JP3973433B2 - Composite rotorcraft - Google Patents

Description

【００４２】
ここで、式の簡略化のため、以下のような近似を行う。
【数２】

【００４３】
これら（２）の近似式を用いることによって、（１）式は以下のように簡略化される。
【数３】

【００４４】
前記（３）式によって、機体に作用する抵抗Ｄｆを増加させると、ロータ迎角α_TPPが負の方向（下向き）に増大して、主回転翼２０が前方に傾斜することが明らかとなる。また、機体に作用する抵抗Ｄｆを減少させると、ロータ迎角α_TPPが正の方向（上向き）に増大して、主回転翼２０が後方に傾斜することが明らかとなる。
【００４５】
次いで、本実施の形態に係る複合回転翼航空機を用いた具体的制御動作について説明する。
【００４６】
＜緩降下飛行領域に係る制御動作＞
まず、ＢＶＩ騒音発生域のうち降下率約０〜約３００ｆｔ／ｍｉｎの飛行領域（以上および以下において、「緩降下飛行領域」という）に係る制御動作について説明する。この緩降下飛行領域に係る制御動作は、回転翼面を積極的に前方に傾斜させて、先行する回転翼羽根の先端から発生する翼端渦が後続する回転翼羽根の「下方」を通過するような状態（図３（ａ）参照）を積極的に作り出すことによって、ＢＶＩ騒音の発生の抑制を図るものである。
【００４７】
具体的には、速度計７０に検出された機体の前進速度が前進速度約４０〜約１００ｋｔの範囲内にあり、かつ、昇降計８０によって検出された機体の降下率が約０〜約３００ｆｔ／ｍｉｎの範囲内にある場合に、制御用コンピュータ９０が固定翼４０の後縁側に取り付けられたフラップ５０を回動させて、このフラップ５０の角度が固定翼４０の翼弦線に対して９０°をなすように設定し（図１参照）、機体に作用する抵抗Ｄｆを増大させる。
【００４８】
機体に作用する抵抗Ｄｆが増大すると、前記した（２）式により、ロータ迎角α_TPPが負の方向（下向き）に増大して、主回転翼２０が前方に傾斜する。従って、先行する回転翼羽根の先端から発生する翼端渦は、後続する回転翼羽根の下方を通過する。この結果、翼端渦と後続する回転翼羽根との干渉を回避することができるので、ＢＶＩ騒音の発生を抑制することができる。
【００４９】
図６に、この緩降下飛行領域におけるフラップ５０の角度と機体の前進速度との関係、および、推進手段である補助推進用ファン６０による推力（重量比）と機体の前進速度との関係を示している。この図６に示すように、機体の前進速度が０〜４０ｋｔの範囲にあるときには、フラップ５０を９０°に設定して、主回転翼２０がつくりだす吹き下ろし流の流れを妨げないようにすることによって、ホバー効率を向上させることができる。
【００５０】
従来は、図６に点線で示したように、機体の前進速度が４０ｋｔを超えるとフラップ５０の角度を９０°から０°へと漸次戻していたが、本実施の形態では、機体の前進速度が４０ｋｔを超えてもフラップ５０を９０°のまま維持して抵抗増大手段として機能させる。機体の前進速度４０〜１００ｋｔのＢＶＩ騒音発生域においてフラップ５０の角度を９０°のまま維持することによって、機体に作用する抵抗Ｄｆを増大させることができ、主回転翼２０を前方に傾斜させて、ＢＶＩ騒音の発生を抑制することができる。
【００５１】
一方、図６に示すように、機体の前進速度は、推進手段である補助推進用ファン６０による推力（重量比）の増加に伴って増大させる。
【００５２】
次いで、緩降下飛行領域に係るＢＶＩ騒音抑制制御動作を、（２）式をグラフ化した図７を用いて説明する。
【００５３】
緩降下飛行領域において、例えば機体の前進速度が７０ｋｔの場合においては、降下率が３００ｆｔ／ｍｉｎの場合にＢＶＩ騒音が最大となる。以下、このように前進速度が７０ｋｔで降下率が３００ｆｔ／ｍｉｎの場合を「マキシマムケース」と称し、このマキシマムケースにおける飛行方向角をγ^*とする。
【００５４】
図７には、縦軸にロータ迎角α_TPPを、横軸に機体に作用する抵抗Ｄｆをとり、前記した「マキシマムケース」における（２）式のグラフを示している（なお、降下飛行状態においては、飛行方向角γが「負」となるため、右辺第２項の「−γ」は「正」の値となる）。この図７に示すように、制御前において機体に作用する抵抗がＤｆ₀であったとすると、「マキシマムケース」においては、図７のＡ点に示したようにロータ迎角α_TPPの値がほぼゼロとなっており、ＢＶＩ騒音が発生する状態にある。
【００５５】
ここで、本実施の形態に係る制御手段である制御用コンピュータ９０により、抵抗増大手段であるフラップ５０を回動させて機体に作用する抵抗を増大させた結果、抵抗がＤｆ₁を超えると、「マキシマムケース」における（２）式のグラフ上のＡ点がＡ₁点に移動して、ロータ迎角α_TPPの値が「負」となる。このことは、主回転翼２０が前方に傾斜したことを意味する。従って、「マキシマムケース」において、先行する回転翼羽根の先端から発生する翼端渦は、後続する回転翼羽根の下方を通過することとなり、ＢＶＩ騒音の発生が抑制される。
【００５６】
以上説明したとおり、緩降下飛行領域においては、機体に作用する抵抗を増大させてＤｆ₁を超えるようにすれば、ロータ迎角α_TPPの値が常に「負」となり、一様流に対して回転翼面が前方に傾斜することとなる。従って、先行する回転翼羽根の先端から発生する翼端渦は、後続する回転翼羽根の「下方」を常に通過することとなり、ＢＶＩ騒音の発生が抑制される。
【００５７】
＜急降下飛行領域に係る制御動作＞
次に、ＢＶＩ騒音発生域のうち降下率約３００〜約６００ｆｔ／ｍｉｎの飛行領域（以上および以下において、「急降下飛行領域」という）に係る制御動作について説明する。この急降下飛行領域に係る制御動作は、先行する回転翼羽根の先端から発生する翼端渦が後続する回転翼羽根の「上方」を通過するような状態（図３（ｃ）参照）を積極的に作り出すことによって、ＢＶＩ騒音の発生の抑制を図るものである。
【００５８】
具体的には、速度計７０に検出された機体の前進速度が約４０〜約１００ｋｔの範囲内にあり、かつ、昇降計８０によって検出された機体の降下率が約３００〜約６００ｆｔ／ｍｉｎの範囲内にある場合に、制御用コンピュータ９０が、補助推進用ファン６０によって機体に作用する推力を増加させ、機体に作用する抵抗Ｄｆを減少させる。
【００５９】
機体に作用する抵抗Ｄｆが減少すると、前記した（２）式により、ロータ迎角α_TPPが正の方向（上向き）に増大して、主回転翼２０が後方に傾斜する。従って、先行する回転翼羽根の先端から発生する翼端渦は、後続する回転翼羽根の「上方」を通過する。この結果、翼端渦と後続する回転翼羽根との干渉を回避することができるので、ＢＶＩ騒音の発生を抑制することができる。
【００６０】
図８に、この急降下飛行領域におけるフラップ５０の角度と機体の前進速度との関係、および、推進手段である補助推進用ファン６０による推力（重量比）と機体の前進速度との関係を示している。この図８に示すように、機体の前進速度が０〜４０ｋｔの範囲にあるときには、フラップ５０を９０°に設定して、主回転翼２０がつくりだす吹き下ろし流の流れを妨げないようにすることによって、ホバー効率を向上させることができる。また、機体の前進速度が４０ｋｔを超えた場合には、フラップ５０の角度９０°から０°に漸次戻して機体に作用する抵抗を低減させる。
【００６１】
一方、図８に示すように、機体の前進速度が４０ｋｔを超えた時点で補助推進用ファン６０による推力（重量比）を増大させ、機体に作用する抵抗を減少させる。機体の前進速度約４０〜約１００ｋｔのＢＶＩ騒音発生域において、補助推進用ファン６０の推力を増大させることによって、機体に作用する抵抗Ｄｆを減少させることができ、主回転翼２０を後方に傾斜させて、ＢＶＩ騒音の発生を抑制することができる。
