Kraton Vitavon Steering ("System" + Bell Crank + Upper Brace) - Pictures

[djrahbee]

I might need to start shopping for a stronger servo. Either my PM1373 is going bad or it just doesn't have enough torque for the Vitavon steering setup. With Kraton at a standstill, full left/right input drops total voltage on TX readout by about 3v. Example at full charge: 33.6v --> 30.6v. I still have BEC set to 8v. In a dusty corner of my memory, I recall higher power draw being a sign of servo failure?

Assuming servo is still ok, I'm thinking cause is likely extra weight of the Vitavon setup.

Just killed my hobbystar but don’t think it’s the steering system.. I think it was a cheap servo. Going for quality now.

 

[stock20]

That voltage drop is crazy high. Do you have endpoints set properly? What batteries are you using?

Thanks for confirming - I thought so too. Endpoints are set properly with vehicle on the bench, wheels off the ground. When it's on the ground at a standstill, the endpoints don't seem to matter since the servo travel is so limited. When I'm driving around, the steering performance is fine (i.e. less energy required to steer with wheels moving). I discovered all this when my TX LVC alarm started going off early with large steering inputs at slow speeds towards the end of a run.

Also should mention that poor steering travel at standstill is not due to servo-saver slippage.

Batteries are 11Ah, 100C Gens-spammers.

 

[SrC]

The Vitavon ST setup there may be the problem. Seems over-engineered to me, just by the looks of it.
What tires are you running? It is also rare to get complete full L-R ST travel when still and on its fat heavy high bite wheels. Once rolling, full travel is achieved, if your Servo saver is also ok. All this assuming you have a decent servo. If the rig is slammed with alot of extra weight, this exacerbates limited St travel more so. In stock trim 30+ pounds is alot of weight right there.

 

[djrahbee]

The Vitavon ST setup there may be the problem. Seems over-engineered to me, just by the looks of it.
What tires are you running? It is also rare to get complete full L-R ST travel when still and on its fat heavy high bite wheels. Once rolling, full travel is achieved, if your Servo saver is also ok. All this assuming you have a decent servo. If the rig is slammed with alot of extra weight, this exacerbates limited St travel more so. In stock trim 30+ pounds is alot of weight right there.

Says the guy who doesn’t own a 8s rig OR vitavon steering system

 

[SrC]

Says me.....yes
And I don't mind you trolling all my 8s posts...
@djrahbee , do you run that Vitavon Steering upgrade also????
I doubt that.
I was just helping him think outside the box to adress his ST. issue. If everything I said is wrong, if so, tell me. I'm good with that.

 

[djrahbee]

Says me.....yes
And I don't mind you trolling all my 8s posts...
@djrahbee , do you run that Vitavon Steering upgrade also????
I doubt that.
I was just helping him think outside the box to adress his ST. issue.

Yes I do. Thought you read all the 8s threads? I only comment on things I have experience with..you should take a page out of that book and stay in your lane!

 

[SrC]

Apparently I never read that book. Not how I fly.
And actually I am in my lane. Make believe I am that guy who works in your LHS. You would understand me better.
Maybe you should find another lane that I am not in.
I like you. Not hating.
And I don't take this seriously at all.

 

[stock20]

The Vitavon ST setup there may be the problem. Seems over-engineered to me, just by the looks of it.
What tires are you running? It is also rare to get complete full L-R ST travel when still and on its fat heavy high bite wheels. Once rolling, full travel is achieved, if your Servo saver is also ok. All this assuming you have a decent servo. If the rig is slammed with alot of extra weight, this exacerbates limited St travel more so. In stock trim 30+ pounds is alot of weight right there.

Thanks - comment on full travel while stopped makes sense. I'm still running the Masher X tires. The Vitavon setup definitely is heavier than stock - but I'm not sure it's enough added weight to cause what I'm seeing. Could be. I've also been running this setup for about 6mos and only recently have noticed the voltage drop at low speeds.

One thing that's notable with the Vitavon steering is that servo endpoints have to be really low to prevent binding. Like around 50% each way. I wouldn't think that impacts torque, but could be wrong. I might try moving the links to the inner notch on servo horn that Vitavon provided.

 

[SrC]

Thanks - comment on full travel while stopped makes sense. I'm still running the Masher X tires. The Vitavon setup definitely is heavier than stock - but I'm not sure it's enough added weight to cause what I'm seeing. Could be. I've also been running this setup for about 6mos and only recently have noticed the voltage drop at low speeds.

One thing that's notable with the Vitavon steering is that servo endpoints have to be really low to prevent binding. Like around 50% each way. I wouldn't think that impacts torque, but could be wrong. I might try moving the links to the inner notch on servo horn that Vitavon provided.

