自制飞机需要多大马力发动机（What high-powered engine does a home-made jet need）

自制飞机需要多大马力发动机（What high-powered engine does a home-made jet need） 自制飞机需要多大马力发动机(What high-powered engine does a home-made jet need) To facilitate your reading, direct reprint, which is written by a person in Shandong, to provide your reference. = = = = = Your plane is finished. The handicraft is popular. To make her fly smoothly, the engine is indispensable. But how big can it fly? Let's first review the definition of horsepower: 1 horsepower =735N/M, approximately equal to 75 kg / M / sec, that is, 1 horsepower, you can raise 75 kilograms in 1 seconds, 1 meters. Then look at the lift drag ratio of your aircraft. In general, the first World War aircraft can do 15. The World War II aircraft with a propeller wing and a trapezoidal wing was also around 15. The modern fighter can reach 10 at subsonic speed (the higher the drag ratio is, the worse the drag ratio is). The technical content and appearance of home-made aircraft, and almost a war like an airplane, generally can reach 15, so, assuming your maximum take-off weight is 280 kg (110 kg aircraft, not exceeding the relevant provisions of the state, ultra light aircraft carrying 2 fat 170 kg), so, in the case of rising ratio of 15 stop, 18.67 kilograms of tension, 0.249 horsepower. Of course, 0.249 horsepower can only drag the aircraft forward at 1 meters per second speed, it is absolutely can not fly, according to the airfoil table to check your airfoil and area at high speed can produce 280 kg lift. For example, the minimum speed of 60 kilometers from the ground, you can produce 280 kilograms of lift, then 17 meters per second, that is, the minimum required 4.233 horsepower rally to ensure that the plane took off. In the calculation of the propeller efficiency, reasonable manual slurry in the efficiency of more than 70%, about 0.6 / 4.233 less conservative 0.6=7.05 horsepower, is your plane can carry 170 kg 7.05 horsepower take-off. If you weigh 70 kilograms, plus 110 kilograms of aircraft, the total weight of 180 kilograms, then 4.7 horsepower is enough to take off. Of course, the horsepower of the bigger the better, you can't put a 7.05 horsepower engine running at maximum engine throttle long time, absolutely can not stand, the general experience is that in half horsepower can take off, cruise 3/4 horsepower quickly in the long time. Full horsepower is a sprint. So, this calculation, 90 kg single ride in the more appropriate 10 horsepower, this data has been verified in the cricket machine. Then 90 kg double ride 15 horsepower is more appropriate. The above estimate is more conservative, if the proposition as the minimum horsepower take-off, you can do: Streamline aircraft, lift drag ratio reached 20 passengers, 75 kilograms of weight, large wing surface meet 40 kilometers off the efficiency of propeller reached 80%, then 185 20=9.25 / kg, 75=0.123, 9.25 horsepower, take-off speed 11 meters per second, then 0.123 * 11=1.35 horsepower pull, consider the propeller efficiency 0.8, 1.35 / 0.8=1.68, which is 1.68 horsepower engine full throttle, can fly, 3 horsepower pony can smooth flight. Reducing power can be tapped from the following ways: 1 reduce resistance. 2 reduce the total weight. 3 increase the wing area. The 1 and 2 is limited, it is not possible to cause the plane awl, less likely to hard weight reduced to 50 kg, the power is limited, only increase the wing area, reduce the flight speed to improve the lift, theoretically, this way is infinite. In fact, the Wright brothers is so clever to do, then, the Wright brothers aircraft weight close to 900 kilograms, the power is only 12 horsepower, then only increase this way because the lower wing area, speed, lift drag ratio as possible, which is why the slow large diameter slurry with higher efficiency, because the lower line speed. Manpower aircraft in this area better, using carbon fiber materials and plastic film and other lightweight materials, streamlined shape, especially the use of large film wing to meet the extremely slow take-off and flight lift required. A person's long power is only 0.4 horsepower, and the total weight of a man's plane is not more than 100 kilograms, so the speed of the flight is only a few meters per second.