Kyosho ROck Force with Brushless System VIDEO!!!

[stampedeproject]

I started a different thread from my build there here becuase I know this will generate comments and questions.

OK so the gear reduction is MASSIVE.

Just to prove the point to my self and do some testing I dropped in a Novak Brushless 4.5R sensored system. Fast to say the least. This is the same system that could drive my Ultra-Rusty to speeds well over 50MPH, yet here is it barely breaking a walking pace at full RPM in the Kyosho Rock Force.

Some might say Oh God, what was Kyosho thinking... but perhaps they are all smarter that us, becuase with the Novak system even cogging and struggling at near dead stop RPM, the gear reduction was so low that there not a jeaky motion on the RC and I could actually crawl with the 4.5R system. There may be hope yet to bring back sensorless brushless back to crawling with this setup. Kyosho does also have a high speed gear set (along with the dig parts) coming out soon. These will probably be standard issue for competitors as some wheel speed is needed.

I don't think a 20T or ever a 10T is up to typical comp type crawling where some wheel spin is needed.

Notice the last segment of the video where I bang on the the throttle and the chassis doesn't even thing about twisting.... cool!!!

Waiting for the video to update... keep banging on it... it'll show up.


http://www.youtube.com/watch?v=6zKF-wtDyT0

[killjoyken]

Ha, that was exactly what I was thinking. Drop in the fastest motor to make up for the gearing. Didn't work out quite like I wanted though. A low turn motor is going to pull some major amps which will require a big battery to handle it. Fine for bashing, but not so great for comps. :-(

The lowest turn brushed motor I had was a 10 turn from way back in the day and that poor motor was screaming like a banshee....and barely going faster than the 35t in my Axial!

Damn it, video still unavailable!

[killjoyken]

Yep, that's pretty much what my 10t was doing on 3s. Spinning crazy rpm but not going anywhere! I tried putting a MM 7700 combo on 2s geared 72/34 in a stock Axial a long time ago, but couldn't get it to move in a straight line. Drove it for 30 seconds, then pulled it out.

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

[RocSpyder]

Originally Posted by killjoyken

Ha, that was exactly what I was thinking. Drop in the fastest motor to make up for the gearing. Didn't work out quite like I wanted though. A low turn motor is going to pull some major amps which will require a big battery to handle it. Fine for bashing, but not so great for comps. :-(

The lowest turn brushed motor I had was a 10 turn from way back in the day and that poor motor was screaming like a banshee....and barely going faster than the 35t in my Axial!

Damn it, video still unavailable!

That was my thought. It will require a large battery, which is not practical on a crawler, and thats still slow.

Seems like high speed gears are going to be a must for these crawlers.

[Harley]

Thanks for the video, I think that is a reasonable amount of wheel speed but an unreasonable motor to have to use to get it.

[JohnRobHolmes]

That wasn't what I had in mind when I said to volt up and gear down

The new Castle motors can spin 100k rpm. Somebody needs to drop a 6900 on 3s and see what happens


The bad part about so much reduction is the speed of the motor required, it makes a very low motor resistance. Tons and tons of power at hand, but the batteries will have to keep up.

[TooSlow]

Is that an A123 battery? The 6.6v might be part of the problem if it is!

Go for 11!!!

[stampedeproject]

Geez - you guys are demanding I will see if I can dig up a 6900 at some point and video it on 3S.

That Novak 4.5R is supposedly 9000Kv. Even on 6.6V with the stock RF pinion the motor is still screaming along slowly. I would bet that with that gear reduction I could run a 1/16th scale brushless system.

[Reflection]

Originally Posted by stampedeproject

with the Novak system even cogging and struggling at near dead stop RPM, the gear reduction was so low that there not a jeaky motion on the RC and I could actually crawl with the 4.5R system.

I never seen you crawl anything but over the big toe on your right foot.

Originally Posted by Harley0706

I think that is a reasonable amount of wheel speed but an unreasonable motor to have to use to get it.

I'd agree.....but on the slower end of reasonable. The thing just flat out needs taller gears.

[goobs]

yeah went to try mine out today with a p2k 27t and fried the motor after 10 sec. literaly because it was spinning so fast.
so im gonna order the hs worm gears and try a 35t or HH 10t cobalt.

im becoming more and more pissed with this kit cuz of all the probs im having, tuning the 3-link, and short wb is really the most of it.
but overall all i wanted were the axles.
if someone had a 4-link conversion for the front then i would have the axles on my sling shot. also why is the chassis so wide my shocks hit the chassis when it flexes.

[stampedeproject]

Originally Posted by raptorman57

I never seen you crawl anything but over the big toe on your right foot.

I think the operative word was "Could" ;)

Originally Posted by JohnRobHolmes

That wasn't what I had in mind when I said to volt up and gear down

The new Castle motors can spin 100k rpm. Somebody needs to drop a 6900 on 3s and see what happens

The bad part about so much reduction is the speed of the motor required, it makes a very low motor resistance. Tons and tons of power at hand, but the batteries will have to keep up.

