brice_arnold

My Feedback: (6)

So I just finished this for RCX as well. There were three things driving this project.

1. Build the worlds lightest baja, while staying true to a baja to the best of my ability

2. Build a drag racer styled car

3. Convert to brushless electric system. I believed that a brushless/lipo setup would be lighter than a gas motor.

So my original target wegith was 15lbs. Final weigh-in with batteries, motors, wheels, everything ready to roll was 11lbs-14.5oz's. I am still looking for a light-weight carbon fiber wing though.

I started with the chassis. Originally this was a custom one-off Rhino Racing one-piece chassis. I had this on a sand build and busted the nose off doing a 30 ft jump out of a sand bowl. I chopped the nose and bolted on a custom machined scorpion nose piece. I also machined the snot out of the chassis to get the weight down.







At this point I will mention that I put together my own hardware kit consisting of all titanium and aluminum screws. During this build I switched out everything in steel for aluminum and titanium. I also swapped out everything in aluminum for carbon fiber or plastic. Nice thing about a light weight build is because of the weight reduction I don't need the strength of steel hardware.

brice_arnold

My Feedback: (6)

Next up was a gearbox. I kind of failed on this one. I opted for a diff set-up when I could have just as easily thrown in a Vertigo locker and saved that much weight. Anyways I went ahead and changed all the gears to the HD gears from HPI which are significantly light. I also machined some custom titanium drive cups for both the diff and the hub. I also ditched both the steel and titanium layshaft and opted for a custom aluminum layshaft.

Here are the titanium cups. This is the first part that I have ever personally machined from titanium. I was pleasantly surprised with how it machined. I have heard horror stories about this material. It is kind of quirky but once you get the hang of it it machines beautifully.



Here is the diff for a weigh-in



Here is the layshaft



And the finished gearbox

brice_arnold

My Feedback: (6)

The brushless conversion:

So I acquired a brushless motor in a trade. The motor was from a HARM EP-1. It is designed to run @ 22 volts and get a 20lb car up to about 40 mph. Though the motor is on the dinky side and looks like it should be in an eighth scale car i figured what's good enough for HARM is good enough for me. Nice thing about the motor is that because of it's size it is also light weight.

The brushless adaptor plates came out pretty good. I designed them to use the stock mounting holes on the baja so that I could potentially explore offering a conversion kit in the future. The motor plate is also adjustable so that I can work with a range of pinion/spur combos.





After mocking everything up the front end looked too wide. To try and scale it down to that of a dragster I figured out a way to use the rear upper arms for the front lower arms. In an effort to help reduce weight and clean up the appearance of the baja I removed the front shock assembly and replaced the front upper arms with carbon fiber leaf-springs. Because this is a drag car I don't need that much front end suspension and the leaf-spring have enough flex to keep the wheels on the ground.







For wheels I decided to use fronts in the rears and make custom disc wheels for the fronts. This was the lights combination possible. To maintain the styling I made the custom three piece wheels in the front and matched the rears be machining out the dish and sandwiching the carbon fiber dish with the beadloc screws and some nuts on the back side.

brice_arnold

My Feedback: (6)

Wrapping up the project.

So for the rear shocks I modified the stock HPI shocks by chopping the cylinder and piston shaft, removing about 1.5" from the shock. Not only did this get the car to the correct ride height but it also helped with getting rid of some weight.

The drive shafts are one-off prototypes from Darksoul Racing machined from 7075 aluminum.

I had my buddy from Rhino Racing do a custom light-weight body for this build it basically his standard CF body except with only two layers of CF and a satin finish. This body is lighter than a painted plastic body.



the body and under-skid fit like a glove. The car looks great and ready to race.



After getting back from RCX I finished up the wiring and took the car out for a test drive in front of the house. It was getting late so the lighting was poor. Manny from Custom Street Toyz and I are going to go out and get some footage this weekend. Hopefully we don't crash it, I don't think it would survive.

http://www.youtube.com/watch?v=kdnbBMrLd4I

dealwithit

My Feedback: (55)

thats one nice looking baja! neat idea for the front end suspension, would be interesting to see how it flexes. good job!

brice_arnold

My Feedback: (6)

Thanks, that was a collaboration between Manny from Custom Street Toyz and myself.

Here are some photos that Mark from TGN took

snoking16

so how fast does it go?

DarkFire989

That CF main chassis is way too cool!

T I G

Again, Brice you are an amazing.
Looks fantastic, the detail is incredible.
I dont expect anything less from you Brice, you are a true craftsman.

Croozer

My Feedback: (1)

I would like to see a light weight chassis like this for gas engines.

jigawatt

I love what I see! Oh factory brushless 1/5 scale... are you on the horizon???

hndaman1

My Feedback: (6)

very cool.. I found your wing for ya out of carbon fiber. I bet you can get them to sponsor you for racing...
http://www.integy.com/st_prod.html?p...99&p_catid=126

vertigo performance

That is a really nice looking machine. Nice work!!!

srt10

My Feedback: (20)

That body looks way cool!

sheograth

Awesome work as usual Brice. I gotta throw some money at my Baja and catch up with you people!

brice_arnold

My Feedback: (6)

So it's a sad day for the electric build. We took her out for some drag runs. Got some great footage. We weren't able to really get on the throttle due to the size of our track but we were able to hit 58mph before hitting a curb. Total destruction.

However, gentlemen, we can rebuild her. We have the technology. We have the capability to build the world's lightest baja; again.

I will get some video up later once i've edited it.

DarkFire989

OUCH. Thats a huge bummer brice... I have a question. How important are the rear shocks? Couldnt you replace them with just some shafts or something? Or would that not work?

nothinbetr2do

damn, i was really digging it. sorry to hear you crashed it, maybe you can rebuild it better

brice_arnold

My Feedback: (6)

Here is the fateful video

http://www.youtube.com/watch?v=Yd0qsB5VrsI

jigawatt

ouch... doesn't look too bad though. Didn't sound pretty!

dealwithit

My Feedback: (55)

ouch! maybe it was too light?

Paul1981

What exactly happened?  It's not clear from the film.

dealwithit

My Feedback: (55)

i think the front end didnt have enough grip to steer at those speeds, hence plowing strait into the curb?