[Sven7]

Sorry it's been a couple days. I had a lot of stuff to catch up on.

Originally Posted by Arragonis

Engines - IMHO - The Aygo KR-FE unit is very much an up to date 3cyl petrol, probably better for compactness and lightness than excellent torque / performance. In my Aygo the gearing is about 22 mph / 1000 (based on sat nav) in 5th, but you do feel the air resistance at anything over 60. With such a streamlined shape maybe a longer geared and higher torque setup would be better.

The equivalent Hyundai engine is the Kappa 3cyl from the i10, similar spec to the KR-FE but heavier, but does have a start stop and intelligent alternator system - reduced load on hills for example.

What is the target weight for this car ?

The FIAT Twin Air is good on paper, it has good performance for the size especially. Reports "from the field" though seem to suggest that even in it's low-boost "eco" mode it can't match the claimed economy figures and isn't as good as the 1.3 Multijet Diesel.

The 1.2tdi from the Lupo 3L / Polo Bluemotion may be a better bet if you want the best torque / economy compromise. Heavier than both and would need more space but a great engine all the same, and has the option of a 6speed.

There is the 1.2 TDI Insight as an example of course. And Vekke is aiming for 2l/100km from his.

Ok, it sounds like the FIAT thing is not going to be the best idea for this. Does the TDI come with manual? haha that's the question to everything

Target weight is about 900kg/2000lbs.

Originally Posted by NeilBlanchard

Low pressure means it is close(r) to separation?

That's how I understand it. And any higher pressure than necessary to keep attached flow results in drag. Right? Maybe Phil or someone else in the know would be kind enough to enlighten us.

Originally Posted by NeilBlanchard

The radii on the front will be good. I would look at the usefulness of the interior volume and see if the windshield plan curve works with it.

I didn't realize the A Pillars got moved back during the creation of this newest model. Oops! I will fix it.

Originally Posted by NeilBlanchard

And the wheels on your model are in a very different situation than the wheels on the Ferrari. I think that the 15 degree angle is an outward flow, not inward? Which is good, and this is the reason why the back is tapered in.

Have you seen the 4 wheel designs by Jason Hill?

If the rear wheels are at least partially engaged, then the strakes do not have to be this large, but the basic idea would help, I think?

So you think the tapering of the body will negate this outward flow? I will be doing something about covering the rear wheels. Probably strakes sticking down from the underbody much like a solar car.

Originally Posted by brucepick

I assumed my Civic's front and rear glass were simple curves. Not so. There is a modest curvature that's perpendicular to the main wraparound curves.

I beg to differ.


Furthermore, the more plan view curvature you have, the more important it gets for it to be a simple curvature.

Originally Posted by brucepick

Somewhere else there was a discussion of 3 wheels vs. 4. If I recall, that discussion came down in favor of 4 wheels for the additional safety/handling/traction benefits. If you want "Aunt Martha" to be willing and able to drive it like a car, four wheels help a lot.

The Aptera opted for 3 wheels, with a single (driven??) wheel in the rear. That configuration is already established as better handling than 1 front + 2 rear, but the Aptera had serious handling difficulties at the X-Prize competition and did not win its class.

Right on. A car needs four wheels to be "accepted" as a car. Think about how even the Prius is teased for looking different, then imagine what a three wheeled car would have to take. It's just not worth it, even in the purely marketing sense.

I know Aptera changed the drive wheels to front to back or vice versa, and that's one reason it's taken so long to develop. If they ever come out, though, I would definitely consider one for a daily.

Originally Posted by kach22i

Sven7, I'm sort of bummed out. Not that the changes make the car look conventional, just that the mission of changing it slightly and retaining it's original character seems lost now.

You can call me Tyler... it's ok

I'm not sure what you mean... did I compromise the design while roughing it out?

Originally Posted by kach22i

I've played with similar concepts for many years, I have yet to do what I'm about to suggest (at least on a 4 wheel car). Make a Styrofoam plug of what you consider the minimum passenger area (don't forget the wheels) and then add globs and globs of clay to it.

...

Cheers, George/kach22i

That's what I'm doing with the Scion blueprint in the model. The Scion's interior volume is the goal. I don't have the time or resources right now to do a clay model.

Originally Posted by euromodder

It's not easy to get near the brochure numbers with Fiat's Twin Air.

If you want tight packaging, look at the new 1L VW 3 cyl. engine used in the VW up!
On CNG in the projected Blue Motion version, it's expected to deliver 75g CO2/km - 2.5kg CNG / 100km - that's lower than anything out there with an ICE.
CNG adds weight though and needs a lot of volume to get some decent range.

The Kia /Hyundai 1.1L diesel is newer and more efficient than the 1.2L VW TDi
In the Kia Rio - not exactly a small car - it's EU rated for 85 g CO2/km / 3.2 L/100km or 73.5mpg

Interesting. I'd love to say that CNG is practical in the US but it just isn't accepted or available as an automotive fuel. I think to compete in the US market this car will probably need to be something along the lines of gas, diesel, biodiesel or electric.

Originally Posted by gtkid2002

Just a suggestion for if you're still looking for specially shaped glass, try finding a small aircraft boneyard, and looking at the glass from one of those. I think something like that would be cheaper than getting one custom made, but you'd have to design around it to a point. Also might be hard to find a replacement.

That or maybe it's possible to bend the glass with careful use of a torch? I'm not familiar with automotive glass though.

Thanks for the suggestions but I'm assuming the car is built by a major auto manufacturer with access to the necessary tooling. Remember, I'm designing it to be put into mass production, not just one or two examples.

Yes, it's only a thought experiment at this point. In the interest of realistic design, though, I'm looking at it from the same perspective as if I were doing a sponsored project at school, with a little more thought toward production.

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Whew!