8 Pole Heli Motor in an E Revo?
 

Hi Guys,

I've always been one to experiment with different motors. This has gave birth to a pretty good motor collection. LOL

Not afraid to think out of the box, I'll try almost anything that might work.

This time, something good was discovered.

Outrunners make tons of torque and I've always been fascinated by them.

Recently a Scorpion 4020-1390kv 8 pole outrunner was acquired.

The shaft had to be cut down since it was way too long to fit. Then a small flat was ground to seat the set screw.

The first setup that was attempted was for 4S, and geared 24/40 using Mod 1 gears. 40mph or so.

The motor was running warmer than I like, and the ESC was getting warm too. 4S power was supplied by a PAIR of 20C 4000mah 4S packs. The packs didn't break a sweat, but everything else was. The setup ran very good though. The run was stopped when things began to heat up.

Time to rethink this.

The gearing was changed to 20/52 using Mod 1 gears. Again, geared for about 40mph on 6S.

6S power was supplied by a pair of Apogee 20C 3800mah packs in Series.

This setup is the sweet spot for this motor. :yes:

Rolling backflips and wheelies. Dirt Slinging fun.

I ran the setup until it just bumped the 3.2 volt LVC setpoint in the MMM.

Motor temps were pretty good throughout the run considering the 95 degree temps outside. The fan on the endbell of the motor moves a fair amount of air. Motor temps didn't surpass 130 degrees or so.

ESC temps were better, and tolerable although the fan ran most of the run.

The Packs on the other hand, I feel, took a beating. I don't think they are quite up to the chore. They came out pretty hot.

The ESC settings will improve this.

I changed the punch control from 50% to 100%. Start Power from High to Low.

Timing was set to low. Which is a no-no for outrunners, so I changed that to high. I will run it again with the new settings.

Anyway, here's what it looks like. Check it out and give me your thoughts.
http://i160.photobucket.com/albums/t...m/DSC08233.jpg

Here are the Specs on the motor:

Specifications

Stator Diameter ............................ 40.0 mm (1.575 in)
Stator Thickness ........................... 20.0 mm (0.787 in)
No. of Stator Arms ................................................ 12
No. of Magnet Poles ................................................ 8
Motor Wind ............................................. 6 Turn Delta
Motor Wire ..................... 28-Strand 0.29mm (29 AWG)
Motor Kv ........................................... 1390 RPM / Volt
No-Load Current (Io) ................. 3.45 Amps @ 10 volts
Motor Resistance (Rm) ............................. 0.007 Ohms
Max Continuous Current ............................... 90 Amps
Max Continuous Power .............................. 1890 Watts
Weight ...................................... 284 Grams (10.01 oz)
Outside Diameter .......................... 48.9 mm (1.925 in)
Shaft Diameter ............................. 4.98 mm (0.196 in)
Body Length ................................. 46.5 mm (1.831 in)
Overall Shaft Length ...................... 78.8 mm (3.102 in)

Good stuff. I have always has good success with outrunners, provided they were well made, such as axi and the scorpion brand you have.

I have a tiny (half the size of a silver can) axi 2217 1100kv in one of my scale 6x6 crawlers. Run 6 1.9 size boggers and the truck is 6 wheel drive. It can drive up a wall, almost. Never stops, it will spin the tires on the beadlocks if I gen it wedged. All on 3s lipo with a MM. And geared for about 12mph, so the motor is loaded.

I also have a 2628 880kv on 4s with a MM in my 6x6 maxx based truck. In 2nd gear it will do around 20mph, and it never dissapoints. Can rn throw ditches with foot tall grass at full tilt, crawl up walls, and other crazy stuff, no problem. I have those 53 series axis you traded me, really want to do something with them, might go in my 6x6 lst on 8-10s or something crazy.

Outrunners work, no doubt about it!

Ok,this is a really stupid question,but I have never seen or used one before so I guess it's a legitimate question? What makes an outrunner an outrunner? And what benefits do they provide over a typical Bl setup,and why are the kv's so low when compared to a regular Bl on the same battery? Aside from my questions,that is a good looking setup Sikeston!--Josh

pull a regular motor inside out, the magnets are mounted in the can and the outside of the can spins. the can is connected to the motor shaft to turn the pinion, the stationary part of the motor is the stator with the wires and bearings..

see here
http://www.youtube.com/watch?v=_F9z900Z-Ok

I always liked the idea of an outrunner used on surface rc's. Got to get a videos of that revo with that in it for us.

Quick Q. What if a rock got in and wedged itself between the chassis and the motor?

Here's a neat animation on how outrunner motors work.

http://www.rcgroups.com/forums/attac...mentid=2691817

I have had a rock get stuck in other setups.

