yakn101

Please help!!! I have a hacker c50 L inrunner brushless motor. I am putting it in a GP U can do SF. Running 5s but have no idea about the prop size. Any help on this would be greatly appreciated. Thanks guys

Dr Kiwi

Is it a 10L, 13L, 14L, 15L... in other words exactly which model do you have and what is its Kv. What gearbox do you have on it?

yakn101

This is the c50 13L no gearbox. Kv 1874 operating amp 35amp. Peak amps 50. Peak watts 1200 resistance 0.0172ohms poles 2. Innrunner motor This is about all the info i have. Running on 5s thank you.

Dr Kiwi

On 5s and limited to 35A -50A you'd need a tiny prop.

MotoCalc suggests that 5x5 seems okay, 6x4 is a bit much:

Motor: Hacker C50 13L; 1874rpm/V; 1.27A no-load; 0.0172 Ohms.
Battery: Thunder Power TP4400 (G4 ProPower 45C) (45C); 5 cells; 4400mAh @ 3.7V; 0.002 Ohms/cell.
Speed Control: Castle Creations Phoenix 60; 0.0012 Ohms; High rate.
Drive System: Direct; 6x4 (Pconst=1.47; Tconst=1) direct drive.
Airframe: Anything you want.
Motor Amps = 54.1
Motor Volts = 17.9
Input (W) = 968.9
Prop RPM = 31575
Thrust (oz) = 73.3
PSpd (mph) = 119.6

For a 3D plane you will HAVE to have a gearbox so that you can fit perhaps an 11"-13" prop.

There is a 3.7:1 gearbox option:

Motor: Hacker C50 13L; 1874rpm/V; 1.27A no-load; 0.0172 Ohms.
Battery: Thunder Power TP4400 (G4 ProPower 45C) (45C); 5 cells; 4400mAh @ 3.7V; 0.002 Ohms/cell.
Speed Control: Castle Creations Phoenix 60; 0.0012 Ohms; High rate.
Drive System: geared; 13x7 (Pconst=1.47; Tconst=1) geared 3.7:1 (Eff=80%).
Airframe: Anything you want.
Motor Amps = 50.7
Motor Volts = 17.7
Input (W) = 895.3
Motor RPM = 31289
Prop RPM = 8456
Thrust (oz) = 123.7
PSpd (mph) = 56.1

yakn101

Hmmm. So not gonna be flying it on a .80 sized u can do sf without a gearbox? The info that i was able to obtain said it eould fly a 3D plane weighing 7-11lbs. So confused now.

Dr Kiwi

If you go to 10S with a 6.7:1 gearbox Motocalc suggests it will get you this (under 50A but watts-in ends up well over the rated 1200W). I honestly have no clue as to whether it can cope with these numbers... but if you restrict it to 1200W.. I can't see doing 3D with anything much beyond an 8lb plane (150W/lb)

Motor: Hacker C50 13L; 1874rpm/V; 1.27A no-load; 0.0172 Ohms.
Battery: Thunder Power TP4400 (G4 ProPower 45C) (45C); 10 cells; 4400mAh @ 3.7V; 0.002 Ohms/cell.
Speed Control: Castle Creations Phoenix 60; 0.0012 Ohms; High rate.
Drive System: Direct; 14x8 (Pconst=1.47; Tconst=1) geared 6.7:1 (Eff=95%).
Airframe: Anything you want.
Motor Amps = 48.6
Motor Volts = 36.0
Input (W) = 1749.6 [it's a 300g motor... that's 6W/g!]
Motor RPM = 65611
Prop RPM = 9793
Thrust (oz) = 232.4
PSpd (mph) = 74.2

Motor: Hacker C50 13L; 1874rpm/V; 1.27A no-load; 0.0172 Ohms.
Battery: Thunder Power TP4400 (G4 ProPower 45C) (45C); 10 cells; 4400mAh @ 3.7V; 0.002 Ohms/cell.
Speed Control: Castle Creations Phoenix 60; 0.0012 Ohms; High rate.
Drive System: Direct; 13x7 (Pconst=1.47; Tconst=1) geared 6.7:1 (Eff=95%).
Airframe: Anything you want.
Motor Amps = 33.2
Motor Volts = 36.3
Input (W) = 1206.6
Motor RPM = 66831
Prop RPM = 9975
Thrust (oz) = 172.1 (only 1:1 thrust to weight... you need ~1.4:1 to hover))
PSpd (mph) = 66.1