[56k bomb] Converting to Brushless. Aka, too lazy for nitro.

[Thirdgen89GTA]

Figured I'd post this up here. I fell out of RC a while ago. It was slow, at first a weekend would go by, then 2 weekends between and it just grew. Winter hit, and I never took out the RC's again.

Mostly now its because its simply too much hastle to get all the nitro cars in running shape for a bash session. Fuel is bad, need new fuel. Glow plug is shot, replace glow plug...crap no plugs on hand. Goes on and on.

Well recently I decided to get back into RC and with the way the Brushless/LiPo scene has taken off it was easy to get even more power with less maintenance. I love speed, and Castle had just the thing for me. Its not the fastest thing out there, but its damn fast regardless.

Below is my converted Jammin X1 CRT Pro truggy. Not shown in the old pics is the conversion to using a Castle UBEC and Savox 1268mg servo. It now turns the tires like they are feathers.

I received a few comments when I was doing some research, it seems quite a few people do not like to convert truggies with a motor forward, saddle battery pack configuration. I however love it. I wanted to do it because of how well balanced the electric cars that use this layout are. The truck is nearly perfectly balanced left to right, and is actually nose heavy so the steering is great. I wanted it nose heavy because of the better steering and decreased wheelie action. But on 6S it doesn't matter. Wheelies everywhere no matter what you do.


Nitro Removed


Obligatory unboxing picture.


Chassis all cleaned but still with old 13mm shocks.


Twin 3S 5000mah 40C lipos. $44/ea. Good deal. Not the best in the world but I'm so happy with these. Never get warm and always tons of punch.


Mock layout #1 - Still waiting on RCM mount, 16mm big bores, and battery trays.


Mock Layout #2


16mm big bore vs 13mm old shocks. Old shock looks nasty because the snap ring groove was shot and it wouldn't seal anymore so it leaked bad. Its as much reason for me to swap as simply wanting better shocks to handle the increased weight.


RCM Mount and Trays have arrived.


RCM Mount installed, motor mounted. ESC tray made out of the Aluminum servo tray that does not fit the CRT. Chassis needs to be clearanced enough so the spur doesn't hit the chassis. Temp spacers installed to raise the Diff up.


Final layout, Motor installed, ESC installed. Battery tray's mock fit.


Problem #1, not enough room in the chassis to fit the tray and pinion hits the battery tray and rear arm pin.



Problem #1 solved. Clearance battery tray. But now if the battery shifted forward the pinion could chew it up. Oops.


An old plastic arms holder is the solution. Cut to size and screwed into the tray to stop the battery from shifting forward.



Problem #1 fixed


Problem #2 - Spur gear hits chassis because there isn't a relief cut for the spur. Dremel removes the problem.



Battery mock fit #2. Perfect. Now to drill the chassis and securely mount the trays.


Existing holes reused when possible, but new holes and to be drilled and countersunk. This is by hand, I don't have a drill press. Probably why the countersink looks wavy.


Battery trays mounted securely. Ended up reusing a single hole on the steering servo side of the truck, but had to drill and countersink 3 new holes in 2.5mm size. Motor side of the truck I drilled 1 new hole and reused the engine mount screws and one of the Z-brace screws.


Trays mounted.


Sweet. Lookin like an RC again.


Man that motor system is low. I actually run the 3S packs now sitting on edge so they care closer to the centerline. Better response on tight tracks. In this pic they are flat.


10.22lbs!!! ESC ads 125g to this bringing weight up to 10.5lbs with twin 3S, and just 9.8lbs with twin 2S packs in series.


Ready to rock!



Old Nitro body provides lots of cool air for the ESC.


___________________________________


Ready for the first speed run! AWESOME!!!


First speed run is a failure after just 1m 11 seconds, and only 194yards. I didn't even get much past 30mph before attempting to give it full throttle. OOPS.


First successful speed run undergeared with a 14t pinion. Only 52mph, it can go MUCH faster. Motor was hot to touch, but not too hot to touch. Probably 140-150*. Batteries and ESC were ice cold.


Speed rash on the wing from the crazy wheelies this thing does on 6S.


First successful track visit. Broke the wing hard car when I overestimated just how FAST it accelerates. Tried to clear the double. Could have cleared the quadruple. Landed and did an endo into a concrete barrier. Oops. Run time on 4S = 21 minutes. Runtime on 3S2P = over 40 minutes.

[firesprink281]

nice

[Thirdgen89GTA]

And here's a crappy video of the wheelie machine that it is on 6S.

Filming AND driving at the same time is rather hard. Pretty much limited to straight line runs and certainly can't pin it or accelerate hard because if it gets squirrely I can't correct fast enough.

[video=youtube]http://www.youtube.com/watch?v=3lUEBdUC0-w]Jammin Wheelie machine - YouTube[/video]

[Mr. Tune]

bad ass

[Thirdgen89GTA]

There have been some changes to it. I've finally received my 180x130mm 2mm thick carbon fiber sheet. So i've made a custom ESC mount in a more protected portion behind the center diff and between the battery trays. Its 70mm by 40mm, so plenty of left over stock for other projects.

I've also ordered the parts needed for the Jammin X2 center differential conversion. This will allow me to get rid of the 62t ferris wheel known as my spur gear, move to a 48t spur, and also lower the center differential almost 1/2". So lower center of gravity and increased impact projection for the ESC.

Updated pics.

[Thirdgen89GTA]

Figure I'll post this here now since it just finished uploading. This was scary the first time I connected the batteries. I had read about the spark one gets as the caps draw in power. But holy cow. On 3S its barely noticible. On 4S its a spark. On 6S its WTF OMG. The spark actually causes pitting on the connectors over time requiring you to replace the connectors as they wear out.

[video=youtube]"http://www.youtube.com/watch?v=xF8GqpqKYlA"]4S vs 6S lipo connection on a Mamba Max Monster.[/video]