ 1/8″ x x
1938 38mm (1.50″) 1.9 x 1.50 = 2.850″ 3/16″ x
1945 45mm (1.77″) 1.9 x 1.77 = 3.363″ 3/16″ x
1950 50mm (1.97″) 1.9 x 1.97 = 3.743″ 3/16″ x
1950/3 50mm (1.97″) 1.9 x 1.97 = 3.743″ 3/16″ x
1955 55mm (2.17″) 1.9 x 2.17 = 4.123″ 3/16″ x
1957 57mm (2.24″) 1.9 x 2.24 = 4.256″ 3/16″ x
1967 67mm (2.64″) 1.9 x 2.64 = 5.016″ 1/4″ x
2035 35mm (1.38″) 2.0 x 1.38 = 2.760″ 3/16″ x
2045 45mm (1.77″) 2.0 x 1.77 = 3.540″ 3/16″ x
2047 47mm (1.85″) 2.0 x 1.85 = 3.700″ 3/16″ x
2050 50mm (1.97″) 2.0 x 1.97 = 3.964″ 3/16″ x
2055 55mm (2.17″) 2.0 x 2.17 = 4.340″ 3/16″ x
2060 60mm (2.36″) 2.0 x 2.36 = 4.720″ 3/16″ x
2137/3 37mm (1.48″) 2.1 x 1.48 = 3.108″ 3/16″ x
2150/3 50mm (1.97″) 2.1 x 1.97 = 4.137″ 3/16″ x
2160 60mm (2.36″) 2.1 x 2.36 = 4.956″ 3/16″ x x
2167/3 67mm (2.64″) 2.1 x 2.64 = 5.544″ 1/4″ x
2250 50mm (1.97″) 2.2 x 1.97 = 4.334″ 3/16″ x
2260 60mm (2.36″) 2.2 x 2.36 = 5.192″ 3/16″ x
2267 67mm (2.64″) 2.2 x 2.64 = 5.808″ 1/4″ x
2352 52mm (2.05″) 2.3 x 2.05 = 4.715″ 3/16″ x
M447 47mm (1.85″) 1.4×1.85=2.590″ 3/16″ x
P735 35mm (1.38″) 1.7×1.38=2.346″ 1/8″ x x
P747 47mm (1.85″) 1.7×1.85=3.145″ 3/16″ x
P767/3 67mm (2.64″) 1.7×2.64=4.488″ 1/4″ x
V937/3 37mm (1.48″) 1.9×1.48=2.812″ 3/16″ x
V947/3 47mm (1.85″) 1.9×1.85=3.515″ 3/16″ x
V955/3 55mm (2.17″) 1.9×2.17=4.123″ 3/16″ x
V967/3 67mm (2.64″) 1.9×2.64=5.016″ 1/4″ x
X427 27mm (1.07″) 1.4×1.07=1.498″ 1/8″ x x
X430 30mm (1.18″) 1.4×1.18=1.652″ 1/8″ x x
X430R 30mm (1.18″) 1.4×1.18=1.652″ 1/8″ x x
X431 3lmm (1.22″) 1.4×1.22=1.708″ 1/8″ x
X432 32mm (1.26″) 1.4×1.26=1.764″ 1/8″ x x
X435 35mm (1.38″) 1.4×1.38=1.932″ 1/8″ x x
X437/3 37mm (1.48″) 1.4×1.48=2.072″ 3/16″ x x
X438 38mm (1.50″) 1.4×1.50=2.100″ 3/16″ x x
X440 40mm (1.57″) 1.4×1.57=2.198″ 3/16″ x x
X440/3 40mm (1.57″) 1.4×1.57=2.198″ 3/16″ x x
X442 42mm (1.65″) 1.4×1.65=2.310″ 3/16″ x x
X445 45mm (1.77″) 1.4×1.77=2.478″ 3/16″ x x
X447 47mm (1.85″) 1.4×1.85=2.590″ 3/16″ x x
X447R 47mm (1.85″) 1.4×1.85=2.590″ 3/16″ x x
X447/3 47mm (1.85″) 1.4×1.85=2.590″ 3/16″ x x
X448 48mm (1.90″) 1.4×1.90=2.660″ 3/16″ x x
X450 50mm (1.97″) 1.4×1.97=2.758″ 3/16″ x x
X450/3 50mm (1.97″) 1.4×1.97=2.758″ 3/16″ x
X452 52mm (2.05″) 1.4×2.05=2.870″ 3/16″ x
X452/3 52mm (2.05″) 1.4×2.05=2.870″ 3/16″ x
X455 55mm (2.17″) 1.4×2.17=3.038″ 3/16″ x
X455/3 55mm (2.17″) 1.4×2.17=3.038″ 3/16″ x
X457 57mm (2.24″) 1.4×2.24=3.136″ 3/16″ x
X457R 57mm (2.24″) 1.4×2.24=3.136″ 3/16″ x
X457/3 57mm (2.24″) 1.4×2.24=3.136″ 3/16″ x
X460 60mm (2.36″) 1.4×2.36=3.304″ 3/16″ x
X460/3 60mm (2.36″) 1.4×2.36=3.304″ 3/16″ x
X462 62mm (2.44″) 1.4×2.44=3.416″ 3/16″ x
X465 65mm (2.56″) 1.4×2.56=3.584″ 3/16″ x
X465R 65mm (2.56″) 1.4×2.56=3.584″ 3/16″ x
X467 67mm (2.64″) 1.4×2.64=3.696″ 1/4″ x
X470 70mm (2.76″) 1.4×2.76=3.864″ 1/4″ x
X47OR 70mm (2.76″) 1.4×2.76=3.864″ 1/4″ x
X470/3 70mm (2.76″) 1.4×2.76=3.864″ 1/4″ x
X472 72mm (2.84″) 1.4×2.84=3.976″ 1/4″ x
X482 82mm (3.22″) 1.4×3.22=4.508″ 1/4″ x
X548 48mm (1.90″) 1.5×1.90=2.850″ 3/16″ x
X560 60mm (2.36″) 1.5×2.36=3.540″ 3/16″ x
X572 72mm (2.84″) 1.5×2.84=4.260″ 1/4″ x
X632 32mm (1.26″) 1.6×1.26=2.016 1/8″ x x
X637 37nun (1.48″) 1.6×1.48=2.368″ 3/16″ x x
X640 40mm (1.57″) 1.6×1.57=2.512″ 3/16″ x x
X642 42mm (1.65″) 1.6×1.65=2.640″ 3/16″ x x
X645 45mm (1.77″) 1.6×1.77=2.832″ 3/16″ x x
X646 46mm (1.81″) 1.6×1.81=2.896″ 3/16″ x x
X646/3 46mm (1.8″) 1.6×1.81=2.896″ 3/16″ x
X648 48mm (1.90″) 1.6×1.9=3.040″ 3/16″ x x
X665 65mm (2.56″) 1.6×2.56=4.096″ 3/16″ x
X665R 65mm (2.56″) 1.6×2.56=4.096″ 3/16″ x
X670 70mm (2.76″) 1.6×2.76=4.416″ 1/4″ x
Y535 35mm (1.38″) 2.125″ 1/8″ x x
Y547 47mm (1.85″) 2.849″ 3/16″ x
Y557 57mm (2.24″) 3.449″ 3/16″ x
Z50 50mm (1.97″) 1.6×1.97=3.152″ 3/16″ x
Z55 55mm (2.17″) 1.6×2.17=3.472″ 3/16″ x
Z60 60mm (2.36″) 1.6×2.36=3.776″ 3/16″ x
1.6 1.6″ 1.8×1.6=2.880″ 3/16″ x x
1.6/3 1.6″ 1.8×1.6=2.880″ 3/16″ x
1.8 1.8″ 1.8×1.8=3.240″ 3/16″ x x
2.0 2″ 1.8×2=3.600″ 3/16″ x
2.0/4 2″ 1.8×2=3.600″ 3/16″ x
2.1/3 2.1″ 1.8×2.1=3.780″ 3/16″ x
2.2 2.2″ 1.8×2.2=3.960″ 3/16″ x
2.4 2.4″ 1.8×2.4=4.320″ 3/16″ x
2.4/3 2.4″ 1.8×2.4=4.320″ 1/4″ x
2.6 2.6″ 1.8×2.6=4.680″ 3/16″ x
2.8 2.8″ 1.8×2.8=5.040″ 3/16″ x

