The postman brought me another package today, some EMAX AVAN-R 5065 3 blade quad racing props. I have titled this blog post as a "discussion" more than anything else as you will see later when I start reporting the bench performance on 3S, I don't think these props will find their way into any of my park jets😐 However, I thought I would discuss them anyway as a matter of a lesson learned, I'm sure I can find someone at my field to take them off my hands unless I do experiment with a 4S setup in the future😏
Banggood did package them up nicely with lots of foam wrapped around the package as you can see above. Below, you see that you get 4 props, two CW and two CCW as you would expect for a quad copter along with more EMAX stickers😊
So a bit of background on why I purchased these props, they were $4.29 USD for the pack of four from Banggood and my research had indicated these props were specifically designed for use on the EMAX RS2306 2750 Kv motor which thus far has been the top performer of all the quad racing motors I tested. I had tested a Gemfan 6x4x3 quad prop on the 2212/6 2200 Kv "workhorse" motor in the past, it generated incredible thrust on the bench (34.9A drawn producing 1039 gr/36.7 oz of thrust), but the blades were too big and created quite a bit of drag in the air. I had hoped that with a smaller blade but higher pitch, I might see some better results.
The prop certainly has an interesting blade shape with almost a bit of a "winglet" at the tip. I put each of the props on the balancer and they were perfectly balanced right out of the package.
I had a bit of trepidation about mounting the prop "upside down" for use in a park jet due to the blade shape and these fears were proven correct. I had to place an old spacer ring from a 6x4 APC prop to keep the blade off the flat top of the motor and as you can see in one of the pictures below it was still a very snug fit while still allowing enough thread on the shaft exposed to secure the prop to the motor.
In this picture, it looks like the prop is still resting on the top of the motor, there is just a "whisker's" width there, however, part of the prop blade is blocked by the motor itself.
Here are the bench numbers for this prop on the EMAX RS2306 2750 Kv motor with the prop mounted "upside down". Tested with a Turnigy Plush 60A ESC with timing set to low and a Zippy Flightmax 2200 3S 40C battery. Further details on all the bench testing that follows can also be found on my motor testing spreadsheet.
50% throttle - 15.5A/185.3W producing 274 gr/9.7 oz of thrust;
100% throttle - 36.2A/429.3W producing 448 gr/15.8 oz of thrust.
So these results are very poor and inefficient, almost 2A required for every oz of thrust produced at full throttle. Compared to the 6x4 APC gas prop numbers of 32.4A/371.2W producing 812 gr/28.6 oz of thrust, this is a pretty sad performance😏
So while I had everything set up, I decided to give it a test on the Multistar Viking 2208 2600 Kv motor . I know based on EMAX's data this prop isn't designed for this motor, but I suppose a prop is a prop at the end of the day😉 The top of the Viking motor slopes away quite a bit from the shaft and after adding a spacer ring again, I ended up with about 4mm between the prop blade and the bell of the motor.
So here are the numbers with this motor and prop, again, same test parameters as above.
50% throttle - 14.7A/176.8W producing 304 gr/10.7 oz of thrust;
100% throttle - 30.3A/348.9W producing 526 gr/18.6 oz of thrust.
So the numbers were a bit better considering this is a lower Kv motor, I suspect the prop having some more room to "breathe" might have helped, but still pretty bad compared to the 6x4 APC gas prop numbers (29.5A/359.5W producing 836 gr/29.5 oz of thrust at full throttle).
So I gave it one more chance on the GearBest 2212/5T 2700 Kv motor, hoping that the extra size/torque and high Kv might produce a "miracle" 😇 Alas, even with increased "prop clearance", twas not to be😊.
Same test parameters as the first two, here are the numbers
50% throttle - 14.2A/171.8W producing 378 gr/13.3 oz of thrust;
100% throttle - 31A/354.7W producing 630 gr/22. oz of thrust.
6x4 APC numbers for this motor on 3S at full throttle are 32.1A/370.6W producing 1004 gr/35.4 oz of thrust.
So it is certainly not the prop's fault, I was trying to use it in a role it was never designed for. It is designed to be used right side up and most quad racing guys are using 4S or higher with the EMAX RS2306 2750 Kv motor. Perhaps with a 4S battery I'm sure it would produce more thrust, but it has a long way to go to make up ground on the 6x4 APC gas prop for the role I need it to play in my park jets.
My challenge to myself when I started this quad racing motor test craze was to find a motor and prop combo that would give me the performance I see in my park jets on 3S, so unfortunately this prop doesn't fit the bill. I do have some other 5" 3 blade quad racing props on the way to try, one never knows until one tries😉
Park Jet noise...the "other" sound of freedom😎
Cheers,
Scott
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