Ok, time for some results. (Put the kettle on, this might take a while...)
I have finally been able to fly a few packs on the new T-motor setup, and new APC props and then also compared them to the stock props. More on that later.....
Firstly a bit of background.
While I was waiting for the wind to die down a bit ( which took a week) I set up some Solo motor pods on a thrust test stand and tested various combinations of motors and props for thrust, power and efficiency (grams of thrust per watt).
The combinations I tried were...
1. Brand new stock Solo motor pod and stock prop. (Supposedly a T-motor, I have doubts as it is vastly different from standard T-motor quality)
2. T-motor 2216 800kv with stock prop
3. T-motor 2216 800kv with APC 1045 MR(ST) prop
4. T-motor 2216 800kv with APC 1145 MR(ST) prop
5. T-motor 2216 800kv with 1033 Mejzlik MR prop
5. T-motor 2216
900kv (TBS Disco Pro motor) with stock solo prop
6. T-motor 2216
900kv (TBS Disco Pro motor) with APC 1045 MR(ST) prop
7. T-motor 2216
900kv (TBS Disco Pro motor) with APC 1145 MR(ST) prop
8. T-motor 2216
900kv (TBS Disco Pro motor) with white Phantom 1/2 9443 prop
9. T-motor 2216
900kv (TBS Disco Pro motor) with generic Phantom replacement CF 9443 prop
10. T-motor 2216
900kv (TBS Disco Pro motor) with HobbyKing 1045 folder prop
11. T-motor 2216
900kv (TBS Disco Pro motor) with 1033 MR Mejzlik prop
In order to have some consistancy in testing these motors, my setup consisted of the following.
1200w power supply set to 16 volts.
Infinity hobby thrust test stand.
3 x Solo motor pods, one with T-motor 2216-12 800kv motor, one with T-motor 2216-11 900kv (TBS Disco Pro motor), and one completely stock Solo motor new out of the packet.
All motors were balanced as per my method mentioned a few posts back
All props were balanced (with the exeption of the HK folder which is rubbish)
Hitec HFP-20 servo checker/programmer to provide a consistant repeatable driving pulse train
Turnigy power meter
All motors were driven by Solo escs, as different ESCs can show differing currents depending on the way they switch.
The Solo motor pods start truning at 1060mS and are at full throttle at 1860mS.
Current, power and thrust readings were taken at
1260mS (25%) 1460mS (50%) 1660mS (75%) and 1860mS (100%)
Thrust is measured on a strain gauge scale with an LCD display and a resolution of 10 grams
Below is the test setup...(leds on motor pods power up as green by default)
And the lineup...(white tape on the Solo motor is what was need to get it balanced)
Sample readings...
The whole idea is to find the best combo of motor prop that will produce the
highest efficency number.
The higher the efficiency, the lower the throttle needed to maintain hover and the longer the flight time on the same battery
Im not going to bore you with all the results of all the readings, but I will show a sample of the readings I took for the stock Solo motor and prop, so you can see where I am heading with this.
EDIT: added spreadsheet snippet
Now if we are assuming an All Up Weight weight of 1.8kg with gimbal and gopro, then we need one motor/prop combo to supply a quarter of that to hover the aircraft, so 450 grams of thrust.
So at 450 grams of thrust we would see a figure slightly less than 8.0g/W, around 7.6.
So hovering with this motor/prop combo at 1.8kg/7.6g/W = 237W total /14.8v=16 Amps. 16amps/5.2AH = flight time of 0.30 hours. or just under 20 minutes...which is pretty much what we see in real life.
The same principles can be applied with the figures for all the other motor/prop combos to figure out flight times based on thrust test and efficiency data.
But Im not going to go there for all the different combos in this post..
So to cut a long story short, here is my bullet point summary based on the figures I found whilst thrust testing.
- The Stock motor/prop combo is actually pretty good (so long as the motor bearings survive and everything is balanced))
- The T-motor 2216 800kv /stock prop combo is slightly more efficient
- The T-motor 2216 800kv / APC1045 MR(ST) prop combo is slightly more efficent again
- For the T-motor 2216 900kv the best prop is the stock Solo prop, using an APC 1045 reduces the efficiency.
- The 1145 MRST is too big for the T-motor 2216 800kv motor, in fact its too big for a 2216 period.
None of the other props are as good as these combinations.
Having said that, these are small motors and have small torque ranges. Bigger motors usually show more differences with changes in props, these motors are really quite close even from the best to the worst performing prop.
So if you were going to change the motors for bought T-motors, Id recommend the 2216 800kv with prop adapters to suit the APC 1045MR (ST) props, you can also fit the stock Solo props to these.
And balance everything.!!
If you wanted to go with the 2216 900 kv, then the APC 1045s are not really an option, and you would be best flying with the stock Solo props. Still a good reliable combination, with quiet motors.
I have a renewed respect for the stock props, they actually work very well in the thrust tests.
I am now flying with the 2216 800kv T-motors and APC 1045MR(ST) props.
I have found these props to be quieter than the stock props, ( the motors are alot quieter than the stock motors) and with the small efficiency gain I can see slightly lower current draw in the air.(around 15-16 amps now, where as previously 18-19 amps hovering)
This should translate to a slightly longer flight time as well, although I havent seen this as I was flying in gust conditions, because the bloody wind here has just not stopped .
The main reason I did this is twofold, to increase reliability as there is no second chance on motor failure, with a quad, and secondly, to reduce the bearing noise, which frankly, I find embarrasing.
Its a high quality machine, it should purr. And now it does.
Im not a big fan of the grey APC props on Solo so I have dyed them black and they dont look any different than the stock setup at first glance. Will post a pic soon.
Its getting late here, more installments as I get more flight time on these motors and props.
Cheers.
Roland.