Tuesday, August 26, 2014

You want to resurrect the Arrow? Fine! Here's how...


Some legends die hard.

It seems that nary a week goes by without a mention of the CF-105 Avro Arrow.  Not only is it revered in a historical sense, but many still think it would be the answer to our CF-18 replacement dilemma.

Let me get this right out of the way.  I LOVE THE ARROW.  I love the very idea of it.  Canada building a world class interceptor during the hight of the Cold War makes my inner fanboy squeal.  I also think that the Avro Arrow is, without a doubt, the most esthetically pleasing aircraft of all time.  It is simply gorgeous.  It is iconic.  Like the original iPhone, the starship Enterprise, or Jaguar E-Type; the Arrow has an elegant simplicity to its design that is made even more impressive by the wonderfulness of what lies beneath its skin.  As far as aircraft go, only the Concorde and SR-71 Blackbird come close.

Looking back, the Arrow does seem impressive, with a higher top speed than many modern fighters, and technology that seemed far ahead of its time.  So why not use an updated version to replace the CF-18 Hornet?

The CF-105 was not, nor could it ever be, a multi-role fighter.

The Arrow was an interceptor, pure and simple.  It was designed to fly very high (53,000ft+) and get there very fast.  While its performance numbers (both tested and estimated) are still very impressive, those numbers do not tell the whole story.

Those big delta wings that give the Arrow its iconic look produce incredible amounts of lift, especially at high speed.  They also stay out of the way of the aircraft's shockwave as it approaches and pasts through the sound barrier.  Unfortunately, they also create a great deal of drag at low speeds, as well as bleeding off energy during hard maneuvers.

Put simply, the Arrow would be just about terrible for low speed, low altitude missions like close-air-support.  It would also be a substandard dogfighter, even if it had a cannon.  It would also require long runways and plenty of hangar space.

Yeah.  It's THAT big.
You will also notice a disturbing lack of range.  Noticeably shorter than the F-35, and a mere fraction of what other modern fighters are capable of carrying external tanks or CFTs.

Clearly, the CF-105 Avro Arrow would be sorely uncompetitive if we simply dusted off the blueprints (if they still exist) and started production (in a factory that no longer exists).  But what would happen if we modernized it?

One way to modernize it would be to take a "clean sheet" design and reimagine the Arrow for the 21st century.  Artist Joe Green has done this with his concept, The Super Arrow.  


Joe Green's Super Arrow
There are others that imagine the original CF-105 design but upgrade it to "Mark III" and higher.  While the idea sounds impressive in theory, claims that the CF-105 would be capable of flying at speeds beyond Mach 3.5 while carrying external missiles seem optimistic.

While the heart seems to be in the right place, this comes across as more of a "wish-list" of sorts.  No specifics are mentioned other than weapons.  Those "80,000 lbs total wet thrust" Iroquis III turbojets would be more than double the thrust of the J-58s used in the SR-71 and even higher than the RR/Snecma Olympus 593 used on the Concorde  Some design choices, like external BVR Meteors and internal WVR Pythons seem downright odd.




Even upgraded with modern weapons, avionics, and sensors; it still seems doubtful that the Arrow would make that impressive of an air superiority fighter.

A "true" air-superiority focused CF-105 would have to contend with the likes of the Su-35, the PAK FA, and Chengdu J-20.  These aircraft have been shaped by over 50 years worth of continued fighter development since the Arrow.  Moreover, a modernized Arrow would have to prove itself competitive against fighters like the F-15 and Typhoon as well.  On top of that, the very idea of a 50s era fighter being able to compete in the same realm as the F-22 is, quite frankly, ridiculous.  With no thrust-vectoring, supermaneuverability, or stealth, the Arrow just does not compare.

The Avro Arrow lacks the low-level performance to be considered a proper strike fighter.  It lacks the modern technology and maneuverability to be considered an air-superiority fighter.  Its role as an interceptor seems rather quaint in an age when much smaller aircraft like the F-16 or Gripen can perform the role just as well.

So why bother?

MiG-25 "Foxbat"
While western military doctrine has abandoned the idea of the the "pure" interceptor, the type has lived on other countries.  The MiG-25 (NATO name "Foxbat"), was introduced well after the cancellation of the Arrow, and was built for 20 years.  Even after the introduction of well rounded air-superiority fighters like the F-14 Tomcat and F-15E Eagle, the Soviet Union continued the concept with the improved MiG-31 (NATO name "Foxhound").

Even to this day, after the fall of communism and the proliferation of the Su-27 and its many variants, the Russian air force continues to fly the MiG-31.  Not only that, but the Foxhound continues to receive upgrades, and a replacement is planned.

So why does Russia seem so enamored with this "obsolete" aircraft type?

Geography.

MiG-31 "Foxhound"
Since Russia (and the former Soviet Union) is so large geographically, it is impractical to depend solely on ground installations for detection against interlopers.  As such, they need to rely on more on aerial assets for defense.

Put simply, the MiG-31 has evolved into a "multirole" fighter in its own right.  Instead of being a "fighter-bomber", the MiG-31 is more of a "fighter-AEW&C".  Equipped with a massive 1.1 meter wide PESA radar consisting of both X-band and L-band transponders, the MiG-31 can track up to 10 fighter-sized targets from over 200km away.  It carries a retractable, chin-mounted IRST sensor.  It also utilizes data-links that enable it to coordinate with other fighters, ground radar installations and AEW&C aircraft.  It was also the only aircraft capable of intercepting the SR-71 Blackbird.