【００６２】
次いで、急降下飛行領域に係るＢＶＩ騒音抑制制御動作を、（２）式をグラフ化した図９を用いて説明する。
【００６３】
図９には、図７と同様に縦軸にロータ迎角α_TPPを、横軸に機体に作用する抵抗Ｄｆをとり、前記した「マキシマムケース」における（２）式のグラフを示している。この図９に示すように、制御前において機体に作用する抵抗がＤｆ₀であったとすると、「マキシマムケース」においては、図９のＡ点に示したようにロータ迎角α_TPPの値がほぼゼロとなっており、ＢＶＩ騒音が発生する状態にある。
【００６４】
ここで、本実施の形態に係る制御手段である制御用コンピュータ９０により、推進手段である補助推進用ファン６０の推力を増大させることによって機体に作用する抵抗を減少させた結果、抵抗がＤｆ₂より小さくなると、「マキシマムケース」における（２）式のグラフ上のＡ点がＡ₂点に移動して、ロータ迎角α_TPPの値が「正」となる。このことは、主回転翼２０が後方に傾斜したことを意味する。従って、「マキシマムケース」において、先行する回転翼羽根の先端から発生する翼端渦は、後続する回転翼羽根の「上方」を通過することとなり、ＢＶＩ騒音の発生が抑制される。
【００６５】
以上説明したとおり、急降下飛行領域においては、機体に作用する抵抗を減少させてＤｆ₂より小さくすれば、ロータ迎角α_TPPの値が常に「正」となり、一様流に対して回転翼面が後方に傾斜することとなる。従って、先行する回転翼羽根の先端から発生する翼端渦は、後続する回転翼羽根の「上方」を常に通過することとなり、ＢＶＩ騒音の発生が抑制される。
【００６６】
なお、機体の前進速度と降下率との相対的関係により、前記した「マキシマムケース」のように緩降下飛行領域と急降下飛行領域の双方に属するケースが生じる。このようなケースにおいては、「緩降下飛行領域」に係る制御動作、または、「急降下飛行領域」に係る制御動作のいずれか一方を採用することによって、ＢＶＩ騒音の発生を抑制することができる。
【００６７】
続いて、本実施の形態に係る複合回転翼航空機を用いたＢＶＩ騒音抑制制御動作を、「ＢＶＩ騒音発生域の移動」という観点から説明する。
【００６８】
本実施の形態に係る複合回転翼航空機を用いてＢＶＩ騒音抑制制御を行わない場合には、ＢＶＩ騒音発生域は図４に示した領域で示されるのは前記したとおりである。この図４に示した領域の中の「最大騒音域」Ｌ（機体の前進飛行速度約６０〜約８０ｋｔ、降下率約２００〜約４００ｆｔ／ｍｉｎの飛行領域）を図１０に実線で示した。
【００６９】
本実施の形態に係る複合回転翼航空機を用いたＢＶＩ騒音抑制制御動作では、図７で説明したように、「緩降下飛行領域」においては機体に作用する抵抗を増大させてＤｆ₁を超えるようにし、ロータ迎角α_TPPの値が常に「負」となるように制御することによって、先行する回転翼羽根の先端から発生する翼端渦を後続する回転翼羽根の「下方」を通過させてＢＶＩ騒音の発生を抑制している。
【００７０】
すなわち、本実施の形態に係る複合回転翼航空機を用いて「緩降下飛行領域」に係る制御動作を施すと、図１０に示した「最大騒音域」Ｌから下方（降下率の大きい方向）に移動した領域Ｌ₁でＢＶＩ騒音が発生することとなる。しかし、「最大騒音域」Ｌから下方に移動した領域Ｌ₁においては、前記した「急降下飛行領域」の制御動作が施されるため、ＢＶＩ騒音が発生することはない。
【００７１】
一方、本実施の形態に係る複合回転翼航空機を用いたＢＶＩ騒音抑制制御動作では、図９で説明したように、「急降下飛行領域」においては機体に作用する抵抗を減少させてＤｆ₂より小さくし、ロータ迎角α_TPPの値が常に「正」となるように制御することによって、先行する回転翼羽根の先端から発生する翼端渦を後続する回転翼羽根の「上方」を通過させてＢＶＩ騒音の発生を抑制している。
【００７２】
すなわち、本実施の形態に係る複合回転翼航空機を用いて「急降下飛行領域」に係る制御動作を施すと、図１０に示した「最大騒音域」Ｌから上方（降下率の小さい方向）に移動した領域Ｌ₂でＢＶＩ騒音が発生することとなる。しかし、「最大騒音域」Ｌから上方に移動した領域Ｌ₂においては、前記した「緩降下飛行領域」の制御動作が施されるため、ＢＶＩ騒音が発生することはない。
【００７３】
本実施の形態に係る複合回転翼航空機は、揚力を発生させる固定翼４０と、前進推力を発生させるため主回転翼２０とは別に胴体１０に設けられた推進手段である補助推進用ファン６０と、を有する。従って、主回転翼２０の揚力の一部を固定翼４０に負担させるとともに補助推進用ファン６０によって推進力を得ることができるので、高速化を図ることができる。
【００７４】
また、本実施の形態に係る複合回転翼航空機は、機体に作用する抵抗を増大させる抵抗増大手段であるフラップ５０と、機体の前進速度および降下率に応じてフラップ５０および補助推進用ファン６０を制御する制御手段である制御用コンピュータ８０とを備え、この制御用コンピュータ８０は、機体の前進速度および降下率がＢＶＩ騒音発生域にある場合に、緩降下飛行領域においてフラップ５０を制御して機体に作用する抵抗を増大させて回転翼面を前方に傾斜させるとともに、機体の降下率が比較的大きい急降下飛行領域において補助推進用ファン６０を制御して機体に作用する前進推力を増大させて回転翼面を後方に傾斜させるものであるため、緩降下飛行領域および急降下飛行領域において異なる制御動作を施して、効果的にＢＶＩ騒音の発生を抑制することができる。
【００７５】
すなわち、「緩降下飛行領域」においては、制御用コンピュータ９０によってフラップ５０を駆動して機体に作用する抵抗Ｄｆを増大させて回転翼面を前方に傾斜させると、先行する回転翼羽根から流出する翼端渦は、後続する回転翼羽根の「下方」を通過することとなるため、これら翼端渦と後続する回転翼羽根との干渉を回避してＢＶＩ騒音の発生を抑制することができる。また、「急降下飛行領域」においては、制御用コンピュータ９０によって補助推進用ファン６０による前進推力を増大させて機体に作用する抵抗Ｄｆを減少させて回転翼面を後方に傾斜させると、先行する回転翼羽根から流出する翼端渦は、後続する回転翼羽根の「上方」を通過することとなるため、これら翼端渦と後続する回転翼羽根との干渉を回避してＢＶＩ騒音の発生を抑制することができる。
【００７６】
この結果、通常の回転翼航空機よりも最大速度が大きくなり、高速での飛行が実現できるとともに、ＢＶＩ騒音の発生を抑制して低騒音化を図ることができる。すなわち、高速化と低騒音化を同時に達成することができる。
【００７７】
さらに、本実施の形態に係る複合回転翼航空機は、固定翼４０の後縁側に設けられたフラップ５０を抵抗増大手段としても機能させることができるため、別途抵抗増大手段を設ける必要がない。
【００７８】
[第２の実施の形態]
本実施の形態に係る複合回転翼航空機は、第１の実施の形態に係る複合回転翼航空機において抵抗増大手段のみを変更したものであり、その他の構成については実質的に同一であるので、重複する構成については説明を省略する。
【００７９】
本実施の形態においては、図１１に示すように、固定翼４２が回動軸５２を中心として回動可能とされてなる。すなわち、固定翼４２は、制御用コンピュータ９０の制御のもとにその取付角が可変とされ、例えば図１１のように９０°回動させることによって抵抗増大手段として機能させることができ、ＢＶＩ騒音の発生の抑制に寄与することができる。
【００８０】
[第３の実施の形態]
本実施の形態に係る複合回転翼航空機は、第１の実施の形態に係る複合回転翼航空機において抵抗増大手段のみを変更したものであり、その他の構成については実質的に同一であるので、重複する構成については説明を省略する。
