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ParrotGod
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I might be wrong but Maurizio has a thing for cars with double rear axle.

It looks like an interesting exercise.
 

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Discussion Starter · #3 ·
Well its going to be my entry in next year's Rockingham Winter Classic if I can get it to work....

Gearbox has a lot of flex so might need beefing up somewhat. We shall soon see as we are nearing a bit of early running!

Engineering Gas Machine Automotive tire Composite material


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Tire Vehicle Automotive tire Wheel Automotive design
 

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ParrotGod
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I thought that you wanted to build it for just the sake of it not as an entry to a national competition.

Do you think that the double rear axle has an advantage?
 

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Discussion Starter · #5 ·
Advantages would be traction out of corners and incedible braking.
Disadvantages will be added friction, small diameter rears and narrower overall width.

Obviously aerodynamics will have too small an affect to be important at this scale.

The smaller diameter rears can be overcome with gearing and possibly a faster revving motor. Torque won't be an issue given the friction in the system and that friction can anyway be largely overcome with said faster motor.

I ALWAYS enter my prototypes in competition. That's the fun of it!!

Andi
 

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A great project Andi! It will be interesting to see how it runs. You never know, just like in real life in the early 1980's (reference the Williams six wheeler), the authorities might have to ban cars with more than four wheels if it proves too successful.
yikes.gif


Will the gearbox be commercially available in the future?

Keep the updates coming!

Thanks,

Philip
 

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ParrotGod
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I wish I had your level of expertise to design and build my own prototypes for the few races I join.

One of the thing I had in my mind when I saw this is the extra fiction so if you can get a faster/torquer motor then you should be able to compensate for it.

If you want to make the gearbox stiffer assuming this is 3D printed, I would suggest to use very thin CA spread evenly (using a toothpick) on the surface - that is how we stiffen up 3D printed chassis and pods.
 

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I've managed to get the car running. It took quite some time to get all the wheels perfectly aligned. The material I printed the pod in had distortions in the bushings holders so they have had to be enlarged by hand.
It goes well and isn't as noisy as I suspected. It will need serious running in anyway.
It doesn't accelerate as it needs but I need a faster motor to compensate the smaller diameter rear wheels. Feels stable.

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Best wishes
Andi
 

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Discussion Starter · #11 ·
Well, not entirely happy with the gearbox design, it just doesn't look close enough to the original so I decided to design my own. Anyway using some one else's didn't seem right so I've done some research and come up with this:

Automotive tire Font Auto part Automotive wheel system Circle


Early running was interesting. It is apparent that there is quite a lot of frictional losses in all those gears so I'm going for a belt drive. Needless to say the exact pulleys I need aren't available commercially so I've designed and printed my own....

More in that in due course once this gearbox arrives.

I've also got some paint in the body so will show that soon.

Cheers
Andi
 

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It's fantastic. I'm sitting here looking at that drawing, trying to figure out where all the pulleys and belts go, wondering how all the dimensions and tolerances are calculated. Can't wait to see it Andi.

Matt
 

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Looking forward to the next instalment, the history of March as a company is fascinating,i wish today's f1 regs allowed more creativity, I read somewhere the other day the theory that the ferrari pu is getting extra prancing horsepower from circumventing the oilburn regs.
 

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Fascinating build, Andi. Why have you altered the gearbox mechanism from cogs to belt drive?
 

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Will it be long before slot cars have 5-speed gearboxes with each crownwheel actuated by a sequential controller button?

Digital technology can surely provide necessary electronics for switchable up- and down-shifting, so...

... think Chain-gang Frazer-Nash mechanical engineering for now, perhaps. ??
 

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Presumably on the grounds that inanimate creations cannot have, feel or experience need, which is an emotion usually associated with living creatures?
 
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