Rear disconect with revo shafts
 

I finally got around to working on my 2.2 tuber again, and since my last thread is pretty old I'll start a new on. I finished my rear disconect today, I still have to put in the servo for the rear brake but I'll get to that later. I am running a 4 channel on this tlt so I will have the option to freewheel the rear or lock it down with a break. I think this will help on steep climbs that otherwise would result in flipping over backwards.
I made the slider out of black delrin, I cut of the male end of a revo shaft and inserted it into the delrin housing. I secured in with two rings that I also machined out of delrin. They are superglued to the revo shaft so that it will spin inside the housing. I keep the housing from spining with the driveshaft by placing the link inside a grove so that it limits the side movement without limiting the up and down movenent of the suspension. With this setup you do not have to limit the rear suspension travel. Also that is a Hitec HS-645MG servo.
This could also work on a txt because obviously it uses revo shafts. Let me know what everybody thinks.

cad rendering

very nice clean work, are you going to add a brake feature too? if so, where?

I am going to mount a servo on the rear axle where it would be if there was rear steer. It will have a push rod connected to it that will run through a rod end and will hit the inside of the rim when ingaged. I just have to make a new mount so I can do that with a four link mount also, the mount I have now was just to get me running for bucks pocket.

check out mini wheelers brake this is how i did mine no need for another servoe or mechanism.you simple adapt a fixed female piece to youre alreedy done piece,so when you slide it all the way against youre rear yoke it locks it walla a break,hope this makes sense to ya, if not check out mini wheelers thread on this slick and very easy to build.i believe he is the original designer of this hole dig thang and his is the best to design off of.you the man miniwheeler thanx.

I don't think you understand, I want to be able to drive with front wheel drive only or have it locked up. I already had all the servos lying around, I already have the 4 channel because my supper class clod has independant speed controls. With the setup your talking about you just have a locked up axle when you disconect the driveshaft, with mine you have the option of brake or free.
Plus my setup is no wear near as "busy" as some of those setups. less parts and links = less stuff to break or bind. This setup is bombproof, it engages and disengages 100% of the time, even if I stand on it with the motor screaming it will disengage and reengage with no problems.

totally understand this setup im talking about will give you rear brake or rear nuetral.check it out its the shat you can do it all off one servoe. and yes i agree you need that option of nuetral

nice work, how did you keep the two female shafts lined up when it is engaged? do you have a rod going thru the two?

There is a dowel pin between the two, one side I reamed out to a press fit and the other is reemed .003 over to provide for suspension movement.

Looks awesome! I thought I read somewhere that the revo driveshafts are indexed, is this true? If so, do you have any trouble with them re-engaging after a dig?

all of the traxxas shafts are all indexed 180*

No, I have the end that the coupler stays on lined up the right way, it is a little snug but it will slide on the other shaft no mater which way it lines up. The will still slide over each other just not as easy. The 645 servo takes care of the rest, even though I tried it with a crappy futaba that only has 48 oz.in. of torque and it worked fine to.

nice brain work. keeps on thinking huh. lol. nice build.

Ive been crawling with front dig for a about 7 months or so and dont recall too mant times when i didnt want the rear locked when doing a front dig.
Youre setup looks good and should work well but too many things to do at the controller makes it hard for a lameo driver like me to do without screwing up

Well I'm in a habit of using my front to pull up on things with my super, so I think this will fit my driving style, as for the controller I'm very comfortable with it, I've never used a pistol grip in crawling before. Anyway heres a quick video. http://media.putfile.com/dig-13 The controles are pretty simple, the throttle and front steering are on the left stick, just like my super, and to disengage the rear you pul down on the right and to brake you go left stick, so if I want to dig its just down and left.
Oh yeah my rear left axle is broken, thats why only one tire is spinning.

looks like it will work great once you get the left axle fixed. great job, i was in the process of working on getting my revo shafts mocked up for a dig. my problem now is finding somewhere to put the servo. looks great and hope to see it in action at green river.

prety cool, I like how smooth it engages and disconects.

Alright, I got the rear brake on this afternoon. I couldn't get in were I work cause we aren't working any overtime so the shop was closed today, so I sorta rigged up my top links. THe geometry works good but the plastic is to floppy to be dependable but for now it will be fine. Whatcha think????

Looks like it would work. Do you have those Servos wired together so they go at the same time?

No there on two different channels. here is how my tx is layed out for this buggy.