Which type of prop works best
- Thread starter rwilabee
- Start date
Bartman
Welcome to MultiRotorForums.com!!
rich,
i'm coming to the conclusion that props are props where vibration is concerned except when the props aren't balanced. there are people using very stiff carbon props that love them and people using very flexible props that equally love them. my preference is very much in the middle in that i've found the Xoar PJA and PJA-P props to be the best combination of lift, cost, stiffness, weight, and most importantly, sex appeal. just kidding about that last part.
for your Gaui, if you like the performance you're getting then I'd say just keep flying. are you looking for more lift? better response from your motors?
it appears to me there is no magic prop for all selections. for response I'd say stick with a lower pitch prop but for stability i'd say use a prop that doesn't give you too much excess lift so it will be more heavily loaded. If your motors are turning near their limit but aren't very hot to the touch then you could probably up-prop your heli and improve performance but it may make it jumpy for any photography or video you may try to do.
are you confused yet?
i'm coming to the conclusion that props are props where vibration is concerned except when the props aren't balanced. there are people using very stiff carbon props that love them and people using very flexible props that equally love them. my preference is very much in the middle in that i've found the Xoar PJA and PJA-P props to be the best combination of lift, cost, stiffness, weight, and most importantly, sex appeal. just kidding about that last part.
for your Gaui, if you like the performance you're getting then I'd say just keep flying. are you looking for more lift? better response from your motors?
it appears to me there is no magic prop for all selections. for response I'd say stick with a lower pitch prop but for stability i'd say use a prop that doesn't give you too much excess lift so it will be more heavily loaded. If your motors are turning near their limit but aren't very hot to the touch then you could probably up-prop your heli and improve performance but it may make it jumpy for any photography or video you may try to do.
are you confused yet?
Hi Bart...
I actually have an xAircraft Quad and I'm running 10 x 4.5 props. They are black and very flexible and look like the Gaui props. I'm getting some jelloing with my gopro so I was trying to figure out if it could be the props which I have balanced or could it possibly be the plastic landing gear which is flexible.
Rich
I actually have an xAircraft Quad and I'm running 10 x 4.5 props. They are black and very flexible and look like the Gaui props. I'm getting some jelloing with my gopro so I was trying to figure out if it could be the props which I have balanced or could it possibly be the plastic landing gear which is flexible.
Rich
DucktileMedia
Drone Enthusiast
I can tell you that flexible props will make the aircraft jitter a lot more when coming down quickly and then throwing on the power. When i switched from Xaircraft props to the graupners and APC props, everything was better. The aircraft comes to a quick controlled hault when i need to throw power into it to slow a rapid decent. The stiff props are probably more predictable because of this. Any prop is better than a prop that breaks mid air!
Did you try the graupner elektro I think they call them with 10 x 5 pitch. Did you like them better than the APC or do they just look better? Another thing I'm wondering is what the difference in performance would be between an 11 x 4.5 or a 10 x 5
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DucktileMedia
Drone Enthusiast
the grauper elektro 11x5's. Quiet, high tech looking, balanced out of the box, not as much lift.
APC- been the best prop I have tried so far. And I would not have thought that initially. the 12x3.8's with my avrotos on 3s are a perfect match.
APC- been the best prop I have tried so far. And I would not have thought that initially. the 12x3.8's with my avrotos on 3s are a perfect match.
Bartman
Welcome to MultiRotorForums.com!!
Ross,
It's all a matter or trial and error but here's a bit to chew on.....we know that props are just little wings that whirl around endlessly in circles. when a wing is lightly loaded and has a lot of lift in reserve, small changes in velocity or angle of attack can make noticeable changes in lift. you would see this as sensitivity to small throttle changes. in planes a lightly loaded wing is more bouncy in turbulence for a couple of reasons having to do with relative wind and stuff. when the wing is loaded up and working to stay aloft, you can have changes in velocity or angle of attack but the wing will just plod through and maybe even buffet on the edge of stall in response. it has been my experience that when we run our props a bit more on the loaded up side the helicopter is less responsive to throttle changes, more stable and easier to fly smoothly. but what I may find nice to fly others might find difficult and vice-versa.
so, to answer your question, if the prop is oversized for the application and the motors have the power to move them easily, the craft will appear to be floaty, yes. go too small though and you may end up like I did with the motors turning in an RPM range that made my video picture go to hell. it's all trial and error and it takes a small investment in different props to find those which you like the best and give the best combination of performance and flight efficiency.
