RCCrawler Forums

Duuuuuuuude · 11-13-2008, 02:40 PM

In an act of pure brilliance, I ordered a 1/4 scale servo without checking its dimensions. Now that I have it in hand I realize I'm not going to be able to mount it onto my axle without it becoming a bumper of sorts.

Somewhere in my random readings here I saw a pic of someone that was working on or had completed a chassis mounted steering servo. I remembered enough of what I saw to start doing the same, but I need more info. I searched for "chassis mounted servo" and didn't find what I was looking for.

Any more info on this would be greatly appreciated. Thanks!

btw: I'll be posting pics of mine when its done and tested.

Mriswith · 11-13-2008, 02:47 PM

Look through the Scale sections, 1.9 or 2.2, take your pick. Most of those run chassis mounted servos

Duuuuuuuude · 11-13-2008, 05:53 PM

I'll check it out, thanks.

Timmahh · 11-13-2008, 06:13 PM

i just looked at this option (chassis mounted steering servo, not a 1/4 scale servo< ya BIG SERVO, lol ) and could find dozens of ways to mount the servo, but no real good way to acount for the changing height differance between the axle and the chassis. as the suspension compresses and reboulds, it will force the steering linkages to want to move on direction or the other, as well as fight to keep the servo input in check...
even with clearanced swival balls in place, i dont think there was a good way i could think of to allow for this to work without the use of some type of adjustable linkage to allow for the distance change. and now its getting Very tricky. lol

Reflection · 11-13-2008, 06:29 PM

I've used a bell crank quite a bit operating dig systems. The servo was actually mounted on the axle and the linkage going to the drive line. I've also used a bell crank on the axle to operate a "brake". The servo in this set up was mounted in the chassis. The bell crank drove rods into the wheel to act as a brake. There's a few pictures here....http://www.rccrawler.com/0607rig.html

If a guy has to much articulation,there might be ill effects to the steering. I honestly don't feel there'd be much issue though if the suspension was set up right.

Duuuuuuuude · 11-13-2008, 06:31 PM

Quote:

Originally Posted by Timmahh

...could find dozens of ways to mount the servo, but no real good way to acount for the changing height differance between the axle and the chassis. as the suspension compresses and reboulds, it will force the steering linkages to want to move on direction or the other, as well as fight to keep the servo input in check...

Actually, I've found that there is a way. I've gotten mine nearly complete, and even tested it. Luck was definately on my side with this one. Other than beefing up a mount and strenthening my stock Traxxas knuckles, its working very well.

This of course depends on how the 4 link is set up, but if you can keep the steering rod in the same plane as the upper link, and as close to it as possible, you will get very little movement. Moving my setup through its full articulation, the steering doesn't change enough to make it an issue. Maybe a degree, maybe two.

I'll try and get pics up tonight, and unless its raining tommorow, do a more intensive test run.

Duuuuuuuude · 11-14-2008, 08:26 AM

Here we go! First is the servo mount.

Here's the crank on the axle. After a short amount of run time its getting kind of floppy, so something better will have to be made. Or a few more rivets if I get lazy.

Here's another shot of the crank. The pic is a bit fuzzy, but there are bearings on either side of the mount. I fabbed up a shaft for everything to pivot on, and it works pretty smooth.

I've found a couple places in the steering that are going to have to be beefed up now that there is a strong servo twisting stuff around. Quite a difference going from a Traxxas 2055 to this 183 oz monster. It does steer much better though so I'm happy about that.

jombo · 11-14-2008, 08:44 AM

looks good , i would of suggested to look at the wheelie king because it has the same setup, a chassis mount servo and the rocker on the center axle . yours looks alot better and solid

Timmahh · 11-14-2008, 09:16 AM

now thats using the noodle. i was wondering on a bell crank type setup, but that works eve better. and being setup like it is, surely will eliminate almost all the flex steer i ws seeing when i tried my setup. but i was looking to run direct from the servo to the hub.

nice implimentation.

Duuuuuuuude · 11-14-2008, 11:59 AM

Thanks guys. I got it out for a few minutes this morning for a more intesive test run and it did pretty well. It was nice to be able to work my way up a gnarly climb by cranking the wheels back and forth. It still needs some beefing up though. I added a couple rivets to it before I headed out, and it helped, but something much more firm is in order.

