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thebeerbaron

The Curse of the Mid-engined Roadster

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A couple of days ago, I printed out some design worksheets. I took the stated 95" wheelbase of this project, drew in some circles that matched the diameter of the stock WRX wheel and tire package, and printed three per sheet. Suddenly, 95" seemed like a really long wheelbase. If you assume that the engine sticks out in front of the rear wheels by a bit, suddenly things start getting difficult. Let's look at why.

The 95” wheel base of the new car is almost identical to that of the second generation Toyota MR2, at 94.5”. Here's an MR2.

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Works pretty well. Rather bland styling, but mass appeal is how Toyota came to dominate the market. There’s nothing wrong with the proportions here. The curve of the windshield, roof, and rear buttress works just fine. The front and rear decks work well together, with the front hood longer than the rear deck. The design flows and nothing looks tacked on.

But wait. The Factory Five car is slated to be a roadster. Let’s lose the top!

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Oops. Look at that massive rear deck. You could land an aircraft on there! The proportions are all wrong. OK, so I helped a little bit by getting rid of that rear spoiler, but we're playing by my rules here. It could be worse. I was actually surprised at how well this works - then I realized that it was because the windshield tilts so far back onto the cockpit. Still, the rear mid-engined design necessitates a long rear deck, which is minimized by a coupe body style. Look what happens to that same car when we move the doors back almost against the rear wheels, the way they are in a front-engined car.
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Forgetting the ugliness that comes from me spending two minutes on the chop, that looks much better if not slightly bland. The curse of the mid-engined roadster then is that the engine forces the cockpit forward, which elongates the rear deck, which is the reverse of classically beautiful designs like the D-type, the E-type, and other front-engined roadsters.

A pretty and proportional roadster is going to be a challenge. Don't kid yourself that this is just a Toyota-is-bland problem.
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Yep, the very pretty R8 suddenly looks hump-backed and stretched once the top is off.

The Lotus 2-eleven works because there is no windshield to describe the front of the passenger compartment. You can’t have a rear deck if you don’t have a front deck. And the wheelbase is five inches shorter, which minimizes everything, making misproportions smaller in scale.

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If we have to retain a windshield, I think a targa design might be in order. But those have their issues too...

I am getting completely excited for the competition to start on Tuesday. I can't wait to have all the rules, dimensions, and specifications laid out so I can wrestle with them. It's going to be a challenge!
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Comments

  1. Rotr8's Avatar
    you forgot that the R8 gets a lot of its proportional sexiness from an additional 10"s in stretch of the wheelbase and something that is typically overlooked, larger wheelwells, good design process.
  2. thebeerbaron's Avatar
    I should go back and clarify, but what I meant to point out was that the R8 works as a coupe, but like the MR2 has issues as a roadster. Or are you OK with the proportions on the R8 roadster? I just can't get over that hump between the cockpit and the rear wheels. It looks far too stretched to me. But these are my eyes, not yours
  3. Rotr8's Avatar
    I think it depends on what angle your looking at it. If you go back through car and driver mags and look at the side orthographic drawings of every car that you've said 'damn that is one sexy body' you'd swear that those little technical drawings were wrong. I think the same thing happens in this specific example(image of the side of the R8 roadster) where as if you've ever seen one in person or an image from say a front 3/4 you'd think otherwise. If we choose to call it an optical illusion or what doesnt matter. In the same sense this view(side elevation) is ironically the one most designs first pen or layout, wierd huh? I would continue with your chops and work your clay(btw I love that your doing this, too many young kids want to get into a 3D modeling software too quickly without a true understanding of volume, or for the matter cant even draw whats in their head) dont get too distracted by one view. Work quickly to flush out your ideas and then refine and edit.
  4. thebeerbaron's Avatar
    See, here is where we disagree. I chose the R8 roadster specifically because I saw it in a dealer show room, on one of those spinning platform things. And I wondered how they botched a beautiful design so badly. About the only angle that worked for me was the front-on view, because I couldn't see the back end.

    I hear what you're saying about the angle being important, but I'm the type of guy who steps a bit to the right of the best angle, just to see if the design works from there too. The best cars look good from all angles, not just a select few. But I'm picky like that and I realize it makes me come across as a jerk sometimes.

    Glad you like my idea to do this in clay. Hopefully I'll hit the why of it in a future blog post, but clay just works better for me than drawing. That and I've been doing ceramic sculpture for several years now
  5. Gollum's Avatar
    Remember that we're talking about a subie H4 package here though. If you haven't I highly recommend visiting some subie shops to see what one of these engine/trans packages look like outside of a car. They're extremely short.

