My (E) did not make it into above post and I cannot figure out how to fix it, so here it the missing info:
either I'm a genius or an idiot...
- Thread starter lamiker
- Start date
While I try to stop my head from spinning like a prop. I will agree, and believe I should reconsider stepping down from the 9450 to the 9443. I will also experiment a bit more with the 8050, although I do not believe they will come close to the performance of the others.
Sometimes I revert in my head to airplane props. Low pitch for low speed, or climb; high pitch for high speed, or cruise. For a given RPM, the high pitch moves more air, until the prop stalls, and produces more lift.
These machines are probably not reaching the point which I refer to as "high speed", so there really is no benefit to the greater pitch... unless the air is really thin, like at high altitudes.
Very cool data yorlik.
Sometimes I revert in my head to airplane props. Low pitch for low speed, or climb; high pitch for high speed, or cruise. For a given RPM, the high pitch moves more air, until the prop stalls, and produces more lift.
These machines are probably not reaching the point which I refer to as "high speed", so there really is no benefit to the greater pitch... unless the air is really thin, like at high altitudes.
Very cool data yorlik.
Thrust goes up by the cube of the rpm, so no, it is not linear from hover rpm to max rise rpm: I believe it is called a parabola.
So responsiveness goes down with the lesser thrust props. Example in our case:
9450 props can do 23oz thrust per motor, pv2+ weighs 11oz (per motor), so will accel at basically 1G (32ft/sec^2 or 9.8m/sec^2). But the cheapos can only produce maybe 19oz thrust, so only 19/23= 26.6ft/sec^2 (8.1m/sec^2). So when we give it max thrust on left stick, we accel from 0 to 6m/sec max speed with 9540 props in (6m/sec)/[.5*(9.8m/sec2)]= 1.2 sec while with cheapos maybe a tad longer at 6/(.5*8.1)= 1.5 sec..... are we able to tell the difference?
So responsiveness goes down with the lesser thrust props. Example in our case:
9450 props can do 23oz thrust per motor, pv2+ weighs 11oz (per motor), so will accel at basically 1G (32ft/sec^2 or 9.8m/sec^2). But the cheapos can only produce maybe 19oz thrust, so only 19/23= 26.6ft/sec^2 (8.1m/sec^2). So when we give it max thrust on left stick, we accel from 0 to 6m/sec max speed with 9540 props in (6m/sec)/[.5*(9.8m/sec2)]= 1.2 sec while with cheapos maybe a tad longer at 6/(.5*8.1)= 1.5 sec..... are we able to tell the difference?
I outlined the 9443 and 9450, with pencil and paper today and found it interesting that the 9443 has a longer chord. The longest chord on the 9443 is closer to the root than the longest chord on the 9450.
Moving away from the root, the longest chord of the 9450 is only about 1/4" away from that of the 9443. From some point between the longest chords of each prop, the 9450 continues to have a longer chord than the 9443. I did not notice any difference in length.
There is some discussion going on elsewhere in the forum about reducing prop noise by filing the leading and trailing edges, blunt and pointed, respectively.
Maybe next week I'll try some of that.
Moving away from the root, the longest chord of the 9450 is only about 1/4" away from that of the 9443. From some point between the longest chords of each prop, the 9450 continues to have a longer chord than the 9443. I did not notice any difference in length.
There is some discussion going on elsewhere in the forum about reducing prop noise by filing the leading and trailing edges, blunt and pointed, respectively.
Maybe next week I'll try some of that.
A lot of this does correlate well with the experiences I have from flying. I have bought and tested way too many props, even some 9450 triblade props from China which I am still not sure about as I get the worst battery performance from them. I balance my props before I use them. To date, the best props I have are the 9443 carbon fiber props followed closely by the DJI 9450 props.
I have sets of the XOXO 9443 props also and they are thin and fexible and you have confirmed what I have experienced in that the lift is just not there and it climbs the slowest.
I like what I am getting so far from the DJI 9450 and the balanced carbon fibers.
I have sets of the XOXO 9443 props also and they are thin and fexible and you have confirmed what I have experienced in that the lift is just not there and it climbs the slowest.
I like what I am getting so far from the DJI 9450 and the balanced carbon fibers.
Hello all!
I started this thread because I'm a new pilot and after I broke all my dji props the props I bought on amazon would not fit onto my 2+. I managed to screw them down tightly using force - forget about self tightening! But when I flew the bird crashed and was unable to hover. So like a good little soldier I sent my bird off to get repaired believing that one of my many crashes must have bent the propellor shafts. Imagine my surprise when hani from UAV who I recommend highly sent me a video of dji props working perfectly on my "bent shafts" lol!!!
I want people to know that most non dji props will quite possibly not work right out of the box on your machine. Those that do including dji need balancing and now that I got a 5\16 drill bit and a prop balancing gizmo my bird flies great. Since all props even dji ones should get balanced might as well spend 10 bucks on a 5,\¹6 bit and for ever more use cheap props which I think was proven to be equally as good at liftoff or whatever. But mainly I want you fuckers to be aware that your props and how they fit and balance can totally affect how well your bird flies and hovers!!!
I started this thread because I'm a new pilot and after I broke all my dji props the props I bought on amazon would not fit onto my 2+. I managed to screw them down tightly using force - forget about self tightening! But when I flew the bird crashed and was unable to hover. So like a good little soldier I sent my bird off to get repaired believing that one of my many crashes must have bent the propellor shafts. Imagine my surprise when hani from UAV who I recommend highly sent me a video of dji props working perfectly on my "bent shafts" lol!!!
I want people to know that most non dji props will quite possibly not work right out of the box on your machine. Those that do including dji need balancing and now that I got a 5\16 drill bit and a prop balancing gizmo my bird flies great. Since all props even dji ones should get balanced might as well spend 10 bucks on a 5,\¹6 bit and for ever more use cheap props which I think was proven to be equally as good at liftoff or whatever. But mainly I want you fuckers to be aware that your props and how they fit and balance can totally affect how well your bird flies and hovers!!!
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