Chadworkz · 11-19-2008, 04:14 PM

Now that's a cool steering setup...I like it! Great job, man!

Stormin2u · 11-19-2008, 04:20 PM

Now that was taking lifes lemons and making lemonade. Got enough steering power?

Duuuuuuuude · 11-19-2008, 05:50 PM

Quote:

Originally Posted by Stormin2u

Now that was taking lifes lemons and making lemonade. Got enough steering power?

Phffftt, thats like asking if you have enough motor torque.

I still wouldn't mind a skosh more, as there are still some instances where it has a hard time turning those big, wide Zombies. However, considering its size, its probably more of a tire setup issue than it is a turning power issue...

norcrawler · 11-20-2008, 04:20 PM

dam..nice
i need to upgrade to some 1/4 scales. are they 805bb's?

Duuuuuuuude · 11-20-2008, 05:42 PM

Quote:

Originally Posted by norcrawler

dam..nice
i need to upgrade to some 1/4 scales. are they 805bb's?

Its a 755HB with karbonite gears and bb's. Got it off the 'bay for around $25.

dirtworkshw · 11-25-2008, 11:33 AM

Nice mechanism...maybe put a bearing inside the second servo horn....

Duuuuuuuude · 11-25-2008, 12:25 PM

Quote:

Originally Posted by dirtworkshw

Nice mechanism...maybe put a bearing inside the second servo horn....

I know its kind of hard to see with the pic I have, but there are two bearings, one between the horn and bracket, and one below. I drilled the holes with a stepper bit so that the bearing centers would not touch the bracket, but the outers would and just settle into the hole so that they wouldn't shift.

Deezul · 11-25-2008, 12:54 PM

wait....so its only around 180oz? thats umm not good for the size

slobert · 11-25-2008, 12:59 PM

It would be cool if you could post some video of your set up in action to wow us all. ( and let is copy your work...) Looks like a good set up.

Duuuuuuuude · 11-25-2008, 01:06 PM

Quote:

Originally Posted by Deezul

wait....so its only around 180oz? thats umm not good for the size

Maybe, maybe not, but it was cheap and 4x's stronger than the one it replaced.

As for a video, I've thought about it, but my connection is so freaking slow that I'd have to limit it to only a couple seconds long. Otherwise it'd take half a day to upload.

If you want to copy it, go ahead. Just remember that each time you do you'll need to send $25 to my paypal account.

j/k ~ do what you want. Its not like I've never taken any ideas off of someone elses rig...lol. Well, unless you want to mass produce them. Then you'll have to buy the rights, and it'll cost you more than $25.

11-13-2008, 02:40 PM	#1
Duuuuuuuude Suck it up! Join Date: Mar 2008 Location: Arkansas Posts: 11,652	Chassis mounted steering servo? In an act of pure brilliance, I ordered a 1/4 scale servo without checking its dimensions. Now that I have it in hand I realize I'm not going to be able to mount it onto my axle without it becoming a bumper of sorts. Somewhere in my random readings here I saw a pic of someone that was working on or had completed a chassis mounted steering servo. I remembered enough of what I saw to start doing the same, but I need more info. I searched for "chassis mounted servo" and didn't find what I was looking for. Any more info on this would be greatly appreciated. Thanks! btw: I'll be posting pics of mine when its done and tested.

11-13-2008, 02:47 PM	#2
Mriswith Rock Crawler Join Date: Dec 2005 Location: Mesa Posts: 602	Look through the Scale sections, 1.9 or 2.2, take your pick. Most of those run chassis mounted servos

11-13-2008, 05:53 PM	#3
Duuuuuuuude Suck it up! Join Date: Mar 2008 Location: Arkansas Posts: 11,652	I'll check it out, thanks.

