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Pumpkin drop event

picking proper prop ?

sundown57

Well-known member
#1
need help now getting the right motor and prop to go with the build. The plane I built weights 23 OZ without battery. I have a 3000 3 cell I plan to use. Also, I just bought the turnigy 30A ESC and I have a lot of 10-inch props. So the other day I bought 4 EMAX MT2212 II 900KV motors, they came with 10-inch props so I figured they were a good choice. Turns out they have very little thrust. On my homemade test bench they only put out about 15 oz thrust at max. My Emax f pack puts out 20 with a 6-inch prop. So can anyone tell me what motor would be a good fit to pull a 23 OZ plane around ? I'm looking at this one but would like to be sure before i buy it. Thanks

https://www.ebay.com/itm/New-Turnig...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
 

Merv

Well-known member
#2
My planes have an all up weight of about 30 oz. I use 2200 3S battery, 50 amp ESC, 12x3.8 slow fly prop.
With the motors below I get unlimited vertical & can hang on the prop @ 50% throttle. Both motors work well, I get the one that is in stock @ the USA warehouse. The 3730 motor is a firewall mount, I flip the shaft by grinding a new flat and snap ring groove.

I recommend using a watt meter on any new prop & motor combination.

https://hobbyking.com/en_us/turnigy-ld3730a-1000-brushless-motor-1000kv.html
https://hobbyking.com/en_us/turnigy-l3537-840-brushless-motor-380w.html
 

Hai-Lee

Old and Bold RC PILOT
#4
A 10 inch prop can have a range of pitches, and even blade shapes, not even counting the number of blades. If the motors come with a prop you need to ascertain the cell rating because so 4S motors come with the Max prop for max cell count and if you run it on a lower cell count you would normally need a larger prop to get reasonable thrust.

What are the details of the props you have?

Have fun!
 

Hai-Lee

Old and Bold RC PILOT
#6
According to manufacturer specs the max thrust you can expect on 3S driving a 10 x 4.5 prop is 640 Grams, (22.57 ounces).

That you are getting around only 75% of the rated thrust could be a feature of your test setup but the motor will not give any more than 30 ozs of thrust and that is on 4S with a different, (slightly smaller), prop.

15 ozs of thrust should get you airborne but it will not be a spirited performer!

Have fun!
 

sundown57

Well-known member
#8
According to manufacturer specs the max thrust you can expect on 3S driving a 10 x 4.5 prop is 640 Grams, (22.57 ounces).

That you are getting around only 75% of the rated thrust could be a feature of your test setup but the motor will not give any more than 30 ozs of thrust and that is on 4S with a different, (slightly smaller), prop.

15 ozs of thrust should get you airborne but it will not be a spirited performer!

Have fun!
I am using a homemade tester so I can only compare motors to others I have. I do not know if it is accurate, in fact, I'm sure it's not