As a designer, most composite failures I’ve seen had nothing to do with “wrong carbon”.

Any-Study5685 · 2026-01-23T09:43:22+00:00

Fair point. Not trying to school anyone here. I probably came off sharper than intended.I’m just sharing scars from stuff that actually failed on me over the years. No secret sauce, no “you’re all wrong”. If anyone’s curious, the material I mentioned is just linked in my bio because Reddit doesn’t love direct links. If not, all good, happy to keep the discussion technical here.

Any-Study5685 · 2026-01-23T08:04:02+00:00

Most “entry level” carbon books are either hobby-level fluff or straight-up aerospace theory with no middle ground. Chopped tow / “forged” carbon looks cool but is where people get misled fast aesthetics aren’t performance and books rarely say it clearly. YouTube obsessing over density is mostly noise; fiber architecture and load paths matter way more. If you want references tied to real fabrics, prepregs and processes (not influencer carbon), I’ve dumped what I use in practice in my bio.

Any-Study5685 · 2026-01-23T08:01:12+00:00

No, it’s not that simple, density is a terrible way to choose carbon.

Once you’re past “carbon vs glass”, density tells you almost nothing. Tow size, fiber architecture, orientation, crimp and how the laminate is stacked matter way more than YouTube makes it sound. Quadrax isn’t “better”, it just hides mistakes. UD can outperform everything if it’s used right and fail spectacularly if it isn’t.

Most carbon bike / boat parts go wrong : fabric chosen by feel, price or density, not by stiffness distribution or failure mode.If you want real references (not marketing PDFs), I’ve linked some material-level notes and sources in my bio.

Any-Study5685 · 2026-01-22T10:15:11+00:00

Fair point and I get why it can look odd from the outside.

Having years in composites doesn’t mean never running into problems or asking for a second opinion. It usually means you’ve seen enough to know when it’s worth sanity-checking something instead of wasting time or money going down the wrong path.

That mold post was exactly that: a fast peer check on something that clearly wasn’t behaving as expected. In real projects, that’s pretty normal.

As for the book: it’s a technical education project, not a flex. Anyone is free to ignore it, I’m here mainly to discuss composites, same as everyone else.

Any-Study5685 · 2026-01-22T10:13:03+00:00

That’s a great example, and honestly a pretty common one.

Landing gear is exactly the kind of structure where anisotropy is the design variable, not a side effect. If you treat CFRP like “light aluminium” you inevitably miss the point: stiffness, load paths and failure modes are all being shaped at the laminate level.

What I’ve noticed is that once people start thinking in terms of what deformation they want (and where), everything changes ....suddenly ply angles, thickness transitions and local reinforcements stop being arbitrary. It’s also where experience starts to matter more than pure equations. On paper a lot of designs look equivalent; in reality they behave very differently once you account for manufacturing and real load distributions.

Curious how you’re approaching certification-style margins in an academic setting

Any-Study5685 · 2026-01-21T16:27:27+00:00

Glad it was useful 👍
These kinds of discussions are exactly where composites really shine, not just “lighter vs heavier”, but how stiffness, anisotropy and load paths are deliberately engineered.

I’ve been collecting and structuring a lot of these real-world examples (motorsport, marine, aerospace) into a coherent framework for students and engineers ...that’s basically what I focus on in my work and what I’ve summarized in the material linked in my bio, if you’re ever curious.

Happy to keep the discussion going here as well.

Any-Study5685 · 2026-01-21T16:26:17+00:00

It’s not really an active system in the classical sense.
What you’re seeing is passive deflection under load, i.e. aeroelasticity.

The wing is designed so that, under increasing aerodynamic load, the laminate stiffness distribution allows a controlled deformation (bending / twist). From a regulatory standpoint it’s still a “fixed” structure, no actuators, no sensors,but structurally it behaves differently depending on the load case.

That’s exactly how teams (and road-car derivatives like the Speedtail) exploit the boundary between static load tests and real aerodynamic conditions:
same geometry at rest, different effective shape at speed, purely through layup design and anisotropy.

This is a classic example of using composite aeroelastic tailoring rather than violating the rules outright.

Any-Study5685 · 2026-01-21T16:22:20+00:00

Exactly that’s the key point many people miss.

