1/5 Brushless 4wd Conversion

[lutach]

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.

[Obeast44]

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.

[Ryu James]

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