generally speaking flat pitch props make thrust more available at slow airspeeds (we hover most of the time so that's zero airspeed) and higher pitch props are most efficient at higher airspeeds. when a high pitch prop is hovering it's blades are at a higher angle of attack and therefore closer to their stall angle of attack where they would stop making lift. that kinda sorta makes them less responsive to small throttle changes but go to high with pitch and they'll likely buffet a bit in the hover.
for my XY-8 i'm looking at the XOAR 12x5 PJA props which are a full blade design for nitro motors or the 13x5 PJN props which are a more narrow blade profile for electric motors. but that's only with the Canon T2i on there. I'd bet that with the Sony NEX (which is a good pound or more lighter) I'd probably prefer the Xoar 12x5 PJN electric props that are currently on there. They're a bit light on lift but very smooth flying and light.
Did any of that make sense? i'm not an aerodynamicist but this is how i've sorted it out and it seems to have gotten me closer to where i want to be with things.
It's all a matter or trial and error but here's a bit to chew on.....we know that props are just little wings that whirl around endlessly in circles. when a wing is lightly loaded and has a lot of lift in reserve, small changes in velocity or angle of attack can make noticeable changes in lift. you would see this as sensitivity to small throttle changes. in planes a lightly loaded wing is more bouncy in turbulence for a couple of reasons having to do with relative wind and stuff. when the wing is loaded up and working to stay aloft, you can have changes in velocity or angle of attack but the wing will just plod through and maybe even buffet on the edge of stall in response. it has been my experience that when we run our props a bit more on the loaded up side the helicopter is less responsive to throttle changes, more stable and easier to fly smoothly. but what I may find nice to fly others might find difficult and vice-versa.
so, to answer your question, if the prop is oversized for the application and the motors have the power to move them easily, the craft will appear to be floaty, yes. go too small though and you may end up like I did with the motors turning in an RPM range that made my video picture go to hell. it's all trial and error and it takes a small investment in different props to find those which you like the best and give the best combination of performance and flight efficiency.
generally speaking flat pitch props make thrust more available at slow airspeeds (we hover most of the time so that's zero airspeed) and higher pitch props are most efficient at higher airspeeds. when a high pitch prop is hovering it's blades are at a higher angle of attack and therefore closer to their stall angle of attack where they would stop making lift. that kinda sorta makes them less responsive to small throttle changes but go to high with pitch and they'll likely buffet a bit in the hover.
for my XY-8 i'm looking at the XOAR 12x5 PJA props which are a full blade design for nitro motors or the 13x5 PJN props which are a more narrow blade profile for electric motors. but that's only with the Canon T2i on there. I'd bet that with the Sony NEX (which is a good pound or more lighter) I'd probably prefer the Xoar 12x5 PJN electric props that are currently on there. They're a bit light on lift but very smooth flying and light.
Did any of that make sense? i'm not an aerodynamicist but this is how i've sorted it out and it seems to have gotten me closer to where i want to be with things.
Macsgrafs
Active Member
Thanks Bart...its ok Im very informed with wing shapes, lift, drag, thrust & weight factors 
but your explanation is good...horses for course I think
I am using APC 12x6E props for now, but I was going to try 14x4.7 props....its just the hassle of reaming out the centres & ballancing them all again & 8 at a time..works out about $80!!!!
Ross
but your explanation is good...horses for course I think I am using APC 12x6E props for now, but I was going to try 14x4.7 props....its just the hassle of reaming out the centres & ballancing them all again & 8 at a time..works out about $80!!!!
Ross
Bartman
Welcome to MultiRotorForums.com!!
rich, do a flight with the volume on in your video and watch/listen for where the jello happens. i had a quad that was underpropped for the load and the jello happened at and just above hover rpm. i propped up a bit which brought down the hover RPM's and the jello went away.
it should go without saying that you should also double check your props' balance (blades and hubs) if you're getting jello in the lens.
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Bartman
Welcome to MultiRotorForums.com!!
i would only up-prop if you're having a problem like Rich or you find that you're needing too much of the available power to slow or stop a descent. lightening up the load on the props when it's already handling things well doesn't do much except make you have to pay closer attention to altitude/power control, IMHO