【００８１】
本実施の形態においては、図１２に示すように、固定翼４３の上面および下面にスポイラ５３が設けられている。このスポイラ５３は、制御用コンピュータ９０の制御のもとに開閉され、抵抗増大手段としてＢＶＩ騒音の発生の抑制に寄与することができるものである。
【００８２】
[第４の実施の形態]
本実施の形態に係る複合回転翼航空機は、第１の実施の形態に係る複合回転翼航空機において、テールブーム後方の構造を変更するとともに推進手段を変更したものであり、その他の構成については実質的に同一であるので、重複する構成については説明を省略する。
【００８３】
本実施の形態においては、図１３に示すように、主回転翼１０のトルクを打ち消すために反トルク制御用ベーン３０に代えてテールロータ３４を設けるとともに、テールブーム１１に水平尾翼１２および垂直尾翼１３を設けている。また、テールロータ３４の後方にプッシャープロペラ６４を設けている。このプッシャープロペラ６４は、制御用コンピュータ９０の制御のもとに駆動制御され、推進手段としてＢＶＩ騒音の発生の抑制に寄与することができるものである。
【００８４】
[第５の実施の形態]
本実施の形態に係る複合回転翼航空機は、第１の実施の形態に係る複合回転翼航空機において、同軸反転型の主回転翼を採用して反トルク制御用ベーンを不要としたものであるとともに推進手段を変更したものであり、その他の構成要件については実質的に同一であるので、重複する構成については説明を省略する。
【００８５】
本実施の形態においては、図１４に示すように、テールブーム１１の後方に水平尾翼１２Ａおよび垂直尾翼１３Ａを設けるとともに、ダクテッドファン６５を設けている。このダクテッドファン６５は、制御用コンピュータ９０の制御のもとに駆動制御され、推進手段としてＢＶＩ騒音の発生の抑制に寄与することができるものである。
【００８６】
【発明の効果】
請求項１記載の発明によれば、通常の回転翼航空機よりも最大速度が大きくなり、高速での飛行が実現できるとともに、ＢＶＩ騒音の発生を抑制して低騒音化を図ることができる。すなわち、高速化と低騒音化を同時に達成することができる。
【００８７】
請求項２記載の発明によれば、「緩降下飛行領域」および「急降下飛行領域」において異なる制御動作を施して、効果的にＢＶＩ騒音の発生を抑制することができる。
【００８８】
すなわち、「緩降下飛行領域」においては、制御手段によって抵抗増大手段を制御して機体に作用する抵抗を増大させて回転翼面を前方に傾斜させ、先行する回転翼羽根から流出する翼端渦が後続する回転翼羽根の「下方」を通過するようにして翼端渦と後続する回転翼羽根との干渉を回避することによって、ＢＶＩ騒音の発生を抑制することができる。
【００８９】
また、「急降下飛行領域」においては、制御手段によって推進手段を制御して機体に作用する前進推力を増大させて回転翼面を後方に傾斜させ、先行する回転翼羽根から流出する翼端渦が後続する回転翼羽根の「上方」を通過するようにして翼端渦と後続する回転翼羽根との干渉を回避することによって、ＢＶＩ騒音の発生を抑制することができる。
【００９０】
請求項３記載の発明によれば、固定翼の後縁側に設けられた可動翼を、フラップやスポイラとして機能させると同時に抵抗増大手段としても機能させることができる。
【００９１】
請求項４記載の発明によれば、固定翼の取付角が可変とされてなるため、固定翼自体を抵抗増大手段として機能させることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る複合回転翼航空機の構成を説明するためのものであり、（ａ）が側面図、（ｂ）が（ａ）のＢ部分の平面図（上から見た図）である。
【図２】ＢＶＩ騒音の発生原理を説明するためのものであり、翼端渦の軌跡と翼端渦干渉位置とを主回転翼の上方から見た状態を示す説明図である。
【図３】ＢＶＩ騒音の発生原理を説明するためのものであり、（ａ）は水平飛行時の翼端渦の軌跡を、（ｂ）は所定の降下率で降下飛行した場合の翼端渦の軌跡を、（ｃ）は（ｂ）よりも大きい降下率で降下飛行した場合の翼端渦の軌跡を、それぞれ主回転翼の側方から見た状態を示す説明図である。
【図４】ＢＶＩ騒音が発生する領域を示す分布図である。
【図５】本発明の第１の実施の形態に係る複合回転翼航空機を用いたＢＶＩ騒音抑制制御動作の原理を説明するための説明図である。
【図６】本発明の第１の実施の形態に係る複合回転翼航空機を用いた緩降下飛行領域におけるＢＶＩ騒音抑制制御動作を説明するためのものであり、（ａ）は抵抗増大手段であるフラップの角度と機体の前進速度との関係を表すグラフであり、（ｂ）は推進手段である補助推進用ファンの推力（重量比）と機体の前進速度との関係を表すグラフである。
【図７】本発明の第１の実施の形態に係る複合回転翼航空機を用いた緩降下飛行領域に係るＢＶＩ騒音抑制制御動作において、機体に作用する抵抗の増大に伴ったロータ迎角の変化を説明するためのＤｆ−α_TPP線図である。
【図８】本発明の第１の実施の形態に係る複合回転翼航空機を用いた急降下飛行領域におけるＢＶＩ騒音抑制制御動作を説明するためのものであり、（ａ）は抵抗増大手段であるフラップの角度と機体の前進速度との関係を表すグラフであり、（ｂ）は推進手段である補助推進用ファンの推力（重量比）と機体の前進速度との関係を表すグラフである。
【図９】本発明の第１の実施の形態に係る複合回転翼航空機を用いた急降下飛行領域に係るＢＶＩ騒音抑制制御動作において、機体に作用する抵抗の減少に伴ったロータ迎角の変化を説明するためのＤｆ−α_TPP線図である。
【図１０】本発明の第１の実施の形態に係る複合回転翼航空機を用いたＢＶＩ騒音抑制制御動作を「ＢＶＩ騒音発生域の移動」という観点から説明するための分布図である。
【図１１】本発明の第２の実施の形態に係る複合回転翼航空機の抵抗発生手段（固定翼）を示す側面図である。
【図１２】本発明の第３の実施の形態に係る複合回転翼航空機の抵抗発生手段（スポイラ）を示す側面図である。
【図１３】本発明の第４の実施の形態に係る複合回転翼航空機の推進手段（プッシャ−プロペラ）を示す斜視図である。
【図１４】本発明の第５の実施の形態に係る複合回転翼航空機の推進手段（ダクテッドファン）を示す斜視図である。
【図１５】従来の複合回転翼航空機の斜視図である。
【図１６】ＢＶＩ騒音の発生原理を説明するための説明図である。
【図１７】従来の回転翼航空機の平面図である。
【符号の説明】
１０ 胴体
１１ テールブーム
１２ 水平尾翼
１２Ａ 水平尾翼
１３ 垂直尾翼
１３Ａ 垂直尾翼
２０ 主回転翼
２１ トランスミッション
２２ エンジン
３０ 反トルク制御用ベーン
３４ テールロータ
４０ 固定翼
４２ 固定翼（取付角可変式）
４３ 固定翼
５０ フラップ
５２ 回動軸
５３ スポイラ
６０ 補助推進用ファン
６１ ファン用ドライブシャフト
６２ ファン駆動用トランスミッション
６４ プッシャ−プロペラ
６５ ダクテッドファン
７０ 速度計
８０ 昇降計
９０ 制御用コンピュータ
１００ 従来の複合回転翼航空機
２００ 従来の回転翼航空機
２１０ 胴体
２２０ 抵抗板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite rotary wing aircraft, and more particularly, to a composite rotary wing aircraft capable of reducing BVI noise generated during a predetermined descent flight.
