發信人: SAAF (武神 伐千秋)    看板: Aero
日期: Wed Dec 23 00:50:39 1998
標題: Re: 我有問題........(1)

==> yehd (pauken) 的文章中提到:
>==> mikoyan (飛來飛去的松鼠) 的文章中提到:
>>>渦輪螺旋槳和渦輪扇所適合的情況不一樣,
>>>比方說適合渦輪螺旋槳的情況下,渦輪扇就比較耗油,
>>>可是渦輪螺旋槳又不見得可以飛到適合渦輪扇的高度與速度,
>>>所以還是看需求吧!
>>TURBOprop在短場起降和低速時有較優的表現(比起turbofan)
>>再來是turbofan有分hbr和lbr兩種.lbr for fighter..hbr for airlines
>>(h/l bypass ratio)
>Low Bypass Ratio for fighter?!
>我不太清楚這是否有合理的說法?像裝置在B727的PW JT8D就是1:1的bypass ratio,
>但是727是民航機...

  1:1的旁通比在戰機上算相當高了..目前戰機中接近1:1的是
  RB199..大多數的戰機引擎其旁通比均未超過0.5...順道提供一下
  RB199的data作參考..

Typical engine data

Thrust                   9550 lbf (42.5 kN)
                         16,700 (74.1 kN) with reheat
Bypass ratio             1.02:1
Pressure ratio           Over 23:1
Compressor stages        3 low pressure, 3
                         intermediate pressure
                         and 3 high pressure
Combustion system        Annular vapourising
                         Turbine stages 1 high pressure, 1
                         intermediate pressure
                         and 1 low pressure
Basic engine weight 
(excluding thrust reverser)    2186 lb (991 kg)
我相當喜歡這款引擎..其結構緊緻,又兼高效率..
不過下一代的Ej200其旁通比又回復到0.4了..這是EJ200的data
Typical engine data

Bypass ratio                        0.4:1
Pressure ratio                      25:1 
Compressor stages                   3 LP, 5 HP 
Combustion system                   Annular vaporising 
Turbine stages                      1 HP, 1 LP 
Basic engine weight with reheat     2180-2286 lb (990-1035 kg)

  
  

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秋臨風起，葉飛此時，不是悲秋客，卻為落葉人。






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