Direct to diff outrunner conversion*update*
 

Copied this from the temp forum. Got bored recently and tried 4s lipo. The truck worked alot better, slight cogging from a standstill, but if I was liberal with the throttle it would take off without problems.

Here is a link to the thread: http://www.rc-monster.com/tempforum/...read.php?t=845

Here is the original post:

Hey guys, just finished my mutant redcat/outrunner truck thingy. It runs great, still playing with the quark settings to get zero cogging from a standstill. I almost have it right. Truck runs well, temps after 10mins were 150 motor, 130 esc and 100 battery. I am running a 5s 2200mah 20c battery. Interestingly enough setting the quark for outrunner does not work as well as the std inrunner setting. I have the torque settings all the way up and the neutral set wide, as the maunual suggests that for cogg prevention.


Differential Ratio: 2.75
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 1
Pinion Tooth Count: 1
Total Voltage: 18.5
Motor KV: 833
Tire Diameter (inches): 3
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1 : 1
Total Ratio: 2.75 : 1
Tire Circumference (inches): 10.21 inches (259.34mm)
Total Motor Speed: 15410.5 RPM
Vehicle Speed: 54.18 MPH (87.03km/h)
Effective Speed Rate: 2.93mph/V (4.7kmh/V)
Effective KV Value: 833
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...

Heres the pics, enjoy. Please excuse the zipties

http://i206.photobucket.com/albums/b...p/DSCF1326.jpg
http://i206.photobucket.com/albums/b...p/DSCF1327.jpg
http://i206.photobucket.com/albums/b...p/DSCF1329.jpg

Love it!

That looks great! I am going to try my direct wheel drive outrunner setup some day... wouldn't that be quiet!

Which motor are you using BTW? Have you considered the new Eflite Power xx series motors? They are supposed to be one of the best outrunners available, from what I hear.

Vids? :yes:

Wow, never thought I'd ever see anything like that!

We did a direct to diff conversion on a Kyosho Inferno GT with a Neu 1512 1900kv motor. On 5S with 3.9" GRP Rally tires, we clocked it in excess of 90 mph several times.

What is the kv rating of the motor that you are using there?

Motor is a 833kv outrunner, got it cheap off ebay.

Not too familiar with the power output of the various sized outrunners. I would do a lower kv next time, 650kv sounds about right. I would also go bigger, like a 45mm can that is longer, so more torque. This setup has plenty of power, but the truck is very light, so that helps. This is not suited to off road IMO, it works great on road, very smooth with the quark and less drivetrain resistance than with a pinion/spur. Seems to be effecient too, not enough testing yet to be sure though.

That is nice. It should be really efficient. Less weight and less resistance. A bigger can would help. More power and may be better off road performance (?).

http://www.greathobbies.com/producti...d_id=EFLM4060A

OR

http://www.greathobbies.com/producti...d_id=EFLM4046A

Those are 50mm cans, and the Power 60 does 1200 watts continuous. It weights the same as an XL motor. 380 grams You can also take the shaft out, and make a custom one, or whatever.

Thanks for the links ZPB (can I call you buggie?):oops:

The 46 size 670 kv looks interesting, The lower kv would let me put larger tires back on it and have more torque for startup. Do you think that the quark 65 would be ablee to handle that motor? Plus I would need to step up to better batteries, I have a pair of 20c 5000 2s lipos to run. And my motor mount would have to be remade to accomodate the larger can size. I will see about finding one of these motors and change up my setup.

if that is a 4 pole out runner, see if your esc has 30 degree timming, that should fix your cogging issue

Not sure if the quark has that kind of adjustability, I will check.

Probably need to do the heatsink mod the the 65 as it appears to be comming of the thermal tape. Any reason why I can't delete the case entirely and just epaoxy a heatsink to the fets and maybe put it in a little box like the MM? Or maybe shrink it like a bk esc?

Call me buggie? lol sure....

I am not sure if the Quark 65 would handle it. What kind of speed would that get you with 670kv? That is what you need to know.

Now I am curious about running one of these in my Revo... I am gonna go do some calcs.

Outrunners are usually 12 pole designs, otherwise, there would be no point to using them in place of inrunner (low pole motors).

Okay, a Power 60 motor (400kv) on 5s2p A123, or better yet 4s lipo (lower top speed) should be just about right for a maxx or Revo truck.

