Aggregated Design

body shaping

2011-03-26T15:37:00.000-07:00

the aesthetic I'm trying to create is that of a modernized 250 SWB or similar sports-racing car. think too many modern cars fall go overboard with the character lines, vents, and other forms of surface excitement. I'd like to have a car with a more balanced look.

Welding Jig Experiments

2011-03-21T12:24:00.000-07:00

I'm trying a few different methods of making control arm jigs. The upper rear arm jig is MDF with bolted-on steel brackets. The rear lower jig is made from steel plate with tacked on steel brackets. The steel jig avoids the fire problem but the material is costly and not as flat as I'd like. It does have the advantage of being reusable. The MDF jig is very cheap and light. It can't stand up to much welding heat, though.

Front Lower Control Arm Jig

2011-02-21T20:57:00.000-08:00

This is my first attempt at a welding jig for a control arm. The first pieces are shown, and main member will be capped with plate. There will also be gussets where the trailing link meets the main member.

Body Progress 2/3/11

2011-02-03T14:34:00.000-08:00

I've made some progress on the shape. There are still some modelling errors on the surface but those will be worked out when the features and proportions are finalized.

2011-01-15T03:25:00.000-08:00

I did some playing around with the body design, trying to clean things up a bit.

Early January Updates

2011-01-08T14:14:00.000-08:00

Some recent progress:
Frame assembly:

2. Bolt-on suspension brackets fresh from the water jet cutter:

3. Body progress. I've got a new tutorial for body styling that will (hopefully) teach mean how to iron out the kinks in CAD model. Also, I'm playing around with some foam models so I can get a hands-on sense of the styling and proportions.

2010-12-01T17:32:00.000-08:00

New body progress:

Body Profile

2010-08-25T01:03:00.000-07:00

More refinements to the body. I'm still going back and forth on the roof style - I like the way this looks with the coupe profile - like a modern Ferrari 250 SWB. The coupe roof would also allow much better aerodynamics and weather protection. I could add a lift-off roof panel for nice weather.

Audacity in Automotive Design

2010-07-31T21:51:00.000-07:00

This is a Tatra T87. It was built in 1941 in what is now the Czech Republic. The basic design dates back to the mid Thirties. It is powered by an air-cooled V8 engine mounted behind the rear axle. The suspension is all independent and the body has exceptionally low aerodynamic drag. It was the result of some of the most original and creative thinking ever applied to a car. Aspects of the design were copied by Volkswagen, Mercedes-Benz, Porsche, General Motors and others. It challenged peoples' ideas of how a car should work and what it should look like. The engineers at Tatra were trying to create a car that was modern on all levels - from the way the suspension interacted with the road to how the body cut through the air. For this reason the Tatra looked like nothing before it. Most luxury car makers at the time were content to mount a great big engine to a chassis and body that wasn't very far removed from a horse-drawn carriage. Tatra cast of these nineteenth century ways of thinking and made a cars that could work on the autobahns and freeways of the modern world.

Refining the Body Shape

2010-07-25T22:19:00.000-07:00

Refining the shape, cleaning things up, working on placing the ducts, etc.

Proportions

2010-06-06T01:31:00.000-07:00

Not being a trained stylist I don't suffer from any loss of ego when I realize that I was incorrect about a styling issue. I've been bothered by some awkward proportion issues with my body design. Something just seemed awkward in the computer model. The full-scale plug seemed much better, but not quite good enough. After comparing the proportions to other cars with a similar layout (2 seat, front (or front-mid) engine, and rear drive. Most of these cars have a very short nose and a relatively long rear overhang. It seems to give the car a windswept look. So I've taken a few inches off the front and added a few at the rear.

Fender Upgrades

2010-05-19T00:52:00.000-07:00

I'm working on adding some visual muscle to the fenders of the car. The thing looks a lot like Kryten right now but it will be smoothed out soon. It should give the car a slightly more modern look. Maybe it will necessitate a performance increase to match the looks.

