sam123

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Im sure you are all familiar with my last project (the 22cc engine bolted to a plate with four wheels). That was my first attempt at building/driving a heavy rc car with no suspension or differential. Now that I have a reasonable understanding of what to expect when building something like this Im going to build another one. This time, I will be setting it up for road use only. It will have smaller wheels, possibly front suspension and more than double the horsepower of the old car. At the moment I have nearly finished building the transmission and have begun planning the chassis layout. Im trying to base the car on the same sort of design that gokarts use. Rather than use rear suspension It will rely more upon the flexing of the rear axle and chassis.
The engine I plan on using is a 40cc german made 'solo 639' chainsaw. I have trimmed the cases down to make the engine as small as possible, and Im fairly certain it will fit. Since this engine had no clutch when I bought it, I had to mount another clutch onto a jackshaft, which was very time consuming. This did remove the problem of dealing with troublesome chainsaw clutches though, which is good.
Below you can see how I made the rear axle bearing blocks, and the jackshaft-clutch setup. More pictures will be posted shortly.

Lars from Norway

Oh yeah!This looks very promising!Where have this aluminium profile been all my life?

Dirty_Vinylpusher

Mmmmm
Very nice looking.

And now for my usual question.....
What are those sprockets from?

Nutech GmbH

LOOKS NICE

sam123

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Thankyou for your comments.
That big 'ol block of aluminium was originally a linear bearing mount. Im lucky the bearings fit into it so well...but it took four hours of cutting, drilling and tapping to get them to that point [:@]
The gears, sprockets, jackshaft axle and aluminium profile are all from an old x-ray machine. That one machine has provided most of the transmission parts for all my projects....and yes, It is perfectly safe - the parts are not radioactive
Today I did some more work on the car. The pictures speak for themselves:

kenazzo2000

good work keep it up hope you get it ready to run

Dirty_Vinylpusher

Looking good!
That thing is gonna be rather fast I imagine.
Love the jackshaft setup with the clutch.
Very clever.




*sigh*
Wish this rain would clear off so I can get some work done.
Work = money = parts = building car.


So does that mean you use the same parts for the different cars, as in you only have one car at a time, or did you get enough bits out of that machine for 3 cars?
hmmm.
My girlfriend works at the hospital.
Maybe they won't notice if she sneaks out one of the X-ray machines.....


....he said, winking with 2 of his 3 eyes.....

kenazzo2000

lol tell her to steal an ambulance instead for the motor lol

sam123

My Feedback: (1)

Haha yeah Im sure they wouldn't notice .
The machine provided me with enough parts for the transmissions of 3 rc cars, my minibike and my motorized razor scooter...lots of useful parts indeed

Just began mounting the jackshaft to the chassis. Now I have to fine tune the gear mesh.



Next I will re assemble the engine and mount a 12t sprocket onto the crankshaft. I will also have to make a new fancover.

da mad maori

NICE!!!
coming along very quickly
well done

Dirty_Vinylpusher

What will the gear ratio be?
Tried to count the teeth earlier but gave up.

sam123

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The final gear ratio will be 3.28125:1
12t on engine > 18t on jackshaft - 16t on jackshaft > 35t on axle.

Today I started working on the front suspension - which is going to take a while to finish. It will be fully independant suspension on the front, with very stiff shck absorbers.

naynay12

Sam i thought your ratio is fore aa little to much speed?Someone on these forums geared it something like that and i though had problems?Anyway...
I have 6 inch tires 26cc engine,and am going to gear it 6.1
Do you think i should gear it for more speed,since i would like a nice amount of torque for bashing etc?

sam123

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Nope. My ratio should be fine. Im only using small wheels so....
Your ratio sounds fine too.

Dirty_Vinylpusher

Holy *bleep*!!!![X(][X(][X(]

That thing's gonna be fast[>:]

Any ballpark figures on the total weight of the project?

sam123

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Haha It should move. The only part that might not be up to the job is the clutch...I guess time will tell. The engine itself will have no problem pulling this ratio.

Hmm Im guessing the weight will be around 5kg.

Lars from Norway

Sorry to say it,but i alredy hear the "baaaaaaap"-sound from the engine.I had about the same gear ratio on my 36 ccm engine,slightly bigger wheels though,the clutch turned totally blue after the first testrun as the engine didnt get the revs high enough to make the clutch grip properly in the bell.If i had get this car to get full revs it would have theoretically hit about 105 mph,so i guess you can change your gear ratio.How small are those wheels by the way?

sam123

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The wheels only have a diametre of 100mm (they are from a traxxas jato). With this gearing, at 9000rpm the car will reach a speed of 51.7km/h, which I think is very achieveable...but if all goes wrong I will just change the ratio.

naynay12

Oh yea I forgot that you are using small wheels,i thought you were going to use 5 or 6 inch tires.

Lars from Norway

Ok,guess it will be ok then.Do you planning to have a body on it?What is the wheelbase and width on the car?

sam123

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At the moment I have no plans to put a body on it. The engine is just too big to hide under any of the bodies you can buy anyways. I might end up making a rollcage for it though.

The width of the car is 330mm and the length will be about 430mm.

sam123

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Here are the front suspension arms and steering knuckles. Took a very long time to make these [:@]. I still have to make the steering blocks out of aluminium. The plastic items you see here are only temporary. Hopefully the geometry of this setup wont be too bad for driving on-road.

kenazzo2000

nice work keep it up homemade stuff are nicer . im building a dragster its going to be about 105 inches with wheely bar on can you suggest and engine for it ? thanks

Lars from Norway

While you are at it and making your own car,why dont you use the wheelbase 535 mm and the width about 400 mm?If you want to later you can put on a body,thats what i did when i built my car

The front suspension arms looks good by the way!

nitrozach54

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Can't wait to see more.[sm=thumbup.gif]