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Everything revolves around CAD

CAD software played a central role in my project right from the start. Without modern tools and technologies, it would simply have been impossible to realize such a complex project as the development of a complete racing car.

Getting started with TurboCAD

I started my work with TurboCAD, which was obvious: For over 20 years I have been running the TurboCAD Training Center and have been responsible for training courses in Germany, Austria and Switzerland. During this time, I have conducted hundreds of training courses and taught numerous customers how to design in 2D and 3D with TurboCAD.

I used this familiar software to create the first designs for the tubular frame and began with the kinematic design of the chassis in 2D. TurboCAD was ideal for this basic work – fast and efficient.

But I soon reached the limits of the program: TurboCAD ‘s functions were not sufficient for the next steps, especially the strength analysis of the frame.

The switch to Fusion 360

It was clear that I needed more powerful CAD software, so I decided to use Fusion 360. Although I have been working with CAD since 1998, this switch was a challenge. The software not only offered significantly more functions, but also a completely different approach to design. Especially the simulation was new to me and required intensive training.

Despite the extra effort, the change was worth it. Fusion 360 enabled me to perform strength analyses and more detailed modeling, as well as handling very large volumes of data, which was crucial for further planning.

Working with 3D scans

Another important part of my planning was working with 3D scans. I captured components such as the bodywork and the gearbox using an Artec EVA 3D scanner and the associated software. I used this data as a reference in my CAD model to ensure that the frame would fit under the GRP body.

I would especially like to thank my friends from MotoPark who not only supported me with the necessary hardware, but also helped with the preparation of the data. Without their help, this part of the work would have been much more difficult.

Chassis development with specialized software

For the development of the suspension I used the Suspension Analyzer from the company Performance Trends, Inc. from the USA. I also experimented with the online tool Suspension Geometry Calculator from racing_aspirations. Both programs offer different advantages and disadvantages and are among the few affordable options for private individuals – in contrast to the professional solutions, which can quickly cost tens of thousands of euros.

Conclusion

The use of software was essential during this phase of my project. Between 2019 and May 2021, I worked exclusively on design and planning – an intensive period in which countless hours were spent on development. Only then did the actual construction begin, with phases of design, the production of components and the actual assembly alternating again and again to this day. This iterative process requires patience, precision and, above all, a great deal of passion for every detail. But it is precisely this variety that makes this project so fascinating for me.

Historical origin: The aluminum sandwich chassis

The Ford GT40 MKIV was the first racing car to use an innovative aluminum sandwich chassis. This construction, consisting of straight panels, set standards for lightweight construction and stability at the time. Nevertheless, I quickly realized that it would be almost impossible to implement this design myself in such a way that all strength requirements would be met.

A look into the past: initial sketches as a basis

This is where my many years of membership of the GT40s.com forum came in handy. An acquaintance from the community, Bob Putnam, had once restored an original GT40 MKIV and created about twelve pages of simple hand sketches with the most important dimensions. He generously made these documents available to me – a milestone for my project, for which I am very grateful to him.

From paper to digital: CAD reconstruction

However, the sketches were anything but easy to decipher. (See below) I spent many hours interpreting the dimensions, converting them and transferring them to my CAD program. But the effort was worth it: piece by piece, the chassis took shape in digital form and allowed me to take a closer look at the design.

The perfect addition: original plans from Sweden

The biggest surprise came later when my friend Göran from Sweden sent me original plans of the chassis from the Ford racing department. These plans enabled me to check all the dimensions again and refine my CAD design. It was a fascinating moment to be able to understand the technology and precision of the engineers of the time at close quarters.

The modern approach: a tubular lattice frame as the basis

As early as 2018, it became clear to me that an aluminum sandwich chassis like the original was not feasible with my possibilities. Instead, I opted for a tubular trellis frame, which I planned in such a way that its external dimensions were within the original chassis. This decision allowed me to create a solid base that was both stable and technically feasible.

Optical illusion: The cladding with aluminum sheets

To achieve the visual impression of the aluminum honeycomb sandwich chassis, I planned to cover the tubular lattice frame on both sides with thin aluminum sheets. The resulting inward width deviation of around 15 mm due to the tube diameters was hardly noticeable and is practically invisible to the untrained eye. This makes it possible to create an authentic look, which visually mimics the original.

Detail work: rivets and angle strips

To further enhance the impression, I decided to install hundreds of rivets and numerous angle strips. Although these steps were time-consuming, they gave the frame the finishing touches and brought it even closer to the historical model.

Spoilt for choice

If you decide to recreate a Ford GT40 MKIV, you are inevitably faced with the question: How true to the original should the vehicle be? It was clear to me that I had to – and wanted to – make compromises in certain areas. The chassis in particular is an area where I deliberately deviated from the original design. My decision in favor of a modern chassis in this classic guise is based on three main considerations:

1. safety first

The long upper trailing arms on the rear axle, as used in the original, make perfect sense from a chassis point of view. They contribute to good geometry and stability. But what happens if the rear of the vehicle hits an obstacle first in an accident? The design carries the risk that these trailing arms could penetrate the passenger compartment and seriously injure the driver. This risk was unacceptable to me. Safety first, and that’s why I decided to use a more modern, safer design that minimizes such dangers.

