倾转机翼/旋翼机过渡姿态规划分析

Design of transition attitude for tilt wing/rotor aircraft

针对带有倾转机翼段的新构型倾转旋翼机复杂的倾转过渡变构型过程,提出一种基于动量叶素理论的高速段倾转走廊边界计算方法。通过低速时机翼失速限制和高速时旋翼可用功率限制建立倾转过渡走廊计算模型,对比了传统构型倾转旋翼机和倾转机翼/旋翼机的倾转过渡走廊差别。对2种构型倾转旋翼机倾转过渡状态下前飞速度、机身迎角、旋翼桨距角姿态进行了对比分析。结果表明:带有倾转机翼段的倾转机翼/旋翼机具有更狭窄的倾转走廊,在短舱角0°状态,倾转机翼段占1/3展长的旋翼机相较于传统构型倾转旋翼机,倾转速度边界从39~57 m/s缩减到41.7~51.2 m/s,倾转操纵难度加大;在大于45°短舱角的倾转前期,同样的前飞速度和短舱倾转角状态下,倾转机翼/旋翼机机身迎角降低约2°,旋翼桨距角增大1°~4°,随着倾转过渡的完成,2种构型倾转旋翼机姿态差异逐渐变小。

Aiming at the complicated tilt transition configuration change process of tiltrotor aircraft with tilt wing segment,a calculation method of high-speed segment tilt corridor boundary based on blade element momentum theory is proposed.The calculation model of the transition corridor is established by limiting the wing stall at low speed and the rotor available power at high speed.The difference between the transition corridor of traditional tiltrotor and tilt wing/rotor aircraft is compared.The forward flight speed,fuselage angle of attack,and rotor pitch angle in tilt transition state are compared and analyzed.The results show that the tilt wing/rotor aircraft with a tilt wing segment has a narrower tilt corridor.Compared with the traditional tiltrotor aircraft,the tilt speed boundary of the rotorcraft with a tilt wing segment accounting for 1/3 of the span at the nacelle angle of 0°is reduced from 39~57 m/s to 41.7~51.2 m/s,which makes the tilt control more difficult;At the earlier stage of the tilt process when the nacelle angle is greater than 45°,at the same forward flight speed and nacelle tilt angle,the angle of attack of the body of the tilt wing/rotor aircraft decreases by about 2°,and the rotor pitch angle increases by 1°~4°.With the completion of the tilt transition,the attitude difference between the two aircrafts gradually decreases.