US 12,409,942 B2
Method for controlling an aircraft capable of hovering and relative aircraft
Luca Medici, Samarate (IT); Fabio Nannoni, Samarate (IT); Marco Braghiroli, Samarate (IT); Andrea Cogliati, Samarate (IT); Tiziano Frattini, Samarate (IT); Lorenzo Masellis, Samarate (IT); Luca Riviello, Samarate (IT); Alessandro Scola, Samarate (IT); Marco Tamborini, Samarate (IT); and Matteo Pizzagalli, Samarate (IT)
Assigned to LEONARDO S.P.A., Rome (IT)
Appl. No. 18/018,961
Filed by LEONARDO S.P.A., Rome (IT)
PCT Filed Jul. 30, 2021, PCT No. PCT/IB2021/056978
§ 371(c)(1), (2) Date Jan. 31, 2023,
PCT Pub. No. WO2022/029581, PCT Pub. Date Feb. 10, 2022.
Claims priority of application No. 20189398 (EP), filed on Aug. 4, 2020.
Prior Publication US 2023/0322400 A1, Oct. 12, 2023
Int. Cl. B64D 31/10 (2006.01); B64D 35/08 (2025.01); G05D 1/00 (2024.01)
CPC B64D 35/08 (2013.01) [G05D 1/0072 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for controlling a hovering aircraft which includes a first engine, a second engine, a rotor operatively connected to the first and second engines, and a transmission interposed between the first and second engine and the rotor, the transmission having a first inlet connected to the first engine and a second outlet coupled to the second engine the method comprising:
a) measuring a series of parameters associated with the operating conditions of said aircraft, the parameters including: i) an external temperature (OAT); ii) an external pressure, an external air density; iii and iv) heights of the aircraft above ground level and sea level; v) an angular speed of the rotor; vii) an indicated speed; viii) a torque delivered by the first and second engines; ix) an altitude above a minimum flight level; and x) a variometric speed (Vz),
b) determining whether the measured parameters indicate one or more of the following conditions: i) the external temperature (OAT) is between a first operating value and a second operating value; ii) the external pressure is between a third operating value and a fourth operating value; iii) the external air density is between a fifth operating value and a sixth operating value; iv) a height above ground level is between 50 and 1000 feet; v) the height above sea level is between 50 and 1000 feet; vi) the angular speed of the rotor is between 0.85 and 1.15 times a nominal angular speed; vii) the indicated speed (IAS) is between 0.5 and 2.5 times a first speed in level flight for which the minimum power at the torque delivered by the first and second engines level and operating temperature is required; viii) is between 0.5 and 3 times a first torque necessary for a straight level flight at the first speed; ix) an altitude above a minimum flight level is between 50 and 1000 feet; and a variometric speed (Vz) is between 0.1 and 1 times a vertical speed of autorotation and 0.1 and 1 times a maximum variometric speed at the first speed,
c) when it is determined that the conditions i) through are ix) fulfilled:
c1) transitioning operation of the aircraft from a first configuration in which both the first engine is operating with first power (P1) and the second engine is operating with second power (P2) to a second configuration in which the first engine is made to operate a third power (P3) greater than the first power (P1) and the second engine is made to operate at a nil power value (P4), wherein the third power being equal to the sum of first power (P1) and second power (P2);
d) when it is determined that conditions i) through ix) are not fulfilled and a difference between the measured parameters and at least one condition i) through ix) is greater than a minor anomaly, and the aircraft is operating in the second configuration:
d1) performing a first automatic transition operating of the aircraft from the second configuration to the first configuration,
e) when it is determined that conditions i) through ix) are not fulfilled and a difference between the measured parameters and at least one condition i) through ix) is within a tolerance considered to minor anomaly, and the aircraft is operating in the second configuration:
e1) performing a second automatic transition of the aircraft from said second configuration to the first configuration, wherein the second automatic transition is slower than the first automatic transition.