Stealin Josh's thunder....building remote control car.....

[Safari Ary]

Ok guys, it dawned on me that I DO in fact have a motor that I kept for just this occasion. It's nothing special, just an old Craftsman 3.3 CI chainsaw motor that runs very well. I'm wanting to do independent front and rear suspensions with 4wd(double wishbones with mini-bike coilover shocks). Kinda along the lines of a baja truck. Anyway, here are my two biggest dilemnas, a gearbox that will incorporate forward and reverse, but I don't need any more than one gear in each direction. I'm also struggling with spindles for the front and rear. I have two D30 knuckles and a pair of unit bearings that are toast, but would work fine for this app, but I think they're a bit heavy and big for this project. to give you an idea of the scale of the car, the chassis will be about 1.5' wide and 2-3' long. The a-arms will hang off of this chassis, so overall width should be about 2.5' outside tire to outside tire. I haven't really layed anything out on paper yet, these are just rough estimates in my head. Anyway, anyone got any ideas on spindle/knuckles or a gearbox?? Also, I was thinking of using steering shafts as my axle shafts, figured they'd be heavy duty enough without going way out of proportion on weight, and they should be fairly cheap/plentiful in the junkyard. Thanks guys

Ary

Edit: big :angel: to Josh, and the gearbox has to be controlable by a servo which has a total throw of approximately 1"

 

[Josh 89XJ]

How beefy are we talking here? I'm custom building the knuckles for mine, as I couldn't really find a cost effective solution otherwise. After talking with a fellow at a bearing shop, he had a few that would fit the application just fine. From there you just need to machine the appropriate sized hole (Note: You need the 1 piece unit bearings) and press the little bugger in there. Get the correct OD tubing and press it into the new knuckle you just made. Tap the ends and there ya go.

Oops, reread that you wanted it to be 4wd. Thats a tricky one you've got there.

I was looking at the tranny problem for my app as well. The best solution that I could come up with was actually buying a tranny from a small quad. I found a few of them used for just a few bucks (under a hundred) The bonus being that you get a few forward gears to boot. To shift, you just need a servo connected to a rack, that way you can use the existing pedal linkage that they use. Cut the foot pedal off obviously, but retain the splined rod to the shifter.

 

[Safari Ary]

Yeaè/ I ran`gy electric car@gs ` 2wä.and th~we vereÐmy two ¢eggest mistakes, getting electric and going with the 2wd. I think H'm 0setty sôwe H'vepgot thepwear seôwp figured nut. #I'd liÚm to use the same setup front and rear and just lock the rear in place.p%Th`t wà{ if I wantdd t~/go really tric;%and adt*rear steer in the future it could be done, and I would only have to design.scrÞungd onô%type ov/sphndlä I duþgo, a fbnend of°bind isÀuorkin on this with me, and I think we can figure it out. I was hopingàuou guyr)mifht ôall me ´dat theàgnubkler-off of0o S`mur0e would do just the trick or something like that. Oh well, guess all t¨engs inoife aren't thad"eary.
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As for thd trPany froý)a quad, that's not a bad idea. Although I'd think they'd be a little largd, n~3 Thanúw, jeep`|he ide u cominm
Ary

 

[Josh 89XJ]

Think kiddie quad. One of those little tiny ones you see the 6 year olds riding with their parents at the dunes. The tranny on those is about the size of two fists.

 

[burntkat]

Take it from me- you guys would be just a little ahead of this thing if you bought a Traxxas Monster Buggy.

I've got... a little.. .experience in these matters <24 years of RC.... you DON'T want to see my collection. 8)>

 

[Tucker]

Yeah, burntkat, me2 ... more r/c junk in boxes than I care to consider ... Ary: check into r/c sail winch servos for beefy motors with 1" or better travel. I don't have any (sailboats don't fly but the trade rags and internet should have lots of sources.

 

[Safari Ary]

Burntkat, I know all about the one you're talking about, but where's the fun in it?? I've assembled someone else's kit before. I want the fun(frustration, anger, annoyance?) of designing it and fabricating it myself.

Josh, the kiddie quad tranny is not a bad idea, thanks.

Edit: Tucker, that's another great idea. We've got a couple of local hobby shops around that are real big into RC, so I'll have to go pick their brains.

Ary

 

[burntkat]

More power to you, Ary- but I've run that path before. By the time you're done, you've got orders of magnitude more money in the thing than you might have spent if you'd bought someone else's product and then modified it.

Now- if I could get a kiddie quad, that would certainly make for a interesting recon vehicle..

 

[Safari Ary]

Well, the motor is free, the remote control stuff is already in possesion(most of it anyway). My partner in crime has a nitro powered RC boat, so we can rob stuff from that too. The chassis should be relatively cheap, one 20' stick of 3/4" tube and some sheetmetal. The budget is 300$, we'll see how badly we blow it :angel: Peace

Ary

 

[Josh 89XJ]

20' stick of tube? You lucky SOB with your smaller version of a buggy... I just went through 40 feet of tubing today and got only the base frame and part of the roll cage done. I'm thinking another 60 feet should do the trick.

 

[Safari Ary]

Josh, are you talking about a full-size buggy or a remote control car that you used that much tubing on?? I mean, I'm prolly gonna pick up a couple sticks 'cause I'm gonna be making a roof rack soon, but I didn't figure any more than 1 or 2 sticks. Am I looney or are you building a full on rock buggy? Peace

Ary

 

[Josh 89XJ]

Yeah...its a full DIRT/SAND buggy. It doesn't have near enough clearance for a rock buggy, just for runnning fire roads, some mud, sand, etc. The whole thing comes in at just a hair under 8 feet long and 4 feet wide. Clearance under the frame is about a foot, but the chain driven rear axle is what really prevents you from using it in rocks.

I just dropped the motor off at a small engine shop today to see if they could squeeze an extra pony or two out of it. Base is 10hp, but I'd really like to get a little above that. I'll be happy if it can do 75

 

[burntkat]

If it's that big, 10HP isn't going to do much at all for it.

Time to find a motorcycle engine!

 

[StuckXJ]

I race go-karts and we run a modified 5 hp briggs, it makes about 15-20hp. Not bad for a lawnmmower engine. You should look into one of those. THeres a guy in town that builds our engines he can cam it for high rpm low anything pretty much. The little engine pushes me about 125 cant imagine the speed on a liter rc.
http://www.briggsracing.com/racing_engines/index.html
THe wazoom or the animal ohv would be best for a drop in. The wazoom makes more power.
Steve D

 

[Matt S.]

dude.... look at dates before you go and post. he doesnt even come around here anymore. sold his jeep!

Matt