The rock gets wedged and the motor just keeps powering on. What happens? It scratches the rotating can.

With this setup, the motor is up pretty good. So it would take a pretty big rock.

You would just about have to use a pair of vice grips to lock this motor. I have tried holding one to prevent it from turning, just to see how powerful they are. It does a burnout on your skin. :lol:

You need to sell a few motors and get a 2.4 radio... :na: JK

Seems like a smaller 'runner with a transmission would be more user friendly versus a larger one for DD. Less cogging, higher off the surface... is that what you're finding?

And how do the outrunners tolerate a dirty environment? That was one of my biggest concerns when I was messing around with an outrunner build...

I am outrunner lover, but for my planes, have quite a little collection started.

Looks good sikes!

Yes, I need to get a 2.4 radio. This old school, glitchy stuff, needs to go. LOL

Yes, it is more user friendly. That's exactly what I'm finding. It makes really good power too.

How do they tolerate a dirty environment? Pretty good actually. All RC bearings have a minimum of metal shields. And all the inrunner motors do deal with dust also.
I've been known to blow the dust out of a motor from time to time, but there's been no real problems.

It's amazing to see how much air an outrunner motor can move while spinning a seemingly way over sized propeller.

Thanks for the kind words redshift.

Nice! Sorry for hijacking your thread but would any of you think this would be an okey motor for a 3.3 Revo Tekno:

Turnigy Typhoon 600H Heli Motor 1100kv (600 class)

Specifications:
Dimension: 42mm x 62mm, 85mm(with shaft)
Weight: 269g
Kv: 1100rpm/V
Voltage: 3~6S
Max Current: 60A
Diameter of shaft: 5mm
Length of front shaft: 23mm
ESC: 80A

Kv (rpm/v) 1100
Weight (g) 269
Max Current (A) 60
Resistance (mh) 0
Max Voltage (V) 22
Power(W) 0
Shaft A (mm) 5
Length B (mm) 62
Diameter C (mm) 42
Can Length D (mm) 40
Total Length E (mm) 85

You're not hi-jacking. That's an outrunner motor too. :yes:

I've often looked at that very motor and wanted to try it. I think it would work very well.

Please do give it a go and report back just how well it does.

I think you might be surprised. :yes:

I found a YouTube movie with a outboardrunner'ed Revo and that got me hawt :).

Nice to see someone doing something outside the box.

I was thinking... the Tekno Revo 3.3 brushless kit states that a motor with the following specs is required:

5 mm shaft and 42mm or less in diameter. They also mention that a target rpm of 30.000 is required.

If I use the Turnigy Typhoon like mentioned above (my previous post) I should use +- 7,3s in order to get those kind of rpms.

Will I be ok with 5s if I gear it right? The sheer amount of torque can make up for the loss of rpms I presume.

To control this motor will I be able to use the Hobbywing XERUN 150A esc?

1 Specification


1.1 Output: Continuous current 150A, burst current 950A.
1.2 Input: 6-18 cells NiMH/NiCd or 2-6 cells LiPo.
1.3 BEC Output: 5.75V/3A (Switch mode built-in BEC).
1.4 Resistance: 0.0002 Ohm.
1.5 Motor Supported: Sensorless and sensored brushless motors
1.6 Suitable Brushless Motor:
When working with 4 cells Lipo: >= 4.5T (KV<=3000)
When working with 6 cells Lipo: >= 6.0T (KV<=2400)
The above T number is the value of a 4274 sized motor (Diameter=42mm, Length=74mm)

1.1 Compatible with all sensorless brushless motors and most of sensored brushless motors such as Novak, LRP and Feigao, etc.


Thanks for taking the time to help me out so far. I'm still a newbie when it comes to making your own brushless combo's. I'm sorry if this is not the place to discuss this motor and esc since RC Monster doesn't sell these items.

When they mentioned a rpm target of 30,000 rpm's, THAT is for an inrunner only. Toss that out the window if you're going with an outrunner motor.

An outrunner motor makes 5 to 7 times the amount of torque that a similiar sized inrunner motor does.

The type of gearing you will run with an outrunner, most inrunner motors would burn up, trying to pull.

5S sounds good.

The Hobbywing ESC? I've never tried that one with an outrunner. Not all ESC's like outrunner motors. I know the Castle line of ESC's do. :yes:

Mike doesn't carry outrunner motors, but if he did, I would be checking those out too. LOL

Welcome to RCM. :yes:

5 to 7 times more torque?! I'm thinking my converted LST might like an out runner motor. Thanks for this thread by the way, I didn't know anything about out runners but you got me curious and I started searching about them and reading.