FR2793470A1 - Twin engine aircraft with reverse rotation of supraconvergent propellers has engines installed side by side and partially set back from each other - Google Patents

Twin engine aircraft with reverse rotation of supraconvergent propellers has engines installed side by side and partially set back from each other Download PDF

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Publication number
FR2793470A1
FR2793470A1 FR9906143A FR9906143A FR2793470A1 FR 2793470 A1 FR2793470 A1 FR 2793470A1 FR 9906143 A FR9906143 A FR 9906143A FR 9906143 A FR9906143 A FR 9906143A FR 2793470 A1 FR2793470 A1 FR 2793470A1
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France
Prior art keywords
aircraft
engine
engines
propellers
twin
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
FR9906143A
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French (fr)
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FR2793470B3 (en
Inventor
Gerard Esnault
Original Assignee
Gerard Esnault
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Publication date
Application filed by Gerard Esnault filed Critical Gerard Esnault
Priority to FR9906143A priority Critical patent/FR2793470B3/en
Publication of FR2793470A1 publication Critical patent/FR2793470A1/en
Application granted granted Critical
Publication of FR2793470B3 publication Critical patent/FR2793470B3/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64CAEROPLANES; HELICOPTERS
    • B64C11/00Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/46Arrangements of or constructional features peculiar to multiple propellers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64DEQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D27/00Arrangement or mounting of power plant in aircraft; Aircraft characterised thereby
    • B64D27/02Aircraft characterised by the type or position of power plant
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64DEQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D27/00Arrangement or mounting of power plant in aircraft; Aircraft characterised thereby
    • B64D27/02Aircraft characterised by the type or position of power plant
    • B64D27/04Aircraft characterised by the type or position of power plant of piston type
    • B64D27/08Aircraft characterised by the type or position of power plant of piston type within or attached to fuselage
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64DEQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D27/00Arrangement or mounting of power plant in aircraft; Aircraft characterised thereby
    • B64D27/02Aircraft characterised by the type or position of power plant
    • B64D27/10Aircraft characterised by the type or position of power plant of gas-turbine type
    • B64D27/14Aircraft characterised by the type or position of power plant of gas-turbine type within or attached to fuselage

Abstract

<P> The invention relates to a towing twin-engine aircraft, the two independent engines of which are mounted at the front of the fuselage and the passenger compartment. They are arranged side by side, partially offset and in opposite direction said upside down (1). They drive by two transmissions (2) two shafts (3) on which are fixed two towing propellers (4) close together without overlapping in the super-converging direction (5). The axes of the propeller shafts have an equal convergence (6) towards the center of gravity of the aircraft. The positive effects of this convergence, the minimum distance of the axes of traction of the propellers to the longitudinal axis of the aircraft and the rotation of the propellers in the super-converging direction lead to a significant lowering of the minimum control speed during the failure of the 'one of the engines. This overall result provides greater ease of flight control on twin-engine aircraft during an engine failure, especially during the take-off, initial climb and go-around phases after a missed approach. During these flight phases, the climb speed required by regulation implies a unitary motive power guaranteeing it. This invention applies to piloted aircraft and drones either with aeronautical engines, or with land or naval engines. It also applies to the re-engining of original single-engine aircraft in towing twin-engine aircraft. </P>

Description

The invention relates to a tractable twin-engine aircraft whose close arrangement of the two propellers without overlapping allows in the event of a failure of one of the two piston engines to reduce the moment around the yaw axis due to the product of the traction force. of the live engine by the reduced length of the lever arm to the longitudinal axis of the aircraft (Fig 1 & 2).

On conventional twin-engine aircraft with the two piston engines arranged symmetrically on either side of the fuselage (Fig 3) the failure of one of the engines creates a significant moment around the yaw axis. It is all the more important that the distance (d) from the point of application of the traction force of the live engine to the longitudinal axis of the aircraft is large and that the traction (T) of the engine propeller lively is high. This results in a violent skid, with oblique attack of the fuselage which, if it is not energetically countered by a corrective action (fa * D) of the rudder causes the speed to drop with risk of stalling on the wing not blown from the dead engine. Hence on this type of twin-engine the imperative respect of a minimum control speed (vmc) always higher than the stall speed in the configuration of the flight phase, the most delicate being, the takeoff and the initial climb and the go-around after a missed approach, the speed margin being limited and the height not high above the ground Driving to protect yourself from this risk remains regular and rigorous training in engine failure under the above conditions but with a high cost on twin-engine What are the possibilities to eliminate these constraints from the conventional twin-engine. They are known to aeronautical specialists. First of all the axial arrangement of the two motors known as push-pull. No vmc, but the mass of the engine behind the cabin requires significant structural reinforcements and the occupants in the event of a crash psychologically fear the projection of this mass towards them. The other solution adopted is characterized by the limitation of the length of the lever arm between the axis of traction of the propeller and the longitudinal axis of the aircraft with the approximation of the engines and propellers without overlapping in front of the fuselage.

But there remains the drag of the time zones and aerodynamic flows disturbed by the front cone of the fuselage.

