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.

Outrunners work great in trucks.

I had an Axi 2826 in my E-Revo until it got slightly damp in the snow and shorted a winding. It was geared 20/40 with mod 1 gears and 5s2p a123. When I first installed it, I hadn't adjusted the slipper clutch from when it was brushed and I twisted the driveshaft into a pretzel.

Axi motor link:
http://modelmotors.cz/index.php?page...ie=8&line=GOLD

I had also run this motor. Made a pile of power.
http://www.centuryheli.com/products/...5&prtnm=CNE274

Depending on where it's run, it won't be a problem with anything getting into it. I had no problems when running on the street or on dirt, rocks, etc. Only when I ran in sand did the outrunner begin to get dirty. It would get dusty, but not get sand in it unless you really crashed it badly, then sometimes some sand would fall out when I shook it after righting it.

The thing I found that was the problem is ferrous dust. Small particles of iron attracted to the magnets. I would take my motor apart every so often and clean this out before it became a problem.
The amazing torque and smooth operation made this worthwhile.

Just my observations. Hope that helps.

It should be noted that the op was the reason I even thought to try an outrunner.

I've also been fascinated with outrunners and thought about using them on trucks, but the KV values are a bit low unless you go 6S or 8S. I've been using them on my airplanes and they work great. I wonder if any of Castle outrunners that they have on sale would work well in any of these trucks?

One of the reasons I will buy Castle's new 8S Car Controller, is for this reason.

8S on some of these outrunners will be insane. :yes:

I ordered one of the Castle Outrunners to try. It's the 34 38 1100kv version.

Yeah,
I cant wait to get a 8s controller either.

I'm liking your idea. I might have to pick one up. I bet that thing stays ice cold on 8S at the end of the run. I was thinking about the 1800kv version too, but it looks a bit smaller in size. Have you figured out their sizing yet? Is it a 34mm or 42.5mm in diameter.

Also do you guys know of any rpm limits on these motors? I havent tried spinning any of my outrunners over 15k rpm yet.

I'm thinking of getting one or 2 of the outrunners to toy with as well.

GREAT build :mdr:

buuutttt.....
mines bigger :lol:



http://i102.photobucket.com/albums/m...n/DSC00753.jpg

is that only 2wd?.....

Aaaah good point! :yes:

Yours might be bigger, but mines 4WD. :na:

shaddup....2wd pwns :lol:


yeah ok so overall you win...least you got a good qual AXI motor.
i did my project because i couldent get enough power to the rear wheels with a center diff and wanted to go to 2wd for a bit.
also the COG is RIDICULOUS :yipi:
flat out turns on the road with zombie maxx tires and no roll over...even without swaybars.

kinda bringing this topic back from the dead but I recently stuck a very cheap 1600Kv 6-pole outrunner in my Revo 3.3 conversion.

http://img826.imageshack.us/img826/5190/frymmp11.jpg
geared 15/36 with Elektri-Clutch. it pulls about 70A from a full-throttle start on 6s. Tops out at almost 40mph, but handles extremely well because it's lightweight (9lbs).

I used that motor cause it's roughly the same size as a standard 540, and will fit in the 36mm Tekno mount I had laying around. For larger outrunner experiments (or if I had the 42mm mount) I was looking at the Castle Vertigo motors that were $40, but the only ones left now are really low 220Kv. Kind of hard to gear those properly as you'd only get 30mph geared 30/36 (RCM sells a 30t 1.0M pinion!) on 12s lipo lol.

what motor is that?

i used the align 600xl and loved it in my buggy on 5cell, sadily i set the timeing wrong and it only lasted for about 6months

^
I use this one. It's almost exactly the same size as a 540 size motor, and works perfectly with the Tekno 36mm motor mount. I just had to drill a hole near the front for the wires to exit...if I need to take it out of the mount again, I will drill more holes for ventilation. It's not a very powerful or extreme setup (running on a 6s 2650mah 20C lipo just fine) but it works well, and makes the 30krpm recommended lower limit.

What timing were you using? I heard outrunners like high timing regardless of what they're in, didn't know they reacted so poorly to bad settings.

http://www.youtube.com/watch?v=io1B6naI9tM
got a video up of my outrunner'd 3.3 :D finally got my Mamba Max Pros back. I still have to lower the shift point, it's at the very upper limit of RPM so when the battery is about 50% discharged it can't reach 2nd anymore...

Good stuff, Subscribed.

http://www.youtube.com/watch?v=uqKrdMwD7GE

shot another short video today after I adjusted the shift point, it's better but perhaps slightly too low.

btw, this particular outrunner is only a 6 pole.

Nice conversion, Shonen. How much clearance is there between the motor OD and the Tekno mount ID? Obviously it works fine but if you're using the 36mm mount with that motor there can't be much clearance.....

Thanks! The inside of the motor mount is roughly 40mm so there is quite a bit of wiggle room. I recall I tried to stuff the 1515 motor in it, I think the only reason why it wouldn't go in was cause of the fins. I didn't take a photo of the clearance but this outrunner has a 36.4mm diameter...compare this to a 540 motor (36mm diameter):

http://img820.imageshack.us/img820/3953/revoconv14.jpg

it's kind of hard to see cause of the lighting but look at the bottom. plenty of room. (:

Ahh....thanks.

I thought the Tekno mount was more of a snug fit for heatsinking ability. In that case I may need to buy a 44mm Tekno mount and try to stuff a 42mm outrunner in it. :)

The heatsink rib looking things are just added to the bits that connect the front and rear lol. The extra space is mainly so that you can attach a 40mm cooling fan to the top and it would still have enough room for air to go around the motor. I think it would've been better from a cooling standpoint to have the sides closed and have a larger bottom opening to better shroud the motor and force air around it, but I suppose it needs to work without a fan too.

If I was starting from scratch I would've done exactly the same thing, but I had this 36mm mount laying around from an eBay bulk auction. 42mm opens possibilities for more powerful motors. (: The best part of running an outrunner is you don't have to get some super long motor that comes really close to the rear suspension arms.

I like the fact that outrunners do make lots more torque, but personally, the advantages are outweighed by the disadvantages:
- Open design, more prone to rock/pebble damage
- Slower speeds require more thought on gearing. Direct drive setups leave little "gearing" adjustments unless you want to change diffs or tires.
- larger diameter makes motor mounting in a geared setup more difficult
- heat producing coils are inside the motor - I personally prefer the heat source to be outside where air flow is greatest. Although, the turbulence created by the motor itself is probably sufficient.

Still, it's nice to experiment!