By Kris Osborn - Warrior Maven

(Washington, D.C.) Why do available renderings of 6th-Gen fighter aircraft and helicopters show fewer vertical structures, blended wing-body structures, fins or protruding configurations? Are there ways scientists, engineers and expert weapons developers are uncovering new aerodynamic developments likely to improve aircraft design configurations to massively enhance performance?

Stealth Fighter Jets

While of course specifics regarding new aerodynamic design configuration for future stealth fighter jets or helicopters are likely not available for obvious security reasons, there is some cutting edge aerodynamic research going on with academia and the Army Research Office to explore a new generation of innovations able to greatly improve aerodynamic performance for future aircraft.

Certainly a more horizontal looking 6th-Gen fighter jet, absent protruding structures such as tailfins, weapons pylons or a sharply angled fuselage structures would make an aircraft stealthier, as electromagnetic pings would have less shapes to bounce off and therefore be less likely to produce an accurate rendering. 

Fewer extended external structures and blended wing-body configurations all naturally improve stealth performance characteristics, so perhaps engineers have discovered ways to turn, maneuver, vector or operate in the air without needing as many tailfins or distinctly separated wing structures? What are some of the technical factors making these kinds of aerodynamic improvements possible? Breakthroughs in the area of aerodynamics related to “boundary layer,” or “air flow” management.

Future Vertical Lift Aircraft

Many of these same principles apply equally to ongoing Army efforts to design, engineer and research possibilities for new helicopter designs and continue to upgrade its most cutting edge Future Vertical Lift aircraft

Certainly available Future Vertical Lift prototypes from both Bell Helicopter and Lockheed-Sikorsky-Boeing appear engineered to generate a low radar signature by virtue of their respective configurations. Much of this likely pertains to evolving advances in aerodynamic designs.

U.S. Army Future Vertical Lift

Future Vertical Lift, U.S. Army and Bell

Aerodynamics

When fast-moving vortices, or “masses of whirling air” collide, large amounts of turbulence can be generated, often sufficient to fully derail intended aerial maneuvers. Managing these collisions between masses of air flow is a factor in aerodynamic aircraft design, as structures such as wings or fins placed in a particular area in a particular shape, can help an aircraft “vector” effectively.

Yet, apart from the question of potentially enhancing stealth properties, there is another key reason why engineers succeed in creating more effective and higher-performing aircraft; designers continue to uncover new methods of directing, managing or controlling “air flow” surrounding an air vehicle, a phenomenon of course critical to flight stability. Should an aircraft’s surrounding air flow or “boundary layer,” be directed or managed for optimal performance, an aircraft can fly faster and smoother with much less turbulence.

This is something of critical significance to Army scientists who are working with academia to discover cutting edge computer simulation technologies able to precisely replicate aerodynamic phenomena such as the way in which air flow can impact turbulence. 

Turbulence in flight is as common as it is both complex and somewhat mysterious, as it can massively destabilize an aircraft’s flight trajectory and even cause it to “lose lift” and crash. Air flow management is vital to flight stability and aerial performance in key areas such as high-speed maneuvering or sharp angle vectoring in combat. 

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So-called “friction” or disruption in the “boundary layer” can throw an aircraft off course. A “laminar” or smooth, air flow boundary layer can optimize flight performance, whereas a turbulent boundary layer can cause significant flight stability programs for aircraft.

These areas of current inquiry are intended, among other things, to generate new possibilities in the realm of air vehicle design sufficient to achieve a new generation of higher-performing aircraft less encumbered by turbulence.

Army Research Office & Purdue University

The Army Research Office funded researchers at Purdue University to advance a turbulence model known as the Coherent-vorticity-Preserving Large-Eddy Simulation, known as CvP LES. Published in the Journal of Fluid Mechanics, the new methodology simulates the entire process of a vortex collision event up to 100 times faster than current state-of-the-art simulation techniques.

Researchers with the Army and Purdue University are able to simulate these kind of collisions, wherein vortices intersect or essential “run into” one another and collide, a process which enables them to closely study the kinds of aerodynamic phenomena essential to generate a smooth or “” air flow.

“When engineers are designing the latest greatest transport plane, fighter jet or helicopter, they have to use computer models to try to understand the flow around the design…..and they have to make some choices about how they account for turbulence,” Dr. Matthew Munson, Program Manager for Fluid Dynamics at the Army Research Office, a division of the Army Research Laboratory, Army Futures Command, told Warrior in an interview.

U.S. Army Future Vertical Lift (FVL)

Future Vertical Lift, U.S. Army and Bell

Munson described it as building up an understanding of the air flow surrounding an entire vehicle to analyze, refine or enhance aerodynamic performance variables.

“Once I have an understanding of the flow over the entire vehicle, I can start to do things like compute ‘lift’ and ‘drag’ .. and I can compute the thrust needed and I can compute how much the airplane can weigh. I can compute what kinds of forces are required to turn the aircraft from straight and level to a diving or climbing position,” Munson explained. “Each of these things requires some treatment of the turbulent flow.”

What might the end result of all of this be? Simply put .. new air vehicles. This kind of research and innovation could very well drive engineers to design conclusions for a 7th-generation aircraft someday or create an entirely new kind of high-speed, hovering attack helicopter. The promise of this research means a higher probability of smoother, faster, stealthier flight.

“If you’re able to accurately simulate the thousands of events in flow like those coming from a helicopter blade, you could engineer much more complex systems,” Carlo Scalo, a Purdue associate professor of mechanical engineering, said in an Army Research Laboratory report. 

-- Kris Osborn is the President of Warrior Maven and The Defense Editor of The National Interest --

Kris Osborn is the defense editor for the National Interest. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Master's Degree in Comparative Literature from Columbia University.