Graupner Carbon Fiber Propellers.

Prop Diameter Pitch Fits shaft size

Carbon
Fiber

2317.40 40mm(1.57″) 1.4×40=56.0mm or 2.20″ 3/16″ x
2317.42 42mm(1.65″) 1.4×42=58.8mm or 2.31″ 3/16″ x
2317.45 45mm(1.77″) 1.4×45=63.0mm or 2.48″ 3/16″ x
2317.48 48mm(1.89″) 1.4×48=67.0mm or 2.64″ 3/16″ x
2317.51 51mm(2.01″) 1.4×51=71.0mm or 2.80″ 3/16″ x

Prather Propellers

Prop#

Diameter Pitch
215 40.6mm (1.60″) 2.5″
220 43.7mm (1.72″) 2.6″
225 46.7mm (1.84″) 2.8″
230 48.3mm (1.90″) 3.0″
235 50.8mm (2.00″) 3.2″
240 53.8mm (2.12″) 3.3″
245 57.2mm (2.25″) 3.5″
250 58.4mm (2.30″) 3.6″
255 61.0mm (2.40″) 3.8″
260 64.0mm (2.52″) 3.9″
265 66.3mm (2.61″) 4.0″
270 69.6mm (2.74″) 4.2″
275 74.9mm (2.95″) 4.3″
280 78.7mm (3.10″) 4.5″