Re: [問題] 那個主起落架設計

看板Aviation作者ahpc82 (Ping)時間10年前 (2014/02/11 00:20)推噓8(8推 0噓 0→)

留言8則, 7人參與討論串2/2 (看更多)

A.net原討論串 http://goo.gl/AlhyrF 簡單翻譯其中兩則回文；才疏學淺，請多指教。 -- Air2gxs Reply 6, posted Tue Sep 11 2001 02:38:34 (UTC +8) The gear is tilted to fit into the wheel well. (...) It is much easier to tilt the gear than to design a wheel-well to accomadate an un-tilted gear. 主起落架會先傾斜再收入輪艙。設計一個能傾斜的起落架比硬挖一個輪艙把起落架直直收進去容易的多。 -- 777236ER Reply 9, posted Tue Sep 11 2001 09:38:02 (UTC +8) The 777 is a good example of all of the tilted-gear issues. When coming out (or going into) the gear bays, the gear is tilted at 5 degrees DOWN t[o] fit into the bays (the 777 MLG is HUGE!). When down (in flight) the MLG is tiled 13 degrees up. This is for a number of reasons. Firstly, the gear will straighten to the horizontal before the full weight of the aircraft is placed on the gear strut, so the landing is softened. Secondly, when the gear goes to the horizontal upon touchdown, the torque produced helps level the aircraft. Admittedly, this torque isn't much, but it helps. 以這類設計來說，777是一個很好的例證。當從輪艙收起（或放出）時，起落架會呈現 5度向下 (*1) 以利收入。但當在空中完全放下時，會呈現13度向上 (*2) 。這當中有許多原因：首先，降落時在全機重量轉移到輪柱前，起落架有一逐漸旋轉 (*3) 至水平的過程，故得以緩衝降落時的衝擊力道。其二，起落架在觸地時向前旋轉時，其產生之力矩有助於航機之landing roll out。當然這個力矩其實蠻小的，但或多或少有幫助。註一：前端較低，如圖 http://goo.gl/pl7PDt 註二：如影片：http://youtu.be/HhWKxJGfS3U

註三：原文 "straighten" ，私以為有更好的翻譯用詞，還請指教。 [Interesting note, the 767 has the unusual tendancy to pitch down quite rapidly during landing, which is why the MLG on the 67 is tilted forwards. Upon touchdown, the MLG straightens and stops the pitching forward. The downside to this, however, is that the the forward gear on the MLG touchdown first, so the 767 landing is quite a bit rougher than the 757 or the 777, both of which have up-tilted gear] 有趣的是，767落地的時候會有迅速減低仰角此一不尋常的現象，所以啦，767的主起落是前低後高的。然而這樣做的缺點是，767落地時靠前的主輪會先著地，所以比起前高後低的757或777，767落地顯得比較...紮實。 The on-ground logic is usually triggered by oleo compression, so tilting the gear doesn't really make that much difference in that respect. (*4) Air-ground的偵測係由減震支柱之壓縮 (*5) 作為判斷基準，與該傾角無關。註四：前文亦討論此傾斜機制用於作為航機air/ground之偵測。註五：此機制Chiardy教官也曾在本板提到。 #1E65pPAp (Aviation) -- 春風吹放自由花。崩崩崩崩。 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 111.243.116.17 ※ 編輯: ahpc82 來自: 111.243.116.17 (02/11 00:21)

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