USOO932 1526B2 (12) United States Patent (10) Patent No.: US 9,321,526 B2 Fink et al. (45) Date of Patent: Apr. 26, 2016 (54) COMPOUND HELICOPTER (56) References Cited U.S. PATENT DOCUMENTS (71) Applicant: AIRBUS HELICOPTERS DEUTSCHLAND GMBH, Donauworth 1939,682 A * 12/1933 Fleming ...................... 244/45R (DE) 3,105,659 A 10, 1963 Stutz 3.241,791 A 3, 1966 Piaseck 3,385,537 A 5, 1968 Lichten et al. (72) Inventors: Axel Fink, Donauworth (DE); 3,448,946 A 6/1969 Nagatsu 5,046,684 A 9, 1991 Wolkovitch Ambrosius Weiss, Munich (DE); 5,503,352 A * 4/1996 Eger ........................... 244/45R Andrew Winkworth, Donauworth (DE) 6,474,604 B1 * 1 1/2002 Carlow ......................... 244,198 6,513,752 B2 2/2003 Carter, Jr. 6,626,398 B1* 9/2003 Cox et al. .................... 244/45R (73) Assignee: AIRBUS HELICOPTERS 2005. O151001 A1 7/2005 Loper DEUTSCHLAND GMBH, Donauworth (DE) (Continued) FOREIGN PATENT DOCUMENTS (*) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 CA 2316418 A1 8, 2000 U.S.C. 154(b) by 168 days. DE 694301.98 T 2003 (Continued) (21) Appl. No.: 13/950,570 OTHER PUBLICATIONS European Search Report; European application No. EP 1240 0032; date of completion of search Dec. 11, 2012. (22) Filed: Jul. 25, 2013 Primary Examiner — Tien Dinh (65) Prior Publication Data Assistant Examiner — Alexander V. Giczy US 2014/OO61367 A1 Mar. 6, 2014 (74) Attorney, Agent, or Firm — Brooks Kushman P.C. (57) ABSTRACT (30) Foreign Application Priority Data The invention relates to a compound helicopter comprising a fuselage, at least one engine and a main rotor driven by said at Jul. 27, 2012 (EP) ..................................... 124OOO32 least one engine. At least one pair offixed wings are mounted in an essentially horizontal plane on a left hand and a right (51) Int. Cl. hand side of the fuselage and horizontally oriented propulsion B64C 27/26 (2006.01) devices are mounted to each of the fixed wings, the fixed B64C39/06 wings encompassing each a drive shaft from the at least one (2006.01) engine. Each fixed wing comprises a lower main wing and an (52) U.S. Cl. upper secondary wing being connected to each other within CPC ............... B64C 27/26 (2013.01); B64C39/068 an interconnection region. The propulsion devices include (2013.01) pusher propellers arranged at the interconnection region and (58) Field of Classification Search the upper secondary wing houses the drive shaft from the at CPC ........ B64C 27/26: B64C 27/22; B64C 27/02: least one engine. B64C39/068; B64D 27/02 See application file for complete search history. 18 Claims, 7 Drawing Sheets US 9,321,526 B2 Page 2 (56) References Cited FOREIGN PATENT DOCUMENTS U.S. PATENT DOCUMENTS EP 2418148 A2 2, 2012 2009/0321554 A1 12, 2009 Roesch GB 895590 5, 1962 2010.006.5677 A1 3/2010 Ferrier WO 2008O85.195 A2 T 2008 2010/0224721 A1* 9, 2010 Wood et al. .................. 244, 12.3 2011/0114798 A1 5, 2011 Gemmati * cited by examiner U.S. Patent Apr. 26, 2016 Sheet 1 of 7 US 9,321,526 B2 U.S. Patent Apr. 26, 2016 Sheet 2 of 7 US 9,321,526 B2 U.S. Patent Apr. 26, 2016 Sheet 3 of 7 US 9,321,526 B2 U.S. Patent Apr. 26, 2016 Sheet 4 of 7 US 9,321,526 B2 U.S. Patent Apr. 26, 2016 Sheet 5 Of 7 US 9,321,526 B2 Fig.6 U.S. Patent Apr. 26, 2016 Sheet 6 of 7 US 9,321,526 B2 Fig. 7 U.S. Patent Apr. 26, 2016 Sheet 7 Of 7 US 9,321,526 B2 US 9,321,526 B2 1. 2 COMPOUND HELICOPTER limits by means of the propulsion units. As a result, the benefit of a higher load factor is obtained along with potential for CROSS-REFERENCE TO RELATED higher speed. The use of a pair of thrust propulsion units— APPLICATIONS opposed and both offset relative to each other and to a longi tudinal axis of the helicopter—enables for a simultaneous This application claims priority to European patent appli torque correction. cation No. EP 124.00032.4 filed Jul. 27, 2012, the disclosure Compound helicopters with two wing-mounted propellers of which is incorporated in its entirety by reference herein. are described in U.S. Pat. No. 3,105,659A, US 2009/0321554 A1 and U.S. Pat. No. 6.513,752 B2. A compound helicopter BACKGROUND OF THE INVENTION 10 with a propulsion device as a single nose-mounted propeller is disclosed in US/2005/0151001 A1 or with a single rear (1) Field of the Invention mounted propeller in U.S. Pat. No. 3.241,791 A, CA 2316418 The invention relates to a compound helicopter with the and in U.S. Pat. No. 3,448,946. Said typical configurations features of the preamble of claim 1. feature a pair of main wings located below the main rotor of Typical compound helicopters comprise a fuselage, a main 15 the compound helicopter. rotor providing lift and a pair of additional propulsion devices A