There were some fishing fires flashing on the lake under the night sky. More than a dozen small boats were lit torches, pointing out the direction for the sailing "Experiment 15" steamship. The experimental voyage has lasted for seven hours and is still to continue.

The crew on the ship had already taken the dry food for evening food. Seeing that the minimum distance was only 60 minutes away from eight hours, everyone was very excited.

This was the longest voyage, and Experiment 1 to Experiment 14 failed to meet this requirement in the "lifetime" for various reasons.

Seeing that the eight-hour voyage was about to be completed, the technicians cheered. The success of the ship shows that their design ideas are not wrong.

There is really no need to be so complicated for steamships at the beginning, because the more complex the machine is, the more problems there will be. A machine with a high failure rate will be more likely to have problems and cause downtime when running.

Initially, the superiors' design requirements for steamships were very complicated. Although it was confirmed that it was paddle wheel propulsion, there were many requirements.

The basic principle of a steam boat is to let the steam boiler generate steam, and then the steam enters the cylinder and pushes the cylinder piston to reciprocate (piston movement), so as to drive the connecting rod to rotate the crankshaft, realize the transition from reciprocating movement to rotating movement, and then drive the oars to make the ship move forward.

Because the reciprocating frequency brought by the steam cylinder is very slow, and the rotation speed is also very slow after the transformation into rotation, it is impossible to achieve propeller propulsion, and only paddle wheel propulsion can be used.

It was determined that the steamship adopts paddle wheel propulsion method, and specific technical requirements arise.

The first technical requirement is that the left and right wheels of the steamboat share a spindle (crankshaft). The crankshaft is driven by four cylinders, and the four cylinders correspond to four steam boilers.

Steam boilers must use specially developed "ship steam boilers". In order to reduce the center of gravity of the ship, the boilers are horizontal.

The second technical requirement is that the left and right wheels have speed variables respectively to achieve different speeds of the left and right wheels. The purpose of this requirement is to make the steamboat more flexible when turning on its own.

It is even necessary to make one oar turn forward and one oar turn reverse, thereby further reducing the "radius" of the steamboat turn.

The two requirements may seem simple, but they are troublesome to implement.

The gearbox is used for gearboxes. The technicians have worked hard to make it, but the durability is very poor and problems often occur. The reason for the problem is that the gears are not hard enough and they are easily broken.

That is, metallurgical technology, manufacturing technology is not good.

Then there is the crankshaft, which is also because of the smelting technology and manufacturing technology that cannot be used, and cannot make a strong and durable crankshaft even under low speeds.

If metallurgical technology is not good, then the strength is strengthened by increasing the size of the components. The consequence is that the weight increases, and the cumulative weight of the gearbox and crankshaft increases, the four steam boilers are simply "unable to push".

Because there are many problems encountered in developing steamships, the technical requirements have been reduced again and again, and finally it has been simplified to the point that as long as the ship can continue to sail, there is no problem, and other "technical parameters" are not important.

Under this premise, the technicians have figured out many new solutions, and finally experimented one by one to screen out the simplest, reliable and easy-to-implement solutions.

This new solution says that the steamship manufactured does not require any crankshaft or speed change device. It uses four steam boilers in two groups, each of which supplies steam to one cylinder, each cylinder pushes a connecting rod, and then the connecting rod "rotates" the coaxial rocker arm of the roller.

Such a technical solution is "simple and crude", bypassing many technical difficulties and is simple and feasible.

Steam boilers use ready-made products, that is, boilers for steam pumps, and there is no need to develop any "new model" boilers; since there is no need for crankshafts, there is no need to worry about how to make a suitable crankshaft.

In this way, although there is no high-strength steam boiler and the steamboat paddles do not rotate very quickly, they can always paddle and make the ship move.

The left and right oars are rotated by different powers, and their speeds are difficult to maintain the same speed, which leads to "drift" during navigation, but this problem is easy to solve: just rely on the stern rudder to maintain the course.

As for the turning problem, because the left and right oars are not equipped with transmissions, the ship will certainly need a large turning radius when turning around. So it is not impossible to turn directly on a human tugboat.

The new solution that has abandoned a lot of technical burdens has given the steamship produced a set of simple but reliable transmission devices, and the vibration generated by the machinery on the ship has also been much smaller.

The largest source of vibration is the vibration generated when the paddle rotates. You only need to add a balance block to the coaxial rocker arms of the left and right wheels to effectively reduce vibration.

If the problem of vibration source is solved, the problem of the ship's hull deforming due to vibration and cracking will be solved.

The efforts of countless people were exchanged for the successful (to be successful) sailing of the experimental steamship today. Everyone was very happy about this, but the only drawback is that the speed of the ship was too slow.

The experimental steamship "Experiment 15" manufactured according to the new plan has a very slow navigation speed. According to the statistical results after seven hours of navigation, the average speed is about eight miles per hour.

This is the speed of sailing on a calm lake. Without the influence of going well or going against the current, it can be regarded as the normal speed of the experimental steamship.

An adult, walking on flat ground and maintains a normal walking speed, has an average walking speed of at least ten miles per hour.

In other words, today's "Experiment 15" only solves the problem of continuous navigation, and the speed is too slow, and even a person's walking speed is not as good as that of a person.

If we use humans as a metaphor, the steamboat at this time is probably just a toddler.

Such a slow "still water" speed makes the steamboat have no practical significance, because the ship's self-weight is great, and the sailing speed is not as good as a normal sailboat that does not require burning coal when it is flowing along the river.

When it comes to the backwater, the steamship will sail even slower.

But this is not a problem that technicians are currently struggling with. Everyone has figured it out. You have to eat it one bite at a time, otherwise you will choke to death.

Technical difficulties must be overcome one by one. First, we must ensure that the steamship can maintain a continuous navigation capacity of at least eight hours. During this period, the boiler will not explode and the hull will not crack and leak. That's all.

On this basis, solve the speed problem.

The superiors' requirements for steamships have been relaxed a lot, which gives technicians enough time to improve and improve their designs and ideas.

Perhaps it takes another five or ten years to "toddler" steamships to "step as fast as they fly" and sail in rivers, lakes and seas.

On the deck, people were watching the wall clock, waiting for the exciting moment to come.

In the cabin, the boiler workers were adding coal to the steam boiler. The place was very hot, so the boiler workers took turns to "on duty". They finally waited for so long, and as time was about to come, they were also very excited.

Then I found a problem: the coal stored on the ship was not enough to burn.

This problem is very serious, because the experimental steamship must be completed at the premise of full speed for eight hours, and must be powered by the coal carried by the ship itself, and must not be used for "external force".

To this end, the technicians took a series of calculations and took into account the size of the coal bin when designing the ship structure, and finally the finished product of "Experiment No. 15" was found.

The coal bin is covered as required, so there is no possibility of piled up hills. Now, there is not enough coal on the ship.

What's the problem? The technicians who learned the bad news were so anxious that they sweated. Finally, they came to a conclusion: there was something wrong with the previous calculation.

This is the root cause of the problem that was found during design. It is too late to change it.

The practice of reducing the power of the boiler is cheating, which is not allowed, so the crew on the ship watched the boat slow down and the oars gradually stopped rotating, and time seemed to solidify.

Eight hours are still thirty minutes away.
Chapter completed!