1/5 Brushless 4wd Conversion
 

Hello guys, Ive been a member since 2008, just never posted before now. Ive been lurking for quite some time :D
Ive been a Largescale gasser guy for a few years coming from Nitro. With my work schedule and my kids I cant get away to my offroad bash sites during the week. This led me to purchase an Ofna JL10e 1/10 Onroad with a CC Mamba Maxx pro 5700KV combo on 3s, to drive during the week. After seeing the amazing power and runtimes I can get with brushless and the fact Redcat is introducing a new lighter 4wd 1/5th scale. It just seems like the perfect time to try a conversion. Here is a thread with a few pics: http://www.redcatrampageforum.com/showthread.php?t=3609

Its roughly 9kg RTR with the gas engine and all associated hardware. After getting rid of all that stuff the weight should drop down to about 6-7kg. Ive considered trying a direct to diff drive setup using a large super low KV outrunner on 12s. The buggy on 12s lipo, with the 130kv outrunner, 6.5inch tall tires, and a 3:1 differential ratio will have a top speed of 37mph@3.7volt per cell. The only thing that worries me is the rollout ratio, its 6.81. I know thats really high and it will probably cog like hell, but would the fact that itll be running at 44volts help? Bear in mind I am a complete brushless newb :)
Thanks again for any input you guys can give.

Great to see another member thinking about 1/5 scale electrics.

There have been a few 1/8 scale direct drive just like you mentioned and from what I can remember they ran great. One member here has a great idea for an outrunner direct drive. A 5th scale is much bigger than a 8th scale and you needing a large outrunner, I think a front and rear motor support will be ideal. I'll be following this to see how it goes.

Its going to be a fall/winter project as far as I can tell.Ive still got a Rampage I need to sell to help fund the project. The new Redcat buggy is at least 3 months away anyway. I will be buying 2, 1 to keep as a gasser and another for the conversion. Once the gas version is RTR then I will start on the electric.
Id like to use 4 of the 6s 5800mah lipos configured to achieve 12s 11600mah. It will be needed to complete those pesky 30min mains. I have a good idea of the ESC I will be using, its the Turnigy 200a Monster ESC from Hobbycity. The outrunner will be Turnigy as well, either the 13k0kv or the 180kv version. That is if the rollout wont be too high for a direct to diff drive conversion. If I cant use the outrunner because of the rollout I will have to use a setup similar to Ryu James's Rampage. Then I could essentially drop down to the cheaper 150amp HV esc from HC. The esc doesnt have a BEC so I probably will use a standard largescale 5000mah pack to power the the RX and steering servo, considering I have a few of those. A bec is something I can do at a later time if $$$ doesnt permit. Man I hope the Rollout ratio of 6.81 isnt too high.

Hello OBeast!!
 

OBeast,
just replied to your pm. very excited to see this build and must warn you that you will be hooked to doing conversions after this one. should be a lot of fun.

i am not familiar with outrunner motors and have never used one. are you wanting to use one cuz they are cheaper?

can you post pics of the buggy? the link you gave isnt working at the moment. i think the forums are down for maintenance.

is the chassis like the TT or more like an HPI baja "channel" type chassis?

anyway, in your pm you stated: "Its weight is approximately 9kg RTR with the gas motor and all associated hardware. My project has several goals that I am hoping I can achieve. Im looking to get 40min of runtime in race conditions, a top speed of 40mph, and cost less than a typical race motor ($600). Thats not counting batteries btw."

if it weighs 20lb with the gas motor RTR then you could get the weight down even more going brushless. and if you are wanting to do the conversion for less than $600 here is my recommendation:

at a weight of 20lb i think the new Castle 1717 1580kv motor would have enough power. plus going with this motor would allow you to run on 6s, also saving a lot of weight. the 1717 motor is 50mm in diameter and 3.3" long. thats a beefy motor and you can get it for $228 on ebay right now.

running the 1717 would allow to use the MMM which you can get for about $140 and also have esc braking so you wouldnt have to worry about any mods to keep mechanical brakes.

for a battery tray i would use the RCM tray that is made for the RC8t conversion kit. its on the drop down list of battery tray in the RCM store.

then i would pick up a 6s lipo that is at least a 30c rating and over 5000mah for extended run times. i doubt you will be able to get 40min of racing run times period but if you went with a 8000mah+ pack you could get close. also, running 6s at 1580kv motor gives you a 35000rpm which is right where you want to be and will yield cool temps.

the mounting holes on the 1717 are same as standard 1/8 motors so i would just take you center diff mount to a machinist, along with an example center diff motor mount, and have them make a custom one. or send your diff mount in to Mike here at RCM and he could do one very easily. i have a 40t spur gear to take the place of the stock beveled spur if interested.

