Set sail1992

Chapter 364 I used two HT150s to build a V2 HT300
Different from Professor Xu, after listening to Zhang Qihang's thoughts, especially his judgment on the global unmanned plant protection machine market, Dean Zhao pondered for a moment, and first asked: "Let's not talk about how to cooperate, just talk about this unmanned plant protection machine market. On the man-machine, the most important subsystem is the engine, can you find a suitable engine?"

In Vice President Zhao's memory, there seems to be no such engine for sale in China.

When Professor Xu heard this, he immediately turned his head to look at Zhang Qihang: he had forgotten such an important thing.

"I used two HT150 engines to build a V90 engine with a 2-degree angle, and redesigned the stroke and bore," Zhang Qihang was already prepared. He said while taking out the engine from his bag. A design drawing was spread out on the table for Professor Xu and Vice President Zhao to see: "Compared to the long-stroke design of the HT150, this HT300 engine adopts a large-bore, short-stroke design, which places more emphasis on power output;

In addition, considering reliability and durability, internal core components such as crankshafts, connecting rods and pistons will all be made of high-strength forged materials;
Considering that the engine will work at high speed for a long time, the heat dissipation of the engine must be considered. For this reason, I have increased the total area of ​​the heat dissipation fins and can connect an external oil radiator to further cool the engine. In terms of overall strength, you two And although you can rest assured, I thought of this at the beginning of the design, this aviation version of the HT300 can even meet the needs of adding a turbo system in the future..."

Vice President Zhao and Professor Xu were stunned: While I was still worrying about the power system of this drone, Zhang Qihang had already completed the design of the engine?
But if you think about it carefully, it seems that it is indeed feasible. Strictly speaking, this HT300 is two HT150s put together. Naturally, there will be a large number of common parts. For the School of Automotive Engineering with the HT110 engine, it is indeed feasible to "combine" two HT150s into one HT150, and it is not difficult, but...

Professor Xu couldn't help asking: "What is the maximum power of your engine? Can it meet the demand?"

"According to my calculations, the maximum output power of this engine is 28 horsepower. As for whether the power is enough, I have thought about it," Zhang Qihang said, "Milliam Robinson has a two-seater civilian helicopter called Robinson R22. This helicopter The maximum take-off weight of the helicopter is 620 kg, and a 133-horsepower piston aeroengine is used. I don’t know anything about helicopter aerodynamics, but I think it should be no problem to reduce the power and take-off weight by 10 times compared with the same period...”

10 times smaller than the same period last year?
That is, the maximum take-off weight is more than 60 kilograms, and the power is about 13 horsepower?
Vice President Zhao and Professor Xu don’t understand helicopter aerodynamics and how to calculate the power required by the helicopter, but they also think that Zhang Qihang’s logic is fine: since a 133-horsepower engine can make a helicopter with a maximum take-off weight A 620kg helicopter takes off and flies smoothly, so a 13-horsepower engine can naturally allow a 60kg drone to take off smoothly.

Since it takes 13 horsepower to fly a helicopter weighing more than 60 kilograms, then the HT150 that consists of two HT300s together is not a problem, but in this way, Professor Xu is also puzzled: "Since this HT300 The power of the HT28 is 150 horsepower, so conversely, you can already increase the power of the aviation version of the HT14 to [-] horsepower, right?"

"Well, that's it."

Professor Xu asked, "Then why didn't you use the HT150 directly, but put together two HT150s to make this... um, HT300?"

This question is not only puzzled by him, but also by Vice President Zhao.

Zhang Qihang explained: "Because I heard that even in the relatively fuel-efficient level flight stage, the aero engine needs to output 14 to 150% of the power of the engine. If it is a 150-horsepower HT[-], the speed will be very high. , the foundation of HT[-] is not an aero engine after all, such a high speed will greatly consume the life of the engine;

But if it is HT150, it will be no problem. The maximum power of 28 horsepower ensures that the aircraft has sufficient reserve power. Even if the power of 15 horsepower is required, the engine speed is only around 6000 rpm, which is the "green zone" of engine power output. scope. "

When taking a bus, if you stand next to the driver and pay attention to the tachometer of the engine, you will find that the tachometer of the engine corresponds to the four speed stages of the white zone, green zone, yellow zone and red zone, needless to say the white zone Yes, if the engine speed is in the green zone, it means that this is the speed stage with the highest engine operating efficiency and the most friendly to the engine, while the yellow zone is a bit dangerous, which means that it cannot run in this range for a long time. Not to mention the red zone, which belongs to the "charging" speed, which needs to be reduced as soon as possible, otherwise it will cause irreversible damage to the engine.

With these four speed zones, the driver can see clearly at a glance, and what he has to do is to make the engine work in the "green zone" as much as possible.

Now Zhang Qihang said that the HT300 can still make the engine work in the "green zone" when it outputs 15 horsepower, which is already very remarkable, because it means that this engine will not be excessively "damaged" during use longer time.

Professor Xu said with emotion: "This is amazing."

"Of course, it's not without problems," Zhang Qihang said with a wry smile, "It's just based on my calculations that even though I have adopted many methods to reduce the weight of the engine, the wet weight of this HT300 engine is still close to 30 kilograms, and The maximum power of an aero engine of the same weight can reach more than 60 horsepower, so I estimate that the net weight of this drone is probably more than 60 kilograms. After being fully loaded with fuel and pesticides, the actual take-off weight is more than 90 kilograms , and it is even very likely to rely on 100 kilograms."

The so-called wet weight includes the weight of engine oil. A 28-horsepower aero-engine has a wet weight of nearly 30 kg. This power-to-weight ratio can make a lot of piston aero-engines laugh out loud, but then again, if If Huateng Company does not want to spend money to buy expensive special aero engines from abroad, this is the only way.

You know, even a small aero-engine with [-] or [-] horsepower dedicated to the powered delta wing of the powered parachute costs thousands or even tens of thousands of dollars each.

The price is all right, but if Huateng really wants to do this project, the number of engines that need to be imported is at least two or three hundred, which is millions of dollars, which is not a small amount.

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PS: I haven’t found any information on Yamaha R-50 before. All I can find on the Internet are information on Yamaha RMAX series of unmanned plant protection drones. I thought that the load of R-50 is also 20 kg. I just found R-50 by accident. The load of the R-50 is based on the data such as the maximum take-off weight, and I realized that I made a mistake. The load of the R-10 is [-] kg. The mistakes in the previous chapters have been corrected. Please forgive me.

(End of this chapter)