RCCrawler Forums

Uli · 08-23-2010, 03:18 AM

Hello Teamdrivers,
since you have been testing the rig for the longest time I was wondering what servo you suggest. I put the 5955TG @6V in my rig, which is definately not enough. Even minor binds totally lock out the steering, since the servo through is so limited. What servos do you guys use with what voltages and what outside temperatures?
I´d really appreciate some feedback.

Thanks, Uli

rekcor · 08-23-2010, 03:55 AM

I use the 7954SH on 7,2 V. The Servo goes very hot.
That interestet me to...

Dr.Frank · 08-23-2010, 06:37 AM

Hello,

i'm running also A Hitec7954SH at 7.4V and it get's sometimes a bit too hot,
so the overload protection comes in. The steering geometrics needs a strong servo, that's for sure. Maybe the Hitec 7950TG or the Savöx 1270TG is a way to go.

Greetings Frank

aaugman · 08-23-2010, 08:01 AM

I smell a new steering set up..

Cruzin Illusion · 08-23-2010, 09:34 AM

Becky's (Holy Roller) is running a Hitec 7950 set at 7.2 volts. Her servo gets hot while running. She back off her end points and that helped some. I know Sparky J runs a 7980 or a 7990, it is bigger in size but it will fit and it does not seem that his is getting that hot. The 7980 and 7990 at 7.4 volts has 611 oz., but the servo is slower than the 7950.

69CrazyHorse · 08-23-2010, 12:55 PM

Tom,

Why do you think the 7950 is getting hot in Becky's car? Did it get hot in her berg? I dont remember mine ever getting hot in my berg but to be honest I dont really check the heat of my servo.

Cruzin Illusion · 08-23-2010, 01:02 PM

Quote:

Originally Posted by 69CrazyHorse

Tom,

Why do you think the 7950 is getting hot in Becky's car? Did it get hot in her berg? I dont remember mine ever getting hot in my berg but to be honest I dont really check the heat of my servo.

I don't really know how hot the servo gets in the berg because of our steering set up. It is cut into the front axle housing and with it resting against the cut out in the housing the housing acts like a heat sink. It is also so tucked in between the axle housing and the motor that you can't really touch it. I am sure the extra heat from the servo could possibly be because of the way the steering is designed but I could be wrong. The only person I can compare it too is Sparky and he runs the 7980 or 7990 servo which is a larger servo.

jkwrangler08 · 08-23-2010, 03:06 PM

I was running the 5990tg in my berg and it got quite hot.. I've switched to the 7980 at 7.4v and it still gets warm, but nothing like the 5990.. I'm considering dropping the voltage on the 7980 to 7v to see if it helps with keeping it cooler..

--freeride-- · 08-23-2010, 03:47 PM

If you change the geometrie of the steering you will be fine. Shorten the servohorn and make the link from the servohorn to the knuckel longer, in neutral steering postition the servohorn should stand to the right side maybe 20° degrees. You have to try out diffrent link length.

TSK · 08-23-2010, 11:46 PM

Just curious as to if you guys are greasing the slider? By the looks of it, when the knuckles apply force to it (the slider), there'll be torque applied against the axle housing that it slides in causing binding.

Just a thought.

gunnar · 08-23-2010, 11:53 PM

Would most likely collect dirt pretty quickly, better to use something like graphite. I'm thinking of making that part in steel and polishing it.

Cruzin Illusion · 08-23-2010, 11:56 PM

Quote:

Originally Posted by TheSCorpionKing

Just curious as to if you guys are greasing the slider? By the looks of it, when the knuckles apply force to it (the slider), there'll be torque applied against the axle housing that it slides in causing binding.

Just a thought.

There is no binding on any of the XR10's I have seen they turn pretty smooth.

Uli · 08-24-2010, 12:46 AM

@all: thanks for the replies so far.

Quote:

Originally Posted by --freeride--

If you change the geometrie of the steering you will be fine. Shorten the servohorn and make the link from the servohorn to the knuckel longer, in neutral steering postition the servohorn should stand to the right side maybe 20° degrees. You have to try out diffrent link length.

