I made up a list of failed ideas that were tested during my lifetime and was surprised at how many there were.
Perhaps the most spectacular was the destruction of the Hindenburg, a German dirigible. It was filled with hydrogen gas and caught fire as it was landing in New Jersey after crossing the ocean. That catastrophy ended the efforts to establish commercial passenger service by giant gas filled zeppelins.
The autogyro was a combination airplane and helicopter. It had a propeller in front and helicopter blades that were not rotated by the engine. They and the craft's stubby wings were to provide lift. It didn't last.
The Army once tried to make their tanks float so they could be launched from landing craft and floated to shore. The floating apparatus would then be discarded and the tank would proceed on its treads. Many of the "floating tanks" sank. Not a good idea.
I think it was England that worked on the idea of having submarines powered by steam engines. Such subs would be able to move fast enough to keep up with surface ships. A steam engine requires a large boiler and a big and hot fire. Those first subs were fast enough but it took more than 30 minutes to submerge. That's because the fires had to be put out and the engine cooled before the craft could dive. When it came back to the surface, it took a long time to restart the fires and build up steam again. Far too long.
There have been many ideas for improving automobiles and that includes some that just didn't prove to be practical. I remember the Chrysler Airflow.
Its radical streamlined shape just wasn't accepted by customers. Maybe it just was ahead of its time. I thought it was kind of cool.
The Edsel was also way ahead of it's time with several new ideas. One of those was a center-mounted headlight. It would turn when the front wheels turned so the light was always shining where the car was going to go, not where it was pointing. Many people made fun of the Edsel and it may be the biggest flop in automotive history.
I remember when some cars were equipped with Free Wheeling. There was a knob on the dashboard that could be pulled out and then every time the driver took his foot off the gas, the car would shift into neutral and coast. That proved to be dangerous and wore out the brakes very quickly.
Some of our most modern electric cars reverse their electric motors to serve as generators when the driver takes his foot off the gas. That slows the car down and recharges the battery. That's better than what Free Wheeling was supposed to do.
Before the automatic transmission replaced the stick shift, I owned a car that had the shift lever on the steering column instead of on the floor. Another shift system that didn't last very long was the electric shift. Those cars had a very small device, about two inches square, with a tiny lever that shifted the gears. I think it was mounted either to the left of the steering wheel or to the right of the steering column.
I remember when windshield wipers were powered by engine vacuum and every time the car labored up a hill, the wipers stopped. That usually happened just when the driver most needed to see where he was going. Bad idea!
This next idea may not have actually been sold to the public, but it may have been tried. Plastic engine blocks! Certain parts would be made of steel and inserted into the plastic block, such as cylinder liners and valve seats. I think the reason that idea didn't work was that the plastic expanded too much when heated and didn't conduct heat away fast enough to cool the engine.
Torsion bars didn't work either. Instead of a coil spring or leaf springs, the car used a bar of spring steel that would be twisted instead of bent. The problem was the bar would twist only so far and then break.
The mangle was another idea that was not accepted by customers. It was an electric ironing machine. It was expensive, used lots of electricity, took up a lot of space, and most women never learned how to use it to do anything more than just iron bed sheets and pillowcases. There is one in the Maple Heights Historical Society Museum. Visitors under the age of 30 or so have no idea what it is. Those over about 60 see it and immediately tell a story of who they knew that had one.
Also in the Bedford museum, you can find an X-ray machine that was used in shoe stores to see how a shoe fit. It was used mostly for fitting children's shoes that needed to be a bit large to allow for rapid childhood growth. Can you imagine the danger of all that radiation?
One of the more stupid ideas was to sell milk in plastic bags instead of glass bottles or jugs, or waxed paper cartons or plastic jugs. All the milk would run out if there was even a little pinhole in the bag. If the bag tore, there was no way to pick it up before all the milk ran out. The store's display case was always a mess.
A similar idea was the self-serve bulk section in a grocery store. Sugar, honey, syrup, flour, salt, coffee beans, rice, and a variety of such merchandise was on display in large containers. Customers were to weigh and package their purchases themselves. There was a lot of waste, and a lot of spilled food items all over the floor. Yukky!
How many drivers remember the rotary left turn? You turned right to go left. How confusing.
The grand-daddy of all failed ideas was Prohibition.