[0002]
[Prior art]
Conventionally, rotary wing aircraft have been used in various fields such as transportation of goods, lifesaving, and national defense. Since this rotary wing aircraft flies by generating lift and thrust by the rotary wing, it has a characteristic that the maximum speed is lower than that of the fixed wing aircraft.
[0003]
For this reason, for the purpose of increasing the maximum speed of a rotary wing aircraft, a rotary wing aircraft equipped with a fixed wing and a propulsion device, that is, a “compound” rotary wing aircraft has been proposed, and its flight has been realized. Yes. This composite rotorcraft has a maximum speed higher than that of a normal rotorcraft because the lift of the rotor blades can be partially borne by the fixed wings and propulsion can be obtained by the propulsion device. In recent years, a composite rotorcraft 100 having a configuration as shown in FIG. 15 has been proposed (see US Pat. No. 5,738,301).
[0004]
On the other hand, when the rotary wing aircraft lands, as shown in FIG. 16, the wing tip vortex V flowing out from the wing tip of the preceding rotary wing blade B1 interferes with the subsequent rotary wing blade B2. Noise is generated. This noise is referred to as “BVI (Blade Vortex Interaction) noise” and is one of the factors that hinder the increase in operation of rotorcraft.
[0005]
In order to suppress the occurrence of this BVI noise, for example, a rotary wing aircraft 200 described in US Pat. No. 5,437,419 has been proposed (see FIG. 17). The rotary wing aircraft 200 is configured to suppress the generation of BVI noise by inclining the rotor wing surface by opening the resistance plate 220 provided on the side portion of the fuselage 210 under flight conditions in which BVI noise is generated. .
[0006]
[Problems to be solved by the invention]
When the composite rotary wing aircraft 100 as shown in FIG. 15 is employed, the maximum speed is higher than that of a normal rotary wing aircraft, but BVI noise is still generated during low-speed flight such as landing.
[0007]
On the other hand, when the rotary wing aircraft 200 shown in FIG. 17 is adopted, BVI noise can be reduced. However, since the resistance plate 220 is provided on the side of the fuselage 210, it is suitable for the structure of the composite rotary wing aircraft. There was a possibility that it was not possible to achieve high speed.
[0008]
An object of the present invention is to achieve both high speed and low noise by reducing BVI noise generated during a predetermined descent flight in a composite rotorcraft.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, the invention described in claim 1 is a propulsion provided on a fuselage separately from a fixed wing for generating lift and a rotary wing for generating forward thrust as shown in FIG. A resistance increasing means for increasing the resistance acting on the fuselage, and a control means for controlling the resistance increasing means and the propulsion means in accordance with the forward speed and the descent rate of the fuselage.With
  The control means controls the resistance increasing means and the propulsion means when the forward speed and the descent rate of the aircraft are in the BVI noise generation range.It is characterized by that.
[0010]
According to the first aspect of the present invention, the composite rotary wing aircraft includes the fixed wing for generating lift and the propulsion means provided on the fuselage separately from the rotary wing for generating forward thrust. A part of the lift force can be borne by the fixed wing and a propulsive force can be obtained by the propulsion means. Therefore, the maximum speed is significantly higher than that of a normal rotary wing aircraft.
[0011]
According to the first aspect of the present invention, there is provided resistance increasing means for increasing the resistance acting on the airframe, and control means for controlling the resistance increasing means and the propulsion means in accordance with the forward speed and the descent rate of the airframe. For example, in a descent flight state where BVI noise is generated, the resistance acting on the fuselage can be increased or decreased by the control means, and the rotor surface can be tilted forward or backward. For this reason, the blade tip vortex flowing out from the preceding rotor blade can be separated from the subsequent rotor blade, and the generation of BVI noise can be suppressed.
[0012]
Therefore, the maximum speed is higher than that of a normal rotary wing aircraft, and high-speed flight can be realized, and generation of BVI noise can be suppressed and noise reduction can be achieved. In other words, high speed and low noise can be achieved at the same time.
[0013]
According to a second aspect of the present invention, in the composite rotary wing aircraft according to the first aspect, for example, as shown in FIG. 12, the control means is configured so that the forward speed and the descent rate of the airframe are within the BVI noise generation range. In the slow descent flight region where the descent rate of the aircraft is relatively small, the resistance increasing means is controlled to increase the resistance acting on the aircraft, thereby tilting the rotor surface forward and making the descent flight with a relatively large descent rate of the aircraft In the region, the propulsion means is controlled to increase the forward thrust acting on the airframe, thereby tilting the rotor blade surface backward.
[0014]
According to the second aspect of the present invention, when the forward speed and the descent rate of the aircraft are in the BVI noise generation area, the control means controls the resistance increasing means in the slow descent flight area where the descent rate of the aircraft is relatively small. Increase the resistance acting on the fuselage to incline the rotor blade surface forward, and increase the forward thrust acting on the fuselage by the control means controlling the propulsion means in the sudden descent flight region where the descent rate of the fuselage is relatively large Since the rotor blade surface is inclined rearward, different control operations can be performed in the slow descent flight region and the steep descent flight region to effectively suppress the occurrence of BVI noise.
[0015]
That is, in the “slow descent flight region”, the control means controls the resistance increasing means to increase the resistance acting on the fuselage, and the rotor surface is inclined forward, so that the blade flowing out from the preceding rotor blade Since the end vortex passes “below” the subsequent rotor blade, the interference between the blade vortex and the subsequent rotor blade can be avoided and the generation of BVI noise can be suppressed. In the “sudden descent flight region”, the tip of the blade that flows out from the preceding rotor blade is obtained by controlling the propulsion device by the control device to increase the forward thrust acting on the fuselage and inclining the rotor surface backward. Since the vortex passes “above” the subsequent rotor blade, the interference between the blade tip vortex and the subsequent rotor blade can be avoided and the generation of BVI noise can be suppressed.
[0016]
According to a third aspect of the present invention, in the composite rotary wing aircraft according to the first or second aspect, for example, as shown in FIG. 1, the fixed wing includes a movable wing on a trailing edge side thereof, and the resistance increasing means is And the movable wing.
[0017]
According to the third aspect of the present invention, the movable wing provided on the trailing edge side of the fixed wing can function as a flap or a spoiler and can also function as a resistance increasing means. Therefore, it is not necessary to provide additional resistance increasing means.
[0018]
According to a fourth aspect of the present invention, in the composite rotary wing aircraft according to the first or second aspect, for example, as shown in FIG. 11, the fixed wing has a variable mounting angle. It is the fixed wing.
[0019]
According to the fourth aspect of the present invention, since the fixed blade has a variable mounting angle, the fixed blade itself can function as a resistance increasing means. Therefore, it is not necessary to provide additional resistance increasing means.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a configuration of a composite rotorcraft according to the present invention and a BVI noise suppression control operation using the composite rotorcraft will be described.
