What Do a Kid's Sneakers and a Warplane Have in Common?

When I was a youngster growing up in the early postwar era, parents used to economize a little more than we do today.  I think we were more likely to wear our clothes until they wore out.  Being second in line, I got a lot of "hand me downs."  But, when my mother did buy me something new, like sneakers, she made sure they were generously sized so I would "grow into them."   The idea was they would last perhaps half again longer before I outgrew them and, if she guessed just right, chances were I'd wear them out at about the same time.

Which brings me to the F-35.

Sometimes when you're shopping for 'new' it's a good idea to look for growth potential.   That's a good idea when you're shopping for high-performance warplanes too.   You want to be sure there's plenty of room to grow.   Why?   Because experience shows that airplanes can grow heavier as they grow older - just like you and me, or at least me.

New stuff comes along, the latest and greatest, that you just can't do without.  You have to modernize the airplane to stay current with the times.  New stuff has to be fitted inside and you take weight and performance penalties in exchange for (you hope) improved overall capabilities.   All you really need is an airframe that's really upgradable - lots of power, available space inside for new stuff, etc.

The F-35 might be like buying your five year old a snug pair of runners.  Right out of the box it's got a weight problem.  How bad is it?   Well, to try to narrow the gap between the aircraft's promised performance and its actual numbers, the manufacturer began stripping out components like the fire suppression system that you don't really need until it's really, really needed.

Like most people with a weight problem, the F-35 also has a size problem.  It has a powerful engine but the stealth design left it a stocky airplane seen from the front.  Stocky means high-drag which means higher fuel consumption.   In the F-35 that also rules out the sine qua non of contemporary combat fighters - supercruise.   This is the ability to cruise at supersonic speeds without having to resort to fuel-guzzling afterburner.  It's a handy quality to have when you need to go long distances at fast speeds to intercept an attacker or outrun pursuing defenders.   The F-35 lacks supercruise which leaves it susceptible to being overtaken by faster, long-range  fighters as it tries to flee hostile airspace.

Another issue is shape.  It's not uncommon for warplanes to grow bumps and appendages as the years go by.   For example, when the Brits decided their Spitfires needed greater firepower they replaced machine guns with cannon but the cannon wouldn't fit inside the slender wing so they had to adapt it with blisters seen here.

Years later the Americans fielded their wonderplane, the F-4 Phantom.   Like the F-35, the F-4 was built around a lot of untested assumptions.  One of them was that, in future, there would be no dogfighting.   Air combat would be a missile fight and so there was no need for an onboard cannon.   Along came Vietnam and they found that those missiles didn't work nearly as well as expected and they were getting dragged into dogfights and they did need a gun after all.   And that left them having to resort to this ungainly, heavy, high-drag and inaccurate gun pod bolted on to the F-4s belly.

Likewise, when the F-18 entered service it became apparent that airflow turbulence was buffeting the rudders, threatening to cause them to break.   That led to a pair of strakes or fences being bolted onto the fuselage leading edge extension to stop the turbulence.

What do blisters, pods and strakes have to do with the F-35?  Unfortunately, pretty much everything.  The F-35's frontal-aspect only stealth masking is based in large part on its radar-reflecting shape.   Start adding blisters, vanes, fences, pods or strakes and that stealth advantage goes out the window.   You can't fix it the way the Spitfire was fixed, the way the Phantom was fixed, the way the F-18 was fixed.

It's these built-in shortcomings and inflexibility that reveal stealth to be a brittle technology.  It already limits the performance of the F-35 even when it remains five years away from the completion of testing.  It's coming out of the plant pretty much at, if not beyond, its performance limits.  One thing you can be sure of - when the Air Force guys come to us in ten or fifteen years telling how this plane urgently needs upgrades they're going to be looking for "Ad Astra" money.