Top speed would be around 48mph with 5s2p A123, or 45mph on 4s lipo.

OR, on the extreme torque end... the Power 110 (295kv) on 5s lipo or 6s2p A123 for a little over 45mph, and crazy, crazy torque... that would be a silent, deadly machine. :mdr:

Yeah, my setup with the 46 on 4s lipo would be around 40mph. My only issue would be lack of a slipper for an off road vehicle, and you would need a good slolid motor mount, like 1/4" 7075 al. I was also thinking that i could incorporate two revo slippers, one on each end of the motor. a custom shaft and adapters to replace the spurs with drive cups would be required. Might add too much length though. If you really want one, I may be able to get a discount, not sure how much but give me the #s you want and I can ask my buddy. Looks like the 46 would be about 80-85 bucks from him.

Hey Lincpimp,

How do you plan on going shaft to shaft with a slipper? If you get that figured out, would you post some pictures please? I've been tossing that around in my head for awhile now, and so far I've come up with nothing.

Before you go paying a wad of money for something that IMO is overpriced. Check out what Lucien has to offer over at http://www.innov8tivedesigns.com/ind...cPath=21_25_38

I'm not sure what length you're looking for, but he has some things that you might be interested in.

I have a 3032-12 that should be here by Thursday. I'm going to test it in my E maxx Direct Drive setup. But soon, I will be doing an E Revo Direct Drive to Diff with a motor similiar to this. The E Revo will probably have to wait on his 40mm motors, which are supposed to be out next month.:yes:

I would ask a airplane guy, but I think you still use 30 degree timming for 12 pole too

test it; heatgun within reach..

Yes, I think the 40mm can would be a better choice, more torque. I like the ring bearing idea, should provide more support for the rear of the can. His prices are good, I will wait on some spec for the 40mm cans and maybe try one out.

No pics yet on the slipper, just ideas in my head. if you are familiar with how the revo slipper works, my idea was to setup each end of the motor shaft with the crosspin hole and a threaded portion for the slipper lock nut. That would allow the main portion of the slipper to mount to the motor. I would then have to come up with some sort of adapter to replace the spur gear. This would have a 5mm (or whatever size needed) extension on it to mount a drive cup to. My only problem is trying to keep the overall length to minimum, and a method to access the slipper adjustment nut. At the moment my adapter looks like a hat that will sit over the end of the slipper nut and mount to the slipper hub with the three screws that usually hold the spur gear. Only problem is that hat covers the nut, requiring removal to adjust the slipper. I could make legs that mount to the slipper and thus leave some room to get a small wrench to the nut, but I think that there would not be enough space b/t the legs to access the nut. I think it would be pretty good having two slippers, as one could be adjusted to give more slip (rear) to aid in cornering traction, etc...

I hope Lucien doesn't mind me quoting him, but he already sent me some of the anticipated specs for the 40mm motors. I'll pass that information on to you.

"Initial plans for the 40mm motors are to have 4 frame sizes. There will be a 4020, 4025, 4035 and 4045 size motor. The 4020 and 4025 will basically be larger versions of the 3008 and 3014 size motors. The 4035 and 4045 will be made a little different, and will have an additional ring bearing that supports the back end of the motor's flux ring. This is done to stabilize the motor, and prevent flexing of the motor shaft under load. I have attached a photo that shows the rear end of a 4045 motor to show this bearing.

The approximate power ratings on the motors and the weights will be as follows:

4020 - 1200 watts, 280 grams, 9.88 ounces
4025 - 1500 watts, 328 grams, 11.57 ounces
4035 - 2000 watts, 488 grams, 17.21 ounces
4045 - 2500 watts, 585 grams, 20.64 ounces

There will be at least 3 different Kv's for each motor, and there may be 4-5 versions of the 4020 size. I have a set of 14 prototypes in the 40mm size right now and they are currently wound with the following Kv numbers, but this is subject to change once the final versions are decided upon.

4020-8 ....... 1000 Kv
4020-10 ....... 786 Kv
4020-12 ....... 701 Kv
4020-14 ....... 591 Kv
4020-16 ....... 526 Kv

4025-10 ....... 631 Kv
4025-12 ....... 565 Kv
4025-16 ....... 422 Kv

4035-10 ....... 446 Kv
4035-12 ....... 386 Kv
4035-14 ....... 328 Kv

4045-10 ....... 381 Kv
4045-12 ....... 315 Kv
4045-14 ....... 272 Kv

Hopefully that answers all of your questions.