[0021]
First, the configuration of the composite rotary wing aircraft according to the present embodiment will be described. As shown in FIG. 1 (a), the composite rotary wing aircraft includes a fuselage 10, a main rotary wing 20, an anti-torque control vane 30, a fixed wing 40, a flap 50, an auxiliary propulsion fan 60, a speedometer 70, an elevator 80 and a control computer 90, and in addition to the main rotor blade 20, in addition to the fixed blade 40 for generating lift and the auxiliary propulsion fan 60 for obtaining forward thrust, low-speed flight At times, it can function as a normal rotary wing aircraft and can achieve a maximum speed close to that of a fixed wing aircraft.
[0022]
The main rotor blade 20 functions to generate lift and thrust, and is driven by the engine 22 via the transmission 21. The structure of the main rotor 20 is not particularly limited as long as it is employed in a normal single rotor type rotor aircraft. Further, the type and number of engines 22 can be appropriately determined according to the scale of the composite rotorcraft.
[0023]
As shown in FIG. 1B, the anti-torque control vane 30 is composed of three airfoil members rotatably attached to the rear end portion of the tail boom 11 behind the fuselage 10. . The anti-torque control vane 30 functions to change the direction of the high-speed gas flowing in the passage in the tail boom 11 and cancel the torque of the main rotor blade 20 to control the yaw motion of the airframe. .
[0024]
The fixed blade 40 contributes to the increase in the maximum speed together with the auxiliary propulsion fan 60 described later by generating a lift and bearing a part of the lift of the main rotor blade 20, and in the present embodiment, It is provided below the side of the body 10. The size, wing shape, and position of the fixed wing 40 can be appropriately determined according to the scale and shape of the composite rotorcraft.
[0025]
The flap 50 functions as “resistance increasing means” used in the BVI noise suppression control operation described later, while suppressing a decrease in lift during low-speed flight and hovering. The flap 50 is pivotally attached to a substantially center of the fixed wing 40 via a rotation shaft, and is 90 at the maximum with respect to the chord line of the fixed wing 40 as indicated by a dotted line in FIG. It is designed to rotate up to °.
[0026]
The auxiliary propulsion fan 60 is a propulsion unit that contributes to an increase in the maximum speed together with the above-described fixed blade 40 by generating a forward thrust, and via the fan drive drive shaft 61 and the fan drive transmission 62. It is driven by the engine 22. Further, an air intake 63 is provided in front of the auxiliary propulsion fan 60.
[0027]
The speedometer 70 detects the forward speed of the aircraft, and the elevator 80 detects the rate of increase or decrease of the aircraft. The control computer 90 controls the flap 50 and the auxiliary propulsion fan 60 in accordance with the forward speed of the airframe detected by the speedometer 70 and the lowering rate of the airframe detected by the elevator 80.
[0028]
Next, the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment will be described.
[0029]
First, prior to the description of the specific control operation of the composite rotary wing aircraft according to the present embodiment, the principle of generation of BVI noise will be described with reference to FIGS.
[0030]
BVI noise is generally caused by a sudden pressure fluctuation on the surface of a subsequent rotor blade due to interference between a blade tip vortex generated from the tip of the preceding rotor blade and the subsequent rotor blade. appear. FIG. 2 shows the trajectory of the tip vortex V generated from the tip of the preceding rotor blade blade and the position where the blade tip vortex V and the following rotor blade blade interfere (hereinafter referred to as “blade tip vortex interference position”). 1) to 7 are viewed from above the main rotor blades. It is known that the main noise source is BVI noise generated at the tip vortex interference positions 2, 3 and 4 shown in FIG.
[0031]
FIG. 3 shows the trajectory of the tip vortex V shown in FIG. 2 from the side of the main rotor blade. FIG. 3A shows the trajectory of the tip vortex V during horizontal flight, and FIG. The trajectory of the tip vortex V when flying down at a predetermined descent rate is shown, and (c) shows the trajectory of the tip vortex V when flying down at a lower descent rate than (b).
[0032]
During horizontal flight, the rotor surface is inclined forward in order to generate thrust by the main rotor, whereas the direction of uniform flow is horizontal. Therefore, as shown in FIG. 3A, the blade tip vortex V generated from the tip of the preceding rotor blade B1 flows horizontally along with this uniform flow, and therefore passes below the subsequent rotor blade B2. To do. As a result, since the blade tip vortex V and the subsequent rotor blade B2 do not interfere with each other, no BVI noise is generated.
[0033]
On the other hand, during descending flight, the rotor surface is inclined forward to generate thrust by the main rotor, and the uniform flow makes a certain angle with respect to the horizontal direction. (See FIGS. 3B and 3C).
[0034]
Therefore, in the case of flying down at a predetermined descent rate such that the angle formed by the rotor blade surface with the horizontal direction and the angle formed by the uniform flow with the horizontal direction are close (see FIG. Since the blade tip vortex V generated from the leading end of the rotating blade blade B1 interferes with the following rotating blade blade B2, BVI noise is generated.
[0035]
On the other hand, as shown in FIG. 3 (c), when flying down at a lower descent rate than that shown in FIG. 3 (b), the rotor blade surface is uniform with respect to the angle formed with the horizontal direction. The angle that the flow makes with the horizontal direction increases. Therefore, as shown in FIG. 3C, the blade tip vortex V generated from the tip of the preceding rotor blade B1 passes above the subsequent rotor blade B2. As a result, since the blade tip vortex V and the subsequent rotor blade B2 do not interfere with each other, no BVI noise is generated.
[0036]
FIG. 4 is a distribution diagram showing a region where BVI noise is generated, with the horizontal axis indicating the forward speed (kt) of the aircraft and the vertical axis indicating the rate of elevation (ft / min). As shown in FIG. 4, the BVI is relatively large in the flight region where the forward speed of the aircraft is about 40 to about 100 kt and the ascent rate is about −600 to about 0 ft / min (ie, the descent rate is about 0 to about 600 ft / min). It can be seen that noise is generated.
[0037]
As described above, the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment has a BVI noise in a specific flight region (forward speed of about 40 to about 100 kt, descent rate of about 0 to about 600 ft / min. Focusing on the fact that this flight region is likely to occur in the “BVI noise generation region”).
[0038]
That is, in the BVI noise generation region, the rotor blade surface of the main rotor blade 20 is positively inclined forward or backward, so that the blade tip vortex generated from the tip of the preceding rotor blade blade is followed by the lower blade blade. Alternatively, it avoids interference between the blade tip vortex and the subsequent rotor blade so as to pass above, and suppresses the occurrence of BVI noise.
[0039]
Here, in the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment, the rotor surface of the main rotor 20 is inclined forward or backward by increasing or decreasing the resistance acting on the fuselage. However, this principle will be described with reference to FIG.
[0040]
This principle is derived from the equation of force balance in the longitudinal direction of the aircraft. FIG. 5 shows the force acting on the fuselage, where T is the thrust generated by the main rotor blade 20, W is the gravity acting on the fuselage, and H is parallel to the rotor blade surface of the main rotor blade 20. The aerodynamic force that acts and Df indicates the resistance that acts on the fuselage. In FIG. 5, γ represents an angle formed by the uniform flow and the horizontal direction (hereinafter referred to as “flight direction angle”), α_TPPIndicates the angle (hereinafter referred to as “rotor angle of attack”) formed by the rotor blade surface in a uniform flow. Where γ, α_TPPIn both cases, the upward direction is positive. That is, γ shown in FIG. 5 is “positive”, α_TPPIs “negative”.
[0041]
As shown in FIG. 5, when the X axis parallel to the uniform flow is taken, the balance of forces in the X axis direction is expressed by the following equation. In the following expression, the forward thrust by the auxiliary propulsion fan 60 is included in the resistance “Df”.
[Expression 1]

[0042]
Here, in order to simplify the equation, the following approximation is performed.
