john agnew

I recently bought a Turnigy SK 4250-500kv motor for my new Monolg 70, it weighs around 2400g ready to fly and I was looking for a motor that would deliver around 1100 watts on a 5S battery. Hobby King advertise the 4250-500 as a 5S motor capable of 1340watts. I thought that sounded fine until I tested it on the meter. The maximum I could get out of it was around 850 watts on an APC 16x10 at around 43 amps on a fresh lipo. ( the max quoted amps for the motor are 57) Ok, the motor is pretty cheap at $36 but the performance is way below that advertised. Any ideas on a 5S motor that will deliver 1100watts without breaking the bank.

John

chuckk2

A better speed control and larger/shorter wires between the battery and speed control may help.
I'm assuming that the 16"prop is as large as you want to use. A three blade prop might also help if you
can find an appropriate size.

Jetdesign

My Feedback: (8)

I would go to 3DHobbyshop.com and look at the 60" Osiris. They will have a 5S power system suggestion, likely a Hacker A50. Look at the kV of the motor and what prop they suggest. That is at least a good place to start. That power system is demanding on batteries. I might see what motor they use and find the A50 with the next lower kV.

Ok so I went ahead and did that - they suggest a Hacker A50 with 480kV and a 15x10 to 16x12 prop on 5S. Since you have 5S with higher kV and same prop and are not seeing power, it would lead me to believe the motor is not meeting its requirements.

You can't really trust Hobby King's recommendations for power. They are guidelines, hopefully you get what they specify but often you get something different. I have decided it's not worth the crap shoot.

Eflite has an offering that is affordable and robust - the Power 60. Hacker is $142, E-flite is $109. Should be fairly similar.

http://www.3dhobbyshop.com/62-Osiris--Red_p_15388.html
https://www.aero-model.com/8_164_198...-12S%20V3.html
http://www.e-fliterc.com/Products/De...odID=EFLM4060B
http://www3.towerhobbies.com/cgi-bin...?&I=LXLWV7&P=0

Jeff Worsham

My Feedback: (28)

John,
The Hacker A50-12S has been great for me. Over 700 flights on Osiris in the last year, today measured 950W on a 25C 5S battery with 65% charge. APC 16-10. Osiris weighs 7lbs. On a fully charged battery it's close to 1100W. For the same money, I could have bought 3 Turnigy SK 4250 motors, but I don't believe even the sum of those three motors would have given the same reliable service and power as this Hacker, and the Hacker is still going strong.

john agnew

Guys

Thanks for your advice. I know the Hacker would work, I have one in my Miss Wind, I was trying to find the holy grail of a cheap motor that does what it promises! The Hacker is $180 in the UK the Turnigy is $36 I guess you get what you pay for. I am going to fly the Monolg 70 today for the first time and will report back. It weighs 5.5 lbs so is a bit lighter than the Osiris. I hear that some guys have been running the Turnigy on 6S and it produces the 1340 watts ok but overheats after a couple of minutes.

John