with this conversion i bet you would be right at 20lb RTR, get 25min+ of race time and 40min of bash time, have esc braking, and spend less than $600 before buying the battery. even with the battery you wouldnt be much over $600.

i really do think this could work and i think you would be very happy. plus it would be an easy conversion.....depending on the layout of the buggy. need to see pics of the chassis and layout. the only thing i would do first is check what the output of the 1717 is. i couldnt find the specs anywhere online but i am gonna say it puts out 2000 watts constant and up to 4000 burst. that is perfect for a 20lb buggy. my buggy weighed in at 27lb and the 2215 motor i ran was capable of 2500 to 5000 watts and i had cool temps and lots of power.

if you have more money and time to spend then you could do things entirely different and go the 12s route, with large outrunner or inrunner, and an HV esc. but all that will put you over $600 for sure.

idk, what do you think forum members? weigh in on this idea. do you guys think it would work? what are some other options that OBeast has?

hit me back on the pm i sent you and will chat more. btw, you said you saw my conversion on the rampage forum. i actually posted my complete build thread here. i am not sure if you saw it but here is a link. http://www.rc-monster.com/forum/showthread.php?t=21657

and here is a vid: http://www.youtube.com/watch?v=Zgx-ySspOhk

be sure to post all your questions in the forum. without the RCM forum members i would have never been able to build mine.

here is the spur gear options you could use. these need to be machined just slightly and then hardened. (or you can use my 40t that this has already been done). https://sdp-si.com/eStore/Direct.asp?GroupID=591


1717 motor:

http://cgi.ebay.com/Castle-Creations...item35a70c24c8

I have been using Neu 1900's to replace the zenoahs they are great value, light cheap and go very hard on the standard gearing. Most important on 10-12s coincides with the max efficiency point under full throttle loads. Unlike outrunners they can handle high power and run much more efficiently across the amp range from 0-140 amps. The performance bonus is huge.

The main reasons I want to use an outrunner are the price, the torque, and it will free up lots of room for batteries. Allowing me to have increased runtimes which is always a plus. The chassis is VERY similar to the Rampage, it uses different diffs and suspension but the center driveline is almost identical.
@ Ryu James If the outrunner direct to diff is a no go, I would definitely like to use the setup you used on yours.

Here is a few pics of the buggy to help show what I want to do.
http://i294.photobucket.com/albums/m...ket/Ninja1.jpg
http://i294.photobucket.com/albums/m...ket/Ninja2.jpg
http://i294.photobucket.com/albums/m...ket/Ninja9.jpg
http://i294.photobucket.com/albums/m...ket/Ninja4.jpg
http://i294.photobucket.com/albums/m...ket/Ninja6.jpg

I have more pics that I have found online, but these show exactly what ya need to see. Its almost identical to the rampage in the center. See what I mean when I said youve been down this road before :)

is this buggy out yet? when do you get yours? where can they be purchased? i like that. i love how it looks just like a 1/8 buggy even more so than the rampage tt. it looks very agile. looks like a great conversion candidate.

i am sure you could do the outrunner direct pinion to spur setup. you just need to swap the bevel spur gear with a standard mod 1.5 spur gear. the last post i included a link to site to order gears that lutach had given me when i did my conversion.....assuming the part is the same as on the rampage.

when will you be getting this buggy?

They are still about 90 days out, unfortunately. Thats why its going to be a winter project for me. If the outrunner wont work with the direct to diff drive, I will just use a big inrunner using the direct drive with the pinion/spur, just like your conversion was.
They cant be purchased just yet, they are still working on the preproduction samples from HSP. I PMed Rob on RRF about possibly doing a conversion on one when they get released, and he said he would see if he could get them to build a brushless sample, after they finalize the gas version. Granted itd probably use the Hobbywing 150a ESC on 6s though, like most of the other chinese conversions. I cant imagine it being terribly fast on 6s, at least not much faster than a gas motor.
I know outrunners dont like dirt and run hot. But at $100 each they are cheap enough to run for a while and throw away when they go bad. Also the low price will allow me to use the 130kv and 180kv version as a kind of gearing option. I know the neu motors are powerhouses and are very reliable, BUT they are more expensive than what I am looking to spend on the entire conversion.
Its all depepnding on how the motor and ESC will handle a rollout of 6.81( possibly less with the FG style tires). If it wont cog so bad that it stalls I can move forward and start designing some things on emachineshop.

hey beast,
do you know if this new buggy is longer than the rampage and more like the length of a baja 5b? i know the new MCD v4's are longer than the predecessor to be similar in length to the baja 5b and more true to 1/5 scale instead of 1/6. i am wondering if redcat did the same thing to answer to MCDs new release.

Judging from the pics its appears to be about the same wheelbase as the Rampage. I cant really say for sure but it does appear to be wider.

