Brushless Traxxas Jato

[crazyjr]

I decided to go back to nitro on my jato. I couldn't get the batteries to fit to my satisfaction, but don't worry i've still got a revo to convertto electric

[Serum]

Take your time fitting the batteries, with converting, the batteries are a struggle to begin with. Perhaps you can do something with the tub from emaxx..?

[crazyjr]

the emaxx tubs won't work (not enough room between the servo and gearbox) there is only enough room for about 5 1/2 cells. I was going to try to use the steering servo vertical but the linkage binds too much so the only 4 options i see are lipo's, smaller batteries (2200's), new gearbox with relocated upper gears (nobody makes one yet) or going back to nitro untill i can afford one of the other options,so that is what i am going to do. Don't worry, i've still got two ele stadium trucks to play withso it's ok for now

[Batfish]

I decided to skip racing last night in favor of spending some time practicing tonight.
The Brushless Jato V2 is a HUGE improvement. Getting the weight distributed more appropriately definitely made the truck more driveable.

One problem remains now...the truck is just too powerful for the track. I'm going to have to spend a bunch of time setting my radio up to dial out the power. There isn't a single spot, including the 96' straight, that I can get over 1/2 throttle. The truck is just too darn fast for a technical racetrack.

I'm learning to drive it all over again since V1, but at least it's controllable as V2 and I don't have the moving motor mount problem anymore. When I race next Thursday night I expect to actually finish both qualifiers and the main. So far I'm 1 for 6, which is a pretty dismal record, heh.

[toby]

that is a cool truck, You are a true inovator and really know what you are doing in this hobby, Props to you man

[coolhandcountry]

You working the kinks out there batfish. I am glad to here it. Should bring home the trophy thrusday. Good luck.

[Batfish]

The Brushless Jato V2 had it's best outing so far tonight.
3 qualifiers and the B main all finished. There were 5 drivers in my group.
I was 3rd in the first qualifier, 4th in the second, and TQ'd my group in the 3rd. I came in 3rd in the B main.

To control some of the power, I adjusted my radio's throttle end point at 40 (the Sensor goes from 0-100). That seemed to do the trick, but once I have better traction in the rear I'll probably have it up to 50 or 60.

Interesting development tonight - I put some white Revo springs on the front of the Jato and lowered the rear about 1cm (threaded shock/spring adjustment) and TQ'd the next qualifier. The front is very stiff now and the rear tires got a little more grip. Overall, I was suprised that this drastic of a change came out so positive.

I hate to add weight to it, but I think my next tuning test will be to re-add the 4-cell pack rear bumper. The last thing I'm missing for stable running is a little more traction in the rear.

Next electronic steps are to upgrade the stock Traxxas 2055 steering servo with a BMS 620MG I already have, and trade the 12012 for the 8012 I got from Mike. The 12012 will be transplanted into my 1/8th buggy.

We'll see how next week goes. With just a little more traction and quicker steering, I'll be in the A mains again in no time :)

[crazyjr]

Hey Batfish. You could add lead weightused in model airplanes. I can get it at my ihs pre cut in 7gram squares.

[crazyjr]

maybe you can find it near you. Beats adding too much weight with all those batteries. Sorry for double post, too late for edit

[Batfish]

Actually, the 4-cell dry pack is pretty good for tunability. If I find out that I only need to add a little weight, I can just put one battery in it...all the way up to 4. It's a quick adjustment to pop a AA into or out of the pack, too.

Heck, I gotta find SOMEthing to do with all these dry cell holders laying around.

:)

[Batfish]

Few more notes to add tonight.

- I got the BMS 621MG servo in for steering and swapped the stock bushings out for bearings in the steering
- I put the rear bumper/battery holder back on
- I changed the gearing from 20/54 to 15/58 hoping to have smoother starts and better low-speed running
- I got the MGM 8012 (new version) ready and will be installing it tomorrow when I get more heatshrink tubing for the wires/connectors

Hopefully another good Thursday night of racing around the corner :)

[Batfish]

It's been a while since I made an update here. I hadn't even realized that I forgot to post about my motor mount finally giving up. The design I came up with to mount it to the chassis ended up failing in the end.
I stopped running the Brushless Jato and decided not to run it again until I got a new motor mount worked out.
People at the track ask me no fewer than 3 times each week where the Jato is, heh :)
Well, I got inspired to get it running again and spent the last few days working out a new motor mount. It came from an idea that crazyjr posted about earlier in this thread. I bolted the mount to the holes in the tranny where the clutch guard comes out of. I made the mount angle upwards to the front so that I could move the battery holders further back on the chassis. End result is that I moved the motor slightly back and up, and also moved the battery holders back almost an inch.
I actually expect the mount to fail at some point since it's still the cheap aluminum I got at Home Depot, but I'm hoping to get in enough races to prove that the design works before it breaks. Once I know if the design is good, I can look at getting one machined.
Here are 3 pictures from V3:

[Sylvester]

the edges look very "sharp" on your desing:P

[Batfish]

Originally posted by Sylvester
the edges look very "sharp" on your desing:P

It's a trap...I want anyone that thinks of messing with it to think twice, heh :)

Now where did I put those band-aids?

:)

[crazyjr]

That is exactly how i did it. I still have mine, but i'm saving it till i can put more money into the project. Thanks for the credit, but you actually made it work. As far as the motor mount failing, i don't think so. The clutch guard mount will probably fail before then