二、防击中 1.贴地飞行在60年代越南战争初期,直升机采用中空和低空飞行,直升机速度低,很容易被地面武器击中。美国在越南战争中损失直升机数量约4500架,其中绝大多数是被地面炮火击落。因此,后来有人提出了直升机利用地形地物作掩蔽进行超低空飞行——即所谓贴地飞行近敌 Second, the attack 1. Affixed to fly In the early Vietnam war in the 1960s, the helicopters used hollow and low-flying, low-speed helicopters, it is easy to hit by ground weapons. The United States lost about 4,500 helicopters during the Vietnam War, most of which were shot down by ground fire. Therefore, some people later proposed that helicopters make use of topographic features as masks for ultra-low-altitude flights - the so-called affixed to fly near enemy