This car is more track oriented, with swaybars ,captured hinge pins, and a significantly reduced weight than its predecessor. So maybe they did set their sights on MCD. :wink:

Im really hoping to get to see one in person this weekend at LargescaleRC's Powerjam. I will have a tape measure and a micrometer onhand just in case :)
Dont hold you breath though :)

Regardless of what powers it, that is a damn nice looking buggy! Being brushless will be the icing on the cake.

-JB

I have more pics since everyone seems to like it :)
Heres a few:

http://i294.photobucket.com/albums/m...ket/Ninja8.jpg
http://i294.photobucket.com/albums/m...ket/Ninja3.jpg
http://i294.photobucket.com/albums/m...ket/Ninja5.jpg
http://i294.photobucket.com/albums/m...et/Ninja10.jpg
and the best for last :D
http://i294.photobucket.com/albums/m...-newbuggy1.jpg

Obeast,
just read through the thread on rrf. so i guess redcat makes an improved version over this one which is available through engage rc? engage's site shows they have 1 roller in stock for $419. have you checked to see if that is really available or just for pre-order? or are you just holding out for the redcat so that you know it has been beefed up?

btw, where are the swaybars you keep mentioning? havent seen them in any pics yet. am i not looking hard enough?

i hate you and love you for showing me this. oh the pain of spending all my money on rc!

Me wants!

Hahah glad I could help :)
I will try and explain this to you the best I can. HSP manufactures the buggies in China, Redcat purchases large quantities with their decals and options required. They order enough they can dictate design changes and improvements. Engage RC gets their buggies from Riverhobby who in turn gets small quantities from HSP. The Riverhobby owner is personal friends with HSP's owner. The reason the pics I have of the buggy dont show swaybars is because they are taken from EngageRCs website. They get the baseline models and sell them.
Redcat has a few pre-production samples they are testing, and after the needed improvements are made they will be importing them. The sample they have has the swaybars, and you can also see them on the truck on RRF
Heres a pic of the MT version with the swaybars, look closely :):
http://i294.photobucket.com/albums/m...-newtruck1.jpg

And trust me, I hate and love you for showing me the brushless conversion Rampage! Hehehe So I guess we are even :D

hahaha. well put.

here is a pic that is a bit larger for those that wanted a closer look.

http://i471.photobucket.com/albums/r...-newbuggy1.jpg

That one is cool and all, but I would rather have the first one you posted, with the nylon parts and the clear body...it's more bashable, the one above is just a "looker" and would get bent up under severe 1/5 bashing.

seriousloy that outrunner and the cells you will need - did the spread sheet power to weight ratios etc - it adds 33% mass to the stock car and its power levels start to look pretty lame and it is VERY innefficient at the amps te car will run at most of the time - but then at 2.3kg its a hell of a heat sink.

If you can change direction smaller motorswill do the job better and not require the sort of strengthening the proposed motor will require. It will be quicker and more nimble .

After reading a bit more, I am probably going to use the layout Ryu James used on his Rampage conversion. Outrunners look cool but the inefficiency, heat and the fact they dont like to be dirty makes them a hindrance IMO. Now I need to find a suitable motor/esc/battery combo that wont break the bank. Looks like more research for me :D

i agree. its just nice to know that aluminum upgrades will be available. i prefer to have aluminum hubs, hingepin carriers, and things like that but keep a-arms and other parts plastic for some flexibility.

its a tough decisions cuz all of the "cheaper" options out there have not had good feedback. for example, kershaw designs makes a 1/5 brushless motor for a couple hundred bucks but i have not been seeing good things about it online.

maybe you should just get a Neu 2215 from offshoreelectrics.com for $425 and then a Castle HV 110. that would put you just over the $600 mark and then you can have my CNC'd motor mount and spur gear for cheap. i will pm you price. it would be a sick buggy but you almost need to wait to get it before dropping coin or doing too much.

obeast,

just a couple of quotes to consider from the forums as i have been reading more on 1/5 conversions:

"Neu, Plett, Lehner and Castle are the only guys with viable 1/5 inrunners I know about"

"I did a lot of testing with the 1717 motor and found that the top speeds are right about the same as with the stock gas motor, but the acceleration is much better."

that quote is with a baja conversion which weighs 28lb. it might do well on a 20lb conversion and could certainly reach that 40mph mark. but, if the buggy weighs 20lb now its likely to weigh a couple pounds more after redcat does their improvements to it.

The lighter setup will serve you much better. A great motor with a 12 cell single series pack will only weigh 2.1 kg and give much more power and much better power to weight and 12-20 minute runtime depending on gearing.

