Abstract: The horizontal takeoff and landing Ma4 high speed aircraft is currently a hot research field， and the turbo-ramjet combined cycle (TRCC) engine is one of the feasible power form. But after 50 years of development， the TRCC exceed Ma3.5 still does not carry out the flight test. To study the factors which block the TRCC engine from the technological areas to the engineering areas， a horizontal takeoff and landing Ma4 high speed aircraft equipped with two TRCC engines， whose maximum flight speed is Ma4 was modeled， and the flight mission profiles was set up. Then the aircraft’s thrust requirements in the whole flight process was calculated. Compared with the calculated results and the engine technology ability， three core elements which limited the TRCC engine from the technological areas to the engineering areas were found. The first is that there is a huge ‘thrust gap’ when the aircraft is climbing at high speed in the high altitude. The second is that the engine thrust weight ratio is too low to the payload and flight distance of the aircraft. The third is that we attribute the low reliability and short life to the long-term working with afterburner at high flight Mach number conditions. At last， some technological development proposals were advised.

Key words: Turbo-ramjet combined cycle engine；Horizontal takeoff and landing Ma4 high speed aircraft；Thrust gap；Mission profiles optimal design

摘要： 水平起降Ma4高速飞机是目前研究的热点，涡轮冲压组合发动机是其可行动力形式之一，但历经50多年发展，Ma3.5以上涡轮冲压组合动力目前仍然停留在地面试验阶段，为了探明限制涡轮冲压组合发动机从技术研究转入工程研制的关键因素，本文设计了一个配装两台涡轮-亚燃冲压组合发动机、最高飞行速度为Ma4左右的水平起降高速飞机模型，设定了飞行任务剖面，计算出了整个飞行过程中飞机对发动机的推力需求，并对比现有航空发动机技术能力，分析出了阻碍涡轮冲压组合发动机向工程应用迈进的三大核心要素:飞机高空高速爬升阶段发动机存在一个巨大的“推力缺口”，现有发动机推重比不够高导致飞机有效载荷和航程受到极大限制，发动机长时间高Ma数飞行导致可靠性和寿命低。据此针对性提出了技术研究措施建议。

关键词: 涡轮-亚燃冲压组合发动机；水平起降Ma4高速飞机；推力缺口；任务剖面优化