Patent Approval
In May 2023, the China National Intellectual Property Administration (CNIPA) approved a utility model patent for China’s first Vertical and/or Short Take-Off and Landing (V/STOL) Fighter. Chengdu Aircraft Research & Design Institute (CADI) – also known as Chengfei – submitted the patent on December 29, 2022, for a twin-engine tandem vertical take-off and landing aircraft. Chengfei is the Research and Development (R&D) institute for the Aviation Industry Corporation of China (AVIC) that handles all R&D of military aircraft. The patent comes after China announced its intention to develop a V/STOL aircraft in a 2015 article appearing in the China Youth Daily.
Diagrams
The patent (Patent application number: 202223528680.3; Announcement number: CN 219056579 U) contains several diagrams showing the twin-engine system within the aircraft’s fuselage. One of the most significant aspects of the diagram is two engines – front and rear engines – and two vector nozzles located on the right and left sides under the root of the wings. Air is brought into the front engine (2) through the back air intake (1) and then pushed through the manifold flow channel (3) then into the right and left vector nozzles (4 & 7).
Both vector nozzles are described as being in the shape of a trouser leg. Air for the rear engine is taken in through the abdominal air intake (5) which will travel down to the rear engine (8) and into the rear thrust vectoring exhaust (9). The rear thrust vectoring exhaust will have the ability point downward at a 90-degree angle to assist in vertical or short takeoffs and landings.
Appearance
Exteriorly, the aircraft does appear to incorporate some stealth features, such as a diamond-shaped nose and the angular shape of the fuselage. Another reason why the V/STOL aircraft would incorporate stealth features is because Chengfei and AVIC developed the J-20 Mighty Dragon 5th generation aircraft for the People’s Liberation Army (PLA). Both the J-20 and the V/STOL diagram appear to share the same modified delta wing shape in addition to stealth features. Finally, the V/STOL’s vertical stabilizers look like the J-20’s stabilizers in both angle and overall appearance.
However, both the abdominal air intake and rear engine layout are like the J-10 Vigorous Dragon, another jet aircraft developed by both Chengfei and AVIC. The V/STOL’s air intake looks like the rectangular abdominal air intake found on the J-10. Another feature the V/STOL shares with the J-10 is the rear engine, which, like the air intake, looks like the J-10’s rear exhaust but without the thrust vectoring feature.
While the V/STOL shares some similarities with both the J-10 and J-20, there are some differences. One of the most significant differences is the lack of canards of any kind displayed in the diagrams. Another major difference between the V/STOL and the J-20 is that the V/STOL only has one rear exhaust nozzle compared to the two found on the J-20. Additionally, the current variant of the J-10 lacks the thrust vectoring capability found on the V/STOL. The capability also differs from the J-20B’s thrust vectoring capability because of its ability to turn downward at a 90-degree angle. The cockpit is different from the J-10 in both appearance and layout. For example, the J-10’s cockpit is a two-piece bubble canopy, while the V/STOL’s cockpit appears to be both smaller and flush with the back part of the canopy.
Similar Western Aircraft
There are three western aircraft that are similar to the Chengfei-designed V/STOL aircraft, such as the AV-8B Harrier II (U.K./U.S.), the F-35B (U.S.), and the Yak-38 (Russia/former USSR). These similarities range from vectoring nozzles (AV-8B and Yak-38) to the rear engine exhaust (F-35B). The Chinese V/STOL and both the AV-8B and Yak-38 are similar because they use vectoring nozzles for vertical launches or short takeoffs. However, both aircraft differ from the Chengfei aircraft in both the number of vectoring nozzles used and how they are used to provide both lift and propulsion to the aircraft. The AV-8B uses four vectoring nozzles—two on each side of the aircraft—to enable the aircraft to launch vertically and to fly.
Similarly, the Yak-38 also uses four nozzles to provide the aircraft with its vertical launch and flying capabilities, but they differ in their configuration. The Yak-38 uses two stationary nozzles to provide downward lift, while two vectoring ones provide the aircraft with forward propulsion. Additionally, the Yak-38 differs from the Chengfei in terms of where the stationary nozzles are located. The Yak-38’s downward nozzles are stacked on top of each other and situated behind the cockpit. Both aircraft also have a different number of engines to provide their flying capabilities, with the Chengfei aircraft having two engines while the Yak-38 had three separate engines.
Both the F-35B and the Chengfei aircraft share similar thrust vectoring nozzles that can turn downward at a 90-degree angle to assist in vertical landings. The vectoring nozzles also use only one engine to achieve both their downward thrust and forward propulsion capabilities. Another similarity is the incorporation of stealth features, such as angular features, into both aircraft to reduce their radar cross sections. However, both aircraft use different propulsion systems for use in vertical launches, with the F-35B using a vertical lift fan located in the center of the aircraft. Conversely, the Chengfei aircraft uses two vectoring nozzles on either side of the aircraft to achieve vertical lift.
Analysis
The patent for the new CADI (Chengfei)-developed V/STOL aircraft indicates the Chinese have advanced the program to the point where they feel comfortable with the technology to patent it. The patent also indicates CADI has either produced or will produce a prototype of the aircraft to conduct test flights. However, the program is still some time from producing an operational aircraft capable of conducting V/STOL operations because of several obstacles. The most substantial obstacle Chengfei faces is the lack of proof of concept for their twin-engine tandem vertical take-off and landing system.
While vectoring nozzles can provide the necessary lift to push the aircraft upwards along with the downward-facing nozzle, the designers will likely be required to modify the nozzle design to increase propulsion. Additionally, the use of two separate engines to power both the vectoring nozzles and the engine will also require further modification for both to work properly. Another obstacle is the engine system’s complex design, which uses two separate engines to provide both vertical and horizontal thrust. This obstacle is compounded by the inability of China to conduct industrial espionage to steal data or information since no comparable engine system exists.
However, if CADI can overcome the various obstacles to produce a viable V/STOL aircraft comparable to the F-35B, it will give the PLA significant power projection capabilities. For example, the Chengfei V/STOL aircraft will enable the People’s Liberation Army Navy Marine Corps (PLANMC) to create units equipped with the aircraft that can provide organic fixed-wing Close Air Support (CAS) fires to PLANMC brigades. These units would be based on either the Type 057 or the planned Type 076 Landing Helicopter Docks vessels (LHD), like the USMC does with F-35Bs when they deploy as Amphibious Ready Groups (ARGs).
These units would expand the type of missions the People’s Liberation Army Navy’s (PLAN) ARGs are currently capable of conducting to include CAS, Combat Air Patrols (CAPs), or anti-air warfare. Additionally, these units would also be used to provide greater power projection to areas in the South China Sea that lack sufficient runways or associated infrastructure due to their vertical launch capabilities. Finally, these aircraft would provide significant CAS capabilities during any forced landings, including in the initial stages of an invasion of Taiwan.