RcGuy16

Hello, I've started to build a weedeater powered truck using a mcculloch mac 85-sx trimmer engine which has a clutch. So far i got it mounted down pretty good on a peice of old store shelving which is going to be my chassis. I do have a plan which is in one of the pictures but i'm wondering what i should use for tires and what a good gear ratio should be? Also let me know what you think so far..

Thanks, Corey

Dirty_Vinylpusher

Hey there.
I don't know if you're new to all this (like I am) but I started out with a prototype just to see how everything was going ot work, and am now about to start building "the real thing"
First off - is that a steel plate?
I'd recommend aluminium.

Check out my dabblings [link=http://www.rcuniverse.com/forum/m_8418631/tm.htm]here[/link].

I started out with a 4:1 ratio but have since got new (smaller and a lot lighter) sprockets and am going for a 6:1 ratio.
I'm getting some 1/5 scale wheels for it (200mm diameter x 100mm wide)

[link=http://scooters.tziworld.com/forum/viewtopic.php?t=2410]This[/link] is a good example of a simple setup.

derbyguy78

how heavy is the shelving? also did you make the motor adjustable to tension your drive chain or belt that you will use? i would consider a alum. or light steel frame for structural reasons. but hey,to each is own.[>:]

Dirty_Vinylpusher

I should add that the dual chain and axle setup is a good idea, as you can play around with different gearing easier.
And also, using 4 sprockets instead of 2 means that they don't have to be as big.

derbyguy78

i was just wondering .........how thick are the alum. square tubes that you are using? do you think that they will withstand crashes or jumps ? i posted pics of my thin wall steel frame in a new post titled "new member first build" if you are interested

773W

My Feedback: (1)

Dam!! I clicked hoping to see something R\C to do the yard work with...........

Dirty_Vinylpusher

Assuming that was directed at me?
Not very thick and definitely not strong enough as I found out after my first test run, but they were never intended to be used for more than the test build.
Am going for a 3-5mm thick aluminium plate when I rebuild it.

Will check out your pictures.

derbyguy78

d.vinylpusher i like your set up of diff. sprockets i would like to do something like that with mine....maybe if the belt drive doesnt work.....sorry i dont mean to change the subject on this post

RcGuy16

Thanks for the replys! The shelving is light but strong as it already has braces running across the bottom. It probably wouldn't weigh to much more then alum would.

All so thanks for bringing that up derbyguy about making the motor adjustable to add tension as i never thought about that!

derbyguy78

no problem i hope that everything works out for you....just dont give up if you get stumped alot of people on this site will help out[8D]

Dirty_Vinylpusher

Yeah keep at it!
And don't expect the car to end up looking anything like what you first intended.
(Or costing as little to build as you hoped...)

Things change as you go along, and you look at other people's builds and get inspiration and ideas and all of a sudden you find yourself going in a completely different direction.
Take your time and be patient.

This messageboard is by far the best place to come with your questions as well.
Lots of good people here who will have a solution to your problems!

RcGuy16

I sure will keep at it and i'm not expecting it work perfect as it's my first time building one but as long as i can have a little fun with it then i'll be happy[8D]

Dirty_Vinylpusher

Expect a few moments like [link=http://www.rcuvideos.com/video/REV-FAIL]this[/link]

And maybe a first test run like [link=http://www.rcuvideos.com/video/FIRST-RUN-avi]this[/link].
(The lack of variable throttle control and....um....fixed front wheels and plastic rear wheels on wet lawn didn't help)

RcGuy16

haha i will probably end up doing the same with mine before hocking up a radio! A good long dog leash should do it! lol

SAVAGEJIM

Those vids ar way too funny! The laugh tracks are genius!

As for the actual running vid, way to go in getting it running!

SAVAGEJIM

As for the shelving, you said you are already adding cross bracing underneath. For that cross bracing, if you already have not though of it, I suggest you use alum perforated angle bars like those used for grage door openers.

Also, instead of doing an under bracing, I would suggest you install the bracing on top of the shelving. The reason why is the smooth belly will actually act like a boogie board going over bumps, rocks, and obstacles. The RC will simply slide like a penguin on its belly until the wheels can make contact with the ground again. If the there is all that underbracing, the RC will catch on obstacles like crazy and you will have alot of annoying moments where you have to run out and give the RC a kick to free it off the obstacle.

Dirty_Vinylpusher

This is why I'm opting for the plate rather than the frame setup this time round.
It will keep all the sprockets and stuff above it and everything is a bit more protected.

Also my reasoning is that if I bend it I can easily cut out a new one and move all the parts over rather than struggling with a tube frame that's bent out of shape.

SAVAGEJIM

Nice move! Moreover, if you can perfect your main chassis plate design (pattern and all), you could uplad it to computer in like Solidworks, and if you need another, you could take it to your local CNC machinist to cut you out a few more plates!

drewcrew6

Hey Rcguy
Yes Keep the bottom smooth also that front mount will bend real easy on any impact that will need some strengthening. Front hubs are the worst to fab in my opinion. As far as ratio what size tires as that will change things. Keep cracking at it and keep us posted on progress and even any setbacks. These guys are the best on here and will help at anytime.

Drewcrew6

Mudgy

yup...and gives you a way to fine tune your ratios.
good luck, and remember
have fun

RcGuy16

Thanks for more tips! The shelving already has braces on the bottom from when it was made and is not in the way of anything but i do have to add a brace accross the front as it was lost when i went to cut it shorter. I all so have to straighten it out as i was holding it down with my foot when i was cutting it which bent it

I'll keep you updated but i'm busy with school stuff most off the time so it may be a while before i can do anything more with it

I think i will try for a ratio of 6:1 but i'll have to see what i got for spockets. As for the tires go i'm thinking about 1/10 scale but not sure how it would work. I'm really only building this for something to drive around the yard with and not intending to do jumps or anything.

Ater this depending on how it goes i may build a better one using my 54cc chainsaw engine or a lawn-boy engine that i have laying around

Dirty_Vinylpusher

Now we're talking.

Lars from Norway

I have a 45 ccm chainsaw engine in my homebuild,so i guess 54 ccm will be enough tooA moped has almost the same displacement,able to pull a 90 kg bike+driver!

rccrawler1985

I would like to know how to build an rc car weed eater and what all I need to do it I'm new to this rc stuff can't find nothing that tells you what you need

mazpr

LOOOooLLzz, seriously buddy, just stop, grab everything you just made, make a big hole in the patio of your ground, and bury it.

Make a new username here on RCuniverse and dont tell anyone about it.

But before you go and not hear from you anymore, what other innovations have you come up with?



You have wasted at least 7000 people's time, for such clueless oblivious project.