Aerospace & defence
The most demanding home for composites. Every kilogram burns fuel for the life of the aircraft and failure is catastrophic — so aerospace pushes the highest strength-to-weight and the most rigorous proof of any industry. Modern airframes are now roughly half composite by weight.
On the numbers: every material named here links to its cited entry — stiffness, strength and density with sources. This page is the map of what flies where, and why the real design number comes from a test, not just a calculation.
A composite is a fibre that carries the load, held in a matrix that transfers it and sets the temperature ceiling. Aerospace chooses both deliberately.
Fibres — the load-carriers
Carbon — IM7
Intermediate-modulus carbon: the primary-structure workhorse where stiffness and strength per kilogram matter most.
Cited data →Carbon — AS4
Standard-modulus carbon: tough, well-characterised, the backbone of countless qualified laminates.
Cited data →Carbon — T300
The original standard-modulus carbon — a reference fibre still used across general structure.
Cited data →Aramid — Kevlar 49
Impact- and damage-tolerant, radar-transparent, light — used in radomes, leading edges and armour.
Cited data →Glass — S2
High-strength glass: cheaper than carbon, radar-transparent, forgiving — radomes and secondary structure.
Cited data →Glass — E
The commodity glass fibre — electrical-grade, low cost, for fairings and interiors.
Cited data →Matrices — the binder
Epoxy
The standard aerospace thermoset: cured in an autoclave, good to ~120–180 °C. Most qualified prepregs are epoxy.
Cited data →PEEK / PEKK
Thermoplastic matrix: tough, reformable, out-of-autoclave, and it can be welded rather than bonded.
Cited data →PEI (Ultem)
Amorphous thermoplastic for interiors — flame-retardant, meeting cabin flame/smoke/toxicity rules.
Cited data →Phenolic
The fire-resistant thermoset behind cabin panels and ducting where smoke and flame are the design driver.
Cited data →Qualified laminae — fibre + matrix, characterised together
A single ply is a lamina. These are the systems we hold cited data for — open one for its stiffness, strength and provenance.
The same material system is chosen differently around the aircraft — stiffness here, fire resistance there, radar transparency at the nose.
| Zone | What drives it | Typical system |
|---|---|---|
| Primary structure | Wing box, fuselage skins, spars and frames — the parts whose failure is catastrophic. Highest performance, fully certified. | IM7 / AS4 carbon-epoxy prepreg, autoclave-cured |
| Control surfaces & fairings | Flaps, ailerons, radome mounts, access panels — secondary structure, often honeycomb sandwich for stiffness at low weight. | Carbon or glass skins on Nomex honeycomb |
| Radomes | Must be transparent to radar — so never carbon. Glass or quartz laminates that protect the antenna without blinding it. | S2 / quartz glass-epoxy, aramid |
| Cabin interiors | Panels, ducts, stow bins — driven by flame, smoke and toxicity rules, not strength. | Phenolic-glass, PEI (Ultem) |
| Engine & hot zones | Beyond epoxy's ceiling — bypass ducts, nacelles, and increasingly ceramic-matrix composites in the hot section. | BMI, thermoplastics, CMC |
| Impact & leading edges | Where bird strike and debris hit first — toughness and damage tolerance beat raw stiffness. | Aramid, glass, tough thermoplastics |
A laminate is a stack of thin plies, each laid at a chosen fibre angle. Because a ply is far stiffer along its fibres than across them, the angle sequence tailors the whole part to its load path.
The default shown is quasi-isotropic [0/±45/90]s — equal fibre in four directions, so it behaves the same in-plane whichever way you load it. It is balanced (every +45 has a −45) and symmetric about the mid-plane (the dashed line), which stops it warping as it cures.
Compute a real layup: run classical laminate theory for the ABD stiffness, micromechanics for a single ply, or read the learning path from first principles.
A calculation starts the design; a test finishes it
Certified aerospace structure is qualified by the building-block pyramid — thousands of coupons at the base, up through elements, details and subcomponents, to a handful of full-scale tests at the top. Each level catches what the level below cannot, so the analysis is anchored to real data at every step.
And the number you design to is not a typical value but a statistical allowable (A- or B-basis), knocked down further for hot-wet conditions and barely-visible impact damage. This rigour — sourced data, validated models, honest knock-downs — is exactly what mpolyco is built on.
Go deeper: the test pyramid and design allowables.
Part of the Make map. Browse the cited materials database, or see the same honesty applied to 3D printing.