Thre corsair was actually designed and built around the motor and prop, the purpose being to attach a plane to the largest and most powerful motor and propeller available. This is the reason that the corsair has inverted gull wings, as the plane was literally designed around the motor and prop combo.
I choose the pitch based on how fast I want my plane to go and then I choose a diameter that puts the right amount of load on the motor. The formula for how much power is required to turn a propeller is: Power = k * rpm^3 * diameter^4 * pitch. So as you can see from this formula, the rpm has a huge effect on the amount of power required, the diameter has a large effect, and the pitch has very little effect. For power in Watts, and diameter and pitch in inches, k is about 5.3×10-15 for an average model airplane propeller. I generally want the diameter to be 1-1/2 to 2 times whatever the pitch is.
Agree James that there is no magic fit when it comes to prop size. Often you need to have a few on hand to test with your aircraft to find the best characteristics of throttle response and desired speed. Fortunately they are very inexpensive and it’s wise to have several on hand. 👍
Great information, so on my pusher plane I'm running a 1400kv motor, 4s lipo battery and a 8×6 folding propeller, I'm trying to slow this bird down and get more thrust for hand launching. If I stay with 8 inch diameter propeller would 8×4 be a better option or maybe a 8×8. Thanks
The pitch is on edf rotors too, like a 12 blade has less pitch than a 9 blade. The 12 blade is great for more thrust and a 9 blade is a great balance of speed and thrust combined. 50K baby! If you did not hear James I received the decals last week but they were not sized correctly hopefully I will receive them this week if I get it done I can always p.m. you some photos if it's in time for the Friday show.
For sport/pattern/warbird type flying 70% pitch to diameter ratio is the golden ratio for good balance of climb, cruise, top speed, and glide performance. 50% pitch is good for 3D type flying. It’s like stuck on 1st gear though, good for climb, but not efficient, really acts like a brake on down line and kills glide ratio. Changing props completely change flying characteristics of a plane, almost like getting a completely different plane. Choose wisely.
So if I'm looking at the motor stats for the motor I have it says it can reach a prop pitch speed of 161 mph close to 100 amps and produces more thrust than AUW. I'm guessing it's too much to ask for MPX FJ to actually reach 160 mph?
The pitch has very little effect on the amount of load that a prop puts on a motor. To compare the load factor of different props, use the formula: Prop Load Factor (PLF) = Diameter³ x Pitch. Solving this formula yields a pure number (no dimensions) - for a 10×8 prop, it equals 8000 (10 x 10 x 10 x 8). To find a prop that will load the motor the same as the 10×8, it must first be the same type of prop. By substituting terms, you can find a prop that is perhaps a larger diameter, different pitch, etc. As an example, a 10.5x7 would be very close (10.5 x 10.5 x 10.5 x 7 = 8103). But would you cut an 11x7 down to 10.5" or would you install a 10x7 and let it rev a little higher (10 x 10 x 10 x 7 = 7000). Or, would you install an 11x7 and put a heavier load on the motor (11 x 11 x 11 x 7 = 9317)?
I love these quick tips and especially listening to James do them. He's a great speaker and has such humility and not afraid to laugh at himself.
Thre corsair was actually designed and built around the motor and prop, the purpose being to attach a plane to the largest and most powerful motor and propeller available. This is the reason that the corsair has inverted gull wings, as the plane was literally designed around the motor and prop combo.
I choose the pitch based on how fast I want my plane to go and then I choose a diameter that puts the right amount of load on the motor. The formula for how much power is required to turn a propeller is: Power = k * rpm^3 * diameter^4 * pitch. So as you can see from this formula, the rpm has a huge effect on the amount of power required, the diameter has a large effect, and the pitch has very little effect. For power in Watts, and diameter and pitch in inches, k is about 5.3×10-15 for an average model airplane propeller. I generally want the diameter to be 1-1/2 to 2 times whatever the pitch is.
Thanks for the formula, very useful!
Another great tip for beginners. Thanks James
Thank you for doing this important Quit Tips and passing them on to the RC community! 👍
Very nice and quick informations! Valuable 5min for a begginner!!
