一、飛機發動機的推重比是什么意思

推力重量比（英語：Thrust weight ratio）簡稱推重比（TWR），是飛機和航空發動機重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)要的(de)技術性能指標。飛機(ji)(ji)發(fa)動(dong)(dong)(dong)機(ji)(ji)推力(li)與(yu)(yu)發(fa)動(dong)(dong)(dong)機(ji)(ji)重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)量(liang)或飛機(ji)(ji)重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)量(liang)之比，它表示飛機(ji)(ji)發(fa)動(dong)(dong)(dong)機(ji)(ji)或飛機(ji)(ji)單位重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)量(liang)所產(chan)生(sheng)的(de)推力(li)。飛機(ji)(ji)發(fa)動(dong)(dong)(dong)機(ji)(ji)在海平面靜(jing)止條(tiao)件下于最大狀(zhuang)態（加(jia)力(li)發(fa)動(dong)(dong)(dong)機(ji)(ji)為全加(jia)力(li)狀(zhuang)態）所產(chan)生(sheng)的(de)推力(li)與(yu)(yu)發(fa)動(dong)(dong)(dong)機(ji)(ji)結構重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)量(liang)之比稱(cheng)為飛機(ji)(ji)發(fa)動(dong)(dong)(dong)機(ji)(ji)推重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)比，與(yu)(yu)飛機(ji)(ji)重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)量(liang)之比稱(cheng)為飛機(ji)(ji)推重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)比。一(yi)般來說(shuo)，戰斗(dou)機(ji)(ji)的(de)推重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)比較高，轟炸機(ji)(ji)等飛機(ji)(ji)的(de)推重(zhong)(zhong)(zhong)(zhong)(zhong)(zhong)比較低。

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二、飛機發動機的推重比怎么計算

推重(zhong)(zhong)比(bi)(bi)(bi)(bi)有(you)兩種：飛機推重(zhong)(zhong)比(bi)(bi)(bi)(bi)和飛機發動(dong)(dong)機推重(zhong)(zhong)比(bi)(bi)(bi)(bi)。計(ji)算飛機推重(zhong)(zhong)比(bi)(bi)(bi)(bi)用發動(dong)(dong)機產(chan)生(sheng)的(de)(de)最(zui)大(da)值的(de)(de)推力除以飛機的(de)(de)最(zui)大(da)起飛重(zhong)(zhong)量，計(ji)算飛機發動(dong)(dong)機推重(zhong)(zhong)比(bi)(bi)(bi)(bi)用發動(dong)(dong)機產(chan)生(sheng)的(de)(de)最(zui)大(da)值的(de)(de)推力除以發動(dong)(dong)機重(zhong)(zhong)量。

由于(yu)噴氣發動機(ji)產生的(de)(de)推力會隨高度的(de)(de)改變而(er)改變，飛機(ji)在攜帶(dai)不(bu)(bu)同載荷時(shi)重(zhong)(zhong)量(liang)不(bu)(bu)同，因(yin)此(ci)推重(zhong)(zhong)比的(de)(de)值在使用(yong)不(bu)(bu)同的(de)(de)推力或重(zhong)(zhong)量(liang)下會產生不(bu)(bu)小的(de)(de)差異。譬如說，當(dang)使用(yong)飛機(ji)的(de)(de)最大起飛重(zhong)(zhong)量(liang)或者是只有50%燃料的(de)(de)重(zhong)(zhong)量(liang)分別計算推重(zhong)(zhong)比時(shi)，計算出來的(de)(de)數字差別很(hen)大。

三、航空發動機推重比越大越好嗎

顯然不是。

對于民航客機而言，發動機的推重比過(guo)(guo)大會導致金屬疲勞加速(su)，噪音過(guo)(guo)大，燃油消耗(hao)過(guo)(guo)高，整個(ge)機型的安全性(xing)和經濟性(xing)都降低。

對于(yu)軍用飛機而言，推(tui)重(zhong)比大(da)是一個很(hen)不(bu)錯的(de)(de)優(you)勢，但是飛行(xing)員的(de)(de)身(shen)體承受能力(li)是有(you)限的(de)(de)，當推(tui)重(zhong)比過高(gao)，推(tui)力(li)過剩，飛行(xing)員無法(fa)在自己身(shen)體允許的(de)(de)范(fan)圍內繼續實施(shi)加速，機動等等，這樣過高(gao)的(de)(de)推(tui)重(zhong)比也形同虛設。