Outrunner CRT.5
 

Yesterday i finished my Outrunner Conversion. I am using the following electrics:
KD36-8XL Outrunner
Modded Quark Competition 80 (Case removed, I've added a 1000µf 35v cap and a heatsink)
Zippy 2000mah 4S Lipo

I have replaced the two chassis braces by a long M4 threaded rod and a carbon fiber tube. I'm using Traxxas Victory rear tires on Jato rear rims. It's working great, cogging isn't existing. Here you can see a small vid: http://www.youtube.com/watch?v=urW7moQkk30

http://i36.tinypic.com/anygbb.jpg

http://i35.tinypic.com/20z5z4x.jpg

http://i34.tinypic.com/2l9odw8.jpg

http://i37.tinypic.com/28r012x.jpg


I hope you like it!

Looks good - I would seriously look at the revo/jato front and buggy rear shock mod...

very nice conversion, neat and clean-now all you need is more voltage :yes:

Wow, thats cool.

Could you explain how you managed to fit the outdrive's of both drive shafts to the motor.

For the motor shaft I understand, but how did you do the rear.

And what is that brace you are using. Can't really see in the pics.

How are its handling capacities now the center diff has gone ?

I've moved the motor shaft through the motor so that 2/3 of the shaft looks out at the front and 1/3 of the shaft looks out at the rear. I have replaced the two braces by the long rod from the front to the rear.

http://i36.tinypic.com/346rmfb.jpg

It's handling very nice, i don't feel a great difference without the center diff.
I'd like some more voltage for speed runs but i couldn't find 5s or 6s batteries with a small capacity like 1800mah or something like that.

Very nice conversion.

some outrunnerscome with the shaft out both sides-some you have to slide it through.

how bout 2 of thes in series?
http://www.hobbycity.com/hobbycity/s...0C_Lipoly_Pack

I would prefer one pack with a smaller capacity, two of the batts you suggested will weight 372g, i think this will bring the chassis out of balance. I think I'll stay with 4S Lipo, i've got a small track here and there i can almost never drive with full throttle.

I know MaxAmps isn't the pregered battery but they will build custom packs. How about to 3s rc18t packs laid end to end?

A 6s1p 2100maxamps would fit easily IF it can take the amp draw is another matter

at 22.2v I can't imagine the amp draw would be all that great. I may be wrong though as this is direct drive and can't be re geared.

I think i'll order two of these and solder them together to one 6s pack: http://www.hobbycity.com/hobbycity/s...idProduct=6293
Soldering Lipos is easy and i've only made good experience with Zippy batts. And if they are stressed to much, i can still sell them to my cousin for his RC18T.

I might have to try this idea out on my crt.5

So whats ideal voltage for doing a direct drive? I have a TON of room on my chassis (55mm longer then stock) And its a little wider then the RCM one. Is 6s good, or would doing 8s or something be better?

And do you have a link to that motor? Im liking this idea, and the price is better then a 200$ NEU lol.

Also, is the bottom end snappy? Or is it kind of slow?

Ideally you want to pick a motor of the appropriate size for your vehicle (for power handling). Unfortunately the knowledge base of outrunners in cars/trucks is very limited, so finding the appropriate motor size could be hit-or-miss. But after you do find a good motor size, check out what kv options are available. For the CRT.5 I think 3s Lipo is a good all-around choice, so I'd pick a motor with a kv of about 1000 for 4" tall tires and about 40mph top speed.

Travis, im going to pm you in a min

Dont want to clog his thread up

I am using this motor:http://www.hobbycity.com/hobbycity/s...idProduct=4659
It is also available with 900kv and 770kv, the size is ideal for the CRT.5
I think for my 1000kv motor, 4s with small tires or 3s with large tires is great. It is so powerful, it's wheeling all the time even when i'm driving around with around 25mp/h it's easy to let it wheely.

Here is another short vid of my Outrunner CRT.5, i'm still lovin it, it's driving so nice and is so powerful. The motor, esc and lipo are staying cold or handwarm.

<object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/ec-L9P80IU4"> </param> <embed src="http://www.youtube.com/v/ec-L9P80IU4" type="application/x-shockwave-flash" width="425" height="350"> </embed> </object>

And here's a large pic my brother made with my cam, it's 16 pics in one second. You can see very well what's happening when i'm accelerating: http://i36.tinypic.com/11hqy5h.jpg

lookin good =) any problems with diff gears blowing?

I checked the diffs yesterday, i've got now about 8 hours of runtime on them and they are holding up well. They look like new, no wear is visible. :yipi:

sweet :D

wie lange fährst du mit den 2,2a lipo wennst auf ner strecke oder so bist?

yep what he said:lol:

you did a great job, looks like tons of power

i take it the motor mount is custom?