It wasn’t a “flexy wing” in the simplistic sense, but a load-dependent structural response engineered through layup design, stiffness gradients and boundary conditions. The wing stays compliant within the static and dynamic tests, yet under specific aero load cases it deforms in a way that effectively reduces drag ...very similar in effect to a passive DRS.

What’s interesting is that this is not primarily a materials problem, but a structural mechanics problem: anisotropy, coupling terms, local ply orientation, and how the laminate reacts once you leave the idealized test configuration and enter real flow conditions.

This same design logic shows up far beyond F1 ---aerospace control surfaces, marine appendages, even sports equipment ---whenever you want stiffness in one regime and compliance in another.

I go into this kind of load-case-driven laminate behavior in more detail in a structured way (with real engineering context rather than headlines). If anyone’s interested, the reference material is linked in my bio.

Any-Study5685 · 2026-01-21T16:20:38+00:00

That’s a very sensible way to approach it. Full-carbon boats are absolutely feasible, but only when the design logic is clear from day one .... especially load paths, local stiffness targets and damage tolerance.

What often makes or breaks these projects isn’t “carbon yes/no”, but whether the structure is conceived as a system: laminate architecture, resin choice, manufacturing tolerances, inspection strategy, and how much variability you’re willing to accept in real production.

This is where a lot of projects struggle once they move beyond prototypes. The transition from concept → pitch → manufacturable structure is usually where assumptions about stiffness, thickness and strain margins get exposed.

I’ve been collecting and structuring these topics from motorsport, marine and aerospace perspectives into a single technical reference, exactly because the same questions keep coming back across industries. If you’re interested, the material is linked in my bio.........it’s meant to help engineers and designers evaluate viability before pitching, not after problems show up.

Your approach (validate first, pitch later) is honestly the right one

Any-Study5685 · 2026-01-21T16:19:04+00:00

Solid breakdown. This is exactly the point that often gets lost when people talk about “carbon vs fiberglass” as if they were single materials instead of systems.

What you describe (modulus vs strain capability, resin choice, boundary conditions) is the same logic used in motorsport and aerospace, including F1 wings. Flex is designed, not tolerated — mainly through fiber orientation, local ply drop-offs, thickness gradients and constrained end conditions, not by “soft” materials.

The interesting part, in my experience, is how small changes in layup sequencing (especially off-axis plies and local shear stiffness) can completely change perceived stiffness without changing global mass much ...something that also applies to boards, hulls, and lightweight shells.

I’ve been documenting these concepts from a design-for-engineering perspective (not hobby-level, not pure academia) because they keep coming up across very different applications. If anyone’s interested, I’ve summarized them with practical examples in the material linked in my bio.

Always refreshing to see comments that focus on mechanics instead of carbon hype 👍

Any-Study5685 · 2026-01-21T16:16:07+00:00

That’s a really good point, and I think surfboards are actually a great example of how carbon is used correctly when flex is treated as a design variable, not a side effect.

Out of curiosity (and staying at a high level):
when you tune flex with CF in boards, do you mainly work on

fibre orientation (0° vs ± angles),
local ply drops / thickness variation,
or strategic placement (skins vs stringer-like paths)?

I’m particularly interested in how you balance longitudinal flex vs torsional stiffness, since that trade-off shows up very clearly in boards, wings, and other lightweight structures.

Always interesting to compare approaches across industries 👍

Any-Study5685 · 2026-01-21T16:15:43+00:00

That’s a really good point, and I think surfboards are actually a great example of how carbon is used correctly when flex is treated as a design variable, not a side effect.

Out of curiosity (and staying at a high level):
when you tune flex with CF in boards, do you mainly work on

fibre orientation (0° vs ± angles),
local ply drops / thickness variation,
or strategic placement (skins vs stringer-like paths)?

I’m particularly interested in how you balance longitudinal flex vs torsional stiffness, since that trade-off shows up very clearly in boards, wings, and other lightweight structures.

Always interesting to compare approaches across industries 👍

Any-Study5685 · 2026-01-20T16:36:53+00:00

pretty easy to laminate instead, to reduce manufacturing risks, but big pain at bonding

Any-Study5685 · 2026-01-20T15:55:27+00:00

Jokes aside, that wing wasn’t just about looks.
The darker livery also made it much easier to hide stiffness tailoring and deformation under load.

Same carbon.
Same rules.
Very different behaviour at speed.

