Carbon propellers

[Dounin Front]

I've been giving the stiff propellers argument some thought. I read a candidate-PhD's paper on quadcopter aerodynamics and although it was about a different (but related) flight characteristic, it did make me think of the stresses on the rotor blades during dynamic flight (transitions from hover to forward flight, changes of direction and altitude...basically any situation where the pilot commands a move from equilibrium). If I am flying at full speed in one direction, then slam the stick in the opposite direction, which components of the aircraft take the punishment? The rotor blades take a lot of it...the change in pitch of the rotor plane will cause them to bend (gyroscopic effects), precession effects, and a violent change in loading. I think the blades absorb a lot of those dynamics (through flexing). If very stiff rotor blades are used, I imagine that those same forces (which still exist) get transferred to the motors, the airframe, and specifically the bearings (where the motor casing (the rotor) sits on the stator (the screws that attach the motor mounts to the printed circuit board).

I guess I should get to my point--I think the more flexible OEM blades act as a sort of "shock absorber" and spare the motor mounts from a lot of the stress of dynamic maneuver. I wonder if using stiffer propeller blades won't result in the motor mounts (or airframe) failing sooner due to increased stresses. Has anyone broken an OEM blade simply from a violent maneuver (not from hitting something)?

Obviously, if you "fly it like you stole it" you are going to break something. My "somewhat informed / somewhat intuitive" opinion is this: If you use stiffer propellers hoping to get better performance (longer battery life, "snappier" response) then realize that you may be overstressing other parts of the airframe, *if* you perform high stress maneuvers. If you don't demand the aircraft to perform high stress maneuvers, then you will probably see some performance improvement, without adversely affecting the longevity of the airframe. I don't do high stress maneuvers, so I may consider stiffer propellers in the future.

I'm not the expert, and I don't plan on testing this, but it is my theory and opinion, based on what I've observed and what I know. Good luck!

(Now I need to see if I can find about $4K lying around so I can buy myself an Inspire 2 package !!)

Your theory gives new meaning to the word snappy in "snappy response". The motor mounts and frame are more likely to snap.
I've been running DJI CF props on my P3A for a year now. There are no signs of cracks anywhere yet - although I did install Strong arm reinforcement plates along with the new props and I really believe they have helped spread the load.
Bu,t after all this discussion about stiffness, I switched back to the OE props last week, although I have painted them black, which was my original reason for changing to CF props - color. I think the OE props might be a little less brutal if (God forbid) they plow into something or someone.
Not sure what your needs are, but for less than half of your hard earned $4k you could pick up a P4 pro+ with a titanium frame and 4 direction obstacle avoidance. Now that sounds like a package!

 

[hblink93]

Your theory gives new meaning to the word snappy in "snappy response". The motor mounts and frame are more likely to snap.
I've been running DJI CF props on my P3A for a year now. There are no signs of cracks anywhere yet - although I did install Strong arm reinforcement plates along with the new props and I really believe they have helped spread the load.
Bu,t after all this discussion about stiffness, I switched back to the OE props last week, although I have painted them black, which was my original reason for changing to CF props - color. I think the OE props might be a little less brutal if (God forbid) they plow into something or someone.
Not sure what your needs are, but for less than half of your hard earned $4k you could pick up a P4 pro+ with a titanium frame and 4 direction obstacle avoidance. Now that sounds like a package!

While enticing (especially the "half-cost" part), I think the I1/I2 are just sexy-looking. My "needs" for flight and photography are easily covered by my P3A. Buying the I2 would be like buying a Ferrari--very cool to have, but kinda impractical, too.

Instead--I'm spending my money on a science project. In other posts, I've been digging around about 360 cameras. My current plan: Buy a Nikon Key Mission 360 ($500, and 7 oz.) and mount it under my P3A's landing gear (flying two cameras). I suspect the 360 videos will be cool, but in need of stabilization. Next purchase will be Feiyu 3D MiNi gimal (about $170 and 6 oz.) and putting together a configuration that keeps the 360 camera level to make the resulting 360 video silky smooth. I may need to add counterweights to balance the camera on the gimbal, but I'm shooting for no more than 16 oz total added weight. (need to do some experimenting with that as well.) Anyway, as I do this, I will post pictures/video and share results.

 

[Dounin Front]

While enticing (especially the "half-cost" part), I think the I1/I2 are just sexy-looking. My "needs" for flight and photography are easily covered by my P3A. Buying the I2 would be like buying a Ferrari--very cool to have, but kinda impractical, too.

Instead--I'm spending my money on a science project. In other posts, I've been digging around about 360 cameras. My current plan: Buy a Nikon Key Mission 360 ($500, and 7 oz.) and mount it under my P3A's landing gear (flying two cameras). I suspect the 360 videos will be cool, but in need of stabilization. Next purchase will be Feiyu 3D MiNi gimal (about $170 and 6 oz.) and putting together a configuration that keeps the 360 camera level to make the resulting 360 video silky smooth. I may need to add counterweights to balance the camera on the gimbal, but I'm shooting for no more than 16 oz total added weight. (need to do some experimenting with that as well.) Anyway, as I do this, I will post pictures/video and share results.

Can't wait to check out your progress. Is the 360º stuff similar to the pano mode you can do in Litchi?

 

[johnyoung]

Not read the thread so not sure if this has been said and this is my own personal experience and observations. I asked myself the same question a few months back and decided to give the props a try.