[Expression 2]

[0043]
By using these approximate expressions (2), the expression (1) is simplified as follows.
[Equation 3]

[0044]
When the resistance Df acting on the airframe is increased according to the equation (3), the rotor attack angle α_TPPIncreases in the negative direction (downward), and it becomes clear that the main rotor blade 20 is inclined forward. Further, when the resistance Df acting on the fuselage is decreased, the rotor attack angle α_TPPIncreases in the positive direction (upward), and it becomes clear that the main rotor blade 20 is inclined backward.
[0045]
Next, a specific control operation using the composite rotary wing aircraft according to the present embodiment will be described.
[0046]
<Control action related to slow descent flight area>
First, a description will be given of a control operation related to a flight region (hereinafter referred to as “slowly descending flight region”) having a descent rate of about 0 to about 300 ft / min in the BVI noise generation region. In the control operation related to the slow descent flight region, the blade surface is positively inclined forward, and the blade tip vortex generated from the tip of the preceding blade blade passes through the “lower” of the following blade blade. By actively creating such a state (see FIG. 3A), the generation of BVI noise is suppressed.
[0047]
Specifically, the forward speed of the aircraft detected by the speedometer 70 is in the range of about 40 to about 100 kt forward speed, and the rate of descent of the aircraft detected by the elevator 80 is about 0 to about 300 ft / When within the range of min, the control computer 90 rotates the flap 50 attached to the trailing edge side of the fixed wing 40, and the angle of the flap 50 is 90 ° with respect to the chord line of the fixed wing 40. (See FIG. 1) to increase the resistance Df acting on the airframe.
[0048]
When the resistance Df acting on the fuselage increases, the rotor attack angle α_TPPIncreases in the negative direction (downward), and the main rotor blade 20 tilts forward. Accordingly, the tip vortex generated from the tip of the preceding rotor blade passes under the subsequent rotor blade. As a result, interference between the blade tip vortex and the subsequent rotor blade can be avoided, so that the occurrence of BVI noise can be suppressed.
[0049]
FIG. 6 shows the relationship between the angle of the flap 50 and the forward speed of the aircraft in this slow descent flight region, and the relationship between the thrust (weight ratio) by the auxiliary propulsion fan 60 as the propulsion means and the forward speed of the aircraft. ing. As shown in FIG. 6, when the forward speed of the airframe is in the range of 0 to 40 kt, the flap 50 is set to 90 ° so as not to obstruct the flow of the downflow produced by the main rotor blade 20. Thus, the hover efficiency can be improved.
[0050]
Conventionally, as shown by the dotted line in FIG. 6, when the forward speed of the aircraft exceeds 40 kt, the angle of the flap 50 is gradually returned from 90 ° to 0 °. However, in this embodiment, the forward speed of the aircraft is increased. Even if the value exceeds 40 kt, the flap 50 is maintained at 90 ° to function as a resistance increasing means. By maintaining the angle of the flap 50 at 90 ° in the BVI noise generation region where the forward speed of the aircraft is 40 to 100 kt, the resistance Df acting on the aircraft can be increased, and the main rotor blade 20 is inclined forward. , BVI noise can be suppressed.
[0051]
On the other hand, as shown in FIG. 6, the forward speed of the airframe is increased as the thrust (weight ratio) is increased by the auxiliary propulsion fan 60 that is the propulsion means.
[0052]
Next, the BVI noise suppression control operation related to the slowly descending flight region will be described with reference to FIG.
[0053]
In the slow descent flight region, for example, when the forward speed of the aircraft is 70 kt, the BVI noise becomes maximum when the descent rate is 300 ft / min. Hereinafter, the case where the forward speed is 70 kt and the rate of descent is 300 ft / min is referred to as a “maximum case”, and the flight direction angle in the maximum case is expressed as γ.^*And
[0054]
In FIG. 7, the vertical axis represents the rotor attack angle α._TPP, The resistance Df acting on the fuselage is taken on the horizontal axis, and the graph of the formula (2) in the above-mentioned “maximum case” is shown (in the descending flight state, the flight direction angle γ is “negative”) Therefore, “−γ” in the second term on the right side is a “positive” value). As shown in FIG. 7, the resistance acting on the fuselage before control is Df.₀In the “maximum case”, the rotor attack angle α as shown at point A in FIG._TPPIs almost zero, and BVI noise is generated.
[0055]
Here, as a result of rotating the flap 50 as the resistance increasing means by the control computer 90 as the control means according to the present embodiment to increase the resistance acting on the airframe, the resistance becomes Df.₁Exceeds A, the point A on the graph of equation (2) in the “maximum case” is A₁Move to the point and rotor angle of attack α_TPPThe value of is negative. This means that the main rotor blade 20 is inclined forward. Accordingly, in the “maximum case”, the blade tip vortex generated from the tip of the preceding rotor blade passes through the lower rotor blade and the generation of BVI noise is suppressed.
[0056]
As described above, in the slow descent region, the resistance acting on the aircraft is increased to increase Df₁The rotor attack angle α_TPPThe value of is always “negative”, and the blade surface is inclined forward with respect to the uniform flow. Therefore, the tip vortex generated from the leading end of the preceding rotor blade always passes “below” the succeeding rotor blade and the generation of BVI noise is suppressed.
[0057]
<Control action related to the steep descent flight area>
Next, a description will be given of a control operation related to a flight region (hereinafter referred to as “suddenly descending flight region”) having a descent rate of about 300 to about 600 ft / min in the BVI noise generation region. The control operation related to the sudden-falling flight region is active in a state in which the tip vortex generated from the tip of the preceding rotor blade passes through the “upward” of the following rotor blade (see FIG. 3C). It is intended to suppress the generation of BVI noise.
[0058]
Specifically, the forward speed of the aircraft detected by the speedometer 70 is in the range of about 40 to about 100 kt, and the rate of descent of the aircraft detected by the elevator 80 is about 300 to about 600 ft / min. When it is within the range, the control computer 90 increases the thrust acting on the airframe by the auxiliary propulsion fan 60 and decreases the resistance Df acting on the airframe.
[0059]
When the resistance Df acting on the airframe decreases, the rotor attack angle α_TPPIncreases in the positive direction (upward), and the main rotor blade 20 tilts backward. Accordingly, the tip vortex generated from the tip of the preceding rotor blade blade passes “above” the succeeding rotor blade blade. As a result, interference between the blade tip vortex and the subsequent rotor blade can be avoided, so that the occurrence of BVI noise can be suppressed.
[0060]
FIG. 8 shows the relationship between the angle of the flap 50 and the forward speed of the aircraft in this suddenly descending flight region, and the relationship between the thrust (weight ratio) by the auxiliary propulsion fan 60 as the propulsion means and the forward speed of the aircraft. Yes. As shown in FIG. 8, when the forward speed of the airframe is in the range of 0 to 40 kt, the flap 50 is set to 90 ° so as not to obstruct the flow of the downflow generated by the main rotor blade 20. Thus, the hover efficiency can be improved. When the forward speed of the aircraft exceeds 40 kt, the flap 50 is gradually returned from the angle 90 ° to 0 ° to reduce the resistance acting on the aircraft.
[0061]
On the other hand, as shown in FIG. 8, when the forward speed of the airframe exceeds 40 kt, the thrust (weight ratio) by the auxiliary propulsion fan 60 is increased, and the resistance acting on the airframe is decreased. By increasing the thrust of the auxiliary propulsion fan 60 in the BVI noise generation region where the forward speed of the aircraft is about 40 to about 100 kt, the resistance Df acting on the aircraft can be reduced, and the main rotor blade 20 is inclined backward. Thus, generation of BVI noise can be suppressed.
[0062]
Next, the BVI noise suppression control operation related to the steep descent flight region will be described with reference to FIG.
