1/8 buggys with outrunner power
 

Hi, I'm thinking of converting a Kyosho MP-6 to brushless using a outrunner to replace the center diff.( I know it's easier using an inrunner mounted next to the center diff, but this intrigues me) How big an outrunner do I need? I saw pics of someone else's conversion and they were using a HXT 50-55-450. Do I really need one that big or could I use a Rimfire 42-50-1000? Thanks, Don

Its an art, trying to figure out which outrunner to use for this kinda thing in any given setup- Sike is the guy to talk to...

Does Sike visit this forum? Don

The outrunner you choose will depend entirely on the speed you wish to achieve, and the voltage you want to use. Keep in mind that 4s Lipo shouldn't be used for anything higher than about 45mph.

That's right where I want to be. I'll be using a 4s a123 pack(13.2 volts). An outrunner with a KV of 1000 would produce 13200 rpm which should give a speed of 40-45 mph. I was also concerned about torque- would the motor I selected (Rimfire 42-50-1000) have enough? Don

1000kv is alot in a DD setup, you will need a huge outrunner to give you the torque you need. 4s A123 probably wouldnt be enough to get you to 45mph with any runtime, you using 1or 2p?

I would go up to 5s a123 and a lower kv motor. Startup load is high with a direct to diff outrunner, and the more voltage you have the better it will run. I guess you plan to run a MM? Or maybe the MMM?

Your rimfire motor should be ok, but I would go with the 42-60-800. What are your diff ratios and tire size?

At the moment the battery is 1p. I've got a MM but would like to have a MMM. Diff ratio is 3.3 and tire size is 4.375 dia. Don

The mm is fine up to 5s a123, just use and external bec and disable the internal bec in the MM. 1p should be ok, to keep the weight down, but you will get 15min runtimes or so.

Forgive me, my earlier advise on the 42-60-800 was not good.

I would say that you should run 5s a123, a 600-650kv outrunner, and the MM. Speed will be in the low 40mpg range, which should work fine. The rimfire 42-60-600 would be ok to use, maybe go up to a 4120/14, 660 kv, outrunner, as those are very nice motors, and they will work well in your application.

http://www3.towerhobbies.com/cgi-bin...?&I=LXPPX8&P=7

OK I'll take a look at the 42-60-600. Thanks, Don

I've got my motor. I've centered the motor shaft (thanks Takedown) and have temporarily mounted the drive cups to it. I find myself in need of 2-6mmto5mm bore reducers and a motor mount to mount it to my MP-6. Is this something Mike could come up with? Thanks, Don

OK, should I e-mail Mike directly? Don

bump

Yeah, Mike should be able to make the bore reducers.

How about the motor mount? Don

Yeah, Mike should be able to do that too- just throw some money at him, and he'll do almost anything usually :whistle:. Some good diagrams with measurements should be all he needs.

OK, I'll drop him an e-mail. Thanks, Don

Hey i have an outrunner powered Duratrax Raze, i used a piece of 2inch angle aluminum on my car. I Talk to takedown almost daily... Sike, myself and Takedown know about these conversions if you need help
http://s152.photobucket.com/albums/s...t=100_0968.jpg
I used a 600kv 50-55 Turnigy Outrunner on 5s and a mamba max, im pushing 49 mph

Your Raze looks good! Have you put in the other drive shaft yet? Don

yep had to get a warhead front shaft, but its awesome, tires dont stand a chance though..

This is how my outrunner powered buggy looks atm, just needs an ESC:grrrrrr:

Glad you finally got it together RcMonkey. i remember building mine you were on my thread 24/7 asking questions. Good questions!! i enjoy answering good questions lol

I'm concerned with the thinkness of the motor mount, without the additional usage of a rear motor brace. In the past I had a mount of greater thickness bend with a Feigao 8L off of a small jump. The idea looks great, just needs more thickness IMO.

my 1/8th inch aluminum mount holds up fine..

To me that material looks about 1/16", though.

I see it flexing quite a bit too. Maybe he could triangulate it forward to the chassis with a link on each side?

I toyed with the idea of making a bracket that could support the other end of the outrunner, with a bearing around the shaft. That way it is bearing supported at each end, not just the mount end. I decided not to, but i am just running a smaller axi in the redcat, which is 10th scale. And my mount is reasonably thick 6061 t6 al.

http://i206.photobucket.com/albums/b...p/DSCF1688.jpg

I agree, as soon as I get my 5mm bore drive cups from UE I'm going to send the car,motor and all to RC Monster Mike. I know he will do it right. Don

The mount is made from 2mm steel I found that was ready bent so there aint alot of flex:wink: I wanted to make a rear mount with one of the CD mounts but there isn't enough motor shaft showing to allow a bearing to run on the shaft as well as the drive cups.

Yeah, steel would make a difference lol

u need 8mm drive cups...

They're going on the motor-it has a 5mm shaft. Don

oh, im sorry, i though u were using the 50-55

No problem, I'm using a Rimfire 42-60-600. Don