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93 votes

Why don't they build airplanes from 3D printer plastic?

My assumption is that there are plastics lighter and stronger than the materials used to build planes. That is not a correct assumption. Typical 3D printer plastics have a best-case tensile ...
Therac's user avatar
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75 votes
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Why is the 787 tail cone made out of titanium?

Whenever you see titanium being used on aircraft, look for heat sources. The metallic alternative aluminum is usually lighter and much cheaper. In most commercial aircraft the APU (Auxiliary Power ...
Gypaets's user avatar
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46 votes
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Why would a jet engine that runs at temps excess of 2000°C burn when it crashes?

How The Jet Engine Works: Inside the typical commercial jet engine, the fuel burns in the combustion chamber at up to 2000 degrees Celsius. The temperature at which metals in this part of the engine ...
Zach Lipton's user avatar
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45 votes
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Why are Li-ion batteries not being used in aircraft but are widely used in electric vehicle industry?

Boeing put them in 787. They caused the type to be grounded for a bit over two months in 2013 due to battery fires. Li-ion battery fires of consumer electronic devices are also semi-regular occurrence ...
Jan Hudec's user avatar
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43 votes
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Why was the SR-71 made of titanium?

Because the specific strength of titanium at higher temperatures is better than that of steel (both are much better than that of aluminium). Specific strength vs. temperature is shown on the above ...
Koyovis's user avatar
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36 votes
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How strong is aircraft-grade spruce?

My recollection of the Modulus of Rupture is about 6000 psi for aircraft graded sitka, based on the maximum allowed grain runout, and a maximum of around 10000 for straight grain. But you should be ...
John K's user avatar
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33 votes

Why don't they build airplanes from 3D printer plastic?

Let's take ABS, which is an extremely common plastic used for 3D Printing. At a typical flight altitude, the exterior air temperature will be in the order of -51°C/-60°F. The lowest rated temperature ...
waiwai933's user avatar
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28 votes

Was wood used in the construction of the TU-144?

You're looking at a typical metal wing's innards with stringers (small lateral stiffeners made from aluminum angle) riveted to aluminum sheet, and the remnants of wing ribs also attached. The colour ...
John K's user avatar
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27 votes

Why are Li-ion batteries not being used in aircraft but are widely used in electric vehicle industry?

If we're talking about using the batteries for propulsion (and we're talking about aircraft that can carry at least one person) then it boils down to, in a word, weight, or in two words energy density....
motosubatsu's user avatar
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21 votes

Why was the SR-71 made of titanium?

There is a great article here that breaks it down in depth but its combination of factors made it the best choice, not a single factor (i.e. heat resistance). But, in reality, the strongest titanium ...
Dave's user avatar
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20 votes

Why has aluminium, rather than steel, prevailed in airliner construction?

You are right, on first sight it is actually surprising that aluminium prevailed. It comes with some disadvantages: Crack growth must come first in this list. With only a small cyclic load, cracks in ...
Peter Kämpf's user avatar
19 votes

Why would a jet engine that runs at temps excess of 2000°C burn when it crashes?

Peter's answer to another question has a nice chart that shows internal jet engine temperatures: You can see that the temperatures are highest by a fairly large factor in the combustion chamber. ...
Dave's user avatar
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17 votes
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Why are the leading edges on the Boeing 787 made from aluminum?

There are probably many factors in choosing aluminum vs. composites. A big one is bird strikes. The leading edges are at the highest risk for this. Metal tends to absorb the impact better while ...
fooot's user avatar
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17 votes

How are engines mounted onto wings?

Engine mounts and thrust links How are engines mounted onto wings? Modern engines are hanged to the pylon struts fixed to the wings, at two mounts, using an attachment device named hanger ...
mins's user avatar
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15 votes
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Who manufactures the landing gear on the Airbus A350 series aircraft?

The landing gears are manufactured by Messier-Dowty, a Safran group company. According to their site, Safran Landing Systems is responsible for the design, development, qualification testing, ...
aeroalias's user avatar
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14 votes

What are all the composites used in the making of fighter jets? What is the green and yellow material on the aircraft in the pictures below?

Composites in aerospace are mostly Kevlar/Epoxy and Carbon/Epoxy, with some fibreglass (which has better compression stiffness than Kevlar and is sometimes combined with it). Carbon composites are ...
John K's user avatar
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13 votes

Why don't they build airplanes from 3D printer plastic?

There's a few things going on here. You assume plastics are stronger and lighter than the metals and composites used for aircraft manufacture today. Therac's answer counters this assumption (spoiler: ...
Dan Hulme's user avatar
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13 votes

Why are Li-ion batteries not being used in aircraft but are widely used in electric vehicle industry?

Actually, Li-ion batteries are used in aeroplanes - the grounding of the Boeing 787 in 2013 was caused by problems with them. From Wikipedia: In 2013, the second year of service for the Boeing 787 ...
Koyovis's user avatar
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12 votes
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Can stainless steel replace titanium for Mach 3+ speeds?

Both the MiG-25 and MiG-31 designs had engines that would overheat and be damaged an anything past Mach 2.83, so both planes were limited by this. Typical speeds were closer to Mach 2.5 to extend the ...
fooot's user avatar
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11 votes
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What components of the Boeing 787 are made out of titanium?

The Boeing 787 is special due to its high count of composite parts. When aluminium comes in contact with graphite fiber, contact corrosion will damage the aluminium whereas titanium will be unaffected ...
Peter Kämpf's user avatar
11 votes

Why are Li-ion batteries not being used in aircraft but are widely used in electric vehicle industry?

Why are Li-ion batteries not being used in aircraft Actually they are. They are widely used in model airplanes, "drones", etc, which the (U.S.) Federal Aviation Administration refers to as ...
quiet flyer's user avatar
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10 votes
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Why is there such a low level of automation in the aerospace industry (compared to other industries such as automobile)?

There are two big factors at play here: scale and throughput. First, automation is very good at repetitive tasks. The Wolfsburg plant produces over 800,000 cars per year. It's taken 25 years to make ...
fooot's user avatar
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10 votes

Why are Li-ion batteries not being used in aircraft but are widely used in electric vehicle industry?

Lithium Ion main ship batteries (non-propulsion) have been making their way into general aviation, helicopters, and business jets over the last 5 - 10 years. Certification of new technology in ...
selectstriker2's user avatar
9 votes

Why don't they build airplanes from 3D printer plastic?

As other answers mention, the strength of molded or printed plastics is an order of magnitude lower than that of typical aerospace metals. But also the stiffness is much lower. Compare Al 7075, which ...
Peter Kämpf's user avatar
8 votes

Can stainless steel replace titanium for Mach 3+ speeds?

Let's note some properties of steel and titanium. For steel, we choose 4340 alloy (oil-quenched and tempered); for titanium, we use the Ti-6Al-4V alloy (solution heat-treated and aged). These are not ...
Sanchises's user avatar
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8 votes

How strong is aircraft-grade spruce?

As mentioned in this answer: spruce has a strength of 27.5 N/mm$^2$ in compression, from the 1941 document also linked. Specific strength of spruce is about 2/3 of that of aluminium.
Koyovis's user avatar
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8 votes
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What material is the B737 wing skin made out of?

Aluminum alloy 7178 on the upper skin Aluminum alloy 7055 on the lower skin Here is some technical information
Aaron Holmes's user avatar
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