The Neu 1917 variant I sell has 8mm shaft and fan and runs approx 18500 on 10 cells (5.2hp peak) or 23000 on 12 (8.5hp peak) - they weigh approx 1.1lbs. They run cool with bucket loads of power and cost $249. I recommend a sock or a open cell foam filter for motor cooling.

You can use cheap esc like the turnigy 200 and moderate rate cells - at least 30C cont and have a fast relaible car.

Got a link to that motor? That motor sounds like itd be plenty powerful for what I need. Especially on 12s.
I was originally thinking of using 4 of the 6s 5800mah 30c packs from hobbycity. I know 4 of those things would weigh a lot, but the 40 minutes of runtime is absolutely critical. When racing I cant afford to change batteries while the gassers can just keep running. The extra weight in batteries is a sacrifice id be willing to make.

so are you going to use 2 packs to create 12s and then 2 more to run in parallel? so you have 12s 11600mah?

what do you mean by Neu "variant"?

here is two thunder power 10s packs 5000mah for $136. normally $500 packs. if you had 10s packs and want to parallel you could saddle pack them on the chassis. just a thought. would look cleaner and might be easier to keep locked down than four packs floating around. this would give you 10s 10000mah.

http://www.espritmodel.com/index.asp...OD&ProdID=9837

The 6s 5800mah 30c packs are small enough I can squeeze 4 of them in. Wired in series and parallel for 12s 11600mah. Unless I can find some 12s 5kmah packs somewhere. Those 10s packs are nice but honestly I dont know if theyd fit. Man I need to get my grubby hands on a test sample :)

@AndrewG Im curious to know more about this motor. I think Ryu James interest is peaked as well :)

The location of the 1900 ZR is

http://www.fastelectrics.com/blmotors1.asp and scroll to the 1900ZR. Ignore the cooling jacket.

A couple of things;from the data logs most cars actually run low average power levels. Typically spikes hit 110-140 (6.5-8hp) but the average is around 15-20 amps.

Petrol vs electric - no brainer electric comes out of turns so hard because the car has a torque to weight ratio double a petrol motor, and it takes less than 0.05 seconds to arrive versus waiting for a petrol motor to spool up. That also means it hits top speed sooner so your approach to a corner is smoother because its a constant speed, not still accelerating.

Before you settle on cell count and capacity I recommend a data logger. For $90 you will know all about the power system and how it is going work. The economy you can find using 12 cells + shorter ratio vs 10 cells + taller ratio and other options like, cell heating, ESC operating frequency, timing, throttle exponentials, bearings, different tyre and wheel combos is stunning.

BTW dont be fooled by cheap cells. In bashing the difference is invisible in racing the difference will be apparent as soon as someone uses a better cell. Better cells have more actual capacity available, higher voltage, and hold up a lot better int he second half of the discharge. Another reason to get the logger as the differences are real and try just one pack at a time and work up.

BTW quick release packs are not that hard to figure and you will be miles ahead. :-)

Looks like this project wont be happening, they are releasing an electric version, so I will just buy it and swap out the motor/esc. Heres a vid:
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i came across this vid a couple weeks ago on youtube. i had no idea it was the new redcat. i hope redcat makes some improvements from this version. like i said before though, i think the 6s could work with the new castle 1717 motor if the buggy is light enough. keep us posted on new developments.

I just exchanged a couple emails with "Mike" at RedCatRacing and he says they are 6 months out yet and a roller is a slim possibility.

Last I heard the new gas versions would be out in September. This brushless version may not even make it to the states, due to cost.

The attitude I got from the RedCat Rep I'd say they'll be here for sure. I'm willing to bet the demand would be high enough, I'd surely buy one!?
A giant "1/8th scale type" 1/5 Buggy would totally Rock !

I sure hope so! Theres a lot of interest in it over on www.redcatrampageforum.com. I really do hope they bring in the electric version, the main cost reason I mentioned is that it uses 2- batteries. Given Redcats trend of supplying the lipos and chargers for most of the brushless stuff, it might be a little pricey. Hopefully, they just decide to drop the lipos and chargers. Considering most of us interested in it, already have those.

I don't see why everyone is limited to the discretion of Redcat Racing. Wonder who they buy the product from and if someone else wouldn't just import the same model under a different brand name.

Well for one reason, spare parts. If they dont carry it, itll make it hard to get parts.

Same point source I'd like to believe for spares. Like the king motors baja, what would stop the OEM from selling to a different distributor?

You cant go directly to HSP and buy just one buggy, then order a part here and there from them. They wont even respond to a request for just one. They have distributors for a reason.
I dont know of any HSP distributors in the US other than Redcat. And theres no way im paying/waiting for parts shipped from overseas :D

Wow, I am extremely impressed with that electric version! He was beating the ever living shit out of that thing and it just took it...not a single broken part or break-down, that's awesome! I would/will definitely buy one of these...very impressive!