China Tests Hypersonic Flight Engine Using Design Developed in US But Rejected Over Costs - Report

A team of scientists has built and successfully tested a prototype based on a novel idea created more than two decades ago by an American space agency expert of Chinese descent.

A Chinese research team has built and tested a prototype hypersonic flight engine, capable of operating in Mach 4 to Mach 8 (4,900-9,800 kph) speed conditions, based on a design cooked up in NASA but later rejected due to high costs and unsolved technical problems, The South China Morning Post reported.

According to the report, while the majority of hypersonic aircraft have engines at the belly, a key feature of the experimental TSV X-plane is that it is powered by two separate engines on the sides.

The design was reportedly conceived by Ming Han Tang, a Chinese American who served as the lead engineer of NASA's hypersonic program in the late 1990s.

An interesting part of the design is that at lower speeds, the engines are able to operate as regular turbine jet engines, then they transition to a high-speed mode with no moving components when the aircraft accelerates to five times the speed of sound or higher.

NASA was ultimately unable to complete the now-defunct Boeing Manta X-47C project, as the dual-engine design's aerodynamics were too complex, and certain key problems remained unanswered, such as whether the engines could ignite after moving to hypersonic speed.

The US government reportedly canceled the program created to test Tang's design in the early 2000s due to technical challenges and costs.

According to the SCMP, the prototype research was taken up by a group of Nanjing University of Aeronautics and Astronautics scientists led by professor Tan Huijun, who have created a prototype machine featuring a pair of side-opening air inlets based on a declassified Tang scheme.

The team reportedly tested the prototype in a wind tunnel that could simulate flight conditions from Mach 4 to Mach 8 for several seconds. They discovered that the engines could start even in the most difficult of flight conditions, precisely as Tang expected.

In China, the design has reportedly gained much attention because "understanding its work mechanism can provide important guidance to hypersonic plane and engine development," according to Tan and colleagues in a paper published in the Chinese peer-reviewed Journal of Propulsion Technology, per the outlet's translation.

However, according to Tan and his colleagues, Tang's design was reportedly not ideal. Strong turbulence could occur around several corners of the air inlet, compromising flying stability, the team stated based on computer simulation and experimental results. The plane's ability to rise steeply without choking its engines was similarly limited.

And more importantly, the Chinese researchers emphasized that even if the dual-engine architecture was viable with some advantages, as the ground experiment revealed, many difficult challenges remain.

China's hypersonic vehicles and weapons currently utilize a rocket to initiate flight. The rocket shuts down after reaching a high altitude and high speed, allowing the air-breathing engine to take over.

And by 2035, Chinese space officials reportedly hope to produce a jet that can transport ten passengers anywhere on Earth in an hour on a new generation of turbo jet engines that could reach the speed of up to Mach 4, replacing rockets in hypersonic flights.

Earlier this year, China successfully launched a rocket into space carrying a hypersonic glide vehicle that circled the globe before rushing towards its target, which US intelligence and military officials admitted was surprising for the US.