Gigantism Is a Never-Ending Temptation for Engineers and Designers

From the pyramids to the Hummer, more is often less

3 min read

There is a fundamental difference between what can be designed and built and what makes sense. History provides a lesson in the shape of record-setting behemoths that have never since been equaled.

The Egyptian pyramids started small, and in just a few generations, some 4,500 years ago, there came Khufu’s enormous pyramid, which nobody has ever tried to surpass. Shipbuilders in ancient Greece kept on expanding the size of their oared vessels until they built, during the third century BCE, a tessarakonteres, with 4,000 oarsmen. That vessel was too heavy, too ponderous, and therefore a naval failure. And architect Filippo Brunelleschi’s vast cupola for Florence’s Cathedral of Santa Maria del Fiore, built without scaffolding and finished in 1436, was never replicated.

The modern era has no shortage of such obvious overshoots. The boom in oil consumption following the Second World War led to ever-larger oil tankers, with sizes rising from 50,000 to 100,000 and 250,000 deadweight tonnes (dwt). Seven tankers exceeded 500,000 dwt, but their lives were short, and nobody has built a million-dwt tanker. Technically, it would have been possible, but such a ship would not fit through the Suez or Panama canals, and its draft would limit its operation to just a few ports.

The economy-class-only configuration of the Airbus A380 airliner was certified to carry up to 853 passengers, but it has not been a success. In 2021, just 16 years after it entered service, the last plane was delivered, a very truncated lifespan. Compare it with the hardly puny Boeing 747, which will see its final delivery in 2022, 53 years after the plane’s first flight, an almost human longevity. Clearly, the 747 was the right-sized record-breaker.

Of course, the most infamous overshoot of all airplane designs was Howard Hughes’s H-4 Hercules, dubbed the Spruce Goose,” the largest plane ever made out of wood. It had a wingspan of nearly 100 meters, and it was propelled by eight reciprocating engines, but it became airborne only once, for less than a minute, on 2 November 1947, with Hughes himself at the controls.

Another right-size giant is Ford’s heavy and powerful F-150, now in its 14th generation: In the United States, it has been the bestselling pickup since 1977 and the best-selling vehicle since 1981. In contrast, the Hummer, a civilian version of a military assault vehicle, had a brief career but is now being resurrected in an even heavier electric version: The largest version using an internal combustion engine, the H1, weighed nearly 3.5 tonnes, the electric Hummer, 4.1 tonnes. I doubt we will see 14 generations of this beast.

But these lessons of excess carry little weight with designers and promoters pursuing record sizes. Architects discuss buildings taller than a mile, cruise ship designers have already packed nearly 7,000 people into a single vessel (Symphony of the Seas, built 2018) and people are dreaming about much larger floating cities (perfect for spreading the next pandemic virus). There are engineers who think that we will soon have wind turbines whose more than 200-meter diameter blades will fold, like palm fronds, in hurricanes.

Depending on where you stand you might see all of this either as an admirable quest for new horizons (a quintessential human striving) or irrational and wasteful overreach (a quintessential human hubris).

This article appears in the January 2022 print issue as “Extreme Designs.”

Gigantism in the Air

Overhead view of four airplanes. The Airbus 380-800, Antonov An-225,  Hughes H-4 Hercules, and the Boeing 737-MAX7

John MacNeill

Many flying behemoths have been tried, and most have failed. Of the planes shown in the illustration, the only one that has succeeded is the Antonov An-225, designed in the Soviet Union in the 1980s. This large cargo-lifter carries up to 130 tons of heavy machinery or construction parts on chartered flights to all continents

The Conversation (2)
Daniel Jassby29 Jan, 2022
LM

The giant ITER tokamak currently under construction is another example of technology “overshoot.”  Assuming that it is actually completed, ITER may turn out to be the Spruce Goose of the fusion R&D world.

Undaunted, fusion energy enthusiasts in the European Union and Asian countries are designing so-called Demonstration fusion reactors that are supposed to follow ITER and look like ITER on steroids.  Fortunately, all these projects will collapse in their design phase.

FB TS21 Dec, 2021
INDV

IMHO the (revolutionary) future of airliners is NOT simply making current designs much bigger (like Airbus A380) nor going hypersonic nor switching to flying wing/body designs!

What is really needed is making airliners much bigger but also making them much safer & able to takeoff/land vertically or from/to extremely short/simple/cheap runways anywhere!

How?

For example, imagine joining together 2 or 3 fuselages & adding 2 or 3 sets of main wings that has highly adjustable angle of attack (& no other complex mechanisms/flaps etc)!

The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

5 min read
Vertical
A photo of a high-stability film resistor with the letters "MIS" in yellow.
All photos by Eric Schlaepfer & Windell H. Oskay
Blue

Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to “accidental beauty: the emergent aesthetics of things you were never expected to see.”

From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don’t spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor.

High-Stability Film Resistor

A photo of a high-stability film resistor with the letters "MIS" in yellow.

All photos by Eric Schlaepfer & Windell H. Oskay

This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film.

Instead of coating the resistor with an epoxy, it’s hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy.

15-Turn Trimmer Potentiometer

A photo of a blue chip
A photo of a blue chip on a circuit board.

It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety.

The resistive element in this trimmer is a strip of cermet—a composite of ceramic and metal—silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It’s a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers.

Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film.

Ceramic Disc Capacitor

A cutaway of a Ceramic Disc Capacitor
A photo of a Ceramic Disc Capacitor

Capacitors are fundamental electronic components that store energy in the form of static electricity. They’re used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator.

A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc’s outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage.

Film Capacitor

An image of a cut away of a capacitor
A photo of a green capacitor.

Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene.

The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value.

Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film.

Dipped Tantalum Capacitor

A photo of a cutaway of a Dipped Tantalum Capacitor

At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid.

Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use.

The device’s positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet.

Axial Inductor

An image of a cutaway of a Axial Inductor
A photo of a collection of cut wires

Inductors are fundamental electronic components that store energy in the form of a magnetic field. They’re used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics.

Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor.

This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value.

Power Supply Transformer

A photo of a collection of cut wires
A photo of a yellow element on a circuit board.

This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet.

The small wires nearer the center are “high impedance” turns of magnet wire. These windings carry a higher voltage but a lower current. They’re protected by several layers of tape, a copper-foil electrostatic shield, and more tape.

The outer “low impedance” windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current.

All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer.

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