Perreault985

I'm just following up with some information about the build. I was hoping to attach an Excel sheet, but don't think I can do it here so they have been converted to images.

I've also added the model to Google Sketchup, just create a new model and search the 3D Warehouse for "1/3 Scale Buggy".

Dirty_Vinylpusher

I think this could be the downfall....
Inner wheel will spin out, outer wheel will engage and with both wheels engaged it'll do a 180 if you're putting down too much power....


Very interested to see how it will work though.
Make sure you have the video camera rolling when you test it.

thailazer

Neat project. What kind of welder did you use for the frame? That is a pretty intricate welding challenge with that thin tubing.

Perreault985

I will definitely have the video camera rolling for the first test drive. Once the driveline is finished I'm going to dive in to the throttle and brake controls. I want to be sure I don't rush in building them since they are going to be critical in keeping money and months of time from a disastrous crash.

As for the welder, you won't believe me when I tell you but it is a cheap flux core wire feed welder. The wall thickness of the tubing is 0.065 inches thick and is just thick enough to not burn through at the lower power setting. I've found the trick is to tack the square pieces of tubing at the corners and then connect the points alternating from one side to another. I'd recommend anyone buy one of these and experiment with it. I have found it handy for so many projects around the house and at $80 USD, it was an easy decision to buy.

thailazer

I've seen those for sale and always wondered if they were worth it. Thanks for the response.

Perreault985

I've had a few other things begin taking time away from the buggy project now that spring is here, but I've got the rest of the driveline finished. I still have to add a couple of chain tensioners to wrap up this part of the work. My next step will be to begin building the throttle and brake control once I have some time to work on it again.

Attached are a few pictures showing the driveline from a few different angles. Right now there is a 5:1 drive ratio, but I can change it quite easily once I make a few test runs to see how the engine does pulling all of this weight.

Lars from Norway

Looks like quality work, very nice

Mudgy

Looking good! Do you have chain tensioner / idler sprockets in mind?

Perreault985

Yes, I've got some Delrin plastic rod and plan to machine a piece that looks like a thread spool. I'm still trying to figure out if it should be rigid and adjustable or spring loaded. Any suggestions?

Dirty_Vinylpusher

I used a spring loaded chain tensioner off a mountainbike for one of my builds.

Mudgy

if it's not a small sprocket, I'd suggest a rotating plastic wheel (both) on a hard mounted, adjustable arm. Try to keep metal - on - metal moving parts to a minimum, as radio hassles can arise. that said, more likely on AM stuff.... But it's better to err on the side of caution. This way you can have as much or as little tension. Spring loaded arms sometimes don't do the job, depends on which side of the chain they are mounted on when the chain is under high tension/load. By having the splitter transmission, you have a choice of ratios, where the middle gears can be swapped out. The gears can be machined down to a very light weight, so your throttle response can increase.

What radio gear did you have in mind?

Perreault985

I've got a 5:1 turndown on the first sprocket set and a 1:1 on the second. I was leaning towards a fixed plastic idler with no teeth, but I guess based on the response everyone has had a little different experience.

Lars from Norway

I have tried to use a plastic gear from a gear shifter arm used on a mountain bike and this wore out very fast.

Dirty_Vinylpusher

I had to look it up cause I couldn't actually quite remember how I did it....

So I welded a piece of tube on to the tensioner arm, pressed a couple of bearings inside and had a 10 tooth sprocket running against the chain.
It's on the topside as the axle is in front of the drive sprocket, hence the "slack" part of the chain was on top.

From memory there wasn't much pressure on the chain, just enough to keep it from jumping.









Thankfully my welding skills have improved somewhat since those days.....

Perreault985

OK, it's been a while and a really snowy winter here, but I've finally got the buggy running. I've uploaded videos of the first test drive and everything seems to be working as it should. Big relief...

https://youtu.be/1xgOp4UZ0jE https://youtu.be/tgkYMolY6w4

Timritchieblue

Thanks for the update,, thats cool, like a r/c gocart. Mabee try a 1/5 gyro? Keep from spinning out.

Maj_Overdrive

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Very cool project, thank you for sharing.

