Lightweight 1/8 buggy project

[Thomas]

Hi there

I am finally converting a 1/8 nitro buggy to electric with the following goals:

• Lighter than nitro original
• At least 15 min runtime going the same speed as nitros on (European style) race track

Are there examples of such buggies? All electric 1/8 buggies I've seen are heavier than the nitro version (maybe except the conversions of Mr. Constructor, which don't use a nitro chassis).

Attached are pictures of my self-designed aluminium motor mount and self-made carbon prepreg battery holder.

Regards
Thomas

[magman]

Even though some of the electric buggies are a bit heavier than their nitro counter parts, what makes the electric conversions so popular is the sheer acceleration and torque of the brushless set ups. My electric truggy is heavier than my friends nitro truggy although he tries, he cannot keep up with mine. So if they are a bit heavier it can be more than made up. However, the lighter you can keep it the better for sure.

Nice job on both pieces.

[el tomaso]

You could use the Losi 810, and use a light 3s setup...

TG

[x-y]

http://www.cochesrc.com/foros/1-8-tt...-de-1-8tt.html

[Semi Pro]

something like this?

http://www.rc-monster.com/forum/show...on+fiber+8ight

[Thomas]

Thanks for the links. There are some pretty light BL buggies out there. My goal was choosing lightweight powertrain components, not just saving weight by using carbon etc.

I have achieved the first goal, my electric conversion is 130 g lighter than my nitro version of the same buggy (even with empty tank). I chose a very small motor to avoid overpowering the buggy (it's for racing, not highspeed bashing), but it didn't go as planned: These Neu motors just make unbelievable power, the buggy is crazy fast.

I haven't been to the track to experience driveability and runtime. What I noticed is that without mechanical brakes, it might be harder to throw the rear end around a corner off-power. But I guess I can adjust caster, ackermann and the dampers to tune that.

[Thomas]

I thought this thread needs some more pictures. Here she is just before the shakedown today:

[el tomaso]

Can you tell us which buggy that is, and the turn/kv for the motor? How many cells are you running it on? Thanks

Thomas G

[Thomas]

Hi Thomas

Yes of course, here you go.

Buggy: Very old TTR S3 EB4 with an aftermarket flat chassis plate
Motor: Tekno Neu 1509/2y/f (1820 kV)
ESC: Mamba Max Pro
Batteries: 2x 3s1p (-> 6s1p) Kokam 2400 mAh 30C

I will probably switch this powertrain over to a new buggy next year (if it works well). Will have to see which one fits the layout, or make my own chassis plate.

[simplechamp]

Can you please tell me more about the carbon battery trays? You made them yourself? What was the process?

[Thomas]

Hi

Yes, I made them myself, at the university where I study. I used carbon prepreg, in this case twill with roughly 200 gsm. For the battery trays, I used a positive mould (plug) made of wood, which I simply cut to the size of the batteries plus some additional space. I used release film and laid three layers of prepreg onto the mould. Then I put them in a vacuum bag and into the autoclave at 2 bar pressure and 130°C to cure for two hours.

One battery tray (without velcro strap and double-sided tape) weighs 25 g. The carbon stripes for mounting with screws are glued on.

I will try to go to the race track tomorrow, to find out the runtime, but the weather is a bit unsure.

[slimthelineman]

6a on 1800 kv is ludacris speed for sure! Mine was insane on 1700 kv and still plenty fast on 1400 kv now. My rc8 is 3330g and has all the lightweight driveline parts too. A lighter buggy runs longer and cooler but I had to change my setup to make it drivable. I like how nimble it is now but I have noticed it gets tossed around a little more in the rough stuff. IMO reducing rotating mass is where it's at. Don't worry about overall weight as much, reduce load on the motor to keep the power system happy and it will reward you with insane amounts of power as you have found(neu motors are my favorite for this reason).

[Thomas]

I'm wondering if efficiency is going up with 0° timing or if there is an optimal spot for my motor. Torque and speed are plenty, so I'm not looking for best power, but highest efficiency.
As said, I'm using a Mamba Max Pro with Tekno Neu 1509/2y. I'm trying to find the best settings for good drivability and long runtime ond an offroad track.

[slimthelineman]

0 degrees is the most efficient. When you go up you gain rpm and loose efficiency. I always run 0 on my 1/8

[x-y]

Originally Posted by Thomas

I thought this thread needs some more pictures. Here she is just before the shakedown today:

¿weight rtr of this car?