I can't find the APC 10x47 SF(P) Style replacement props anywhere on the website of HobbyKing. All I find is 10x4.5 and so on. The 2nd number never gets so high. Can someone explain this to me? Which ones do I need to order?
You need to be a member of diydrones to add comments!
Replies
From a practical standpoint, there's minimal difference between a 10x4.7 and a 10x4.5. According to ecalc, the higher pitch would increase the power per motor by a whopping three watts.
Going the other direction, reducing the pitch from 4.7 inches to 3.8 inches would increase your available hover endurance by about 36 seconds, while reducing current draw per motor by around 1.9 amps. (3S 3300mAh 25C LiPo, 1020kV motor, 10" APC slow-fly prop.)
(4 Pairs) 10x4.5" Carbon Fiber CW CCW Propellers
http://www.rctimer.com/product_665.html
(4 Pairs) 10x3.8" Carbon Fiber CW CCW Propellers
http://www.rctimer.com/product_880.html
These work really well providing you never strike anything http://www.rctimer.com/product_638.html
Very cheap, but light and workable (best for initial testing etc...) http://www.hobbyking.com/hobbyking/store/__22447__Slow_Fly_Electric...
hope this helps
For multicopters, for a given diameter, a given RPM, can someone confirm my understanding that a bigger pitch will produce more thrust? ( for example a 14x6 will produce more thrust than a 14x4.7)
No man, the best props I have EVER used are the carbon reinforced GemFam that were easy to find at one time, but not as much any more.But now Amazon sells them. You have to buy 2 packs.1 4 pack of Cw HERE, And one matching set of 4 CCW props HERE.
They handle much better in the wind....and Like I said there carbon reinforced. Think of it as Carbon Fibers baby brother. I have found that that the stiffer blades hold up better under windy conditions, and a host of other conditions. Don't get me wrong, sometimes more flex can be a good thin. Put ive found more good then bad. I as just relieved when I found another source.
Props on Multicopters are for operating at Static thrust this means relative air speed is for all practical purposes zero with a small margin either side of that, but not much.
On multicopters you want the biggest diameter 2 bladed props you can run and then match your pitch for maximum static thrust.
Maximum efficiency (battery life) is achieved on a multicopter with big slow turning props with low pitch numbers.
Increasing pitch on static thrust copters causes cavitation and turbulence much more than on airplanes.
Increasing the number of blades on a prop does not work well for a static thrust copter because the more blades the more they interfere with each others air in the form of turbulence, cavitation and their own prop wash.
In an airplane multi blade props work better because the plane is actually moving through the air column at a high rate of speed.
Basically the larger the prop diameter in a multicopter the higher the current (power requirement) like wise the higher the pitch, the higher the current (power requirement) at any given RPM.
It is necessary to have the motors RPM power range matched to your specific prop (diameter and pitch) so that at the normal RPM it is producing a thrust (consuming power) that is within the operating parameters of the motor for it's KV rating and the number of cell in your battery. If it is drawing too much current it will overheat and fail.
Finally optimized multicopter props are not identical to airplane props specifically because they are designed for maximum static thrust.
The best of them tend to be wider at the base and taper towards the tip and they often have a variable pitch as you proceed along the cord of the propeller.
The longer Graupner multicopter propellers are examples of this.
Some of these responses on props is bogus. Props are not well understood by a lot of people.
High pitch props are used for speed like the high gear on a car. Lower pitch props are for power like 1st gear on a car.
The multicopters need power not speed. This is why they are typically below a 5 in pitch. The current pulled by the motor is a combination of the prop diameter and pitch. If the voltage is the same, then a bigger pitch will draw more current so you may need to reduce the diameter to keep the current in the motor range.
If you decrease pitch the current will decrease so you can increase the diameter to increase the current to motor's specifications.
I take one of the motors and try different prop combinations to get the current to the motor's spec, then I prop the rest of them. The pitch between 3.8 and 5 is typically what you are looking for and a diameter that gets the current you need.
Some props are really soft and won't hold pitch when they spin up. Some are not drilled straight in the center hole and impossible to get to spin without vibration. Some are horribly balanced. If you have do a lot to balance a prop, you may as well toss it and get another one. CF props are expensive if you are just starting and you don't want to break many of those. They are also pretty stiff and you can bend a prop shaft in a crash. Some CF props are also way out of balance too.
If you are not sure about a prop, it is best to buy a couple and see how they work. If you have a hex or bigger, you may not want to buy a lot of them..
It is a 10x4.7 prop, not a 10x47. The APC props are available from most online hobby shops.
Why buy from Hobby King? How about from 3D or Udrone or some retailer that's local to you?
47 is 4.7 and is the pitch value. In inches.
4.7 is meh anyway - go get 3.8 or something if you can find it. 4.5 is alright too really.
tl;dr those two separate sentences: buy the hobbyking props.