Did that to start out with. Still hot.

Quote:

Originally Posted by Cruzin Illusion

There is no binding on any of the XR10's I have seen they turn pretty smooth.

Same here. The plastic seems slippery enough.

Sounds like the 7950th will be the minimum servo-requirement for the rig to compete with. Darn, another bottleneck.

What about the S9157 users? it´s got less torque than the hitecs. don´t they overheat quite badly?
Uli

TSK · 08-24-2010, 12:50 AM

Quote:

Originally Posted by gunnar

Would most likely collect dirt pretty quickly, better to use something like graphite. I'm thinking of making that part in steel and polishing it.

Perhaps you should try a delrin slider. That is if it'd hold up.

Quote:

Originally Posted by Cruzin Illusion

There is no binding on any of the XR10's I have seen they turn pretty smooth.

I'm sure they feel smooth , but I'm talking when there is actual load on the system when it's crawling. But eh, what do I know. I have no MOA experience. I just find it odd that all of you have hot servos.

--freeride-- · 08-24-2010, 01:42 AM

Quote:

Originally Posted by Uli

@all: thanks for the replies so far.

Did that to start out with. Still hot.
Same here. The plastic seems slippery enough.

Sounds like the 7950th will be the minimum servo-requirement for the rig to compete with. Darn, another bottleneck.

What about the S9157 users? it´s got less torque than the hitecs. don´t they overheat quite badly?
Uli

Hey Uli,
show us some pixs of your steering please. I think you can handle it with changing the geometrie, the original one is really bad.

This mod should help a lot improving the steering:

kenne · 08-24-2010, 03:51 AM

I couldn't see that upper pic but.....
Din't that mod need even more power from the servo ??
If you shorten the servo arm and make knuckle longer will help servo load ?????

--freeride-- · 08-24-2010, 04:17 AM

Quote:

Originally Posted by kenne

I couldn't see that upper pic but.....
Din't that mod need even more power from the servo ??
If you shorten the servo arm and make knuckle longer will help servo load ?????

Shortening the knuckle, dass not make any differenz. It would change the servo load, if you would shorten the knuckel on the side where the link from the servohorn goes to.

With this mod you reduce the Ackerman:

Whith the original setup the outer frontwheel -while turning- only makes a small ankle. That is what causes the problems(the servo makes a very small way). With the mod, the ankle gets much better as you see in the picture. The servo makes mor way what is reducing the load.

Creepy Inc. · 08-25-2010, 10:07 AM

Quote:

Originally Posted by gunnar

Would most likely collect dirt pretty quickly, better to use something like graphite. I'm thinking of making that part in steel and polishing it.

This sounds good. More weight right were you need it as well.

Dr.Frank · 08-25-2010, 12:12 PM

Hello,

made a little change to my steering today:

The new plate allows the servo more to travel, EPA before was 63 L/R now it is at 83 L/R,
the arm of lever has now 6mm more length:

that sounds not dramatically, but the 7954 stays only slightly warm and has a bit more power.

Greetings Frank

TSK · 08-25-2010, 12:36 PM

I think Dr. Frank's idea is killer. Better geometry for the servo = more applied torque + cooler operating temps. I see a vendor opportunity.

08-23-2010, 03:18 AM	#1
Uli Quarry Creeper Join Date: May 2008 Location: Clarkston Posts: 277	XR10 Servo suggestions Hello Teamdrivers, since you have been testing the rig for the longest time I was wondering what servo you suggest. I put the 5955TG @6V in my rig, which is definately not enough. Even minor binds totally lock out the steering, since the servo through is so limited. What servos do you guys use with what voltages and what outside temperatures? I´d really appreciate some feedback. Thanks, Uli

08-23-2010, 08:01 AM	#4
aaugman Rock Crawler Join Date: Jan 2007 Location: in my bubble Posts: 532	I smell a new steering set up.. Last edited by aaugman; 08-23-2010 at 08:05 AM.

