B747與B777的引擎

B777的引擎是比B747大的,雖然B777比B747輕及細小,但由於最大起飛重量依然達B747的60%-85%,故只使用兩個引擎的B777的引擎推力高較高,自然就會更大.

一般而言,B747每個引擎的推力大概是59,000-63,000磅左右,而B777則視乎型號,由最少的77,000磅到最高的115,000磅,足足是B747引擎的兩倍. 以下是各型號引擎的資料:

--B747-400
P&W PW4062 63,300磅
General Dynamic CF6-80C2 59,500磅
Rolls Royce RB211-524 62,100磅

--B777-200
P&W PW4077 77,100磅
Rolls Royce Trent877 81,300磅
General Electric GE90-77B 81,700磅

--B777-200ER
P&W PW 4090 88,800磅
Rolls Royce Trent985 92,900磅
General Electric GE90-94B 97,300磅

--B777-200LR
General Electric GE90-110B1 110,000磅

--B777-300
P&W PW4098 95,300磅
Rolls Royce Trent892 92,500磅
General Electric GE90-94B 97,300磅

--B777-300ER
General Electric GE90-115B 115,000磅

事實上B777所使用的引擎都是目前的民航噴射機中最大的,而B777-300ER所使用的GE90-115B,它的直徑甚至跟B737的客艙直徑一樣. B777之所以使用雙引擎而非四引擎,是因為雙引擎的耗油量較少,而且營運成本較低,加上新一代的引擎非常可靠,飛行途中引擎損壞的機率極低,使本來只能用兩具以上引擎飛行的越洋航線現在可以使用雙引擎飛機飛行.

B777 have a bigger engine than B747...
This is because B777 require a more powerful engine with increased thrust that these engine require to fly longer distance and faster with only 2 engine and is doing B747 mission...
If you look at a real aircraft, you would notice that B777 have the biggest engine out of all passenger jet in operation... And also with the highest thrust although it is likely to be taken over by B787/A350 when they come into commercial operation...

B747is biger

But B777 is faster