[0063]
FIG. 9 shows the rotor attack angle α on the vertical axis as in FIG._TPP, The resistance Df acting on the airframe is taken on the horizontal axis, and the graph of the formula (2) in the above-mentioned “maximum case” is shown. As shown in FIG. 9, the resistance acting on the airframe before control is Df.₀In the “maximum case”, the rotor attack angle α as shown at point A in FIG._TPPIs almost zero, and BVI noise is generated.
[0064]
Here, as a result of reducing the resistance acting on the airframe by increasing the thrust of the auxiliary propulsion fan 60 which is the propulsion means by the control computer 90 which is the control means according to the present embodiment, the resistance becomes Df₂When it becomes smaller, the point A on the graph of the formula (2) in the “maximum case” is A₂Move to the point and rotor angle of attack α_TPPThe value of becomes “positive”. This means that the main rotor blade 20 is inclined backward. Therefore, in the “maximum case”, the tip vortex generated from the tip of the preceding rotor blade passes through “above” the succeeding rotor blade, and the generation of BVI noise is suppressed.
[0065]
As explained above, in the sudden drop flight region, the resistance acting on the aircraft is reduced to reduce Df.₂If it is smaller, the rotor attack angle α_TPPThe value of is always “positive”, and the blade surface is inclined backward with respect to the uniform flow. Accordingly, the tip vortex generated from the tip of the preceding rotor blade always passes “above” the succeeding rotor blade, and the generation of BVI noise is suppressed.
[0066]
Depending on the relative relationship between the forward speed of the aircraft and the rate of descent, there are cases that belong to both the slowly descending flight region and the steeply descending flight region, as in the “maximum case” described above. In such a case, the occurrence of BVI noise can be suppressed by adopting either one of the control operation related to the “slow descent flight region” or the control operation related to the “sudden descent flight region”.
[0067]
Subsequently, the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment will be described from the viewpoint of “movement of the BVI noise generation area”.
[0068]
When BVI noise suppression control is not performed using the composite rotorcraft according to the present embodiment, the BVI noise generation area is shown in the area shown in FIG. 4 as described above. The “maximum noise range” L (the flight range where the aircraft has a forward flight speed of about 60 to about 80 kt and a descent rate of about 200 to about 400 ft / min) in the region shown in FIG. 4 is shown by a solid line in FIG.
[0069]
In the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment, as described in FIG. 7, in the “slow descent flight region”, the resistance acting on the aircraft is increased to increase Df.₁Rotor angle of attack α_TPPIs controlled to be always “negative”, so that the tip vortex generated from the tip of the preceding rotor blade is passed through the “lower” of the following rotor blade to suppress the generation of BVI noise. ing.
[0070]
That is, when a control operation related to the “slow descent flight region” is performed using the composite rotorcraft according to the present embodiment, the “maximum noise range” L shown in FIG. Moved area L₁Therefore, BVI noise is generated. However, the region L moved downward from the “maximum noise range” L₁In the above, since the control operation of the “abrupt descent flight region” is performed, no BVI noise is generated.
[0071]
On the other hand, in the BVI noise suppression control operation using the composite rotorcraft according to the present embodiment, as described with reference to FIG.₂Smaller, rotor attack angle α_TPPBy controlling so that the value of is always “positive”, the tip vortex generated from the tip of the preceding rotor blade is passed through the “upper” of the following rotor blade, thereby suppressing the generation of BVI noise. ing.
[0072]
In other words, when the control operation related to the “sudden descent flight region” is performed using the composite rotorcraft according to the present embodiment, it moves upward from the “maximum noise range” L shown in FIG. Region L₂Therefore, BVI noise is generated. However, the region L moved upward from the “maximum noise range” L₂Since the control operation of the “slow descent flight region” described above is performed, no BVI noise is generated.
[0073]
The composite rotorcraft according to the present embodiment includes a fixed wing 40 that generates lift, and an auxiliary propulsion fan 60 that is a propulsion means provided on the fuselage 10 separately from the main rotor 20 to generate forward thrust. Have. Therefore, a part of the lift of the main rotor blade 20 can be borne by the fixed blade 40 and the propulsive force can be obtained by the auxiliary propulsion fan 60, so that the speed can be increased.
[0074]
Further, the composite rotorcraft according to the present embodiment includes a flap 50 which is a resistance increasing means for increasing the resistance acting on the aircraft, and a flap 50 and an auxiliary propulsion fan 60 according to the forward speed and the descent rate of the aircraft. A control computer 80 which is a control means for controlling, and when the forward speed and the rate of descent of the aircraft are in the BVI noise generation range, the control computer 80 controls the flap 50 in the slow descent flight region. In addition to increasing the resistance acting on the rotor, the rotor blade surface is tilted forward, and the auxiliary propulsion fan 60 is controlled to increase the forward thrust acting on the airframe in a suddenly descending flight region where the airframe descending rate is relatively large. Since the wing surface is inclined rearward, different control operations are performed in the slow descent flight region and the steep descent flight region to effectively It is possible to suppress the generation of noise.
[0075]
In other words, in the “slow descent flight region”, if the flap 50 is driven by the control computer 90 to increase the resistance Df acting on the airframe and the rotor surface is inclined forward, it flows out from the preceding rotor blade. Since the blade tip vortex passes “below” the subsequent rotor blade, interference between the blade tip vortex and the subsequent rotor blade can be avoided to suppress the generation of BVI noise. Further, in the “sudden descent flight region”, when the control computer 90 increases the forward thrust by the auxiliary propulsion fan 60 to reduce the resistance Df acting on the fuselage and tilt the rotor surface backward, the preceding rotation Since the tip vortex flowing out from the blade blade passes "upward" the subsequent rotor blade, avoiding interference between the blade tip vortex and the subsequent rotor blade to suppress the generation of BVI noise. can do.
[0076]
As a result, the maximum speed is higher than that of a normal rotary wing aircraft, and high-speed flight can be realized, and generation of BVI noise can be suppressed and noise reduction can be achieved. In other words, high speed and low noise can be achieved at the same time.
[0077]
Furthermore, in the composite rotary wing aircraft according to the present embodiment, the flap 50 provided on the trailing edge side of the fixed wing 40 can also function as a resistance increasing means, so that it is not necessary to provide a separate resistance increasing means.
[0078]
[Second Embodiment]
The composite rotary wing aircraft according to the present embodiment is obtained by changing only the resistance increasing means in the composite rotary wing aircraft according to the first embodiment, and other configurations are substantially the same. The description of the configuration to be omitted is omitted.
[0079]
In the present embodiment, as shown in FIG. 11, the fixed wing 42 is rotatable about a rotation shaft 52. That is, the fixed wing 42 has a variable mounting angle under the control of the control computer 90. For example, the fixed wing 42 can be rotated 90 ° as shown in FIG. This can contribute to the suppression of the occurrence of
[0080]
[Third embodiment]
The composite rotary wing aircraft according to the present embodiment is obtained by changing only the resistance increasing means in the composite rotary wing aircraft according to the first embodiment, and other configurations are substantially the same. The description of the configuration to be omitted is omitted.
[0081]
In the present embodiment, as shown in FIG. 12, spoilers 53 are provided on the upper surface and the lower surface of the fixed wing 43. The spoiler 53 is opened and closed under the control of the control computer 90, and can contribute to the suppression of the occurrence of BVI noise as a resistance increasing means.
[0082]
[Fourth embodiment]
The composite rotary wing aircraft according to the present embodiment is the composite rotary wing aircraft according to the first embodiment, in which the structure behind the tail boom is changed and the propulsion means is changed. Therefore, the description of the overlapping configuration is omitted.