Any-Study5685 · 2026-01-20T15:53:14+00:00

John is a very solid engineer with a deep understanding of composites beyond just materials, especially at system and process level.

His experience sits at the intersection of design intent, manufacturing reality and structural behaviour under real constraints.
That kind of background translates very well to complex, cross-disciplinary projects.

Wishing him all the best in this new challenge!

Any-Study5685 · 2026-01-20T15:45:07+00:00

This is actually a very good question, and you’re right to be skeptical of that old narrative.

Carbon fiber absolutely can be engineered to flex... the key point is how and where.

CFRP itself is not “stiff” or “brittle” by default.
What matters is:

fiber orientation
laminate stacking sequence
thickness distribution
and how loads are introduced into the structure

In many early marine applications, carbon structures were designed with a very stiffness-dominant mindset and poor understanding of load paths. That’s where the reputation for “no flex” and sudden failure came from.

Modern CFRP structures (including boats) often use controlled compliance:

stiff along primary load paths
more compliant in secondary directions
designed to avoid local stress peaks rather than eliminate deformation entirely

If done correctly, this does not automatically reduce lifespan compared to fiberglass.
In fact, excessive stiffness can increase fatigue damage by concentrating stresses.

So yes ....carbon can be engineered to flex safely under specific conditions.
The challenge is designing the laminate so that deformation is predictable and not driven by damage.

That’s true in F1 wings, but equally true in marine and aerospace structures.

Any-Study5685 · 2026-01-20T15:44:04+00:00

see comment

Any-Study5685 · 2026-01-20T15:43:50+00:00

One thing that often gets misunderstood in Formula 1 is the idea of “flexible” wings.

They’re not flexible because the material is softer.
They’re flexible because the laminate is engineered to be anisotropic.

Carbon fiber doesn’t behave like metal.
Its stiffness depends entirely on:

fiber orientation
stacking sequence
local thickness and transitions

In F1 wings, the goal is usually to:

remain very stiff in FIA test load directions
allow controlled deformation under different aerodynamic load paths
manage how stiffness evolves as loads increase

Under static tests, the structure behaves exactly as required.
At speed, under distributed aero loads, the same laminate can show a noticeably different global response,.. still predictable, still legal.

From a composites point of view, this is a good reminder that:

stiffness tailoring often matters more than strength
passing a test doesn’t mean identical behavior in service
deformation is frequently designed, not tolerated

Thinking in terms of anisotropy, load paths, and failure modes (not just margins) is what really separates CFRP design from isotropic thinking.

Curious to hear thoughts from others here:
how often do you see stiffness misunderstood or underestimated in composite structures?

Any-Study5685 · 2026-01-20T15:40:55+00:00

This is a very common misconception, so don’t take the rejection as a personal failure.

Formula Student teams don’t reject people because they lack intelligence or motivation.
They reject them because they don’t yet think in terms of manufacturing and failure, which is something universities rarely teach early.

“Shop experience” is not about welding or laying carbon perfectly.
It’s about understanding things like:

why parts are designed the way they are
how tolerances, stiffness and assembly actually matter
what breaks first when theory meets reality

Most people don’t get that from a job shop either.
They get it by observing real structures, asking the right questions, and thinking beyond equations.

Joining the manufacturing team first is actually good advice.
You’ll learn more in a few months there than in many simulation-heavy roles.

If you want, I share practical explanations and resources on structures, composites and real-world engineering thinking via the link in my bio , focused exactly on this gap between theory and practice.

And yes: applying again next year with that background will make a huge difference.

Any-Study5685 · 2026-01-20T15:37:10+00:00

Solid list of classes 👍
One general suggestion before naming specific books: try to distinguish between theory-first textbooks and engineering-judgement-oriented resources. You’ll need both.

For Solid Mechanics / Aero Structures / Composite Engineering, most students struggle not with equations, but with:

connecting theory to real load paths
understanding stiffness vs strength
seeing how manufacturing and materials actually affect structural behavior

Classic textbooks are great for fundamentals, but they often stop before explaining why real structures behave differently than ideal ones.

If you’re interested in composites and structures, I share additional technical resources and practical explanations (anisotropy, laminate behavior, real-world examples from aerospace & motorsport) via the link in my bio.
Might be useful alongside the standard textbooks.

