[交流] 汽车发动机可以改造为好的飞机发动机么？By Stephen Pope / Published: Apr 09, 2012 已有2人参与

You can find the question posed on just about every well-trodden aviation message board on the Internet: Why can’t we just use fuel-efficient and cheap car engines in our airplanes? The answer, in a nutshell, is that the best automobile engine in the world is usually still a poor aircraft engine. Here are the reasons why:% R9 K6 L# u& @3 U$ Q& J 你可以经常从那些航空类BBS上看到一些说烂掉的话题：为什么我们不能在飞机上使用燃油效率更高、价格更低的汽车发动机呢？答案是：极其简单的说，世界上最好的汽车发动机，仍然是一种烂航空发动机。以下是原因：# }& c: s) y5 p% b2 ~ * X! i8 P  [4 n1 M& A2 Y1 f Car engines are designed to provide quick bursts of relatively high power output for acceleration, and then only modest power output for steady-state cruising. It’s unusual for an auto engine to operate anywhere near its redline rpm or max-rated power output. Airplanes, on the other hand, usually take off and climb near 100 percent power output, followed by steady-state cruise often at 75 percent power. Aircraft engines are designed to sustain this punishment reliably over a typical 2,000-hour service life. Try running your car’s engine at or near redline rpm all the time and see what happens. Of course, we don’t know what will happen, and in an airplane we can’t pull over to the side of the road when it does. 汽车发动机设计在相对较高的功率输出下提供更快的加速能力，用于加速，但是在定常巡航状态功率输出平平。对于任何汽车发动机而言，长时间让它工作于接近红线的RPM状态或者最大标称功率输出条件下，是不太常见的。飞机，则是另一种应用需求了，通常要求在起飞和爬升时期使用接近100%的功率输出，在定常巡航状态下使用75%左右的功率。飞机发动机设计为适用于这种高度苛刻的可靠性要求之下，并且使用寿命一般还要达到2000小时。你试试让你的汽车发动机在红线RPM附近一直运转，再看看会发生什么？当然了，我们并不准确的知道这样会发生什么，但是在飞机上，我们不能像使用汽车一样，当发动机真正出故障了，我们可以把它停在路边。& _+ X6 ?6 w- c, U+ h* J$ }   Q* ~4 W4 s% U2 T% u5 P; j Why couldn’t your car engine run at, say, 2,700 rpm all the time, about the same as that of many piston aircraft engines producing full power? Reciprocating aircraft engines generally spin a propeller via direct drive, with the prop essentially bolted to the crankshaft. Typically, piston aircraft engines produce peak power output at a redline near 2,700 rpm. But compared with car engines, aircraft engines produce gobs of torque at relatively low rpm. Auto engines, on the other hand, usually produce very little torque at those settings, while also relying on liquid cooling. They’re generally designed to produce their peak power at settings above 6,000 rpm, and so to work they need a reduction gear box.( [* i( \8 M7 F6 `# V) p 为什么汽车发动机不能这样使用？即在2700RPM条件下提供最大功率？这种转速与许多的活塞飞机发动机转速相同。往复式飞机发动机通常是直驱的，螺旋桨通过螺栓连接到曲轴上。通常，活塞飞机发动机产生峰值功率输出，其红线位于2700RPM左右。但是与汽车发动机相比，飞机发动机的最大扭矩数值产生在相对较低的RPM条件下。汽车发动机则是另一种情况了，通常在这些设置下扭矩较低，而且也要依赖于水冷。他们通常设计在6000RPM时产生峰值功率，这就是为什么他们需要减速箱。0 S2 F9 y/ L9 n3 r' s- \; s/ _' N Still, that hasn’t stopped some manufacturers from adapting automotive engines for aviation duty, and often with impressive results. Austro Engine did it with its super-efficient AE300 turbodiesel based on a Mercedes-Benz engine. Viking Aircraft Engines of Edgewater, Florida, meanwhile, has adapted the engine from the tiny Honda Fit for use in LSAs. Its liquid-cooled gasoline engine (pictured) produces 110 hp at 5,800 rpm and burns just 3.5 gph at its economy cruise setting. 但是，这都没有阻止很多制造商将汽车发动机改装为航空发动机的努力，他们有时候也会取得一些令人印象深刻的成果。Diamond飞机公司的Austro AE300涡轮增压柴油发动机基于Mercedes-Benz汽车发动机设计，FL的Edgewater的Viking也将许多Honda Fit发动机成功改装到LSA上。它的液冷汽油机可以在5800 RPM条件下产生110 hp功率，而巡航油耗仅仅3.5GPH。 073645esbge4gcgb7l0azi.jpg

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