# What's the maximum extent an airliner can be built out of composites? **URL:** \ **Category:** Factual Questions\ **Created:** [February 1, 2015, 1:47pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509 "2015-02-01T13:47:16Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [February 1, 2015, 1:47pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509/1 "2015-02-01T13:47:16Z")
Composite-made airliners seem to be all the rage these days, being lightweight and saving fuel. I am assuming many airplane manufacturers are using composites as much as possible in designs in order to make the airplane lightweight, so what is the maximum percentage of content that an airplane could be made out of composites? Could an airliner be 70% or 80% comprised of composite materials? Could fighter jets be made of composites to save weight, or is that not practical? ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [February 1, 2015, 2:09pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509/2 "2015-02-01T14:09:52Z")
What parts? The fusalage? The wings/tail? The engines farings? ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [February 1, 2015, 2:36pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509/3 "2015-02-01T14:36:31Z")
The Boeing 787 Dreamliner and the Airbus A350 XWB are both at over 50 percent composites, according to the manufacturers. I don’t know how much higher they can go. > [@](#): > > Over 70 percent of the A350 XWB’s weight-efficient airframe is made from advanced materials combining composites (53%), titanium (14%) and advanced aluminium alloys (19%). Most of the A350 XWB’s wing is made of the lightweight carbon fibre reinforced plastic (CFRP) composites, including its upper and lower covers – measuring 32 metres long by six metres wide, making them the largest single aviation parts ever made from carbon fibre. The nose section uses a mix of 55 per cent aluminium/aluminium-lithium alloys, 40 per cent composites and five per cent titanium. There’s more info, including some factors which are limiting more use of composites, in the full article, here: [http://www.lemauricien.com/article/airbus-versus-boeing-composite-materials-sky-s-limit](http://www.lemauricien.com/article/airbus-versus-boeing-composite-materials-sky-s-limit) Fighter jets use composites to both save weight and aid in stealth capabilities. Most of the visible surfaces on an F-35 are composites. To be fair, though, much of the inside of the plane is not composites. Only about a third of the total weight of the plane is composites. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [February 1, 2015, 2:38pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509/4 "2015-02-01T14:38:15Z")
> [@AK84](#): > > What parts? The fusalage? The wings/tail? The engines farings? Well, the airplane as a whole. I’m assuming that many aircraft manufacturers would have maximum incentive to make as much of the aircraft out of as lightweight material as possible; no point in making the airplane 45% out of composites if it could be 53%. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [February 1, 2015, 2:54pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509/5 "2015-02-01T14:54:03Z")
F1 cars, which are practically aeroplanes with wheels, are, apart from the engine and gearbox, almost entirely made of carbon fibre. The very strict and rigourously enforced rules make the cars heavier and less aerodynamic than they could be. When they crash, the car practically disintegrates but the driver is left sitting in his shell. [![]( " - YouTube") ](https://www.youtube.com/watch?v=CbtiW8W8wfA) ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 1, 2015, 4:30pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509/6 "2015-02-01T16:30:59Z")
The Boeing 787 is just about as much composite as possible. IOW, 100% of the things which can be composite are composite. What’s not composite are things like engines and landing gear. The result is that measured by cubic inch of material, a huge fraction of the material is composite. But composite is light and the vast majority of what’s still metal is fancy grades of steel which is 10x as heavy per cubic inch. So measured by weight the aircraft is a much lower percentage of composite. I read some numbers last week but I’m having a hard time locating them to cite now. Ballpark IIRC it’s 95+% composite by volume but only 60% by weight. ---
**Author:** ![Enlightening\_Meditation](https://avatars.discourse-cdn.com/v4/letter/e/ecc23a/32.png) [@Enlightening\_Meditation](https://boards.straightdope.com/u/Enlightening_Meditation)\ **Post date:** [February 3, 2015, 5:42pm UTC](https://boards.straightdope.com/t/whats-the-maximum-extent-an-airliner-can-be-built-out-of-composites/711509/7 "2015-02-03T17:42:08Z")
> [@LSLGuy](#): > > The result is that measured by cubic inch of material, a huge fraction of the material is composite. But composite is light and the vast majority of what’s still metal is fancy grades of steel which is 10x as heavy per cubic inch. So measured by weight the aircraft is a much lower percentage of composite. Also, many of the metal components (turbine blades, etc) in jet engines are creep resistant nickel-based superalloys which have density slightly greater than steel.