Prather 215 vs Octura x640 vs x442

[Nutbar]

Apparently, the p215 or x442 seem to be the safest choices for stock Spartans, but does the p215 really run any cooler than the x640? The x640 and p215 have almost the exact same diameter and pitch, am I right? What is the difference between the x640 and p215 that makes the p215 run cooler than the x640?

Also, how are temps comparing the p215 and the x442? Which one runs the coolest?

[Make-a-Wake]

The x640 has a bit more total pitch than the s215, and the s215 is a 1.5 pitch compared to the 1.6 pitch of the x640. I am not a "know it all" by any means, but i find that its harder to turn more pitch than diameter. I would run an x442 max............I bet in a controlled test that the x442 has the highest top speed of the three.

[traeside]

I think the Prather 215 is a 2.5 pitch that is why it is slightly faster than the stock prop. i am trying to prop my 4092 1480 and i am thinking i need to be bigger than stock since i am at a lower KV. I made a quick chart and I also found this nice chart on line. not having them infront of me but i am sure the blade size of the stock prop is much smaller.

http://blakbirdz.com/rcboats/propchart.htm

Prop OD Pitch total MM OD MM Pitch
Stock 1.65 2.322 3.8313 41.91 58.9788
215 1.6 2.5 4 40.64 63.5
220 1.72 2.6 4.472 43.688 66.04
X442 1.65 1.4 2.31 41.91 35.56
X445 1.77 1.4 2.478 44.958 35.56
X447 1.85 1.4 2.59 46.99 35.56
X448 1.9 1.4 2.66 48.26 35.56
X640 1.57 1.6 2.512 39.878 40.64
X642 1.65 1.6 2.64 41.91 40.64
X645 1.77 1.6 2.832 44.958 40.64

[Steven Vaccaro]

I think the Prather 215 is a 2.5 pitch that is why it is slightly faster than the stock prop. i am trying to prop my 4092 1480 and i am thinking i need to be bigger than stock since i am at a lower KV. I made a quick chart and I also found this nice chart on line. not having them infront of me but i am sure the blade size of the stock prop is much smaller.

http://blakbirdz.com/rcboats/propchart.htm

Prop OD Pitch total MM OD MM Pitch
Stock 1.65 2.322 3.8313 41.91 58.9788
215 1.6 2.5 4 40.64 63.5
220 1.72 2.6 4.472 43.688 66.04
X442 1.65 1.4 2.31 41.91 35.56
X445 1.77 1.4 2.478 44.958 35.56
X447 1.85 1.4 2.59 46.99 35.56
X448 1.9 1.4 2.66 48.26 35.56
X640 1.57 1.6 2.512 39.878 40.64
X642 1.65 1.6 2.64 41.91 40.64
X645 1.77 1.6 2.832 44.958 40.64

test with the stock prop and move from there. the next step up for me would be a x445 or m445.

[traeside]

i must be missing something. this chart shows the having a 2.323 pitch. X442 1.654 42 2.323 59

[traeside]

thanks Steve, what about the X642?

[traeside]

i see what i was doing wrong please ignore the chart above

Prop OD Pitch total MM OD MM Pitch
Stock 1.65 2.32 3.83 42 59
215 1.60 2.50 4.00 41 64
220 1.72 2.60 4.47 44 66
X442 1.65 2.31 3.81 42 59
X445 1.77 2.48 4.39 45 63
X447 1.85 2.59 4.79 47 66
X448 1.90 2.66 5.05 48 68
X640 1.57 2.51 3.94 40 64
X642 1.65 2.64 4.36 42 67
X645 1.77 2.83 5.01 45 72

[Steven Vaccaro]

http://www.offshoreelectrics.com/propeller-chart.php

[traeside]

book marked, thank you again Steve.

[Banzee]

What is the difference between a prop of 42 mm in dia and a 45 mm with both the same pitch, 55 mm for example ? I mean how it will change the performance ?

[Steven Vaccaro]

A 45 will have a larger thrust cone than a 42mm prop. So the load is larger. Also the larger diameter prop has more total pitch, so in theory for each revolution spun, the farther it will travel.

[Make-a-Wake]

I think the Prather 215 is a 2.5 pitch

The 215 is a 1.5 pitch..............dont confuse pitch with total pitch. Total pitch is 2.5 as an x442 is a 1.4 pitch and 2.31 total pitch.

[Banzee]

A 45 will have a larger thrust cone than a 42mm prop. So the load is larger. Also the larger diameter prop has more total pitch, so in theory for each revolution spun, the farther it will travel.

thank s for your answer !!

[traeside]

The 215 is a 1.5 pitch..............dont confuse pitch with total pitch. Total pitch is 2.5 as an x442 is a 1.4 pitch and 2.31 total pitch.

yeah i cought my mistake in a few more minutes I knew I had something wrong. Thanks Make a Wake

[Make-a-Wake]

yeah i cought my mistake in a few more minutes I knew I had something wrong. Thanks Make a Wake