Agree James that there is no magic fit when it comes to prop size. Often you need to have a few on hand to test with your aircraft to find the best characteristics of throttle response and desired speed. Fortunately they are very inexpensive and it’s wise to have several on hand. 👍
Another great tip James 👍🏻
Altitude/air density is a factor. We generally fly 1 point of pitch higher at this altitude (5300 ft ask)
I am a newbie in RCs, thank you
Great information, so on my pusher plane I'm running a 1400kv motor, 4s lipo battery and a 8×6 folding propeller, I'm trying to slow this bird down and get more thrust for hand launching. If I stay with 8 inch diameter propeller would 8×4 be a better option or maybe a 8×8. Thanks
The pitch is on edf rotors too, like a 12 blade has less pitch than a 9 blade. The 12 blade is great for more thrust and a 9 blade is a great balance of speed and thrust combined. 50K baby! If you did not hear James I received the decals last week but they were not sized correctly hopefully I will receive them this week if I get it done I can always p.m. you some photos if it's in time for the Friday show.
For sport/pattern/warbird type flying 70% pitch to diameter ratio is the golden ratio for good balance of climb, cruise, top speed, and glide performance. 50% pitch is good for 3D type flying. It’s like stuck on 1st gear though, good for climb, but not efficient, really acts like a brake on down line and kills glide ratio. Changing props completely change flying characteristics of a plane, almost like getting a completely different plane. Choose wisely.
When are you going to be getting some variable pitch prop assemblies? That is really what we need.
i just watched now and found what I was looking for he is worth recommending
Hello Si.
How to calculate and find the prepallers size based on wight?
Which is better for an underwater ROV: a two-blade or a three-blade design? and how to calculate pitch?
Awesome video tips James Thanks for sharing👍😎✨✨✨✨✨🎬✔that block
Oh I'm waiting for your wisdom off the props with E's and P's on them.
freewing pandora 1400mm 2엽으로는 사이즈 몇이 좋을까요?
Measured in ballistic gel.
If I’m running a 9x8 pusher prop but I’m upping the motor size can I up the pitch? To a 9x9?
I have a question...
I have 8x6 triblade ,what kv is compatible?
So if I'm looking at the motor stats for the motor I have it says it can reach a prop pitch speed of 161 mph close to 100 amps and produces more thrust than AUW. I'm guessing it's too much to ask for MPX FJ to actually reach 160 mph?
Good video
If i went up in diameter but not pitch is that bad if i keep everything else the same?
I wonder why we don't start with thrust?
Hi sir can i use 125cc Honda bike engine for aircraft
& if u go bigger in size, u wanna reduce pitch! (Rule of thumb I learned 20+ years ago)
The pitch has very little effect on the amount of load that a prop puts on a motor. To compare the load factor of different props, use the formula: Prop Load Factor (PLF) = Diameter³ x Pitch. Solving this formula yields a pure number (no dimensions) - for a 10×8 prop, it equals 8000 (10 x 10 x 10 x 8). To find a prop that will load the motor the same as the 10×8, it must first be the same type of prop. By substituting terms, you can find a prop that is perhaps a larger diameter, different pitch, etc. As an example, a 10.5x7 would be very close (10.5 x 10.5 x 10.5 x 7 = 8103). But would you cut an 11x7 down to 10.5" or would you install a 10x7 and let it rev a little higher (10 x 10 x 10 x 7 = 7000). Or, would you install an 11x7 and put a heavier load on the motor (11 x 11 x 11 x 7 = 9317)?
lol I shattered my carbon cub s2 prop yesterday when the wheel got caught on some grass while taking off.
u rock !!!!!!!!!!
Legit did not know that.
Will you sell turbines
🦄 Hi.
what about 8045.
thats mean 8 inches
Pitch does not equal advance ratio
سلام دواتساف نمبر راکړه
Why is he yelling at me?...
Because I am mad at you. You shouldn't have done that thing you did way back when
Which is better for an underwater ROV: a two-blade or a three-blade design? and how to calculate pitch?