11-13-2008, 06:13 PM	#4
Timmahh RCC Addict Join Date: Jun 2008 Location: Mudville Posts: 1,592	i just looked at this option (chassis mounted steering servo, not a 1/4 scale servo< ya BIG SERVO, lol ) and could find dozens of ways to mount the servo, but no real good way to acount for the changing height differance between the axle and the chassis. as the suspension compresses and reboulds, it will force the steering linkages to want to move on direction or the other, as well as fight to keep the servo input in check... even with clearanced swival balls in place, i dont think there was a good way i could think of to allow for this to work without the use of some type of adjustable linkage to allow for the distance change. and now its getting Very tricky. lol

11-13-2008, 06:29 PM	#5
Reflection TEAM MODERATOR Join Date: May 2004 Location: Tennessee Posts: 10,855	I've used a bell crank quite a bit operating dig systems. The servo was actually mounted on the axle and the linkage going to the drive line. I've also used a bell crank on the axle to operate a "brake". The servo in this set up was mounted in the chassis. The bell crank drove rods into the wheel to act as a brake. There's a few pictures here....http://www.rccrawler.com/0607rig.html If a guy has to much articulation,there might be ill effects to the steering. I honestly don't feel there'd be much issue though if the suspension was set up right.

11-14-2008, 08:26 AM	#7
Duuuuuuuude Suck it up! Join Date: Mar 2008 Location: Arkansas Posts: 11,652	Here we go! First is the servo mount. Here's the crank on the axle. After a short amount of run time its getting kind of floppy, so something better will have to be made. Or a few more rivets if I get lazy. Here's another shot of the crank. The pic is a bit fuzzy, but there are bearings on either side of the mount. I fabbed up a shaft for everything to pivot on, and it works pretty smooth. I've found a couple places in the steering that are going to have to be beefed up now that there is a strong servo twisting stuff around. Quite a difference going from a Traxxas 2055 to this 183 oz monster. It does steer much better though so I'm happy about that.

11-14-2008, 08:44 AM	#8
jombo Pebble Pounder Join Date: Jul 2008 Location: Trumbull, CT Posts: 111	looks good , i would of suggested to look at the wheelie king because it has the same setup, a chassis mount servo and the rocker on the center axle . yours looks alot better and solid

11-14-2008, 09:16 AM	#9
Timmahh RCC Addict Join Date: Jun 2008 Location: Mudville Posts: 1,592	now thats using the noodle. i was wondering on a bell crank type setup, but that works eve better. and being setup like it is, surely will eliminate almost all the flex steer i ws seeing when i tried my setup. but i was looking to run direct from the servo to the hub. nice implimentation.

11-14-2008, 11:59 AM	#10
Duuuuuuuude Suck it up! Join Date: Mar 2008 Location: Arkansas Posts: 11,652	Thanks guys. I got it out for a few minutes this morning for a more intesive test run and it did pretty well. It was nice to be able to work my way up a gnarly climb by cranking the wheels back and forth. It still needs some beefing up though. I added a couple rivets to it before I headed out, and it helped, but something much more firm is in order.

11-19-2008, 04:14 PM	#11
Chadworkz Quarry Creeper Join Date: Aug 2008 Location: Gadsden, Alabama Posts: 198	Now that's a cool steering setup...I like it! Great job, man!

11-19-2008, 04:20 PM	#12
Stormin2u I wanna be Dave Join Date: May 2007 Location: Taylors Falls just hanging with the MNRCRC crew. Posts: 7,843	Now that was taking lifes lemons and making lemonade. Got enough steering power?

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11-20-2008, 04:20 PM	#14
norcrawler Pebble Pounder Join Date: Jul 2008 Location: ov, sacramento Posts: 198	dam..nice i need to upgrade to some 1/4 scales. are they 805bb's?

11-25-2008, 11:33 AM	#16
dirtworkshw Pebble Pounder Join Date: Aug 2008 Location: Indonesia - Rock Heaven Posts: 161	Nice mechanism...maybe put a bearing inside the second servo horn....

11-25-2008, 12:54 PM	#18
Deezul RCC Addict Join Date: Feb 2006 Location: ccxc Posts: 1,176	wait....so its only around 180oz? thats umm not good for the size

11-25-2008, 12:59 PM	#19
slobert Pebble Pounder Join Date: Jun 2008 Location: Federal Way, WA Posts: 139	It would be cool if you could post some video of your set up in action to wow us all. ( and let is copy your work...) Looks like a good set up.

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Thread: Chassis mounted steering servo?