• Thanks for stopping by. Logging in to a registered account will remove all generic ads. Please reach out with any questions or concerns.

ADVENT Plus HEETE Technology


Army.ca Legend
Reaction score
The USAF has created the technology to combine cruise, loiter, and produce thrust for supersonic ++ strike airframes into one package.




ne highlight in the exhibition hall at this year’s AIAA Joint Propulsion Conference in Denver, Colorado was an updated cutaway model of the U.S. Air Force Research Lab’s ADVENT (adaptive versatile engine technology) future strike/persistent engagement aircraft engine. Unlike earlier models, this latest version is rendered in a lighter plastic which makes for better photography of the innards.

The feature to notice most about ADVENT is the unusual extra duct for bypass air seen running along the top and bottom of the engine. This is the critical third flowpath which will be opened or closed as part of a variable cycle to transform it from a strike aircraft engine to a transport-type engine, or vice-versa. If the flowpath is open the bypass ratio will increase, reducing fuel burn, and enabling range to increase in a subsonic strike engine by 40% and loiter time by up to 60%. If the ducts are closed, additional air is forced through the core and high pressure compressor, enabling thrust and speed to increase.

The impact is even more dramatic on the more extreme cycle of a supersonic strike engine. With ducts closed for maximum performance in the combat zone, the flow would be opened up again for the transit to and from the target, resulting in increased engine efficiencies which would give up to an 80% range increase and a staggering 135% increase in loiter time.

Unfortunately there was no model on show of HEETE (highly efficient embedded turbine engine), the advanced engine aimed at producing similar range, payload and loiter time improvements for transport and persistent ISR aircraft. The new core of HEETE, which will feature a pressure ratio rumored to be in the 70:1 range, is what’s causing all the excitement. A leap beyond the advanced compressors on fifth generation high bypass turbofans like the GEnx and Rolls-Royce Trent 1000, it could give US engine makers – military and civil – an unbeatable advantage in the next decade and beyond.

For AFRL there’s more to come when ADVENT and HEETE are combined in around seven or eight years time to produce AD-HEETE. “That’s the whole enchilada,” exclaims AFRL engine division chief engineer Bill Koop.
My colleague Graham Warwick and I only had one issue with the new model – from time to time the ADVENT was prone to seizing up violently as if in the grip of the world’s most destructive surge. We were sure the stand manager was last seen heading off to find that most reliable of high-tech engine solutions – a can of WD 40.

Another article