Desertkart with Rotax 583?

[masterfabr]

I'd stay with the .095(or more) whether dom or 4130. My rear engine dragster(runs 7 flat) has .058 4130X 1.625 and 1.25 and 1.0 and .625. No way would I consider it for an offroad vehicle tho. My first build was an 8.20 et door car I built from scratch 25 years ago from 4130. I stayed with the min. wall thickness(.125) for mild steel as per NHRA tho.Long story made short is I was able to walk away AND salvage the chassis with no bent parts after a 130 mph crash that endo'ed and barrel rolled for over 800 ft..In other words- Use what is appropriate for your protection-not what is trick or lite. By the way I have 100's of passes on the digger with NO cracks ever. Just use proper welding methods if you use 4130.GOOD LUCK!

[Mike]

If I go with 4130 I will just tack it and take it to Maule and let those guys tig is up good. Im not sure what I will use. Maule may not have 1.25" 095 tubing as its not something they would use.

Mike

[tenaja]

Just an FYI...

1.5" OD x .095" tubing is (slightly) lighter and a LOT stronger (~50% stronger) than 1.25" x .120 wall tubing. Many mini buggies are built with 1.25" x .095", though, so there probably isn't much of a strength issue either way, unless you've got a poor design.

Going to thinner wall tubing will require better welding. If you aren't an expert welder, you might be better off going with the thicker wall.

I know Yoshi would love to put his 2c in here, because he's had so much fun with it on GD lately, but he said he can't log in to the new server...

[Bugpac]

lol, he should be able to, he hasn't been here for a week before the change, anyway i built my car .120 mild all the way, and if your thinking about going to 1.50 do it, protodies cars are 1.50 and it looks a lot better just in appearance, with the size of the car its more proportional, some will say its overkill, but wth from what i found you can buy 1.50 cheaper than 1.25 anyway, seems smaller diameters get higher in price, but 1.75 is expensive to many people use supply and demand.... 8)

[Rorty]

I would look at what's the safe minimum requirement and then go upwards from there and even to 1.5: tube if you like the chunky look.

For a (mini buggy) short course car with a full protective cage, all you'll need is 1.25" x .083 wall mild steel DOM tube. For a (mini buggy) desert basher, you'd be advised to use 1.25" x .095" as the minimum with possibly .120 for either the rear hoop, or slabs, depending on construction type.

I've been involved in racing buggies for years and as TORC's Chief Scrutineer, I've seen dozens of stacks, rolls, barrel rolls, endoes etc. etc. and 1.25" x .083" tube takes the knocks without spearing tubes into drivers like 4130 can. Before I became Scrutineer, the stipulation was for .065 minimum wall thickness, which proved too hard for some builders to weld properly and the thinner stuff would occasionally crack around welds and motor mounts etc.

4130 is simply not necessary in a car of this size except for some suspension arms. Mild steel is so much easier for the home buggy builder to weld and construct with too without running into problems. *The only people who should build a CroMo buggy are those who work with it in an associated industry, design for it properly and know how to weld and post treat it properly.

The only other people who would build a mini buggy out of 4130 are those who just want the bragging rights because they think CroMo sounds cool, or because they really don't understand metallurgy and basic engineering principles.

[Mike]

Well put. My dad has built a number of airplanes and it was his idea to use 4130 as well as we are friends with David Maule who owns Maule aircraft which builds Maule airplanes. LOL He can get up 4130 for as cheap as Mild steel as long as we use something they use at the factory. After taking with my dad more about this he is unsure if they even have any 1.25" tubing as almost all the fuselages and parts are made from 1" and smaller tube. I think using 4130 is out the door for me. You guys build buggies and know what your talking about so Im going to follow what you tell me.

How much faster will a R6 powered Panther be than a snowmobile powered panther? I have not even got the snowmobile setup in *yet and im already thinking about selling it. LOL

Thanks
Mike

[MuddMachine]

Mike, no way in hell would a 583 take you to 120 mph in a sled unless it's extremely modified. And I mean extremely.

[masterfabr]

The bottom line is proper design.I have never had an issue with "brittle" 4130 or "soft" mild steel. Each needs attention to design.I will admit that most people think that because they use moly they can build everything thinner and lighter. Not so. moly will stress and crack in stressed areas if you use an inappropriate thickness.Suspension mounts,engine mounts,etc. need to be thicker to resist flex and ensuing fatigue cracking when using moly. Mild steel is very appropriate for beginner fabricators that are not familiar with moly fabbing or welding.There is no reason for a piece of moly breaking and "spearing" someone other than poor practices when designing or welding.The small weight reduction is probably not worth the expense to the average builder. .02

[ProtoDie]

Mike,,,,welcome

We used .083 x 1 1/2 mild steel tubing on several bugies. They were flipped , *rolled, and went end over end in some of our first testing stages. The rollcage proved very solid and safe. *I would use .095 in future cars we build, because some racing classes require it.

Just my .02, but the 1st buggies we built with snowmobile motors, and then redesigned and switched to GSXR 600s on our current buggies.

Clutching , and guessing how much of the horsepower was transmitted to the wheels was tough. You can have all the horsepower in the world, but if you only get 50% transmitted to the wheels, do to improper clutch setup,,,,,,,you only have 1/2 of all the horsepower in the world [smilie=banghead.gif] .
Properley setup clutching, the CVT would kick ass,,,,,my .02 is just our experiences and problems we ran into.

Another thing on sled engines. It may be hard to run the exhaust out the frame and still get a nice clean look, especially if you run twin or triple pipes. You have to either mount the motor up real high, or run you exhaust up like tractor stacks. At least with double a-arm suspension setup, most stock exhaust will interphere with the travel area of the a arms. *Maybe with trailing arms it could work.
The 2 stroke exhaust can not be cut and modifed like a 4 stroke without affecting performance.

Jetting on sled motors also needs to be changed according to outdoor temps. Here in Michigan, we changed them often.

[Mike]

The sled this engine came from had a speedo that registered 160mph so it must go some what fast. Im going to be building two buggies at the same time so I will give the rotax 583 powered buggy with reverse to my wife and Im going to go check on a R6 motor for my buggy. LOL

Oh, I got my Panther manual in today. For the most part the whole chassie is made from 1" tubing. Do most people go with 1.25" or 1.5" on this buggy?



Mike