jebster's mini super

[jebster]

I have to thank MRCrackHead and Dlux for implanting the bug to build one of these myself. My wallet is not happy! (And like others I'm not sure which board to post in so this will do for now.)

That being said I am looking to do this on a budget. I will probably never comp with it but I thought it would be a good fun rig to bring along to run 2.2p courses between runs.

Following MRCrackHead's lead I decided to go with madtorque axles. I got the berg gear and RCBros locker combined with the plastic gears.

I cut down the axle tubes to the desired length then needed to figure out how to turn them down for vanquish c-hubs. I don't have a lathe but I do have a drillpress. So, I put a aluminum tube of the perfect diameter through the axle tubes and spun them on the drill press and used different files to get them to the correct diameter. I used a nylon block at in the vice to hold the bottom of the tube straight. It all worked out really nice. I left them a little big because I plan on press fitting the c-hubs on to cut some splines.
The one real problem I have is the gearbox is binding. It appears the 14t small gear is binding against the 40t gear. Not sure why this is an issue. I've tried a few adjustments but it isn't working. My next option is to get a 12t gear, cut the shaft down to the right length and use that instead. From the last picture below it looks like this would still provide plenty of gear engagement.

I have some pics of the progress so far. This may take awhile but I couldn't wait to get started.

 

[Erik D_lux]

Great to see you doing a build! This class has a faster growth rate than any other class right now! LOL.

I hope this does not come accross the wrong way as it is one of my growing pet peeves so, if it does, please forgive me.

When it comes to gear issues, there are gear issues and then there are gear issues. Let me explain...

Seems like most in the hobby want to get their cars and have everything turn super smooth from the start. All the way back to my Losi Comp Crawler days, I have tried to explain to people that you do not want your gears to turn smooth from the start! A bit of resistance maybe even some chunkiness is what you want. A great set of gears will marry to each other and have perfect mesh after running for sometime. If its smooth at the beginning before even running, that means that mesh is pretty sloppy (weak engagement).

So, the above is if mesh is tight. The other problems you can run into is if gears are rubbing things they shouldnt be, like screws or bearings etc,. That obviously needs fixing.

I dont know what your gear issue is, but if its just tight, run it. I have no idea how many cars I have built at this point but almost all of them need to have the gears broken in, again, this is a great thing. Just keep an eye on your motor temps and usually they will break in within 1 pack. If you go through 2packs and they dont spin smooth after that, its still a good thing because now you can usually take the gears out and inspect them for odd wear and see where the problem is.

Looking forward to more.

 

[MRCrackhead]

I'm not sure what to tell you, my gears seem fine; they're kinda noisy but no binding issues.

Maybe it's the case, not the gear.

Do all the gears work fine in the other case?

Metal gears vs. plastic?

Are the cases matched "halves" and you got the left and right of the front and back mixed up?

Just grasping at ideas, sorry.

 

[MRCrackhead]

Brilliant work on the axle tubes, by the way.

Great start.

 

[jebster]

Erik, I understand the point you are making on gear mesh. A little tight with some tension isn't typically a problem as it will break in. I don't think that is what I have going on. This may not be the ideal test but once fully assembled I slid a screwdriver blade into the locker and tried turning it. I was having to put enough pressure on it to turn I seriously thought I would break something. Starting at the locker I did the same thing with each gear individually and it seems to originate with the 14t to 40t gear mesh. That is why I was looking to see if others had this issue. I guess I should run the motor on it to see if it is that bad from the other end of the tranny.

I am running plastic 40 and 42t gears with the metal berg gear.

MRCrackHead, sounds ad if this is something with my parts if you aren't seeing the same problem. I'll check the cases again just in case.

 

[MRCrackhead]

It may be very difficult to turn from the locker.

You're at the wrong end of the mechanical advantage the gears are producing, just keep that in mind.

It may be very easy to turn from the motor end, relatively speaking, of course.

I'm bummed you're having trouble. My steel gears worked fine and swapping plastic in didn't affect anything except weight.

 

[jebster]

It may be very difficult to turn from the locker.

You're at the wrong end of the mechanical advantage the gears are producing, just keep that in mind.

It may be very easy to turn from the motor end, relatively speaking, of course.

I'm bummed you're having trouble. My steel gears worked fine and swapping plastic in didn't affect anything except weight.

You are right that I am at the wrong end which is why I'm going to make another attempt with the motor in.

I'm not too worried either way. Just part if the build process.

 

[Erik D_lux]

You have two sets of gear boxes, right? Do both do the same thing?

 

[jebster]

You have two sets of gear boxes, right? Do both do the same thing?

yes, and both are doing the same thing. i haven't done my test of running with the motor yet but both gearboxes feel the same right now.

 

[jebster]

got some more work done. bought some cheap (GCM I believe) c-hubs and press fit them on the axle tubes. worked out fine. I made a servo mounting plates (still need to drill some holes to lighten it up) and also made up some link/shock mounts that slide right on the axle tubes snug. everything seems to be fitting together pretty well. I am keeping mine axles narrow and will widen it out with hubs on the wheels if necessary.

it is moving along slowly but there is progress.

 

[JohnRobHolmes]

Could you possibly cram more onto those little axles! Wow thats a compact package of stuff!

 

[JohnRobHolmes]

Great to see you doing a build! This class has a faster growth rate than any other class right now! LOL.

Now that my 2.2P rig is running I'm starting an unlimited rig too. Not sure if I will do 12" gate or 16" gate class. Just ordered a grip of special parts :mrgreen:

 

[jebster]

Now that my 2.2P rig is running I'm starting an unlimited rig too. Not sure if I will do 12" gate or 16" gate class. Just ordered a grip of special parts :mrgreen:

looking forward to seeing more rigs in this forum.

Could you possibly cram more onto those little axles! Wow thats a compact package of stuff!

maybe! thinking I could squeeze the bec between the axle tube and servo plate. probably have the battery on the back of the tranny.

this rig is an experiment for me. I definitely want to run it on 2.2p courses so keeping it narrow is the plan.

 

[FLOKI-81]

what kinda pinions are you using??

 

[FLOKI-81]

PS,, I love this consept.. Anything is legal,, I am waiting to see the first MOW crawler in this section...

 

[jebster]

what kinda pinions are you using??

I haven't decided on gearing yet. Want to get electronics and wheels/tires figured out first.

 

[jebster]

Looking for some advice from people with supers out there. What do people do for clocking the chubs on the rear axle? After some searching (with limited results) it seems like most people don't clock the chubs on the rear axle. In most cases they did that because they had no idea of what else to set them to.

Thoughts?

 

[JohnRobHolmes]

depends on how you want it to react. Flat is good all around. Pins tilted to the front gives better steering during climbing, pins tilted to the rear gives better steering during decent.

 

[jebster]

depends on how you want it to react. Flat is good all around. Pins tilted to the front gives better steering during climbing, pins tilted to the rear gives better steering during decent.

Thanks for the info. Given this is my first 4ws comp style rig I think flat sounds like the right option for me.

 

[jebster]

some additional progress. made some upper link mounts. also started mocking up links. using my normal nylon cutter board material I made up a quick skid and side plates to determine a few things. the links are things I had laying around but they might be good enough to keep. as shown it is about a 13.5" wheelbase. I've been toying with the idea of a narrow track width and long wheelbase. until it is all running i'm not sure what is going to work best.

still collecting more parts but I am still working it.