Takin' it to the E-side....
 

After lurking for a few days, this is my first post. Here's my story...

After trying for four months to get my Revo 3.3 tuned and running consistantly, I'm giving up on gas (at least for a while). You see I'm a No0B at this RC stuff, but have taken to the E-side of things with an E-Maxx and a couple of e-minis with a lot more luck than the gas. So, I"m swapping my Revo out to a brushless system. I just ordered one of Mike's motor plates and a few other parts to get me moving, but I'm still wondering about motor and ESC. I would also like to keep my two speed tranny even if it means using a forward only ESC and retaining my mechanical brake set-up. The goal is to be able to keep up with the nitros at the local track. It's a short track and I'm pretty confident I can get there with a little help from you guys. I have a bunch of 7 cell batteries with Dean's I'd like to use to begin with, but eventually switch to lipo once the truck is complete and working correctly.

I'm going to use Mike and RC Monster for as much of the conversion stuff as possible, so I'm hoping to be able to document the plunge here on the RC Monster forums. Thanks in advance and I hope you guys don't get tired of the nooby questions. :032:

Cajun

Heya Cajun! welcome to the forum!

Please read the sticky i wrote in the brushless section.

good choice on the motorplate! on 14 cells you should be able to keep up with the nitro vehicles. (you need good cells though)

an 8XL and a mm controller with a seperate UBEC would get you up and running. You figured out where you're putting the batteries?

Cajun, welcome to the forums and congrats on your decision to take the plunge. I've recently turned to the "E" side with my larger vehicles and don't regret it.

If/when you take the plunge into lipo, perhaps you should consider the trakpower 4900 packs. With that revo, you'll probably run two packs in series, and the trakpowers are some good packs.

Thanks for the warm welcome guys!

I have one set of IB4200s and plan to get enough loose cells to assemble another set of two 7 cell packs. I hadn't figured out where to put the batteries yet, I was hoping to find some carbon fiber channel or angle to make trays. I'd like to have a pack on each side and try to center my other electrics along the chassis, keeping the packs back toward the rear clip. I'm going to strip the chassis and reduce everything as much as possible, i.e. single steering servo, smaller reciever box, etc. The one thing I do want to keep is my 2 speed tranny, so the brake servo will stay someplace.

Anyway, is the Mamba controller programable to forward only? That's what I'd have to run for the 2 speed and mechanical brakes to work, right?

One more totally noob question...what's this UBEC I keep hearing about? :032:

Thanks
Cajun

A UBEC replaces the receiver battery. It transforms the higher voltage of the batteries into 5 or 6V.

If you want to use the mechanical brake, you need the Y cable. (the revo uses a Y cable allready, you can use that one) put both the controller and the brake servo on the same channel. (throttle) you need a servo that works into the right direction. Some work in opposite to others.

and yes, the MM controller is programmable to forward only.

Ok, got the UBEC.

So I'll need to test which side of the "Y" works with the brake servo and which works with the ESC?

I think he means the direction of the servo. Some turn clockwise, some turn counter. Is that right Serum?

WELCOME!

what radio are you running some like JR , Hitec and Nomadio can use the third channel for mixing with steering or throttle

I'll be putting a Spektrum receiver in it. I'll be switched over by the time I'm done with the Revo to a Spektrum in my E-Maxx, so I'm gonna go ahead and get the DX3 so I'll have both receivers I need. My minis will be staying 27am.

welcome cajun, glad to see you made it, these guys are the best around, they wont steer you wrong, and keep us posted on your build

You'll like the motormount! I got mine in today and it exceeded my expectations. And thats saying alot, actually...Personally, if I were you, I would simply put all the batteries on the opposite side as the motor. I'm currently doing a Revo that retains the stock 2 speed, center diff, and f/r brakes, with both servos on the left side, and the RX, ESC, and battery on the other. I'm gonna run 4S, which should be pretty balanced, but the slight imbalance with running both batteries on the right side shouldn't be a problem. BrianG has his like that and says he doesn't notice it at all...

Yep, I like the batteries on one side too. Plus, when I decide to get lipos eventually, I can get one pack instead of dealing with two. However, I went with the single speed tranny so I can have reverse and motor braking. You can see some pics in the BL conversion link in my sing, or see the whole buildup in the Revo section.

I've done the saddle pack route as well, but like the current one much better. And Mike's nitro conversion motor mount is VERY nice.

+1 to the single battery, when i get a diff mtr/esc i will get a 4s pack and use the 2 i have in parallel

Welcome to the forums Cajun!

Good luck with the E-REVO! No doubt you'll be out there beating up on the nitro guys soon!

