Help Please

[Pito]

at last i have to bow & ask questions not too proud or ashamed but cause i dont want too much trial & error is there a formula that works for size plans [i.e] length, width, height, I know enough about steering geometry to make that work well & ideas are coming thick & fast but overall is there any set formula that works for single seat kart for heavy teenage boy [200lbs] that might work straight to the road without being a camel i am stuck to a budget & using a 4 stroke self propelled briggs vertical shaft motor so rear axle width is 17" with extra width being put on by adding extra bigger air filled tyres bolted to the lawn mower solid plastic wheels hope fully to give more speed & make the whole thing a bit more shock resistant plus comfort for the old man builder & designer gotta have 1st test drive don't i pics will come tomorrow when i learn how to send them from my partner the boys mum oh yea its belt driven & also using the gearbox from the mower [assuming]that will hold up that gearbox required to take drive from vertical to horizontal otherwise everything else will be standard from the motor point of view [if there is a standard in this game that is] it looks to me like about 1/3rd of the length could be the width but that might be an old mans bad eyeballs if you know what i mean any help greatly appreciated but i know this is just the beginning how long should i wait for replies is a week long enough?
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[2or3wheels]

you can make it any way it doesnt matter. My carts front it bigget than the length. and the rear is narrower that the front.

 

[Pito]

thank you

thanks mate just concerned because the boys have NO repeat NONE driving experience & are only used to V.R. from computer games again thank you will get some pics posted if you want to keep track of it

 

[RobertD]

Click "user cp" at the top and you can change the signature. I forget what thread it was but you said something about wanting to change it.

 

[ryf]

what are you making it for? off road,paved surface? my offroad is 8 ft by 4 ft... i have 23" tires in the back and 21" in the front, they clear most obstacles handily, though I do have front suspension.

my central frame bars are about 15" in the front and almost 20" at the back, this was to make room for the front suspension.

you need to get hubs for your fronts and rears to make sure you clear them with your 17" axle... I'd guess that'll be about 12" wide frame center section, that is assuming narrow tires.

I myself used a mower trans, worked very well for me. you might look at my first build thread for pics of my drive train, I stepped from the transaxle to a wider rear axle, cost about $60 to do so, but gave me a way to change final gear rations using chain... I used a 500cc 17.5 hp tecumseh, this worked VERy well, but I weigh in at close to 300lbs, so I needed some extra go for the cart.


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most adults will need a cart thats around 6 ft... assuming 3.5 ft for foot to butt, and add room for pedals, and a motor on the back... 3ft wide would be nice to easily fit in a garage space, and in a small pickup bed....

 

[Pito]

Thanks for the reply all that makes sense to me what i want it for is grass & park lands [until the cops arrive at least]. The rear end starts from an old shopping trolley with wheels removed, the bottom U shape is the start of proceedings, from the end there's the back axle the motor & the transmission from the mower obviously needing to be geared up wait & see till they get at least some drive practice that can wait if it will do 10 or 20 mph thats enough to start at the moment its looking ok. 19.5 is the inside rear wheel track the seat will be in front of the motor & everything goes as normal from there i can make it any length I guess make it to my size will leave room for the boys to grow into it .total tyre height is 10" that gives me 4.5" ground clearance [enough you think] they are 3.5 wide from a hand trolley which will be mounted straight to the mower wheels filled with air to give some damping from the bumps maybe bigger on the front but not sure yet, almost everything still open to negotiation time is now my biggest problem as work sometimes has to come 1st pics will come so keep looking if you like

 

[2or3wheels]

sounds good.

 

[Pito]

Heres the pics

sounds good.

Any Comments????

 

[ryf]

I think it looks good, that looks like a walk mower/snow blower transaxle, which might need to have 2 bearings on the long side as the casing isn't designed for a lot of weight or bouncing at speed. that'll keep the load on the frame and not on the gearbox.

I would consider mounting the transaxle sideways (pulley vertical) and using a conventional go cart engine if you haven't bought one yet. that way the motor can be setup with a torque converter on a larger cart later and saves you money long run. but if verts what ya got, run what ya brung

 

[Pito]

thank you sounds like good advice & i like the idea of saving money later cause i can feel this is going to go on for a while. The transmission is from a walk mower & did not realize that i might do that later. [another reason i think this is such a great site]. Getting such good ideas is sooo good saves you so much time in not messing things up at the start thanks again

 

[2or3wheels]

well thanks, and thatnk you for trying this.

 

[Pito]

hi guys i am back with some new ideas getting tired of waiting for others to do things for me even if i have to pay [so hard to buy good help these days lol] A thought that has been plaugeing my every waking moment since i started looking at electric / hybrid karts why can't i build with a small electric motor & a big generator/altenator, anyone see where i am going, battery reserve & small motor driving big generator keeping motor going & battery charged can anyone tell me why this cannot happen PLEASE must be someone else thought of it too, can it be done any replies greatly appreciated

 

[Russ2251]

Sounds like perpetual motion. Generators rob horsepower.

 

[2or3wheels]

i think he meant seperat motor for generator. I donr know. Maybe might work but if the motor draws to much to spin then it might drag to much.

 

[Pito]

i must not have been clear enough i think you have it right, my idea is to have a small motor [petrol powered] driving a generator that would supply all the power for the electric motor plus a little more to keep the battery charged at the same time could/would this work ?

 

[Pito]

sorry i should said something as small as a weed eater / whipper snipper motor

 

[Pito]

sorry i should said something as small as a weed eater / whipper snipper motor

 

[ryf]

in theory... but an alternator requires 4+ hp in some cases depending on what kind of load and output. as a fail safe (in case you go too far) a pull start engine to recharge would make sense.

due to whats called parasitic loss, you loose efficiency every time you convert one form of power to another, due to friction, parts weight and mostly heat.

converting fuel to rotation is one conversion of power. converting rotation to electric is another, and then your converting electric to rotation...

OR..you could just convert fuel to rotation.

assuming 90% efficiency for each conversion which is overly generous, your spending at least 4x as much for 30% less power at the output shaft of your drive unit.. the motor controller alone will probably cost you about what a harbor freight engine costs.

 

[2or3wheels]

gear it right and a weed whacker will work, de[pending on the draw i think all that would do is give you a longer running time. What was the prupse of using electric motor? If its noise then i think you should just o with a 5 hp motor and be done if its to be different then GO FOR IT.