Hello all,
I have been doing quite a bit of analysis for what would be the best tiger motor model/propeller combination for improving my heavy lift octocopter.
I am sharing here an excel analysis sheet I made for that, as it may be useful to share this with the community. The objective is to find the combination of tiger motor model/propeller size (propellers are assumed to be APC slow fly, I think they are the best ratio price/quality wise) to :
-to lift a 10 pounds octocopter
-Throttle close to 50% at hover point
-Have some amps/watt reserves on the motors and ESCs when throttle 100%
Fixed constraints for me : ESC 40 amps, Battery weight is asssumed to be 1130g, All Up weight including battery is 4850 g, propellers must be APC slow fly.
Here is the result of my the analysis in the excel sheet below (the file is also provided in annex). The calculation were made with the online eCalc tool for multicopters:
Conclusion : I will get the tiger motor model 3510 360Kv, with 6S battery and 14x4.7 propellers. It provides me all I wish for:
-good flight time duration : 18 minutes (for a heavy beast!)
-50% throttle at hover point
-All amps and wattage are well below the limits of the motors and ESCs.
Hope this would help others who are looking what would be best motor/prop combinations for their setup,
Accesorily and as a consequence, I must sell my current 3110-17 (700Kv) tiger motors to help me finance the acquisition of this other model (see picture above). They are like new (were purchased recently in june 2013) and they flew a total time of less than 50 minutes of use. I sell them in their original boxes with the original 6 mm tiger motor propeller mounts plus their carbon prop mounts. If interested, pm me. I am thinking for a price of 45 US$ each (price of new is around 64 US$ each).
Cheers,
Replies
You guys should test iPower iFlight motors. They are similar to SunnySky, being good quality for a moderate price.
I'm using the MT2217 930kV motors on my Octo. Not efficient, but they perform well. What I particularly like about these motors is they are only 22mm stators, but use 4mm shafts, which means the bearings are much larger. That's a good thing. I'll never use 3mm or 3.17mm on any high-value multirotor again.
Some good news!
So far found one system that runs as efficiently as the Tiger, but runs a lot cooler, has a much higher top end, and saves you $320 US, nearly half the cost of the Tigers (SunnySky X4112S running 15x5.5 RC Timer heli-props. I'll run more tests tomorrow on other props and at least one other motor. I'll try to finish up the tests tomorrow.
If it's not too late, hold off on the Tiger MN3510-25. It runs too hot for your application. I'll see if there is another motor that will work better.
Got tired of waiting for the 6S ESC so got lucky and my local hobby store had one.
here an updated version of the excel table where I have added the MN4012-340 we are talking about. Versus the first candidate, MN3510, in relative terms based on eCalc, the MN3510 still seems to be the best candidate (lower throttle to hover and much longer flight duration, lower consumption). That is if we can trust the eCalc tool better than the tables given by RC tiger motor, of course:
I did not look yet at the 3508 motor. No insight on it :(
At which best price can you get a pack of 8 motors MN3510-25 in the states?
In Europe it is around 61 euros (x1,3 in dollars)
That is one kick-ass motor! Nice pick.
I was only able to take it up to 4S with my ESC, so can't wait to get the 6S ESC. At lower voltages, it can get a net efficiency of 9. That's darn good.
With a 15" prop, I can get up to 900 grams thrust using 4S.
I also like the quality. The motor is solid, no movement when tweaking the prop. The prop mount is well done with recesses for the prop bolts. Long wire leads if you need them. Has a bottom closure that allows plenty of air circulation. Low vibration. Fast reaction swinging a 15" light prop.
For the esc, i will use the hobbyking blueseries 40 amps but any 6s compatible esc will do, for ex the HK SS series 50-60A. I will pay the esc if you need to get it.
The proposed props are pefect.
Question about the test bench: are the weights of the motor and prop "cancelled" by zeroing the scale when motor is stopped?
nice tests Frantz.
the issue i have with thrust on my current octo (X8) is it is too low although I'm using already 4S voltage , relatively large props (12x3,8) and relatively high KV (tiger motor MN3110 700KV).
I do not have any margin to increase prop size nor battery voltage (motors are at their limits in wattage, amps and heat), so are my 20 amps ESCs (I burned two of them by the way).
So in this case I have not other choice than change everything : new motors, new battery (6S), larger props.
At the moment I am thinking of the tiger motor 3510-360KV with 6S and 14x4,7 props and then using 40A ESCs.
According to your discussion with RL it seems it is a bad idea to oversize my ESCs to 40 amps but I guess I prefer less efficiency and a bigger safe margin not to burn an ESC in flight.
I know you have tested many motors from HK and turnigy. If you had to lift 12 pounds on a coaxial octo, what combination of motors you've tested and what props would you use ?
Anhway be aware that this table is not the result of real life measurements but comes out of a simulation calc tool that mentions an error range of 10%.
I therefore personally read the table in relative trends And not so much in absolute terms (more or less thrust for example) using the orange cell as my base (corresponds to my current config).
I see the in the excel document that you assume a battery weight of 1130g with 8000 maH capacity. Did you take into consideration the 50% weight increase when going from 4S to 6S in the calculations?
-
1
-
2
-
3
of 3 Next