Lucien Miller"

The new 30mm outrunner that I'm getting has the endbell bearing also. They are upgrading that line as well.

On the slipper idea, Is there a way to use a thrust bearing on the driveshaft and just control spring tension by how just pressure is on the bearing? Then make both sides of the clutch material stationary? This would move the adjustment to a more external location. The Thrust bearing would have to have a Spring Loaded housing with a "track".
Hmmmm, I'm still processing on this one. Let me read your post a few more times. LOL

I followed the last thread and this one. Its been awhile since I read the last thread about all this. One question: Can this be done with a in-runner (BL) motor? I mean direct drive it to a transmission?

You could use an inrunner, but it would have to be a low kv, like 600-800kv. There is better selection with outrunners, and for me it just is something different!

the out runners tend to have more poles (mentioned earlier) for more torque.

I am not trying to change the way this thread is going but could you not go with a little bigger kv say 1000ish and still have plenty of torque? This would be more efficient and have a sealed can. No dust problem in the motor. I don’t have the experience you all do. I just see in-runners utilizing the direct drive setup would be almost unstoppable IMO. I have no desire to try an out runner direct drive here in southern utah. The dust is harsh enough on my in runners. I am following all this hopping that some tries an in runner.

No... you simply can't take a low kv. inrunner (low pole) and run it at the voltages we use, and expect to get decent power from it.

You 'could' get a quite large inrunner, something at the very least a 1527 motor and run it way under powered (for it's size) to get the right rpm out of it to be used on the tranny. I can't really tell you how efficient this would be though.

IMO, the way to do this, is to use higher pole motors (which has higher torque lower rpm, but same power output as similarly sized inrunner) and go directly onto the diffs.

Or, if what you are talking about Hickoryhead, try and find an appropriately sized outrunner and go direct drive to transmission, but I see little gain doing this, IMO.

This is a territory no one has really been yet... it makes things interesting. :neutral::yes:

I like what you are saying though Hickoryhead, about using an inrunner so everything is nice and sealed from dust.

I wonder about the 19xx Neu motors? I will check this out. :smile:

Good to see that you are interested in this, Buggie:smile:

I will try a larger out runner, maybe with my slipper mod if I have the time to get parts made. Thinking a 46 or 60 in a very light 1/8 buggy. Would like to do 6s or more, what esc choices do i have for running an outrunner? The quark works well but it is 5s max.

I don't know about this dual slipper setup you want to do, it sounds good, but I think the torque will be far to high to be able to use them, they don't have enough holding force, IMO.

If you mod your Quark with some exra caps, like 4 extra to the power lead, you should be able to do 6s lipo. Have you seen my Quark? I am running 7s2p A123, that is higher on state voltage than 6s lipo, and it runs like a dream.

I just checkd out the 19xx Neu motors, but they don't have anything that would work...

Ok, the slipper will not have the benifit of tranny gearing and will be overtaxed or simply just not work? Did not think of that. Any idea of a method to give the drivetran a little shock protection. Maybe mount the outrunner to the chassis with some sort of isolator. Rubber, or stiffer material, kind of like full size engine mounts. That would "give" a little to help the shock issue but be solid enough for good power transmission.

I will add a few caps to my quark, thinking of ditching the case and mounting up a heatsink directly to the fets that can also be attached to the chassis for addl heat dissapation. Mybe an al L bracket to the fets and then a heatsink onto that and attach the leg of the L bracket to the chassis. Probably a good idea to support the esc with shrink or some other method so that the weight is not completely supported by the fets. Maybe just shrink the esc to the bracket with some thermal paste and epoxy the heatsink to the bracket. Just an idea, something similar to yours but a little smaller!

AAngel, I would like to hear more about your conversion. How did you mount it to the transmission? Did you modify the motor or leave it stock? Who is we and do you or they have pictures? What kind temps did you get? What batteries where you running with?

For me I would like to see this all happen. Both outrunner and inrunner. I like seeing new stuff come to pass. There are many people were I live and on this forum that can't afford to build what most of us talk about. They can't spend the kind of money we do on Lehner's, Neu's, Quark's.... I can see a way for others to build what we have at a 3rd of the cost.
:great: Thumbs up to every one commited to this project!!!