Update after 3 months:
After around 40 runs with the Quark, fire came out in early November. So i shipped it to the adress in Korea that was printed on the box of the ESC. Online tracking showed me that they received it on November 17th. Since then i heard nothing from Sky&Technology, my emails are just not answered. So i'll never buy a Quark product again. :grrrrrr:
I replaced it with a Sidewinder with UBEC and it's really the best Outrunner ESC i've ever tested. It has a smoother startup than a Kontronik Jazz 80, a Mamba Max and a Quark Competition 80 with capacitors attached. After 2 battery packs, it's never warmer then 120f.
When i had destroyed the gears of my Hitec 225 the third time, i decided to replace it by a low-profile servo. First i tried the HXT9612 but it was even to weak to turn the wheels when they weren't touching the ground. :yes: I'm sure it has not more than 1.5kg of torque although it should have 5.4kg. Now i'm using a Bluebird high speed servo, it has metal gears and found it for 30€ at my hobby shop. I've mounted it using Traxxas 4-Tec servo mounts. It works nice and is really fast.
The RTR weight of my CRT.5 with Jato Wheels is now only 1840g, thats 4.06 lbs. I'm now very happy with it and I can't find anything i could improve.
Here are some pics for you: http://picasaweb.google.de/Brushless...NorCRT5Setup3#

@ Semi Pro: I found the motor mount at my hobby shop, they had it there for 1.50€

@ Burnsi: The runtime is about 13min - 17min.


If you find anything really useful i could improve, please let me know.

What dogbones and outdrives did you end up using on there? I can't seem to find any that fit.

I found the dogbones and outdrives at my hobby shop, i don't know the car they are spare sparts for. But the dogbones are 41mm long and the outdrives have to be made for 5mm shafts for my outrunner.

Would these be the right thing?
http://www3.towerhobbies.com/cgi-bin...&I=LX2558&P=SM

Could you post some pictures of your battery mount. Do you ever have any problems with it, like the battery falling out or anything?

@ Metallover: If they are 41mm long or even a bit longer, they should fit.

@ E-Maxx: My battery mount is consisting of 2 long M3 screws who are screwed through the chassis and have a piece of fuel tube on them. The battery is fixed to a 2mm thick piece of carbon by fiber tape. I've never had any problems with it, the battery is fixed really nice.

@Bl-Power:

I understand you had converted your CRT.5 using both inrunner and outrunner motors. If you had to only pick 1 conversion, which type would you recommend?

Thanks for your comments!

That's correct, at the beginning i had the inrunner, then the outrunner. I've already sold my CRT.5, but if i look back, i think i would take the inrunner.
The outrunner setup is nice and you can save a lot of weight, but it didn't like that you can't change the gearing. With a new Outrunner it's really great and powerful, but when I had about 50 runs on it, i could feel that the power is decreasing. Outrunners aren't made for offroad use, they don't like the small stones and all the dust. I did the outrunner conversion because nobody had done it before and i love trying out and finding new solutions. The outrunner setup is funny but if you want something that is easy to use for over 100 runs without any problem, then take the inrunner.

Currently I have my CRT.5 converted using a SpeedPassion 7.5R with 11 tooth pinion using only 2SLipo. The conversion is easy and clean. However, I didnt really like the noise from the metal-to-metal gears.

Thus when I researched on other alternatives, i found this site and the idea of using outrunner motors. From your video, the car seems so smooth and noiseless. I really like it!

However, the place I play RC cars is actually a gravel field.... so maybe outrunner is not a good idea. (unless I built a stone-proof housing around the outrunner... but it may get really hot!)

Anyway, thanks for you comments.

Reaserch the plastic spur mod.

yeah, i read about the Kyosho plastic gear. in fact, i have 1 right now, but because i will run the car in a gravel field, the plastic gear will be chewed up in no time.

i still find the outrunner option a very 'cool' setting, since it is direct drive which provides lots of torque and is ultra-quiet.

You are completly right, it's smooth, light-weight, quiet and powerful but not very durable under real offroad conditions. It's not to expensive, if you've already got a ESC and a battery you have to spend around 50$ for the motor and some small parts like cups, dogbones and a motor mount. If it works stable under the conditions of your driving spot, you can keep and have a lot of fun. If you've got problems with it, you don't have lost too much and you can use your inrunner again.
The Kyosho gear is quite durable, i don't think it will be damaged.

If you are worried about dirt and dust getting in the motor, use some kind of foam or screen on the holes of the outrunner. It will still provide cooling and keep the rocks out. I say try the kyosho plastic gear and if that gets chewed up and you feel an outrunner is your only option to quiet it down, go for it.