I too started off with a cheap Harbor Freight MIG welder and flux core wire. I found myself using any excuse to make stuff with it, so much fun! I too highly recommend starting off with a something like this as there's plenty of projects it can handle. I would recommend getting a model that can use solid core wire and shielding gas as well though. In the Harbor Freight line I think it costs about $50-$75 more than the flux core only model but you get a slightly more powerful unit as well. Also I feel solid core with shielding gas is actually a little easier to weld and definitely results in much cleaner welds, well worth the extra investment in my opinion. Once I was proficient with the flux core I made the switch and got even more excited about welding. So much that I sold my Harbor Freight welding setup, recouped about 2/3 the purchase price (I believe because of its solid core with shielding gas capability) and bought myself a much bigger Miller welder.

Frederik_b

Very nice!! I really like the proportions it's got and the design is awesome. It looks like it drives nicely, with pretty smooth spin outs they looked like manageable spinouts though once you get used to it? Do you feed the bearings diff doing it's thing, does it feel much different from what a regular diff would?

I like that diff idea, especially for the space it takes and still be a functional diff. I recall someone posted in my 5th scale impreza build recommending one way bearings to build a diff, if it works well for you I guess I will have to dig up that information again and reconsider The FG diffs are so bulky, it is hard to design a scale suspension and driveline around them.

Keep us updated on the further testing! And more vids please

cbaker65

Thats an awsome ride you built!..
It looks like you can use some beefier rear tires...

Perreault985

Thanks for commenting, this has been such a fun project and glad to see others are interested. There will definitely be some more fine tuning. I'd looked for "beefier" rear tires, but my $1,000 budget only allowed me to outfit this fine machine with $5 harbor freight pneumatic tires. It is a bit loose but I haven't finished the front stabilizer bar and the mono-shock setup has ZERO lateral stability at this point. If I put a nice thick bar up there it should make the front push a bit more and help make it a bit easier to drive. I was also driving one handed with the camera in the other, so I wasn't on my game.

The differential works pretty well and allows nice sharp turns without the rear wheels binding up. It's hard to say if it works as well as a geared diff. since I've never driven a 75lb. home made buggy with wimpy rear tires before. One of my biggest headaches is going to be that crap pocket bike motor. The throttle response is terrible going from idle to full speed as soon as it gets up on the pipe. I'm willing to take bets on how much longer the head bolts will keep on stretching and be tightened before they snap off.

Frederik_b

Haha yes I was thinking you might not have much to relate to when driving that one. If your wife can make the movie while you drive with two hands it would be awesome, I'd like to see you get on it just a tad more! I think the tires look ok, they fit the scale as far as diameter goes, maybe just a tad wider in the rear. I am wondering if you could reuse something to make a front sway bar and not bust the budget? I'm sure you'll come up with a neat bar idea that won't cost too much. I guess the trickier part to do without spending are the links/joints to attach the bar to the arms.

What motor is it exactly? I bought a brand new pocket bike motor for my Impreza build (long time with no update on it) but I never ran the motor actually, and the project have been on a back burner for a good while (years! lol). I am wondering if mine will be just as bad response wise, or are there any hopes it will be better/different model. The carb seems different though. Don't pay too much attention to the wooden prototype lol

Perreault985

I have a PCC "Stage 2" 49cc big bore motor motor, part number EN06 and the link is below (OK to post it ?). I believe the block is the same as yours but the head, intake, and carb are different.

http://www.pccmotor.com/492hipeenmop.html

I'm working on the stabilizer bar using heavy piano wire and will make most of the linkage ends on my lathe so the cost isn't a problem for me there. I did run it around a parking lot for a few speed tests and I'd guess its in the 25mph range. Next time I'll strap my old GPS on it and see if I can get an actual top speed and post another video.

Frederik_b

Thanks for the motor information, I'll look it up.

A video showing the car's dynamics at higher speeds through turns or bumps (or both! Lol high speed turning through bumps!) would be very cool, it looks very well designed and it is always nice to see custom builds going and see how a given design handles.

Perreault985

It's been a while, but I've finally finished the project. I went with a military theme and ended up replacing the engine with a 4-cycle. I hope to have a video soon, but here are a few pictures.



I've also added two Sketch-Up drawings showing the "as built" design.

Perreault985

I've taken two videos running around the back yard and posted them to YouTube (follow link). It's funny how small the space seems compared to running a 1:10 scale buggy there. I'm going to try a larger lot at some point once the weather warms up a bit.



https://youtu.be/EMKr1K4VxJ0 https://youtu.be/uOpcfWQZy8I