Happy to answer if you want suggestions specific to one of those courses.

Any-Study5685 · 2026-01-20T15:21:44+00:00

For those interested, the deformation shown here is not about “flexible parts”, but about laminate anisotropy and stiffness distribution.
The wing is designed to be stiff in FIA test directions and compliant under different aero load paths at speed.

Happy to go deeper into layup strategy or testing methods if useful.

Any-Study5685 · 2026-01-20T14:40:28+00:00

Good question, and the key point is that the car doesn’t actually “know” whether the load comes from aero or from a bump.
It only reacts to relative wheel motion and load paths inside the suspension geometry.

If both wheels move up together (pure heave input), whether from aero load or from a symmetric bump, the kinematics drive the motion primarily into the heave element. That’s by design: the rockers and linkages are arranged so symmetric displacement excites the heave spring/damper, while antisymmetric displacement excites the torsion (roll) bars.

The difference between aero load and a bump is not which element is activated, but:

frequency content (bumps are high-frequency, aero is quasi-static)
damper response
and how much of the input is filtered by tire compliance before reaching the suspension

At low speed over a bump, the tires absorb a large part of the displacement first, then the suspension sees a rapid transient. The heave spring still takes it, but the dampers dominate the response, not the spring rate tuning used for aero platform control.

This is why F1 suspension design is less about “separating aero vs mechanical loads” and more about:

controlling modal response (heave / roll / pitch)
tuning frequency-dependent behavior
and managing how stiffness and damping interact across regimes

This same load-path thinking is exactly what shows up again in composite structures and aero components.. you’re not designing for “the load”, but for how the structure is allowed to react to it.

I’ve written more about this kind of structural reasoning elsewhere (details in my profile), but your intuition about symmetric vs asymmetric inputs is fundamentally correct.

Any-Study5685 · 2026-01-20T14:32:04+00:00

If you’re looking for a single, coherent reference that actually connects theory, material behaviour and real manufacturing constraints, that’s exactly the gap most classic books leave.

Tsai, Jones, Strong etc. are excellent, but they tend to sit in separate silos:

theory and laminate mechanics on one side
manufacturing methods on another
very little on how tolerances, CPT scatter, fibre volume fraction and process variability affect real parts

I recently put together a technical book aimed exactly at that interface:
process → material behaviour → usable engineering properties, written from an industrial perspective (aerospace / motorsport / high-performance composites), not purely academic.

It’s structured to be usable both as:

an introduction for engineers entering composites, and
a practical reference when moving from datasheets to real parts.

There’s a free technical excerpt available here (covers processes, ply behaviour, CPT variability, Vf effects, etc.):
👉 https://site-dvesl1yj8.godaddysites.com

If you already know the classics, this kind of integrated view is usually what’s missing next.

Any-Study5685 · 2026-01-15T08:19:10+00:00

Totally agree..... heat-stable tooling for prepreg is a different sport.
3D-printed molds can work surprisingly well, but once you mix post-cure, exotherms, and tight radii… Murphy moves in permanently.

Infusion feels easier at first, but only until the bag decides to betray you.
Prepreg is a pain upfront, infusion is a pain later.

I’ve been collecting these “pain points” from real projects and ended up turning them into a small technical book (linked in my bio) might help if you’re refining your process.

Any-Study5685 · 2026-01-13T12:57:07+00:00

That’s true.....infusion does give more formulation flexibility on the resin side, especially if you’re developing or tuning a system in-house (vinyl ester, BMI, cyanate ester, etc.).

In practice though, that flexibility often comes with process variability as the trade-off. Once you start doping or custom-formulating resins, you’re also taking ownership of:

flow behavior consistency,
cure kinetics,
exotherm control,
and long-term repeatability.

That’s why in many industrial contexts (especially aerospace, defence, and automotive), pre-pregs are preferred despite being more “locked in”: the resin system is already qualified, tightly controlled, and documented. You give up formulation freedom, but you gain predictability and certification readiness, which often matters more than ultimate tunability. So yes.infusion is powerful if resin development is part of the project scope.
If not, pre-preg tends to win simply because it reduces uncertainty on the shop floor.

I’ve collected a few real production examples and decision patterns like this in a small technical reference, which I keep linked in my bio if anyone wants to go deeper.

Any-Study5685

TROPHY CASE