First time out, the P3 flew more stable and seemed to be a bit more stable maneuvering, I would say a lot more. The P3 also stayed put on the hovering even in the wind. Sounds and noise levels were the same to my unturned ears. One major difference was lift (I suspect so anyway). Landing the P3 for the first time turned it into a grass cutter. First time I ever had this happen and I noticed that the blades increased in speed when I tried to shut off the motors by bring both control sticks to the 4pm position which causes the drone to lift and topple, this never happened with plastic props. Now I simply bring the left control to 6pm which shuts the motors off straight away and stop the tipping and grass cutting. I like the props and genuinely feel there is an improvement. John

Sent from my F3311 using PhantomPilots mobile app

 

[Dounin Front]

Not read the thread so not sure if this has been said and this is my own personal experience and observations. I asked myself the same question a few months back and decided to give the props a try.

First time out, the P3 flew more stable and seemed to be a bit more stable maneuvering, I would say a lot more. The P3 also stayed put on the hovering even in the wind. Sounds and noise levels were the same to my unturned ears. One major difference was lift (I suspect so anyway). Landing the P3 for the first time turned it into a grass cutter. First time I ever had this happen and I noticed that the blades increased in speed when I tried to shut off the motors by bring both control sticks to the 4pm position which causes the drone to lift and topple, this never happened with plastic props. Now I simply bring the left control to 6pm which shuts the motors off straight away and stop the tipping and grass cutting. I like the props and genuinely feel there is an improvement. John

Sent from my F3311 using PhantomPilots mobile app

Sounds like you learned the hard way to only use the CSC maneuver to start the motors - never to stop them. Just 2 seconds at full and straight down on the left stick. (And it will never shut off the motors midair, only when it can't go any lower.) It also works well when you hand catch if you hold it still.

 

[johnyoung]

Bit of a shock as I was flying a brand spanking new P3A, wished I was using my P3P or a works drone. John

Sent from my F3311 using PhantomPilots mobile app

 

[Mydrone70]

they are great quieter but add just a little difference of weight

Sent from my SPH-L720 using PhantomPilots mobile app

 

[Dounin Front]

they are great quieter but add just a little difference of weight

Sent from my SPH-L720 using PhantomPilots mobile app

A set of Dji CF props add 5.67g to the overall weight. Of course that's spinning weight that must be controlled by the motors and there is constant accelerating and braking going on.
I hear a different sound from them, but wouldn't say they are quieter. (IMO of course)

 

[johnyoung]

If anything maybe quieter on braking. Due to the flip I have avoided using on jobs but always fly with the rotors with my private phantoms. I would say that the rotors chip easy. My first encounter left the rear ccw prop with a 1mm chip on the leading edge. John

Sent from my F3311 using PhantomPilots mobile app

 

[phxbird57]

I've been giving the stiff propellers argument some thought. I read a candidate-PhD's paper on quadcopter aerodynamics and although it was about a different (but related) flight characteristic, it did make me think of the stresses on the rotor blades during dynamic flight (transitions from hover to forward flight, changes of direction and altitude...basically any situation where the pilot commands a move from equilibrium). If I am flying at full speed in one direction, then slam the stick in the opposite direction, which components of the aircraft take the punishment? The rotor blades take a lot of it...the change in pitch of the rotor plane will cause them to bend (gyroscopic effects), precession effects, and a violent change in loading. I think the blades absorb a lot of those dynamics (through flexing). If very stiff rotor blades are used, I imagine that those same forces (which still exist) get transferred to the motors, the airframe, and specifically the bearings (where the motor casing (the rotor) sits on the stator (the screws that attach the motor mounts to the printed circuit board).

I guess I should get to my point--I think the more flexible OEM blades act as a sort of "shock absorber" and spare the motor mounts from a lot of the stress of dynamic maneuver. I wonder if using stiffer propeller blades won't result in the motor mounts (or airframe) failing sooner due to increased stresses. Has anyone broken an OEM blade simply from a violent maneuver (not from hitting something)?

Obviously, if you "fly it like you stole it" you are going to break something. My "somewhat informed / somewhat intuitive" opinion is this: If you use stiffer propellers hoping to get better performance (longer battery life, "snappier" response) then realize that you may be overstressing other parts of the airframe, *if* you perform high stress maneuvers. If you don't demand the aircraft to perform high stress maneuvers, then you will probably see some performance improvement, without adversely affecting the longevity of the airframe. I don't do high stress maneuvers, so I may consider stiffer propellers in the future.

I'm not the expert, and I don't plan on testing this, but it is my theory and opinion, based on what I've observed and what I know. Good luck!

(Now I need to see if I can find about $4K lying around so I can buy myself an Inspire 2 package !!)

Hey if you find $8k and you send $4k to me

 

[RC Madman]

There are pilots that have 800+ miles on stock props with no signs of damage. Yes there are a percentage of air frames that show premature signs of stress cracks but the majority of Phantoms are good to go. DJI programed the flight to be on the "Softer" side and there is not really any violent maneuvers. Compare the flight of a F450 with a CC3D FC with the PID's tuned to "snappy" flight and the Phantom seems slow and relaxed.

I have never broken a prop on sport flying quads just from the stress of flying but I don't fly aerobatics and I am sure some have been able to snap them in flight..

I installed a set of the DJI Carbon Nylon props and flew them for 2 flights so far and they do seem a bit more responsive. Not sure on flight times though.

 

[RC Madman]

I haven't flown with them yet, but here's a pic of the tmotor carbon fiber props. Each prop is 8.4 / 8.5g.

Be careful, many that have used carbon fiber props have ran into stability issues and have even crashed while testing. I have seen little on the net with tests that have shown that anything other than the stock props or DJI's carbon nylon props work better. Flight time and overall performance don't seem to see any improvements from the tests done.