This is all the more impressive when you consider the MiG-31 is a 30-year-old aircraft based on a 50-year-old design.

By now, you should know where I am going with this.

Putting the pieces together...
The Arrow shares some important traits with the MiG-25, size and speed.  While it never broke Mach 2 with its J58 test engines, it was theorized that it could very well approach Mach 3 if it made production.  At 77 feet long, it is larger than both the MiG-25 and the MiG-31.  The Arrow has an extra benefit that the MiGs do not have.  A swappable "weapon pack" that could house fuel, missiles, or surveillance equipment, depending on the mission.

So what would it take to resurrect the Arrow as a NATO sourced MiG-31-type aircraft?

Construction

The original arrow utilized near all metal construction, namely stainless steel, aluminum, magnesium, and titanium.  Obviously, plenty of weight could be saved by switching to more modern carbon-fiber composites wherever possible, especially for the aircraft's exterior skin.  Not only would this save weight, but it would also have the benefit of making the Arrow stealthier than it was.

Internal hydraulics would be of course converted to a more modern fly-by-wire system (the Arrow already had a rudimentary FBW system) to save additional weight and make room for additional fuel.

Reducing weight has the dual benefit of increasing range, as well as increasing the maximum payload.

Engines

Perhaps one of the more ambitious features of the original Arrow was its Orenda Iroquois turbojet engines.  These engines would have been among the most powerful jet engines of the time.  Unfortunately, they also added an extra layer of complexity and risk to the Arrow project.  Thankfully, there are enough "off-the-shelf" options available now.

Turbojets have fallen out of favor in modern times, with good reason.  They are less flexible than turbofans, being optimized for a high speed and altitudes.  Turbofans have the extra benefit of running cooler than turbojets, as the bypass air helps cool the engine and exhaust.  Most importantly for us, a modern turbofan offers significant fuel efficiency improvements.  

Ideally, the best modern Arrow engine would likely be the Pratt & Whitney F119 as used in the F-22 Raptor.  It is roughly the same size as the Iroquois, yet boasts slightly more thrust (35,000lbs vs 30,000lbs).  It also allows for supercruise speeds.  The vectored thrust nozzles would be an extra benefit.  As an alternative, the GE F110 would be an excellent choice, again offering more power (32,000lbs) in a easily accessible and proven package.

Sensors

If there is one area to splurge, this is it.  Designs like the PAK FA and J-20 illustrate the fact that stealthy aircraft could very well make up a future threat.  

The Arrow's generous nosecone dimensions should be able to fit a modern AESA radar, roughly the size of the MiG-31's.  At current time, there appears to be no western equivalent to the MiG-31's Zaslon.  Instead, perhaps we could incorporate an "upsized" version of the Eurofighter's CAPTOR-E, complete with repositioner.  This is similar in concept to the APG-82 currently being fitted to the F-15C.  It uses the Super Hornet's processor with a larger dish.  

Like the MiG-31, an IRST sensor should be included.  A modern HMD, data links, and the like as well.  

Weapons

Currently, the west has no missile analogous to the MiG-31's R-37.  The older R-33 is roughly equivalent to the long-range AIM-54 Phoenix, but the R-37 is an updated version in much the same way as the AIM-120 AMRAAM is an updated AIM-7 Sparrow.  Dubbed "the AWACS killer" the R-33 can shoot down larger aircraft from a distance far enough to avoid any escorts.  

This capability would need to be matched with either an updated Phoenix, an entirely new missile, or perhaps a existing missile, such as the AMRAAM or Meteor, equipped with a second stage "booster" rocket of some kind.  

At the very least, provisions should be made for 4 BVR AMRAAMs or Meteor carried conformally, similar to that of the Eurofighter Typhoon.  Given the mission profile, no cannon would be needed.  Ideally, 2 WVR missile stations would be added as well.  This adds minimal drag, and would free up the Arrow's "weapons pack" for other things.

Despite the Arrow being developed as an interceptor, many remarked that it would have made an impressive light bomber as well.  For this, the Arrow could be fitted with long range ALCMs like the AGM-158 JASSM or the Storm Shadow.  Close air support operations are probably still best left to other aircraft however.  

 

Multi-mission pack

Instead of a "weapons pack", the Arrow would instead utilize a modular "multi-mission pack" that could be swapped out depending on the mission.  Variations of this could include:  
  • A module outfitted with additional air-to-air weapons
  • A module outfitted with air-to-ground weapons and a targeting pod
  • A reconnaissance module with cameras and/or other surveillance equipment
  • An electronic warfare module, with jammers and possibly anti-radiation missiles.
  • Possible future upgrades, such as DEW weapons.

Other features

An aerial refueling probe would be mandatory of course.  

A possible redesign of the engine inlets as well, either incorporating a variable ramp to improve performance at high-speed, or a divertless inlet to improve stealth.  

Modern ECM, RWR, towed decoys, and other countermeasures would be a must-have, of course.  Possibly even a DIRCM system.


This is all speculation and estimation, of course.  It seems unlikely that the Arrow will ever live again as a military project.  The current trend in military spending is seemingly no spending at all.  With the CF-18 replacement pushed off until the 2020 time frame, it seems unlikely that a larger fighter-type aircraft would be chosen to operate alongside it.  

Then again, maybe somebody might just figure out that those Russians are on to something.

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