Thanks for all the encouragement guys! :)

I like the idea of a single sided battery pack. I had toyed with the idea of getting enough stuff to make a 14 or 16 cell pack to a single connection. Anyone tried that yet? So I may consider the single sided battery set up. I know that's the way I'd prefer the lipo when I go that way. I'm really excited about the whole thing. Hopfully I'll be able to get my motor and ESC soon. I'm going to start the strip down tonight. As a part of this, I also have RPM corners I'm adding along with Lunsford Ti hinge pins.

Yeah, I use a 14 cell pack right now. Feels heavy in your hand! I just basically take two 7 cell packs and lay them on top of each other and then heatshrink the whole thing. And with an even number of cells, the + and - wire come out the same end of the pack for the shortest wire run.

When I built my pack, I used a piece of thin hobby foam between the two layers. With all the vibration and impacts, I thought the label on each cell may wear away shorting out (the thin plastic label is the only thing insulating the whole outside can - which is the - terminal). The foam help cushion the cells a bit and also acts to insulate them if the label gets worn. I also put some double thickness noteboook paper between each cell for the same reason.

So running them on one side doesn't throw you sideways off jumps? I like the way the set up looks and it sure would simplify wiring. Not to mention when I do go lipo, I'd want to be running a single cell anyway.

Do you guys have any suggestions for finding carbon fiber angles and tray parts? I know about Graphite Elegance, but they're closed until June. :031: Everyone deserves a vacation, but 8 weeks....must be nice. Waiting for them would put a big delay in the plans or I would have to go aluminum, so suggestions are welcome.

Welcome to the forums Cajun.

Check out these two suppliers..........

http://www.composite-resources.com/o...s/default.html

http://dragonplate.com/ecart/categories.asp?cID=34

Not that I've noticed. Don't forget, I have the motor, ESC, and assorted heatsinks on the other side, so it helps to balance the weight quite a bit.

Thanks for the welcome and info Procharged. CF isn't cheap is it? $300 for an 1/8" x 1 1/2" x 48" angle, WOW! The first place is near me, I may try them in person and see what I can find. I may have to go aluminum simply from a budget stand point.

I'm going to go forward with the sigle sided design on the batts. Thanks for the input Brian!

NP Cajun!

BTW: Aluminum works well too and is MUCH cheaper, lol. I usually get 6061-T6 2mm thick sheets from onlinemetals.com. You could probably get it cheaper elsewhere, but beware the quality. I've gotten some supposedly 6061 Al from elsewhere and it doesn't bend without stress cracking. The onlinemeetals stuff is MUCH better from my experience. Maybe the other stuff wasn't "T6" (wasn't specified), I dunno. Not sure if you plan on making bends or whatever, but it's something to think about.

Ok, so I've been giving the mechanical braking verses ESC braking and I had this thought. I'f I remove the mechanical braking servo and the brake disk, then use a ESC that has a forward and brake setting with no reverse can't I still use the two speed tranny? Where I run into trouble with the one way bearing is with reverse, right?

You could keep the reverse shifting mechanism and shifting servo, but reverse is very weak. I don't think it will last long at all. Other than that, you cannot use motor braking or reverse without locking the tranny in second. The OWB bearing on first gear is what prevents it.

Most here use ESC braking but if you use the mechanical dual disk (1-front, 1-rear) you gain the ability to adjust the brake bias and keep the ESC cooler.

You add the weight of the brakes, linkage, & servos but it's worth considering.

I've already done the forward only conversion on my Revo tranny, so the reverse servo and mechanism and gear is gone already. That's why I thought I might be able to use the ESC braking. If I'm not using reverse at all, I shouldn't be hitting the OWB, unless the ESC brakes actually function like reverse. In which case the OWB wouldn't engage until the truck completely stopped and tried to go backward. Right?

I guess I don't understand what effect the OWB could have on the braking function if it never goes to reverse.

EDIT: After looking over the exploded view of the tranny, the only OWB I'm finding is on the shaft that came out with the FOC. Is there another one on the gear set? The exploded view only shows regular bearings I think other than those two.

I think if you lock it into second gear that you're good to go, if not the consider dropping in an E-Maxx trans locked into second gear (with an upgraded idler gear).

or the RC-Monster slipperential.

I wanted to keep the two speed tranny, that's sort of the root of this whole conversation. I guess I could lock it into second......I just like the fact that it shifts.

OK, here's a breakdown on your options:

Option 1: Keep the two speed tranny, mech brake, and mech reverse. Of course, you'll need servos for the reverse shifter and the brake. The downside to this is that the reverse is generally pretty weak and God help you if you don't come to a full stop before you shift into reverse. And you cannot use a center diff (the diff replaces the shift fork, dog gear, and second output gear).

Option 2: Keep the two speed tranny and mech brake, but no reverse. Like above, you need a servo for the brake. But this option lets you do the FOC for a simpler, lighter, and more reliable tranny. You could also go with a center diff with this setup.