When it comes time to actually build the body, I'd like circumvent the normal plug and mold building process. There are companies that have five-axis CNC machines designed to carve out large scale molds - I have some experience with Janicki Industries and I know they can do a very impressive job but I'd like to see what can be done with some of the lower cost CNC routers on the market now.

Diff Mount Fabricated

2010-04-26T13:29:00.000-07:00

The diff bracket has been fabricated. The setup is a bit different from most miata-based locosts. The challenging part of the design is the diff mounts want to interfere with the location of the upper rear control arm mounts.

Side Sill

2010-03-12T00:55:00.000-08:00

The yellow box mounted to the side of the cockpit is one of the side sill structures. These will provide additional torsional and beam stiffness in addition to providing side-impact protection. Ideally these boxes be made of a composite sandwich structure and bolt to the steel beams on the side of the cockpit. The advantage of composite materials is that they provide maximum stiffness and crash energy dissipation for their weight. In the event of a collision a new box could be bolted to the frame. An alternative option is to make the boxes out of square steel tubes paneled in aluminum sheet.

The transmission tunnel - the other major source of torsional stiffness - could also be made out of a composite structure and bolted to the steel frame. It would be a more practical solution than the full carbon fiber tubs used on many modern supercars. By using a few composite elements bolted to a steel framework the size of the parts become much more manageable. Smaller composite parts don't require the huge and expensive molds, ovens, and autoclaves full composite tubs require.

Frame Design progress

2010-03-11T00:57:00.000-08:00

The concept behind this design is to create a more modern counterpart to classic minimalist sports cars like the Lotus Elan, keeping the precise driving experience but with the benefit of more modern crash safety and reliable mechanicals. The miata has done a fantastic job but I want something less compromised feels more alive.

To provide a tight feel the chassis needs to be very stiff. I am using a spaceframe design, which uses triangulation to make a stiff, light structure out of small tubing. It is a very efficient way to transmit loads between suspension hardpoints. Unlike many existing space frames, I am using substantial side sills that provide stiffness and strength to the what is generally the weakest part of an open car. The wide sills also protect the occupants from side impacts by preventing intrusion and absorbing crash energy. My spaceframe also surrounds the engine bay, allowing a higher mounting point for the spring units which results in a more linear spring rate. It also provides a more direct load path for frontal impact energy to the windshield frame and roll cage. I will have structures front and rear to absorb crash energy to protect the occupants.

Another take on the roof

2010-03-03T12:57:00.001-08:00

A quick sketch of a more classically British roof. I think this is turning out pretty good - it has a lithe, elegant feel in keeping with my goals for the car. The roof panel could still lift off, as with the targa with sail panels concept illustrated in the previous post.

Roof Design, continued

2010-03-01T22:50:00.000-08:00

This is the latest iteration. I cleaned up the roof line a bit. The top panel would be removable. I did raise the body slightly at the rear, and I think this made it a bit too heavy looking at the back. By raising the body line I can make the sail panel smaller and more elegant while retaining enough height for the roll bar and roof.

Roof ideas

2010-02-25T00:33:00.000-08:00

Another roof concept, this time with a targa roof with sail panels behind it to smooth out the profile. A roof panel could be added, and the roof could be braced between the windshield frame and roll bar for structural integrity. The door would have "horns" molded into it - those would be the triangles above the main part of the door - to support a side window or secure side curtains.

Roof Design

2010-02-22T23:53:00.000-08:00

I'm working on a setup for the roof. I would like to have a cage structure on top to improve the integrity of the chassis and allow for a place to clip in some roof and side panels for aerodynamics and weather resistance. The problem is getting a shallow enough taper for the rear (steeper than about 23 degrees creates flow separation) and keeping the proportions correct. I'm still not quite happy with it.

