FlyingTyger
Elite member
The general rule of thumb that I've known and used, is to drop 1" in diameter OR drop 1" in pitch when going from 2 to 3 blades.
Solved The right prop for my scratch built Rc plane
- Thread starter Dawson
- Start date
Dawson
Member
Ok so can the reamer cut through wood and plastic/carbon fiber? And if I did a wood propeller, would it make the motor perform differently because wood is heavier?
FlyingTyger
Elite member
The reamer should be able to cut through all prop materials.
There won't be much difference if any between wood and plastic. The carbon props are a little stiffer, but the difference is still negligible for general flying.
Tench745
Master member
Can you tell us what motor you actually have and/or post a link to it? You said it is 510kv, but I didn't see anywhere that said what size it is or who makes it.
A prop reamer can cut through plastic, carbon, or wood with no trouble and the motor will behave similarly with a prop made of any of those materials.
Wood may actually be lighter than a plastic propeller of the same size. As long as the plane is balanced on the CG, I doubt you would notice any difference in flight between a lighter or heavier prop.
A prop reamer can cut through plastic, carbon, or wood with no trouble and the motor will behave similarly with a prop made of any of those materials.
Wood may actually be lighter than a plastic propeller of the same size. As long as the plane is balanced on the CG, I doubt you would notice any difference in flight between a lighter or heavier prop.
Dawson
Member
It is actually flite test that makes it. It’s the 510kv monster brushless motor on their store website. Here is a link- https://store.flitetest.com/ft-radial-4030-510kv-monster-brushless-motor/
Dawson
Member
Okay, thank you for all your help!
Tench745
Master member
Got it. I see now that you said as much in the very first sentence of your post. I need to read better.
Are you using the free trial version? If so, it greys out a lot of options that are available in the paid version. Still, you can often find something close enough to get a ballpark idea of what will work for you.
Dawson
Member
I’m not sure what I was using but I will check now
Dawson
Member
Would this reamer work? https://www.amazon.com/dp/B07K48BR4P/?tag=lstir-20
FlyingTyger
Elite member
He has the FT Monster motor.
It should.
Dawson
Member
Dawson
Member
Just to clarify, a 6s battery will work for the 14x8 propeller and my motor?
Thanks
FlyingTyger
Elite member
Yes.
Dawson
Member
Ok I just wanted to make sure because the motor description says that if I used a 6s, then I should use a 16-18 inch propeller but maybe that was for a different pitch or something.
Thanks for all the help.
Last edited:
Tench745
Master member
A 16" or 18" prop might bring you closer to the maximum output for this motor. A 14" will draw fewer amps, so going smaller than their recommended sizes won't hurt anything.
The best way to know what a prop will do on a motor is to hook up a watt meter and test it.
Dawson
Member
Ok thanks. If I went bigger, would it give me more thrust? Or would it just hurt the motor? Would the pitch need to change?
Tench745
Master member
Okay. I think we need to start this lesson from somewhere near the beginning...
Pitch is the distance the prop will try to pull itself forward in one rotation, measured in inches. Pitch speed is your pitch x prop RPM, then converted into Miles Per Hour. You want a pitch speed at least twice the stall speed of the airplane. The more pitch the faster the plane can theoretically fly (ignoring drag).
Here's a link to a stall speed calculator.
https://www.rcplanes.online/calc_stallspeed.htm
Thrust will increase a little when you increase pitch, but the primary factors in producing thrust are diameter and blade count. Larger diameter props produce more thrust and props with higher blade counts produce more thrust. Thrust is what makes a plane accelerate more quickly and be able to hover or climb vertically. Thrust is also what helps pull a high-drag airframe around the sky.
Keep in mind that producing more thrust will require more power. Power is measured in watts and is calculated by multiplying voltage x amperage. For example, if you are flying on a 6s battery the voltage is a fixed number, so if you go from a 14" prop to a 16" prop, it will need to draw more amps to produce more power and thrust. As long as the amperage the prop draws is below the maximum amperage rating of the motor, all is well.
If you go too big you will draw too much amperage and can cook the motor.
The reason people use and recommend prop calculators is that every one of these factors will interact with all the others in some way. The easiest way to see how every piece interacts and get a good final result is to use a tool like eCalc or something similar like this:
https://www.rcplanes.online/calc_motor.htm
Pitch is the distance the prop will try to pull itself forward in one rotation, measured in inches. Pitch speed is your pitch x prop RPM, then converted into Miles Per Hour. You want a pitch speed at least twice the stall speed of the airplane. The more pitch the faster the plane can theoretically fly (ignoring drag).
Here's a link to a stall speed calculator.
https://www.rcplanes.online/calc_stallspeed.htm
Thrust will increase a little when you increase pitch, but the primary factors in producing thrust are diameter and blade count. Larger diameter props produce more thrust and props with higher blade counts produce more thrust. Thrust is what makes a plane accelerate more quickly and be able to hover or climb vertically. Thrust is also what helps pull a high-drag airframe around the sky.
Keep in mind that producing more thrust will require more power. Power is measured in watts and is calculated by multiplying voltage x amperage. For example, if you are flying on a 6s battery the voltage is a fixed number, so if you go from a 14" prop to a 16" prop, it will need to draw more amps to produce more power and thrust. As long as the amperage the prop draws is below the maximum amperage rating of the motor, all is well.
If you go too big you will draw too much amperage and can cook the motor.
The reason people use and recommend prop calculators is that every one of these factors will interact with all the others in some way. The easiest way to see how every piece interacts and get a good final result is to use a tool like eCalc or something similar like this:
https://www.rcplanes.online/calc_motor.htm
Dawson
Member
Yes, but there’s a lot of things on there that I have no idea what they mean so that Is why I’m asking things on here. Also some of those things I don’t even know how to find on my motor, battery, and Esc so that is why I’m asking on here.
Tench745
Master member
Every plane is different and has different needs, so I can't tell you what prop to use without finding answers to those questions and running the numbers myself. So, how about we go through the list of things you don't know and/or don't know how to find and come up with the answers together?
Dawson
Member
Sure i can send you some links of my motor Esc and battery
Motor -https://store.flitetest.com/ft-radial-4030-510kv-monster-brushless-motor/
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