08-25-2010, 12:12 PM	#19
Dr.Frank Rock Crawler Join Date: Feb 2008 Location: Dortmund, Germany Posts: 876	Hello, made a little change to my steering today: The new plate allows the servo more to travel, EPA before was 63 L/R now it is at 83 L/R, the arm of lever has now 6mm more length: that sounds not dramatically, but the 7954 stays only slightly warm and has a bit more power. Greetings Frank Last edited by Dr.Frank; 08-25-2010 at 12:15 PM.

08-23-2010, 03:55 AM	#2
rekcor Pebble Pounder Join Date: Apr 2009 Location: germany Posts: 138	I use the 7954SH on 7,2 V. The Servo goes very hot. That interestet me to...

08-23-2010, 06:37 AM	#3
Dr.Frank Rock Crawler Join Date: Feb 2008 Location: Dortmund, Germany Posts: 876	Hello, i'm running also A Hitec7954SH at 7.4V and it get's sometimes a bit too hot, so the overload protection comes in. The steering geometrics needs a strong servo, that's for sure. Maybe the Hitec 7950TG or the Savöx 1270TG is a way to go. Greetings Frank

08-23-2010, 09:34 AM	#5
Cruzin Illusion Keep Crawling in Crawling Join Date: Jan 2009 Location: Commerce City Posts: 797	Becky's (Holy Roller) is running a Hitec 7950 set at 7.2 volts. Her servo gets hot while running. She back off her end points and that helped some. I know Sparky J runs a 7980 or a 7990, it is bigger in size but it will fit and it does not seem that his is getting that hot. The 7980 and 7990 at 7.4 volts has 611 oz., but the servo is slower than the 7950.

08-23-2010, 12:55 PM	#6
69CrazyHorse Quarry Creeper Join Date: Dec 2008 Location: Aurora Colorado Posts: 346	Tom, Why do you think the 7950 is getting hot in Becky's car? Did it get hot in her berg? I dont remember mine ever getting hot in my berg but to be honest I dont really check the heat of my servo.

08-23-2010, 03:06 PM	#8
jkwrangler08 Quarry Creeper Join Date: Jul 2009 Location: Derby Posts: 491	I was running the 5990tg in my berg and it got quite hot.. I've switched to the 7980 at 7.4v and it still gets warm, but nothing like the 5990.. I'm considering dropping the voltage on the 7980 to 7v to see if it helps with keeping it cooler..

08-23-2010, 03:47 PM	#9
--freeride-- Newbie Join Date: Feb 2009 Location: Germany Posts: 25	If you change the geometrie of the steering you will be fine. Shorten the servohorn and make the link from the servohorn to the knuckel longer, in neutral steering postition the servohorn should stand to the right side maybe 20° degrees. You have to try out diffrent link length.

08-23-2010, 11:46 PM	#10
TSK Shelf queen Join Date: Aug 2008 Location: Internet Posts: 5,857	Just curious as to if you guys are greasing the slider? By the looks of it, when the knuckles apply force to it (the slider), there'll be torque applied against the axle housing that it slides in causing binding. Just a thought.

08-23-2010, 11:53 PM	#11
gunnar Ex Nor-CalRCRC slave Join Date: Dec 2008 Location: San Mateo, CA. Posts: 2,242	Would most likely collect dirt pretty quickly, better to use something like graphite. I'm thinking of making that part in steel and polishing it.

08-24-2010, 03:51 AM	#16
kenne Rock Stacker Join Date: Mar 2009 Location: Finland Posts: 65	I couldn't see that upper pic but..... Din't that mod need even more power from the servo ?? If you shorten the servo arm and make knuckle longer will help servo load ?????

08-25-2010, 12:36 PM	#20
TSK Shelf queen Join Date: Aug 2008 Location: Internet Posts: 5,857	I think Dr. Frank's idea is killer. Better geometry for the servo = more applied torque + cooler operating temps. I see a vendor opportunity.

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Thread: XR10 Servo suggestions