Mounting the Engine and Steering

2009-12-07T13:09:00.000-08:00

I would rather route the exhaust through the transmission tunnel than use side pipes. This does present a few challenges. The stock Miata exhaust manifold outlet points directly at my motor mounts. With some cutting and welding the exhaust could be re-directed into the transmission tunnel. An alternative solution would have been to install a turbocharger kit which has a very compact manifold that has an outlet in the center if the engine between the #2 and #3 exhaust ports. There is plenty of clearance for hardware there. Unfortunately the turbo kit is out of budget so the modified manifold will work for now.

The upper steering column supports have been tacked in place. The upper colum will be lengthened so that the upper u-joint will be just inside the firewall.

More body updates, Sept. 22

2009-09-22T11:44:00.001-07:00

I've been sanding and filling to smooth out the body. I added a coating of red filler primer to better judge the body surfaces.

Suspension Truss idea

2009-09-06T13:56:00.000-07:00

I've been trying to find an elegant way of moving the front upper spring perch outward to get a more linear suspension rate. This truss is a possible solution, and it would use the same hardpoints as a pushrod suspension in case I wanted to "upgrade" later.

I was also thinking that I might as well triangulate everything back to the firewall and use the taller structure to triangulate over the top of the suspension, although that would introduce a bunch of clearance issues.

Body Changes

2009-09-03T22:35:00.000-07:00

I haven't been happy with the shape of the car so I have been rendering some possible changes. Primarily lowering the bulges behind the headlight to give a more sleek profile. I've created some crude renderings to work out some of the issues.

yet more body filling

2009-07-25T00:59:00.002-07:00

Yet more filling and smoothing. The shape doesn't really show up very well in the photos but I am happy with the progress

plug updates

2009-07-22T23:38:00.001-07:00

I've filled in most of the gaps in the plug between the templates to raise the rear of the body. I've also lowered the bulges behind the headlights as I am using the smaller headlight units in the photo.

Filling in the frame details

2009-07-08T00:43:00.001-07:00

Still more triangulation and sheer panels. I've been having trouble making space for the master cylinders. Tilton 75 series master cylinders should work fine.

Styling Changes, 6/12/09 Edition

2009-06-12T23:12:00.000-07:00

I'm working on raising the tail section of the car a bit to give it a stronger profile. I'm working out the changes by bonding polyurethane foam sheet to the plug. This gives me an idea of how the proportions of the car. I can shape the foam very easily or remove it completely.

I'm also raising the body line slightly at the base of the windshield. I had planned on covering the base of the windshield with a fairing so I can keep the body line very low - emphasizing the coke bottle shape. It might make a cleaner shape overall if a raise the body line (I'm mocking up the new line with the foam templates) and not have an identifiable fairing.

working on broken cars in the street

2009-06-04T23:56:00.001-07:00

Ferrari cooling fan replacement, Spokane style.
The neighbors didn't seem to mind.

Not my car, but fun opportunity to check out some unusual machinery.

Wheel Arches

2009-06-04T23:39:00.000-07:00

I've been working on getting the wheel arches shaped properly. The wheel needs clearance as the suspension is compressed and the wheels turn. I want the wheel arches to blend in smoothly with the rest of the body to create and integrated shape rather than a distinct flare. The body should look to be shrink-wrapped around the wheels and engine.

Frame

2009-05-31T12:19:00.000-07:00

The incomplete frame. It still needs a few more elements to be added along with shear panels and mounting brackets. The frame is being fabricated by Hayes Cages LLC.

Body Photos

2009-05-31T11:58:00.000-07:00

This is the as-yet incomplete body pattern. It is made from foam, MDF, and polyester filler. When the shape is correct and the surface is smooth I will layer fiberlass over it to create the body molds. Also shown is the steel measuring rig.

Introduction

2009-05-22T19:18:00.000-07:00

This is the first post for Aggregated Design. This blog will document my design and build projects, which I am taking on to explore the technology used in small-scale production. My current project is the design and fabrication of a lightweight sports car. Some of the topics I will cover are CAD, composites, CNC machining, reverse engineering, data acquisition, and project management.