Option 3: Mod the tranny for single speed (2nd gear). You don't have to, but you can remove first gear altogether for a simpler and lighter tranny. Regardless, this is the ONLY option where you can use the brake and/or reverse using the motor. Trust me.

You are right, there is a OWB for reverse, but there is also one for first gear. How the tranny works is like this: The input shaft spins both first and second gears at the same time. But since 2nd is not engaged, it just spins freely on a regular bearing. 1st gear, being in a OWB turns the primary shaft, which turns the output shaft. When the speed gets high enough, the centrifugal clutch engages. When this happens, 2nd gear is now spinning faster than 1st gear, and since 1st gear is on a OWB, it spins freely. This OWB on first gear is what makes it so you cannot use motor reverse and/or brake.

Excellent answer Brian!

:)

Thanks. It can be difficult to visualize until you get into the tranny and see how it works. This would be an excellent candidate for a Flash animation so you can see exactly how it works. Unfortunately, I don't know Flash. Poo.

Me neither. :002:

I agree it would be excellent to animate! Maybe we have a graphics/media student as a forum member who might want to tackle the project????

The idea of a two speed is nice, but you really don't need it with an electric motor. The motor is going to put out more than enough torque to drive second gear from a standstill. I didn't do a traxxas vehicle, but I did do a Monster GT and I had a similar dilemma. I acutally wound up locking the tranny into first gear. By going with a large pinion and the smallest spur, I actually get a respectable top end out of it, but it is crazy wild on the bottom. Doing back flips off of walls and trees is really easy. It suppose it gets to about 30 mph, but it gets there in a couple of seconds. I considered opening up the tranny and going with second gear, but I like it the way it is.

Another thing that concerned me was the OWB. I didn't want to have to worry about it. I drilled right through it and locked the whole up. Now I do have motor breaking and reverse. I don't worry too much about the braking heating the motor up. You'd be surprised at how little braking it is that you need to stop the truck. I think I have mine set at 20 or 30%. Really, if I had it any higher, the truck would flip over.

Thanks for all the info. I'm going to go ahead and lock 2nd gear. You guys have done a lot of the experimenting for me, so I should listen to the words of wisdom. I like the idea of getting rid of the mechanical brake set-up and servo anyway and I'll have reverse again via the ESC for bashing.

If you don't mind, could you post the procedure for locking out 2nd gear and is there anything I need to add or change to ditch the low gear while I'm in there? I really appreciate the advice!

Thanks!

You can remove first gear and the OWB altogether. Then, pull out the clutch assembly and remove the shift point set screw, spring, gray plastic plug, and ball-bearing. File some round "half moon" spots at three locations around the metal hub and then screw three 4mm bolts into 2nd gear. The "half moons" in the hub should fit right up to the bolts for best results.

http://www.rc-monster.com/forum/atta...1&d=1160192341

The clutch arm is out in this pic, but it really has no use now.

If you want to revert back to 2 speed, you'd have to buy a new clutch.

If you don't want to mod the clutch, b0gh0s makes a locking hub which replaces the clutch and does the same thing. His solution is totally reversible. Depends if you want to go the cheaper route.

Thanks Brian!

I got Mike's motor mount and a few other goodies in the mail today. I have to say, the motor mount is a very nice piece of machining. I can't wait to get going. I also picked up my Spektrum system yesterday, (reciever 1 is going into my E-Maxx tonight) so I have enough stuff to get a good start on my conversion. Next month I'll get the motor and ESC.....decisions, decisions, decisions....:027:

Well, I got started with the conversion this weekend. I'm doing a bare chassis rebuild, I got the rear clip and Mike's motor mount done. I had to clearance the roll bar slightly but a little Dremel work took care of that (last pic). I like the mount, I can't wait to get a motor in it. Here are a few pics.

http://i128.photobucket.com/albums/p...irstSteps1.jpg
http://i128.photobucket.com/albums/p...irstSteps4.jpg
http://i128.photobucket.com/albums/p...irstSteps5.jpg
http://i128.photobucket.com/albums/p...irstSteps2.jpg

Funny - Brian mounted the rear brace the same way. The rear brace(latest versions have two rear braces - one for a smooth motor and one for a Feigao "c" motor) has a recess milled into it so it rests on the lower plate. While I am sure the screws will hold the motor just fine, the idea was to have the rear brace only held in position/adjusted by the screws(one screw would be plenty) with the recess over the lower plate. Basically, the rear brace is backwards, though I am sure it will work fine(my fault, as I did not include any instructions). :)

Also, on the test truck here, the mount just clears the roll bar. It may rub, but I was able to mount it without any use of the dremel. :)