These Scorpian motors look great, I would like to see the 40mm cans... in my hands.

I am just thinking about how much more space I would have on my Revo if the motor was gone from the engine mount, no tranny, and the outrunner motor was mounted down kinda under the tranny. wow. Get some bullet proof diffs and you are set! Nothing to wear out in the tranny... at least anytime soon. :yes:

Yes ZPB, that's exactly what I'm thinking of. The motor will set about 60% "submerged" in the chassis. Just enough to make the drive shafts as straight as possible.

RCM has the 4.3:1 diff gears. This will drop the gear ratio to almost equal to an E maxx locked in second gear. If more gear reduction is needed, we can do that with the tire height.

The end result will be alot of lost weight. There will be alot of room opened up on the already tight E-Revo chassis. Alot of wear items eliminated means this thing is going to perform longer and hold up better.:yes:

The only thing that I am wondering about is the 'spool up' of an outrunner in this configuration... will it have enough 'zap' to make for a pleasant throttle response, you know?

I think the acceleration will be dependent on how the ESC is programmed. If it's not fast enough, you could always decrease punch control on the MM, or do the equivalent on the Quark. If that's not enough, then a little adjustment to the exponential on your radio or to the throttle curve on the MM should fix any slow spool-up issues. I can tell you that the outrunner in my 2.2 rock crawler (the size of a 540 brushed motor) gets up to speed VERY fast, even when geared for 12mph and running a Mamba 25 on 3s Lipo.

This whole idea of outrunner-in-the-middle has intrigued me to try the same sort of setup in my MT2. The dual slipper clutch (torque control) idea is excellent, if it could be pulled off efficiently (not too heavy or takes up too much space). Thankfully outrunners are built such that custom shafts could be made, more specificially to fit into a custom slipper clutch setup.

Speaking of slipper clutch setup, we gotta get some sort of 3D model of one made using Revo components. The slipper clutch items would most likely need their own chassis-mounting hardware, so as not to put too much strain on the motor's bearings. I'll be thinking about it and maybe drawing one up.

From experience with my setup, the more aggressive starting power settings work much better. Using small throttle input cuased my setup to cog. If more throttle(around 1/10-1/8 total throttle) was given the motor started up with no problem and would easily spin the tires from a standstill. I am thinking a isolated mount for the motor may be a simpler choice than the slipper.

Dug this thread up from the graveyard...

Thought more about the potential slipper clutch idea I had. I gave up on it due to weight length and overall complexity.

But I am back with this direct to diff outrunner idea as we now have a good solid programmable 6s esc (MMM) better lipos with higher c ratings, and the cost of motors is slowly going down. So this is getting more viable.

But we still do not have any shock protection, or do we???

New idea, make the outrunner mount absorb some shock. Well not too new, I said it on page 1 3+ years ago...

But I have figured out a way to do it. Imagine the pressure plate on a manual transmission clutch. It has springs setup radially around the drive hub to absorb some shock by allowing the pressure plate to move slightly in the same direction as rotation. The springs are strong and stiff, but will give under heavy loads and provide some shock absorbsion. Or for you motorcycle guys, the cush drive on the rear wheels of a chain drive bike.

Same idea, just between the outrunner and the mounting bracet to the chassis. Imagine 2 disks, with springs setup in recesses that can act on each other. One disk mounts to the chassis bracket, and the other to the outrunner. The driveshaft from the outrunner would have to go thru the center, and both disks would have to be held together solidly to support the weight of the outrunner. But when shock was transmitted thru the tires,diffs, back to the motor this would allow the motor to "twist" a few degrees and absorb some of the shock.

So whatcha think bout dat?

Linc, what about a torsion bar type driveshaft? Just like a standard dogbone, but
made to flex under load. Spring steel dogbones for all six shafts could limit gear busting shock.

use a centrax clutch, or just mount the motor on rubber bushings, or make a 2 peice motor mount designed like an old servo saver to take off the shock loading

just some ideas for you linc

Just what I am thinking. I have the design mostly worked out. Pretty sure this will be in an emaxx, as I have a 3905 roller with lst diffs just hanging out.

Would a motor like this be viable for something like this?

http://hobbyking.com/hobbyking/store...idproduct=5140

Was thinking of trying out something like this on a buggy for fun. Installing a outrunner and running it wouldn't be that difficult.. would it?