[0083]
In the present embodiment, as shown in FIG. 13, a tail rotor 34 is provided in place of the anti-torque control vane 30 in order to cancel the torque of the main rotor blade 10, and the horizontal tail 12 and the vertical tail are provided on the tail boom 11. 13 is provided. A pusher propeller 64 is provided behind the tail rotor 34. The pusher propeller 64 is driven and controlled under the control of the control computer 90, and can contribute to the suppression of the occurrence of BVI noise as propulsion means.
[0084]
[Fifth embodiment]
The composite rotary wing aircraft according to the present embodiment adopts the coaxial rotary main rotor wing in the composite rotary wing aircraft according to the first embodiment and eliminates the need for an anti-torque control vane. The propulsion means is changed, and the other constituent elements are substantially the same, and therefore, the description of the overlapping structure is omitted.
[0085]
In the present embodiment, as shown in FIG. 14, a horizontal tail 12A and a vertical tail 13A are provided behind the tail boom 11, and a ducted fan 65 is provided. The ducted fan 65 is driven and controlled under the control of the control computer 90, and can contribute to the suppression of the occurrence of BVI noise as propulsion means.
[0086]
【The invention's effect】
According to the first aspect of the present invention, the maximum speed is higher than that of a normal rotary wing aircraft, and high-speed flight can be realized, and the generation of BVI noise can be suppressed and noise reduction can be achieved. In other words, high speed and low noise can be achieved at the same time.
[0087]
According to the second aspect of the present invention, different control operations can be performed in the “slow descent flight region” and “sudden descent flight region” to effectively suppress the occurrence of BVI noise.
[0088]
In other words, in the “slow descent flight region”, the resistance increasing means is controlled by the control means to increase the resistance acting on the airframe so that the rotor surface is inclined forward, and the tip vortex flowing out from the preceding rotor blade is discharged. By passing the “downward” of the subsequent rotor blade and avoiding the interference between the blade tip vortex and the subsequent rotor blade, the generation of BVI noise can be suppressed.
[0089]
In the “sudden descent region”, the propulsion means is controlled by the control means to increase the forward thrust acting on the airframe to incline the rotor surface backward, and the tip vortex flowing out from the preceding rotor blade By avoiding the interference between the blade tip vortex and the subsequent rotor blade so as to pass “above” the subsequent rotor blade, the generation of BVI noise can be suppressed.
[0090]
According to the third aspect of the present invention, the movable wing provided on the trailing edge side of the fixed wing can function as a flap or a spoiler and simultaneously function as a resistance increasing means.
[0091]
According to the fourth aspect of the present invention, since the fixed blade has a variable mounting angle, the fixed blade itself can function as a resistance increasing means.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram for explaining a configuration of a composite rotary wing aircraft according to a first embodiment of the present invention, in which (a) is a side view and (b) is a plan view of a portion B in (a). (View from above).
FIG. 2 is an explanatory diagram for explaining the principle of generation of BVI noise and showing a state in which a blade tip vortex trajectory and a blade tip vortex interference position are viewed from above the main rotor blade;
FIGS. 3A and 3B are diagrams for explaining the principle of generation of BVI noise, wherein FIG. 3A is a trajectory of a tip vortex during horizontal flight, and FIG. 3B is a tip vortex when the aircraft flies down at a predetermined descent rate; (C) is an explanatory view showing the state of the blade tip vortex trajectory viewed from the side of the main rotor blade when flying down at a descending rate greater than (b).
FIG. 4 is a distribution diagram showing a region where BVI noise occurs.
FIG. 5 is an explanatory diagram for explaining the principle of BVI noise suppression control operation using the composite rotary wing aircraft according to the first embodiment of the present invention;
FIG. 6 is a diagram for explaining a BVI noise suppression control operation in a slow descent flight region using the composite rotary wing aircraft according to the first embodiment of the present invention, wherein (a) is a resistance increasing means; It is a graph showing the relationship between the angle of a flap and the advancing speed of a body, (b) is a graph showing the relationship between the thrust (weight ratio) of the auxiliary propulsion fan which is a propulsion means, and the advancing speed of the body.
FIG. 7 shows a change in rotor attack angle with an increase in resistance acting on the airframe in the BVI noise suppression control operation in the slow descent flight region using the composite rotorcraft according to the first embodiment of the present invention. Df-α for explaining_TPPFIG.
FIG. 8 is a diagram for explaining a BVI noise suppression control operation in a steep flight region using the composite rotary wing aircraft according to the first embodiment of the present invention, and (a) is a flap which is a resistance increasing means; Is a graph showing the relationship between the angle of the aircraft and the forward speed of the aircraft, and (b) is a graph showing the relationship between the thrust (weight ratio) of the auxiliary propulsion fan as the propulsion means and the forward speed of the aircraft.
FIG. 9 shows the change in the angle of attack of the rotor as the resistance acting on the fuselage decreases in the BVI noise suppression control operation related to the sudden drop flight region using the composite rotorcraft according to the first embodiment of the present invention. Df-α for explanation_TPPFIG.
FIG. 10 is a distribution diagram for explaining the BVI noise suppression control operation using the composite rotorcraft according to the first embodiment of the present invention from the viewpoint of “movement of the BVI noise generation area”;
FIG. 11 is a side view showing resistance generating means (fixed wing) of a composite rotorcraft according to a second embodiment of the present invention.
FIG. 12 is a side view showing resistance generating means (spoiler) of a composite rotorcraft according to a third embodiment of the present invention.
FIG. 13 is a perspective view showing propulsion means (pusher-propeller) of a composite rotary wing aircraft according to a fourth embodiment of the present invention.
FIG. 14 is a perspective view showing propulsion means (ducted fan) of a composite rotary wing aircraft according to a fifth embodiment of the present invention.
FIG. 15 is a perspective view of a conventional composite rotorcraft.
FIG. 16 is an explanatory diagram for explaining the principle of generation of BVI noise;
FIG. 17 is a plan view of a conventional rotary wing aircraft.
[Explanation of symbols]
10 torso
11 Tail boom
12 Horizontal tail
12A Horizontal tail
13 Vertical tail
13A Vertical tail
20 Main rotor
21 Transmission
22 engine
30 Anti-torque control vane
34 Tail rotor
40 fixed wings
42 Fixed wing (variable mounting angle)
43 fixed wing
50 flaps
52 Rotating shaft
53 spoiler
60 Auxiliary propulsion fan
61 Drive shaft for fan
62 Fan drive transmission
64 pusher-propeller
65 Ducted Fan
70 Speedometer
80 Elevator
90 Control computer
100 Conventional compound rotorcraft
200 Conventional rotorcraft
210 fuselage
220 Resistance plate

Claims (4)

In a composite rotorcraft having a fixed wing for generating lift and propulsion means provided on the fuselage separately from the rotor for generating forward thrust,
Resistance increasing means for increasing the resistance acting on the aircraft,
Control means for controlling the resistance increasing means and the propulsion means according to the forward speed and the descent rate of the aircraft ,
The said control means controls the said resistance increase means and the said propulsion means when the advancing speed and descent | fall rate of a body are in a BVI noise generation area, The composite rotary wing aircraft characterized by the above-mentioned . The control means includes
When the aircraft's forward speed and descent rate are in the BVI noise generation area,
In the slow descent flight region where the descent rate of the airframe is relatively small, the resistance increasing means is controlled to increase the resistance acting on the airframe to incline the rotor surface forward,
Tilting the rotor surface backwards by increasing the forward thrust acting on the aircraft by controlling the propulsion means in a sudden descent flight region where the rate of descent of the aircraft is relatively large;
The composite rotary wing aircraft according to claim 1, wherein The fixed wing is
It is equipped with movable wings on the edge side,
The resistance increasing means includes
The composite rotary wing aircraft according to claim 1 or 2, wherein the movable wing is the movable wing. The fixed wing is
The mounting angle is variable,
The resistance increasing means includes
The composite rotorcraft according to claim 1 or 2, wherein the composite rotorcraft is the fixed wing.

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