2. driving stability and controllability

With an output of over 500 hp, a displacement of 7 liters, more than 700 Nm of torque and a vehicle weight of only around 1100 kilograms, the GT40 MKIV is already a beast. Without modern driving aids such as ABS or traction control, a vehicle like this demands everything from the driver. In order to better control the enormous power and dynamics, I wanted a chassis that was as simple and controllable as possible in terms of its basic kinematic design. A complicated or vulnerable geometry would only have led to problems here. With my modern solution, I have found a compromise that combines stability and riding pleasure.

3. a claim to modernity

Of course, a certain amount of ambition also plays a role. I wanted a car that was not only safe and controllable, but could also keep up with the chassis technologies of modern GT3 cars. I was less interested in historical correctness than in meeting my personal demands in terms of handling and performance. It’s impressive how far technology has come in the last 60 years and I wanted to use these advances to get the best out of my project.

My car, my decision

I am aware that not everyone will like my decisions. There are certainly purists who are critical of my approach. But ultimately I’m building this car for myself. It’s my dream, my project and my interpretation of a GT40 MKIV. The mixture of classic design and modern technology is what makes the vehicle so special for me – and that’s what matters.

1. introduction: The start of the search

What was the trigger?
When I started building my Ford GT40 MKIV, I knew that the body panels would be one of the biggest puzzles of the whole project. The MKIV is a car that has a very distinctive shape and is very different from its MK I and MK II predecessors. So for my replica build, the right body parts are crucial to make the car look authentic. It was clear to me right from the start that I would face many hurdles in my search for parts that were true to the original – and that turned out to be true.

The challenge:
The body of a classic racing car like the GT40 is not easy to find. As this car is a model that was developed more than 50 years ago, there are only a few suppliers who supply original parts. And even when you do find them, they are usually extremely expensive or simply no longer available. So I had to find a way to get body parts that were both high quality and realistic without breaking my budget.

2. research and first attempts

How did I proceed?
About 12 years ago, there was a brief glimmer of hope: a friend from the USA imported a kit and wanted to sell it as a European dealer. But tragically he died in an accident, and for me the subject seemed a long way off again. When I was finally ready to contact the kit manufacturer Fran Hall from RCR (Race Car Replicas) in the USA, I found out that he was no longer allowed to sell the body parts due to an ongoing legal dispute.

Weighing up the options:
At first it looked as if there would be no way of getting hold of the parts. But then I came across an interesting twist: RCR was sourcing its parts from another supplier – a certain Gregg Sidoti from New York. Even more intriguing, he was also active on the same forum I’ve been a member of for over 20 years – GT40s.com. This discovery was a game changer.

3. the breakthrough: success story

After learning that Gregg Sidoti was the original supplier of the body parts, I contacted him directly. It turned out that Gregg had a fascinating story to tell: almost 30 years ago, he came across original spare parts from the No. 4 factory car at a Shelby dealer. Without hesitation, he acquired these parts, which were like a piece of motorsport history for me.

But that’s not all – Gregg was clever enough to make a set of molds from these original parts. He later used these molds to reproduce the body parts that would now make my project possible. It was as if a door had opened that had previously been closed. And when he finally offered to sell me the original parts, it was a moment for me that took the whole project to a new level.

4. procurement and first impressions

Shipping the parts was a particular challenge. Gregg, as an experienced lawyer, had the contacts and knowledge to organize the process, but I had to step in with practical details such as procuring the right impregnated wood for the huge transport crate. Together we found a solution and finally everything was ready for transportation from New York. Of course, this involved a lot of paperwork with the shipping company, customs, etc.

When the box arrived, it was a moment full of excitement. The sheer size and weight already gave me an idea of what was to come. In the end, the process went without a hitch and when I opened the box, the first glance far exceeded my expectations.

5. the quality of the parts

The body parts that I have received undoubtedly bear the hallmarks of their time. From today’s perspective, they appear imprecise and heavy. With modern manufacturing methods, they could be produced more precisely and, above all, much more easily. But the special thing about these parts is not their perfection, but their history.

These parts were manufactured under the conditions of a racing team that was working with almost unlimited financial resources – but also under enormous time pressure. There were only a few months between the 24 Hours of Le Mans races in 1966 and 1967 to develop and build these cars. The precision of the GRP parts was not a priority at the time. What mattered was functionality: a racing car that would win not because of its looks, but because of its speed and reliability.

For me, that is precisely the core of their significance. These parts bring a piece of the incredible time and spirit that prevailed back then into my car. Each component tells its own story, and this story becomes part of my project.

6 Reflection: What I have learned

The path to the body parts was anything but easy, but that’s what made it exciting. Looking back, I realized how important perseverance and the right contacts are. Without the support of Gregg Sidoti and the long-standing connections in the forum, I would probably never have got the parts.

The practical challenges – from finding the right wood for the transport crate to organizing the transport – also demanded a lot from me. But in the end, every effort was worth it.

This stage of my project shows me that it’s not just the parts themselves that matter, but also the story behind them. It is these small successes and encounters that make building my GT40 MKIV something very special.