Brushless Kyosho Inferno ST-RR

Finally finished converting a Kyosho ST-RR to brushless.

Thanks very much to Shark413 for his help, as well as another user who I can't find the name of right now.

At the moment its running:

4s2p A123 batts
Fegaio 8XL 2000kv motor
Monster Mamba Max ESC
15T pinion gear with the standard 50T spur

I just tested it on the street outside and I'm quite happy with its performance. It could probably do with a 16T or 17T spur, but I'll make that decision after I give it a go on the track.

Let me know what you guys think. I'll take a photo with the batts in when I get home.

More pictures here :D

[Gee]

Look great! Is that the RCM motor mount? I'm slowly gathering all the parts to make my US Sport a ST-RR. Once I get that I want to convert it. How does the manual brakes work? Meaning how do you set them up to work with the esc and your controller?

Yea, its the RCM motor mount. I had a US Sport as well, which I just sold. I was going to do the same thing as you and try to upgrade it, but getting a new kit and selling the sport seemed easier.

With the manual brakes, the brake servo is plugged into the 3rd channel and I did some funky mix thing with my DX3.0 to make it work. I've programmed the MMM to have 0% brakes, so when I apply brake it actuates the servo. I forget what exactly I did, but if you have a dx3 I can look it up.

Took some more photos with the battery packs in:

ST-RR


Side


Top

[bl-is-future]

2 questions and 1 suggestion

Why are you using manual brakes? the motor brakes on the MMM are fantastic
Is that the RCM kyosho motor mount? I am going to do a st-rr and jsut would like to know

I would put some padding over the nuts that hold your battery tray. That way your battery will not get dented or damaged in any way. Lipos are very dense and prone do denting and damage.

Yep its the RCM Kyosho motor mount.

I'm using manual brakes because I'm planning to race it with the nitro boys and I wanted front/back brake bias. With manual brakes I should hopefully put less stress on the drivetrain gears.

I tried it with motor brakes first before mech brakes and it just didn't "feel" right to me. I've got a nitro ST-RR also, so I was trying to keep the driving feel the same.

I got some foam pieces that go under the batteries to keep them off the nuts :D I tried really hard to make everything countersunk but I wanted the nuts on to make sure that tray didn't come away from the chassis.

Also, it doesn't make sense to me to use motor braking when there is a center differential. I'm sure that a debate has been had on this issue lol. Basically, I don't understand how you could get consistent braking with a center diff. If the center diff was locked, then the braking power would be the same every time, but as the diff can move, I'd assume that you'd get more braking at higher speed than at lower.

[bl-is-future]

Well just like mechanical brakes the harder you push the trigger the more brake it gives. Functionally the motor brake does the same exact thing as the mechanical but it DOES feel different. The motor brakes feel more consistent to me. I admit it took some getting used to. But now i love the motor brakes, easier setup too, less wheight. And no replacing pads to keep your stop on.

Fair enough. I'll probably give them another go when my pads wear out a bit :D

[bl-is-future]

yeah like i said it is some getting used to. Also the brakes on the MM and MMM are good and others i have not tried but from what i hear they are not the best so mechanical is the way to go there. I was like you took forever to switch but i like it now, also it DOES create more heat for the motor so that is a down side, so make sure your temps are cool to begin with.

[gimpygolden]

I'm currently building/gathering parts fom my ST-rr conversion.
I also am going mech brakes on this conversion strictly as a temp issue. I am using a Medusa 36-60-1600 which might be 'smallish' in a truggy until they release their 70 and 80mm motors.

[z1nonly]

Why did you set it up to have the weight mostly in the rear half? How does it feel compared to your nitro st-rr, handling-wise?

Well, the main reason was because I used one of the nitro motor mount plates under the battery tray and I wanted to use the existing holes in the chassis as much as possible.

I made a second set of holes in the tray so that I can move it up if required, but where it is provided the best overall balance for the car.

Handling wise, its feels as good as the nitro. Its a tad heavier so it seems a bit more settled in the air but the landings are harder obviously.
Its hard to compare them too closely however, as I run a DX3R/SR3100 in the nitro, and a DX3.0/SR3000 in the electric.

I haven't had a chance to let both loose on the track just yet as its been closed for the last few weeks. Had the Queensland electric state titles, and this weekend is our annual 2 day nitro event so they've had the track closed to "spice" it up a bit and make changes so its a level playing field for everyone on the weekend.

I'll hopefully get some track time with both this weekend and post up after.

[z1nonly]

I see. When I said handling-wise I meant did it feel different from how the nitro handles since most of the weight is at the rear?

Please give us an update after you race it around at the track. I'd like to know if it handles just as good as the nitro in the speed and cornering department. Would be nice to even have some laptime figures. Please take record of the runtime as well. I'd like to know how long the pack goes in race condition. Thanks.

BTW, your conversion is very clean and simple. I especially like the fact that you barely modded the chassis. I plan on giving my ST-RR some HV therapy sometime next year.

[bl-is-future]

Where so you think the nitro engine goes? that sits in the rear.

Originally Posted by z1nonly

I see. When I said handling-wise I meant did it feel different from how the nitro handles since most of the weight is at the rear?

Please give us an update after you race it around at the track. I'd like to know if it handles just as good as the nitro in the speed and cornering department. Would be nice to even have some laptime figures. Please take record of the runtime as well. I'd like to know how long the pack goes in race condition. Thanks.

BTW, your conversion is very clean and simple. I especially like the fact that you barely modded the chassis. I plan on giving my ST-RR some HV therapy sometime next year.

[z1nonly]

Yes, I know it does, but not that far back. If you look, the ESC and the second battery pack is practically right next to the rear arms. The nitro version was designed with more of the weight towards the front, and that's what gives it its awesome handling traits. The motor and the batteries are the majority of the weight, and judging from the pics, those two and the esc outweigh the 2 servos and that tiny rx sitting up front. The weight bias is mostly towards the rear. For that reason, that's why I asked how does the handling differ from the nitro version.

[gimpygolden]

Not to try and hi-jack here, but heres a few of my ST-rr in progress.
Still waiting on my MMM, should be here this week.