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In lugnet.general, Thomas (T. J.) Avery writes:
> In lugnet.general, Allan Portillo writes:
> > The steering was not impresive. It had a tunring circle of 1.62 meters. The
> > worm gears in the axles meant that I could use fewer gears in gearing it
> > down. This decreased the amount of play in the complete transmission and so
> > starts climbing as soon as it hits an obsticle. In first and second gear it
> > would climb slopes as steep as 68 degrees, at which point it's front wheels
> > lifted and it would roll end over end down the slope. Those wheels are just
> > so grippy. In third gear it would climb a 63 degree slope at its maximum. On
> > a 64 degree slope, it would make it 1 time out of 3.
> >
> > Now lets see. 63 degrees is 0.7 of a full right angle and it weighs 4.5
> > kilograms. 4.5 multiplied by 0.7 is 3.213 kilograms of tractive effort. This
> > is the power it has to go forward ( I think ). At this point the motors just
> > stop with a twitch or two every now and then.
>
> I might be wrong, but if your incline is at 63 degrees, then the component
> of force (force being the weight of your model) along the inclined surface
> is = 4.5*sin(63) = 4.0 kg. That is the force, or pull, your model is
> generating in a "forward" direction in 3rd gear.
>
> However, I would use the 1st gear case on a 68 degree incline for this
> calculation. Your model wasn't stable, but the motors didn't lock up, right?
> Therefore the force is = 4.5*sin(68) = 4.2 kg.
>
> You are absolutely right. How could I have missed this, I studied that in A level physics last week ( Doh! ). Thanks for that.
>
> > In fifth gear it can travel 1.18 meters per second.
>
> =4.2 kph, 2.6 mph
>
> That's probably faster than most people walk! Impressive for a large Lego model.
You should have saw the weird looks I got when I was walking down the street
with it. I spotted a women in a bus shelter with a dog next to her sleeping.
So what did I go and do. I drove over the dog, boy did it jump (smirk)8-).
This top speed was designed just for monster trucking. It would get a good
run up and speed its way towards my 8880 supercar. The front wheels hit and
the whole thing bends like a spring. Then as soon as the front wheels lift
off the ground, it springs up. Now it is doing a wheely (just like a real
monster truck) and the front crashes down onto the car, crushing it. Take it
from me, it is worth spending all that time building and designing the thing
just to see that, it was a brilliant site to see. The 8880 would roll onto
its mangled roof with lego flung every where, why did I roll the 4x4 down
the stairs 8-(
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Message is in Reply To:
 | | Re: a most splendid 4x4
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| (...) I might be wrong, but if your incline is at 63 degrees, then the component of force (force being the weight of your model) along the inclined surface is = 4.5*sin(63) = 4.0 kg. That is the force, or pull, your model is generating in a (...) (23 years ago, 24-Oct-01, to lugnet.general, lugnet.technic)
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