    Being such a short engine you might not be forced to put the cockpit so far forward compared to a normal MR design. The front axle outputs are right at the front of the trans too, meaning that measurement from crank pulley to axle won't be very far at all.

    I do agree though, that a roadster in MR fashion is almost doomed to be ugly. There's very few good examples. I'm personally much more in favor of a targa design, maybe even with some fastback styling like the elise, if the weight of a real fastback like the exige would add too much weight.
  6. Dave Smith's Avatar
    I saw an attack K1 in person and it resolved some of these challenges. The Lotus seems too track focused, but the design competition is wide open.

    Dave Smith
  7. thebeerbaron's Avatar
    Gollum - The H4 is indeed a short engine in length, compared to just about anything longitudinal. Compared to a transverse four though, the distance from hub center to front crank pulley is not inconsequential. It is certainly very short in height. I haven't thought of how to take advantage of that short height in the MR location though. Time and experimentation will tell.

    I saw a beautiful coupe design last night that I thought I could eliminate the roof from and end up with a very good looking roadster. I think I may have isolated why it works on that particular car, now I just have to sketch a bit to see if it still works out with the given dimensions and guesstimated engine/cockpit location.

    Dave - I haven't taken the K1 too seriously because its design compromises just irk me to no end. The windshield is all wrong and those exposed front shocks just feel... tacky. (Tacky'd on!) I'll take a look again, just for you. Hope you get some joy out of the excitement you're causing here!
  8. JRL's Avatar
    I think the Porsche Boxster and Cayman give a pretty good indication of what can be accomplished with a mid engine and 95" WB.
  9. thebeerbaron's Avatar
    JRL - I agree with you on the Cayman, I think that's a great looking coupe and if Porsche could withstand the firestorm from the 911 worshippers, it could easily be a better car than the 911, if it's not already there. The Boxster is not terrible, I'll give it that. I'd still like to see the distance between the rear edge of the door and the front edge of the wheel well shortened up. But I know the crank pulley is practically rubbing the firewall, so that's not going to happen. It works much better than the R8 at least.

    OK, I'll concede, the Boxster would rate an A- for me on styling. I'm feeling generous. But I'm a goody-two-shoes sometimes and I want the A+ (and that big first prize!).
  10. Dave Smith's Avatar
    I agree as well on the Cayman. Double plus for the packaging that enables storage. Yeah, the K1 Attack had some quirks, but it accomplishes, in my mind, a fairly radical and cool look... for the price the performance, weight and over-all car never delivered on the looks, but as Ive seen some of the early design submissions, I am BLOWN away and really having fun.

    Dave
  11. Cooluser23's Avatar
    I would love a K1 Attack style design, that car looks beautiful.

    Also there is nothing wrong with a "cab-forward" design. That's the design language of mid engined cars. Look at the Lamborghini Gallardo, that car has basically no hood. (or Acura NSX, etc..)

    It may be a cultural thing.. I grew up in Europe, where we worshiped Exotics, the likes of Lotus, Ferrari, Lamborghini. Americans love cars with long hoods like the Corvette, and 60's muscle cars (as mid-engined cars had less cultural impact). (Think of what kids had on their bedroom wall posters. In Europe it was exotics, in America it was muscle cars.) It's a difficulty of making a truly international design, and I don't envy FFR in having to make that decision.

    All I hope for is that the final car will have plenty of storage space like a Porsche Boxster/Cayman, or a Pontiac Fiero, where there is a trunk in the front, and in the back. - It would make it much easier to pack for road-trips (which will keep the "significant other" happy, and thus make it easier for customers to make a purchase decision)

    I also hope that the car will feature an exposed engine under glass, as with many modern exotics. (Lamborghini, Ferrari, Audi R8) It makes the engine look like a crown jewel and really brings forward the "mid-engined" flair of the vehicle.

    A K1 Attack style visible "push-rod" suspension would be nice, as it looks visually striking, but I think that ship has sadly sailed early in development.

    I know what you meant about the 95" wheelbase. It seemed short at first, but then I noticed that short wheelbases quite common on small mid-engined cars. (Pontiac Fiero, Porsche Boxster/Cayman, Lotus Evora, '11 Lancia Stratos, 2nd gen Toyota MR-2, etc.) I'm glad FFR decided to build such a nimble "canyon carver", to replace my aging Pontiac Fiero.

FFMetal

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