canard configuration of a compound helicopter, featur providing thrust and a fixed wing structure on each side in an ing two main wings behind the main rotor and two nose essentially horizontal plane of the fuselage. Said fixed wing mounted canard wings, is described in US 2010/0065677 A1, structure provides additional lift during horizontal cruise said configuration outstanding by the lack of a tail boom and flight. The propulsion devices are arranged on said wings. the rear position of propulsion propellers, which results in (2) Description of Related Art comfort by reducing noise and vibrations and increased pas The dominant helicopter configuration in the present time senger safety. Moreover, the canard configuration provides is based on Sikorsky's basic design with a main rotor and an for additional lift, which means that the center of lift of the auxiliary tail rotor to counter torque. Said conventional heli main wings is allowed to not coincide with the main rotor copters show excellent hover capabilities but suffer from 25 mast, hence allowing locating the main wings far in the rear of limitations in terms of horizontal flight speed. These limita the helicopter. The document US 2011 0114798 A1 discloses tions are associated to two aerodynamic phenomena at the a compound helicopter based on a tandem wing configuration main rotor: the retreating blade stall and the maximum blade with an arrangement of a pair of wings on both the fuselage tip velocity. In general terms: The lift and thrust force capa front end and aft end, the propulsion devices being arranged bilities of a helicopter rotor decrease with increasing forward 30 near the tips of the front wings. speed. Canard configurations are—as well—not unusual in fixed The compound helicopters and so-called convertiplanes wing aircraft design. The canards can have a lifting or a are basically the most relevant concepts aiming to overcome control function. Lifting canards contribute to the total lift of the horizontal flight deficiencies of the dominant helicopters the aircraft, hence allowing for a significant aft position of the by introducing attributes of fixed-wing aircrafts as compro 35 main wings and the center of gravity (CofG). To ensure pitch mise. However, a compromise between both aircraft types has stability, the lift slope of the canard wing has to be lower than always to be conveniently adapted to the planned mission that one of the main wing. Typical configurations with aft profile of the helicopter. tails have a loss of efficiency as a result of the downward lift Compound helicopters with lift compounding, thrust com that must be compensated with extra lift of the main wings. pounding or a combination of both basically aim to off-load 40 An important penalty arises from the aerodynamic interfer the main rotor from its simultaneous lifting and propulsive ence between the canards and the main wings. From a struc duties to allow for higher forward speeds of the compound tural point of view, lifting canard configurations or even tan helicopter. dem wing configurations offer considerable advantages. A lift compounding entails adding wings to a helicopter The propulsion devices of compound helicopters are typi hence enabling to increase the load factor of the helicopter 45 cally attached to the fuselage or arranged at the wings or at the and to reach a higher manoeuvrability. This improves the aft end of either the tail boom or the fuselage. The attachment efficiency of the helicopter at moderately high speed but at the of the propulsion devices to the fuselage is only feasible if expense of reduced efficiencies at lower forward speeds and using turbojets, allowing undisturbed wings but not allowing in the hover. anti-torque capabilities, hence still requiring an additional tail A thrust compounding implies the addition of essentially 50 rotor. The same applies for configurations with a single main horizontally oriented auxiliary propulsion units to the heli rotor and a tail-boom mounted pusher propeller. Hence pro copter. This has been typically accomplished by means of a pellers are typically arranged on the wings, somewhere single or a pair of propellers being driven by drive shafts between the wing tip and the fuselage or at the wing tip. powered by the main turboshaft engines. The use of a pair of Typically, the winged compound helicopter features a propulsion units has the advantage of providing for anti 55 monoplane design with one set of wing Surfaces in cantilever torque capabilities without the need of an additional tail rotor, design as either low-wing, mid-wing or shoulder-wing hence relativizing the inherent system complexity of the arrangement.