A New Concept in Jet Propulsion

XA100 Adaptive Cycle Engine

The only known photo of the engine

The Logical Next Step in Jet Engines

In search of a new engine that could economize fuel consumption, the US Government created the ADaptive Versatile ENgine Technology (ADVENT) Program with the goal of developing an engine that is optimized for several combat missions. And the answer to reach that goal was the creation of the Adaptative Cycle Engine, with Pratt & Whitney, Rolls Royce and General Electric Aviation joining to design such an engine. But what is the difference with the regular turbofan?

The adaptable cycle engine (ACE), also referred to as variable cycle engine (VCE), is an aircraft jet engine engineered to operate efficiently under mixed flight conditions, such as subsonic, transonic and supersonic flight regimes.

And how an ACE Engine works?

Speaking easy, while a turbofan engine has its bypass ratio fixated in either low (combat aircraft, higher thrust and fuel consumption) or high (cargo/passenger aircraft, lower fuel consumption but more efficient), an ACE engine can switch to either of them depending on the flight regime in order to be at peak performance with a better use of the fuel capacity, making the aircraft less dependant on refueling over long distances.

Simplified Schematics of a VCE Engine (and its advantages):

concept of the Adaptable Cycle Engine

Evolution of the code from monke to homo sapiens:

PID(Throttle*3, max, 3, 1, 0.5)

Throttle*lerp(1,4,IAS/30)|Throttle*lerp(1,3,IAS/300)|Throttle*lerp(1,6,IAS/417)

clamp(Throttle*lerp(1,4,IAS/111.111111),Throttle*lerp(1,3,IAS/416.666667),Throttle*lerp(1,4.5,IAS/823.333333))

IAS<343.333333&IAS>138.888889?Throttle*lerp(1,2,IAS/343.333333):(IAS<138.888889&IAS>111.111111?Throttle*lerp(1,1,IAS/138.888889):Throttle*lerp(1,3,IAS/111.111111))

Plans for the future

Since this engine its only a prototype, the first step forward is to make the code more understandable and user-friendly so every user can configure it to suit its needs. Later on, the planned updates with an unknown deadline are:

• upgrade the inputs to effectively lower fuel consuption (main goal is a 25 to 35% fuel efficiency) compared to a regular engine while maintaining or upgrading performance
• Greater thrust
• Research the use of ACEs in twin engine configuration in both light and heavy fighters
• investigate the possibility of making a ACE capable of propelling a Hypersonic missile with low or null initial speed
• research the advantages of the ACE for both flying wings and civil aviation

Of course, the use of the code, improvements and everything related to its its heavily encouraged

Stock Aircraft equipped with ACE engines:

Hellkeska

Vertigo

Wasp

Credits:

KGcheater for the basic structure of the vectoring thrust engine he made

11qazxc for turning the horrible PID controller the FT code was in its start into somewthing that was actually intuitive to work with

JuanShot2Go for its help in fixing mistakes and making the code fully work

Extra Data:

Brief Introduction in Wikipedia
ADVENT Program
General Electric XA100
Video by General Electric
Other video by General Electric
Wikipedia Entry in audio format