Yes that is how I see it possibly.
50% is not much travel actually. A servo BEC voltage drop is a sign of exceeding a servo's Stall Amp rating. Or even a ESC BEC issue. Stall Amps also increase when the servo is bound up. All this does not preclude simply a bad or incorrect servo. With that $Vitavon$ setup there, a more expensive and better servo would be in order. But don't rule out a bad BEC at the ESC...

 

[stock20]

Yes that is how I see it possibly.
50% is not much travel actually. A servo BEC voltage drop is a sign of exceeding a servo's Stall Amp rating. Or even a ESC BEC issue. Stall Amps also increase when the servo is bound up. All this does not preclude simply a bad or incorrect servo. With that $Vitavon$ setup there, a more expensive and better servo would be in order. But don't rule out a bad BEC at the ESC...

Good info for troubleshooting. To be clear - the voltage drop is coming from telemetry read of main batteries. XLX2 logs show BEC voltage at constant 8v without a blip. So what I think this means is that voltage is dropping at main leads due to increased current draw to maintain the 8v BEC.

 

[djrahbee]

Apparently I never read that book. Not how I fly.
And actually I am in my lane. Make believe I am that guy who works in your LHS. You would understand me better.
Maybe you should find another lane that I am not in.
I like you. Not hating.
And I don't take this seriously at all.

It’s a shame with all the rc knowledge you have you still find a way to contradict people on the forum which I think hurts your credibility. I’m done.

 

[SrC]

The ESC's discrete Power supply of the BEC should always remain constant regardless of the the Mains power voltage drop. There should always be plenty Overhead for the servo no matter the mains voltage drop. I would use a DVM to check the actual voltage drop at the servo's power leads to confirm better. This will eliminate the ESC versus the Servo as the problem. If there is any probem with either, in the first place.

 

[Bassamatic 2000]

I run a Savox "glitch buster" seems to keep things smooth for me.
Only issue I'm having is weak turning in one direction vs the other.
Not sure if it's adjustment or servo,just don't have the time at the moment.

 

[stock20]

I run a Savox "glitch buster" seems to keep things smooth for me.
Only issue I'm having is weak turning in one direction vs the other.
Not sure if it's adjustment or servo,just don't have the time at the moment.

So that capacitor plugs into RX? And the idea is to help stabilize BEC power? Never seen one of these before.

 

[SrC]

A glitch buster is used to prevent Rx 'Brown outs', if its an issue for you. Otherwise it is just a Placebo. And it doesn't really "smooth out" anything . A Glitch buster is used with servos that are Amp Hogs, over burdening the BEC output which is shared with the Rx. The Rx loses signal briefly, here and there intermittently, as a result. This is a Brown Out.
The servo may just be no good at this point. Sometimes the Potentiometer fails. Remove servo's link to see if it is the servo causing the issue. Check the sweep angles while disconnected. A bad Endpoint Setting could also be your issue.

 

[SrC]

Thanks - comment on full travel while stopped makes sense. I'm still running the Masher X tires. The Vitavon setup definitely is heavier than stock - but I'm not sure it's enough added weight to cause what I'm seeing. Could be. I've also been running this setup for about 6mos and only recently have noticed the voltage drop at low speeds.

One thing that's notable with the Vitavon steering is that servo endpoints have to be really low to prevent binding. Like around 50% each way. I wouldn't think that impacts torque, but could be wrong. I might try moving the links to the inner notch on servo horn that Vitavon provided.

That Vitavon ST setup "appears" to have more moving joints versus stock., hence more friction to overcome by the servo?? Maybe need a way stronger servo?
It surely looks nice.......Maybe just over engineered.. IDK.
Definitely adds more heft/weight to the chassis over the front wheels.

 

[Moirae]

Masher X tires aren't even heavy. Actually some of the lightest 1/5th scale tires you can get.

 

[stock20]

That Vitavon ST setup "appears" to have more moving joints versus stock., hence more friction to overcome by the servo?? Maybe need a way stronger servo?
It surely looks nice.......Maybe just over engineered.. IDK.
Definitely adds more heft/weight to the chassis over the front wheels.

When not linked to servo or steering bell crank the whole thing moves freely with just a finger-tip nudge. There's definitely a "reduction" of sorts given end points needed to prevent binding. I haven't had a chance yet to try moving links closer on servo horn or suggestions you offered. More to come.

 

[stock20]

Update - removed metal servo horn supplied by Vitavon and replaced with plastic round horn originally included with servo. Moved links closer to center on round horn and was able to increase EPA back up to ~85% (from ~50%). Tested last weekend and problem appears to be solved.