06.19.2017

The Generation Gap of Aircraft Classification

It was an interesting debate; the white-bearded English aerospace engineering professor argued the merits of his country’s Supermarine Spitfire with a first year AE student’s passion for the North American P-51.  The professor suffered yet admired the young lad’s enthusiasm knowing full well that it was his job to direct and nurture that energy.  In 1974 those were three-decade old planes, all relegated to an aircraft boneyard except for a few in personal hands and in foreign countries even as late as the mid-1980’s.  The English gent even waxed romantically about the Gloster Meteor, the very first British jet fighter still designed with straight wings and considered a first-generation fighter jet. But, three generations later, outside those academic doors the McDonnell Douglas F-15 was undergoing flight tests, soon to redefine air superiority.

Fast-forward four decades (great Scott!) and now that same young lad who became a design engineer on the F-15 variants Strike Eagle and ASAT (satellite launcher) watches Boeing (nee McDonnell-Douglas) struggle to keep the aging F-15 program alive. Time flies and technology seems to be the thrust.

It was easy to differentiate airplane fighter groups when the thrust was from either a propeller versus a turbofan engine. Most everyone in the 1980’s expected X-wings, TIE fighters and even DeLoreans to fill the air by the early 21st century. Not so much now — the major differences being the ones you can’t see, or detect — cloaking being today’s competitive advantage.

You’ve probably heard of jet fighters being classified in “generations”, implying a historical reference.  As you’d imagine, classifying jet aircraft this way is quite complex and, not unlike in the aforementioned classroom, subject to debate. The term was coined in the 1990’s to demark non-retrofittable technological advances, not necessarily superiority. Consider the early third generation cannon-less,McDonnell Douglas F-4 Phantom, dependent on unreliable missiles, versus the second generation MiG-17 in Vietnam – not our finest hour.

The definition of each generation is a four-way debate at that, between Air Force Magazine, Air Power Development Centre Bulletin from the UK, USAF historian Richard P. Hallion, and the nascent Aerospaceweb. If you have a passion for jet fighters, see if you agree.

Of course the very first jet-powered aircraft is Germany’s Heinkel He 178 but the Me 262 was the first fighter. Britain followed with the Gloster Meteor with the US’s P-80 to follow right behind at the end of WWII. The first generation of jet propulsion and high subsonic speeds had begun.

Transonic speeds and swept wings characterized the second generation, which included the legendary F-86 and its counterpart, the MiG-15. Infrared missles were introduced.

For the third generation jet fighters exceeded the speed of sound and had advanced weaponry that were separate from the aircraft itself such as beyond visual range missles (BVR).  From the F-100 to the F-4 it was a tremendous period of technological advancements. You won’t see many third generation fighter aircraft in service for the 21st century. As an airframe experiences thousands of cycles of stress, fatigue takes its toll.

But you will see plenty of fourth generation models, including the venerable F-15, F-16, F-14, and F-18.  Most of these models have been modified and classified as either 4+, 4.5, or 4++.

The newest jet fighters receiving your federal spending are the F-22 and F-35, both considered the fifth generation.  Their advantages depend on being able to detect the enemy before they can be detected.

What you won’t see yet or detect — definitively — are the upcoming sixth generation fighters. There’s considerable argument that technology and autonomy have ruled out scenarios like the 1950’s MiG Alley in North Korea where stick and rudder skills prevailed. Aviation technology may be suffering from its own version of Moore’s law where advancement far outpaces the product development time.