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Lotus 7 modernized
(95 posts, started )
Strictly speaking a "mid-engine " car has the engine in front of the rear axle but behind the passenger compartment. But strictlier speaking it's only because that's the way the only 'mid-engine' cars in actual production are laid out. Most of them are two passenger or front seat only sports or at least "sports-type" cars. There are 'experimental,' prototype,concept, and special purpose vehicles with the engine in a more central location, between the front and back seats ( actually more like two separate passenger compartments), some with the engine to one side or the other, so if they ever went into production we could have a right-front- mid-engine car or a mid-mid-engine. But maybe not, things can get complicated.In a rear engine car, like the old Volks 'Bug', the engine is over, or even behind the rear axle. In a front engine car the engine is over or in front of the front axle. In the early 60's Chevrolet sold a Corvair van with an air cooled engine mounted under the cargo compartment behind the front seat. That was the most 'mid' of any arrangement I can think of. But it wasn't called 'mid-engine' it was a 'Forward Control' vehicle. The front seat was over, mostly in front of the front axle. Around the same time the Big 3 came out with full size vans with the axle in front of most of the engine and the passenger seat moved back where it was supposed to be, the engine extended into the passenger compartment, I think Ford was the first and the most extreme with most of the engine actually between the front seats. They weren't called 'mid-engine' or even 'Tween the seats', they were 'Cab Forward' apparently the engine was where it should be for a 'front engine' but the seats had been moved forward to straddle it, but not so far as to become a 'Forward Control.' So if any of the bizarre proto-types go into production, or more likely as "hybrids' and 'alternative' become more common, with electric motors on each axle or even each wheel, or mounted here or there, who knows what they will be called. Or by whom, "official' names given by manufacturers have a way of being replaced by common usage names. That "Forward Control" Corvair became known as a "Bouncing Bobtail. "

That was a huge off topic. I suggest we return to discussing about that modernized Lotus 7.
Quote from Joris :But it does look like a cheap Halfords Add-on.

Where do you think those come from... Just like those angel-eyes really.
super nice!
The dp1 is actually a true mid-right-engine layout.
I had a look at this at the MotorShow on Sunday. They had a chassis with the bodywork off and I have to say, from an engineering perspective, it's very nice. I think comparing it to a 7 is a bit unfair. It's similar in looks to some extent, but it's built very differently. I have to say, I though it would have been lighter than 750kg, and it's a shame it's so expensive, but the suspension design is very good....far better than a 7 and far far better than an Atom.
You could replace the headlights with scale models of the Smart Car, only improving the looks.
EDIT: Without making it worse i mean
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Quote from frokki :You could replace the headlights with scale models of the Smart Car, only improving the looks.
EDIT: Without making it worse i mean

I'm sure they'd be very excited at this design breakthrough, if only they didn't have issues with not having the rights to the design of the smart car!
Quote from Jakg :Are those lights or speakers? I really can't tell

i think they are the speakers from which the horn sounds

modern car, stereo horn... hmm, that makes sense!
This car isn't clearly designed for people who like the original Lotus 7, like me, but for people with very bad taste, as like majority of cars are done nowadays.
Ah, what's wrong with the current, yet ancient, design of my beloved seven?

It looks like they took a bunch of parts of bad American cars and slapped them on a Caterham.
#62 - Osco
meh, I'd do it
Quote from Rappa Z :Ah, what's wrong with the current, yet ancient, design of my beloved seven?

It was just never light enough... "How can we make a car really light?" [pause] "We could... um... take out the engine?" [applause]

The Lotus 119
Quote from nihil :It was just never light enough... "How can we make a car really light?" [pause] "We could... um... take out the engine?" [applause]

The Lotus 119

That would actually go faster with more weight.
Quote from Mustafur :That would actually go faster with more weight.

If you mean adding an engine of some sort, then yes. If not, no. Lightweight is the name of the game from gravity powered cars.
Quote from tristancliffe :Lightweight is the name of the game from gravity powered cars.

In terms of speed I'd imagine that good aero + extra static weight* (I imagine that they have rules about the latter though, but it would help since getting the former perfect is trickier) would do the trick, no?

* on-board weight, but keep the wheels lightweight - or atleast if there's a maximum weight limit, place as much of the weight as balance allows in the rear.

EDIT:
And since I got some time to kill: due to the resistance that will exist in the various forms of friction involved we'd need to maximize the potential energy the car would have in order to have gravity produce more work for us to overcome said resistances - the newtonian formula for that energy would be PE=m*g*h - g is (unless we're really really high - literally or metaphorically) constant, height is the same for all contestants so therefore we only get to play with the car's mass and trying to keep it at the highest part of the incline (hence: the rear of the car). At least, that's how I visualize this; as always I can stand to be corrected.
That'd be for your potential energy, which has to be converted into kinetical energy - 0.5*m*v². Notice the little m there? Yeah, that's the same mass as in the potential energy, they cancel each other out. It's a common misconception that heavy things get faster than light things when falling.
In a complete vacuum a feather falls at exactly the same speed as a bowling ball.
Indeed, it has to be converted to kinetic energy and, theoretically and barring all loses to friction, it will be "completely" converted to it at the bottom of any incline. The object with the most mass will have more kinetic energy at a level section and since we are not in a vacuum and have things like friction to consider, having more energy would be a good thing in overcoming said friction, no?
i dunno all about this theory...
all i know is that if you want to test all this, just get in a car, do some timed laps, then repeat the laps with the car fully loaded.
Quote from xaotik :Indeed, it has to be converted to kinetic energy and, theoretically and barring all loses to friction, it will be "completely" converted to it at the bottom of any incline. The object with the most mass will have more kinetic energy at a level section and since we are not in a vacuum and have things like friction to consider, having more energy would be a good thing in overcoming said friction, no?

A big truck can technically roll down a mountain as fast as a little car. But the truck will catch more wind, it'll have bigger tires, thus a higher rolling resistance, so it will be slower in the end.
Quote from sgt.flippy :A big truck can technically roll down a mountain as fast as a little car. But the truck will catch more wind, it'll have bigger tires, thus a higher rolling resistance, so it will be slower in the end.

Indeed so - however, in real world circumstances, during the descent and assuming two identical soap box cars in terms of aerodynamics but different in weight, which car will reach terminal velocity faster while overcoming aerodynamic drag?
Assuming friction, rolling resistance and aero drag are the same - in fact, assuming the cars are absolutely identical in every way, and interact with nature in exactly the same way, but one has more mass - then they will go at the same speed!
However, terminal velocity is given by Vt = sqrt(2*m*g / p*A*Cd) - where:

p = density of fluid (air density in our case)
A = projected surface
and
Cd = drag coefficient

So, more mass would mean higher terminal velocity.

EDIT:
And for those in need of illustration:
http://www.regentsprep.org/Reg ... phys01/terminal/term2.htm

EDIT2:
I think I see where the discrepancy is - it seems that you visualize drag as some static force only relevant to the shape of the object. However that is not the case - drag increases with speed. And speed increases by an applied force as long as the said force is larger than the force of drag. So there are two ways to attain a higher speed - either by reducing drag or by applying a greater force and since our example soap box cars are only propelled by gravitational pull the only way to increased the force is by adding more mass.
Quote from tristancliffe :Assuming friction, rolling resistance and aero drag are the same - in fact, assuming the cars are absolutely identical in every way, and interact with nature in exactly the same way, but one has more mass - then they will go at the same speed!

where is the added mass located? on the wheels? then it is not certain which will go faster. in the body? then the heavier will go down faster. distributed? not certain again

Lotus 7 modernized
(95 posts, started )
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