Just tried a 6900MM on 3S... uhh yeah the RPM is there but I will be damned if I am going to want to drive it that way. Actually much smoother power delivery than I was expecting too.

[Harley]

Originally Posted by raptorman57

I'd agree.....but on the slower end of reasonable. The thing just flat out needs taller gears.

I agree 100%. I would personally prefer more wheel speed and the high speed gears are going to be REQUIRED for this rig.

[stevep]

Originally Posted by goobs

yeah went to try mine out today with a p2k 27t and fried the motor after 10 sec. literaly because it was spinning so fast.
so im gonna order the hs worm gears and try a 35t or HH 10t cobalt.

im becoming more and more pissed with this kit cuz of all the probs im having, tuning the 3-link, and short wb is really the most of it.
but overall all i wanted were the axles.
if someone had a 4-link conversion for the front then i would have the axles on my sling shot. also why is the chassis so wide my shocks hit the chassis when it flexes.

While I agree the stock gearing is on the low end of the scale, I don't think it's even remotely fair to say that it's the reason that the motor fried, especially in ten seconds. Your motor was the problem, not the truck. The four link set from the rear can be used on the front, you just have to find somewhere else to mount the steering servo. I would also add that the three link in the front is part of what gives the Rock Force virtually zero torque twist. Give it a chance and I think you'll find that once you have the right set-up, there's not too many rigs that are going to run better.

[JohnRobHolmes]

Tony- What happnens with the sensorless motor if you step on a tire? Does is cog like crazy, or does it smoothly power out?

[stampedeproject]

Originally Posted by JohnRobHolmes

Tony- What happnens with the sensorless motor if you step on a tire? Does is cog like crazy, or does it smoothly power out?

Something kinda in between. It stalls then bursts or just keeps going... let me see if I can pull together a video tonight. This will definitely need some tinkering with. I am thinking the gear swap is the answer for the comp driver that needs some wheel speed. For the out of the box buyers/drivers the gearing will probably be fine initially.

[goobs]

Originally Posted by stevep

While I agree the stock gearing is on the low end of the scale, I don't think it's even remotely fair to say that it's the reason that the motor fried, especially in ten seconds. Your motor was the problem, not the truck. The four link set from the rear can be used on the front, you just have to find somewhere else to mount the steering servo. I would also add that the three link in the front is part of what gives the Rock Force virtually zero torque twist. Give it a chance and I think you'll find that once you have the right set-up, there's not too many rigs that are going to run better.

i have reason to believe that cuz it worked fine in my scaler.
i cant use the 4-link up front cuz it is recessed(think keyed) for the rear but me and my dad are working on some aluminum 4-link mnts for the frnt and rear.
i wont have to find a different spot to mount the servo cuz look at the dig for the rear! u just trim a specified section out.
and the 3-link has nothing to do with torque twist. honestly im more worried about the shocks hitting the chassis when it flexes and the axle walk more than tt.

[Reflection]

Originally Posted by goobs

and the 3-link has nothing to do with torque twist.

Thats a pretty blind statement. It can very well have ALLOT to do with it.

[zoojunkie]

Originally Posted by goobs

and the 3-link has nothing to do with torque twist. honestly im more worried about the shocks hitting the chassis when it flexes and the axle walk more than tt.

So you flipped your chassis around 180 and now you're complaining about your shocks hitting the chassis and axle walk? I hope mounted your panhard correctly after you flipped your chassis 180.

[mulepic]

Originally Posted by stampedeproject

Geez - you guys are demanding I will see if I can dig up a 6900 at some point and video it on 3S.

That Novak 4.5R is supposedly 9000Kv. Even on 6.6V with the stock RF pinion the motor is still screaming along slowly. I would bet that with that gear reduction I could run a 1/16th scale brushless system.

This is the line of thought I was going with. Using 1/16th brushless you reduce the weight and lower the CG. Anyone else thinking this?

I personally love low wheel speed. I can't get my axial to go slow enough even w/ a 12 tooth pinion and 97 tooth spur w/ a novak goat.

[stampedeproject]

Originally Posted by mulepic

This is the line of thought I was going with. Using 1/16th brushless you reduce the weight and lower the CG. Anyone else thinking this?

I personally love low wheel speed. I can't get my axial to go slow enough even w/ a 12 tooth pinion and 97 tooth spur w/ a novak goat.

On the 1/16th scale though I was really just joking. The RPM and current requirements would probably be too much for a smaller system. I just got a nice little puff of smoke out of my Sidewinder doing some more testing with a 6900Kv motor. Stock/cheap motor or not, gearing that low is really pulling some curent through both motor and ESC.

I once believed super slow was the answer, however I have been assimilated to the idea of high wheel speed bursts - it just works when all other hope is lost.