Hence the choice of grouping the two engines in the same cowling at the front of the fuselage and the passenger compartment, engine installation "All at the front" (Fig 1). Only the two propellers emerge on either side of this cowling each driven by a transmission. According to the particular mode of this power plant according to the general architecture of the motors (1), these are arranged either side by side in parallel or partially offset in the three planes with overlap. Each motor drives a propeller independently of the other via a transmission. The two propellers (4) have their planes of rotation close to each other on the longitudinal axis of the aircraft without overlapping. They are mounted on two shafts, the bearings of which are supported by a frame secured to the corresponding motor. The propeller shafts (3) each have an equal convergence (6) towards the center of gravity of the aircraft. In the event of an engine failure, this arrangement creates a transverse force FT (Fig 2) partially opposing the moment of rotation around the yaw axis. But there remains the CRITICAL MOTOR when the two propellers rotate in the same direction.

The installation of the two motors at 180 one relative to the other called upside down provides the solution. By driving the transmissions (2) and the propellers (4) in reverse rotation, the advantages of SUPRACONVERGENCE (5) can be used: elimination of the critical motor, shifting of the resultant of the propeller's traction towards the axis longitudinal hence reduction of the lever arm, positive effects of each helical blast on the upper surface of the horizontal tailplane (Fig4) with in the event of an engine failure a pitching moment in slight nose-up and a moment of roll with slight tilt on the engine side. The mass of the two engines at the front of the fuselage advances the center of gravity and increases the length of the rudder lever arm, therefore for the same steering efficiency. The sum of these advantages represents a new combination of means known individually. This, in the event of an engine failure makes it possible to greatly limit the moment around the yaw axis or even after attempts to obtain a VMC very slightly greater than or equal to the stall speed in the configuration. The easy maintenance of a rectilinear trajectory provides greater reliability in flight, especially during the abovementioned flight phases. These conditions, fulfilling the regulatory requirements for ascending speed, imply that the motorization makes it possible to satisfy them. A feathering of the propeller and retractable trains is desirable to reduce parasitic drag in flight on an engine. This provision of the powerplant applies to aeronautical, land and naval engines with use on piloted aircraft and drones. The use of two two-stroke engines, light but recognized as less reliable, brings a very low probability of simultaneous breakdowns of the two engines. This provision of the power plant also applies to existing and future single engine aircraft remotorized with two identical engines to those mentioned above. For the latter type of aircraft, compliance with the maximum engine power supported by the airframe, the maximum admissible take-off mass and the centering range of the original aircraft is imperative.

Claims (5)

1) A twin-engine towing aircraft with two independent engines installed at the front of the fuselage and the passenger compartment. Depending on their architecture, their installation is either side by side in parallel, or partially offset from each other, in the three planes according to their length, width and height (1) Figl.
2) Aircraft according to claim 1 characterized in that the two motors drive with two transmissions (2) two propeller shafts independent of one another (3). These support at the front two close propellers ( 4) without overlapping their plane of rotation on either side of the longitudinal axis of the aircraft. The axis of each of the propeller shafts is characterized by a convergence (6) towards the center of gravity of the aircraft.
3) Aircraft according to claims 1 & 2 characterized by the arrangement of the two motors in the opposite direction to 180 called spade head. It allows the reverse rotation of the two propellers in the super-converging direction (5).
4) Aircraft according to Claims (2) & (3) characterized in that in the event of an engine failure, the moment around the yaw axis of the aircraft and the minimum control speed are reduced , or even its elimination if equal to the stall speed.
5) Aircraft according to one of the preceding claims, characterized in that it may be a new design aircraft and single-engine aircraft whose single engine and its propeller are replaced by two engines. For the latter type of original single-engine aircraft, compliance with the maximum engine power supported by the airframe, the maximum permissible take-off mass and the centering range is imperative.
FR9906143A 1999-05-12 1999-05-12 Tractive twin engine with near superconvergent propellers Expired - Fee Related FR2793470B3 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR9906143A FR2793470B3 (en) 1999-05-12 1999-05-12 Tractive twin engine with near superconvergent propellers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR9906143A FR2793470B3 (en) 1999-05-12 1999-05-12 Tractive twin engine with near superconvergent propellers

Publications (2)

Publication Number Publication Date
FR2793470A1 true FR2793470A1 (en) 2000-11-17
FR2793470B3 FR2793470B3 (en) 2001-07-13

Family

ID=9545579

Family Applications (1)

Application Number Title Priority Date Filing Date
FR9906143A Expired - Fee Related FR2793470B3 (en) 1999-05-12 1999-05-12 Tractive twin engine with near superconvergent propellers

Country Status (1)

Country Link
FR (1) FR2793470B3 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008032789A1 (en) * 2008-07-11 2010-01-14 Airbus Deutschland Gmbh Aircraft having at least two spanwise spaced apart drive motors

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008032789A1 (en) * 2008-07-11 2010-01-14 Airbus Deutschland Gmbh Aircraft having at least two spanwise spaced apart drive motors

Also Published As

Publication number Publication date
FR2793470B3 (en) 2001-07-13

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