Aircraft Landing Gear Layouts 飞机起落架设计（中英文对照图）发布人：圣才学习网发布日期：2010-06-25 14:36 共292人浏览[大] [中] [小] Most aircraft today have three landing gear．许多现代飞机使用三点式起落架。
Two main landing gear struts located near the middle of the aircraft usually support about 90% of the plane’s weight while a smaller nose strut supports the rest．重心附近的两个大的主轮，承担约90% 的重量，小轮子承担余下部分。
This layout is most often referred to as the "tricycle" landing gear arrangement．However，there are numerous other designs that have also been used over the years，and each has its own advantages and disadvantages．Let’s take a closer look at the various undercarriage options available to engineers．目前的飞机以前三点起落架为主，让我们来回顾一下后三点起落架及其优缺点。
（意译）Tail wheel or Tail dragger Gear后三点尾轮式与后三点尾橇式起落架Though the tricycle arrangement may be most popular today，that was not always the case．The tail wheel undercarriage dominated aircraft design for the first four decades of flight and is still widely used on many small piston－engine planes．虽然前三点起落架比较普遍，但是在几十年前的飞机，及当今的许多小型飞机是使用后三点起落架的。
The taildragger arrangement consists of two main gear units located near the center of gravity （CG）that support the majority of the plane’s weight．后三点起落架，由两个在重心靠前位置的主轮支持大部分的飞机重量。
A much smaller support is also located at the rear of the fuselage such that the plane appears to drag its tail，hence the name．一个非常小的尾轮装置在机身，看上去这个小轮子是被拖着走，所以，英文Taildragger 也因此而得名。
This tail unit is usually a very small wheel but could even be a skid on a very simple design．它即可以是一个小尾轮，也可以是一个尾橇。
后三点起落架What makes this form of landing gear most attractive is its simplicity．后三点起落架最吸引人的优点就是“简洁”。
The gear are usually relatively lightweight，and the two main gear can also be easily encased in streamlined fairings to produce low drag in flight．后三点起落架通常重量都比较轻。
两支主轮子可以配置整流置用来减小飞行中的阻力。
Another potential advantage results from the fact that the plane is already tilted to a large angle of attack as it rolls down the runway．另一个潜在的优点，是飞机在跑道滑行时，机翼已经有一个较大的迎角。
This attitude helps to generate greater lift and reduce the distance needed for takeoff or landing．合适的大迎角，有利于在较低的速度下产生足够的升力，以便于减少起飞滑跑距离。
This attitude is also an advantage on propeller－driven planes since it provides a large clearance between the propeller tips and the ground．对于牵引式螺旋桨飞机，机头向上抬起，使螺旋桨不会接触跑道。
（意译）Furthermore，taildragger planes are generally easier for ground personnel to maneuver around in confined spaces like a hangar．同时，后三点起落架的飞机，更便于地勤人员把飞机拖到停机棚等窄小的空间里。
However，the greatest liability of this landing gear layout is its handling characteristics．另一方面，后三点起落架也有一个最大的缺陷——着陆时的操纵（handling characteristics）．This design is inherently unstable because the plane’s center of gravity is located behind the two main gear．造成此天生缺陷的原因，是因为两只主轮在重心的前面。
If the plane is landing and one wheel touches down first，the plane has a tendency to veer off in the direction of that wheel．如果着陆时起落架只有一只主轮前触地，这时，飞机有向此轮子一边转弯倾向。
This behavior can cause the aircraft to turn in an increasingly tighter "ground loop" that may eventually result in scraping a wingtip on the ground，collapsing the gear，or veering off the runway．严重时，这种转弯的倾向（ground loop）将可能使翼尖触地、起落架受损、滑出跑道。
Landing a taildragger can be difficult since the pilot must line up his approach very carefully while making constant rudder adjustments to keep the plane on a straight path until it comes to a stop．这就要求在飞机着陆触地前，需要使用方向舵修正自己的航线，使它能够笔直的滑翔直到安全触地。
Many taildragger designs alleviate these handling problems by fitting a tailwheel that can be locked instead of swiveling on a castor．Locking the tailwheel helps keep the plane rolling in a straight line during landing．使用尾橇，能减轻这种现象。
（意译）前三点起落架与后三点起落架的安定性对比Another disadvantage of the taildragger is poor pilot visibility during taxiing since he is forced to peer over a nose that is tilted upward at a steep angle．后三点起落架的另一个缺点，许多飞机在地面滑跑，机头向上翘起时，会影响飞行员的视线。
（意译）It is also often difficult to load or unload heavy cargos because of the steep slope of the cabin floor．对于货机，飞机的迎角不利于货物的装卸。
Similarly，pilots and passengers are forced to walk uphill during boarding and downhill after arrival．此问题，对于乘客来说，也是一样的道理。
（意译）Many aircraft also rely on gravity to bring fuel from tanks to the engine，and some planes have been known to have difficulty starting the engine because it is uphill from the fuel supply．发动机抬起，有时也不利于供油，造成启动困难。
道格拉斯DC－3的后三点起落架Good examples of taildragger aircraft include the Spitfire and DC－3 of World War II．后三点起落架的典型例子：喷火战斗机、道格拉斯DC－3。
Tricycle or Nosewheel Gear前三点起落架Now the most popular landing gear arrangement，the tricycle undercarriage includes two main gear just aft of the center of gravity and a smaller auxiliary gear near the nose．前三点起落架，由两支在重心后的主轮，与一个在机头的辅助前轮组成。
